Three odorant Schiff bases of methylanthranilate, an aroma constituent of blossom essential oils, with naturally occurring
odorant aldehydes- anisaldehyde, benzaldehyde and cinnamaldehyde employing microwave (MW) irradiation method were
synthesized. Elemental and spectral (FT-IR, 1H-NMR) analysis of these compounds supported their molecular structures.
Olfactory properties of these Schiff bases indicated their suitability for use in various fragrance compositions. These
compounds also showed varied antimicrobial activity against Aspergillus niger, Penicillium chrysogenum, Staphylococcus
aureus and Escherichia coli.
Synthesis and antimicrobial activity of some methyl (4- (benzo[d]oxazol-2-yl)...QUESTJOURNAL
ABSTRACT: In the present study, a new series of methyl (4-(benzo[d]oxazol-2-yl)phenyl) carbamodithioate amine derived from methyl (4-(benzo[d]oxazol-2-yl)phenyl) carbamodithioate (4TO1-TO6) have been synthesized by reacting the thio methyl group with different amines in presence of ethenol. The structural assessment of the compounds (TO 1- TO 6) was made on the basis of spectral data. The synthesized compounds were screened for their in vitro growth inhibiting activity against different strains of bacteria and fungi viz., Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, S. aureus, Candida albicans and Cryptococcus neoformans were compared with standard agents such as Norfloxacin (10μg/ml) and Amphotericin B (10μg/ml) using broth dilution method. Compounds exhibit moderate to high antibacterial and antifungal activity
Determination of Riociguat by Oxidative Coupling Using Visible SpectrophotometryRatnakaram Venkata Nadh
A simple spectrophotometric method was developed to determine riociguat in bulk and tablet formulation. The present method lies on the oxidation of MBTH by Fe+3 ions in acidic medium to form active coupling species and followed by its coupling with riociguat to form the chromophore having lmax 660 nm. Validated the proposed method as per the existing guidelines of ICH. Good linearity (r~ 0.999) was observed for calibration curve in the studied concentration range (6.25 – 37.50 μg mL-1). Reproducibility, accuracy and precision of the method were confirmed from low values of % RSD.
Various human diseases have oxidative stress as one of their component. Many herbs have been reported to exhibit properties that combat oxidative stress through their active constituents such as flavonoids, tannins, phenolic compounds etc. Different Plants of Dillenicea family has been shown in in vitro experiments to be endowed with antioxidant activity. Therefore this study was carried out to evaluate Dillenicea family for its antioxidant activity.
Synthesis and Anti-Inflammatory activity of Sulpha/substituted 1,2-Diazolesinventionjournals
A Novel compound namely N1 (3 Nicotinoyl) 3,5 dimethyl-4-(N-4-sulfamoyl-azo)-1,2-diazoles has been synthesized by two step processes. Synthesis of N1 -4-sulfamoylphenylhydrazono-3,5-dimethyl propane-1,3-dione and sulfonamide, which interacting with 3-Nicotinoyl hydrazine to form final compound. The newly synthesized compound N1 -(3-Nicotinoyl)-3,5-dimethyl 4-(N1 -4-sulfamoyl phenyl azo) 1,2-diazoles was screened for antiinflammatory activity
STUDIES ON TREATMENT OF PHARMACEUTICAL WASTE EFFLUENTS BY POLYMER MATERIALS M...EDITOR IJCRCPS
In the present study, sorption technique was used to achieve the optimum recovery of the pharmaceutical waste from effluents.
The modified urea formaldehyde resin was prepared and mixed with inorganic adsorbent at various proportions. The removal
capabilities of pharmaceutical waste by the prepared composite materials were investigated. Different factors affecting the uptake
such as contact time, pH value and aqueous volume to resin weight ratio have been investigated. The reaction mechanisms and
the optimum conditions for the treatment were deduced in the light of the obtained results.
Keywords: Sorption technique, Pharmaceutical waste, Different factors.
Synthesis and antimicrobial activity of some methyl (4- (benzo[d]oxazol-2-yl)...QUESTJOURNAL
ABSTRACT: In the present study, a new series of methyl (4-(benzo[d]oxazol-2-yl)phenyl) carbamodithioate amine derived from methyl (4-(benzo[d]oxazol-2-yl)phenyl) carbamodithioate (4TO1-TO6) have been synthesized by reacting the thio methyl group with different amines in presence of ethenol. The structural assessment of the compounds (TO 1- TO 6) was made on the basis of spectral data. The synthesized compounds were screened for their in vitro growth inhibiting activity against different strains of bacteria and fungi viz., Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, S. aureus, Candida albicans and Cryptococcus neoformans were compared with standard agents such as Norfloxacin (10μg/ml) and Amphotericin B (10μg/ml) using broth dilution method. Compounds exhibit moderate to high antibacterial and antifungal activity
Determination of Riociguat by Oxidative Coupling Using Visible SpectrophotometryRatnakaram Venkata Nadh
A simple spectrophotometric method was developed to determine riociguat in bulk and tablet formulation. The present method lies on the oxidation of MBTH by Fe+3 ions in acidic medium to form active coupling species and followed by its coupling with riociguat to form the chromophore having lmax 660 nm. Validated the proposed method as per the existing guidelines of ICH. Good linearity (r~ 0.999) was observed for calibration curve in the studied concentration range (6.25 – 37.50 μg mL-1). Reproducibility, accuracy and precision of the method were confirmed from low values of % RSD.
Various human diseases have oxidative stress as one of their component. Many herbs have been reported to exhibit properties that combat oxidative stress through their active constituents such as flavonoids, tannins, phenolic compounds etc. Different Plants of Dillenicea family has been shown in in vitro experiments to be endowed with antioxidant activity. Therefore this study was carried out to evaluate Dillenicea family for its antioxidant activity.
Synthesis and Anti-Inflammatory activity of Sulpha/substituted 1,2-Diazolesinventionjournals
A Novel compound namely N1 (3 Nicotinoyl) 3,5 dimethyl-4-(N-4-sulfamoyl-azo)-1,2-diazoles has been synthesized by two step processes. Synthesis of N1 -4-sulfamoylphenylhydrazono-3,5-dimethyl propane-1,3-dione and sulfonamide, which interacting with 3-Nicotinoyl hydrazine to form final compound. The newly synthesized compound N1 -(3-Nicotinoyl)-3,5-dimethyl 4-(N1 -4-sulfamoyl phenyl azo) 1,2-diazoles was screened for antiinflammatory activity
STUDIES ON TREATMENT OF PHARMACEUTICAL WASTE EFFLUENTS BY POLYMER MATERIALS M...EDITOR IJCRCPS
In the present study, sorption technique was used to achieve the optimum recovery of the pharmaceutical waste from effluents.
The modified urea formaldehyde resin was prepared and mixed with inorganic adsorbent at various proportions. The removal
capabilities of pharmaceutical waste by the prepared composite materials were investigated. Different factors affecting the uptake
such as contact time, pH value and aqueous volume to resin weight ratio have been investigated. The reaction mechanisms and
the optimum conditions for the treatment were deduced in the light of the obtained results.
Keywords: Sorption technique, Pharmaceutical waste, Different factors.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Solvent Extraction Method for the Separation of Cerium(III) as
Cations From Aqueous Media By use 4-[N-(5-methyl isoxazol-3-
yl)benzene sulfonamide azo]-1- Naphthol Coupled With
Spectroscopic Method For Determination
To Study The Viscometric Measurement Of Substituted-2-Diphenylbutanamide And ...IOSR Journals
Recently in this laboratory the viscometric measurement of 4-[4-(4-chlorophenyl]-4-hydroxy piperidin-1-yl]-N, N-dimethyl-2, 2-diphenylbutanamide[CPHDD] and (2S, 6R)-7-chloro -2, 4, 6-trimethoxy-6'-methyl-3H, 4'H-spiro[1-benzofuran 2, 1’-] cychohex-2-ene]-3,4'-dione[CTMBCD] were carried out at different percentage compositions of solvent to investigate the solute-solvent interactions of drugs with solvent and the effect of dilution of the solvent. The effects of various substituents were also investigated. The results obtained during this investigation gave detail information about pharmacokinetics and pharmacodynamics of these drugs.
Some physicochemical properties such as density, refractive index, solubility, conductance, dissociation constant etc. have been studied for some newly synthesized chalcones in different solvents at 308.15 K.
Synthesis, characterization and antimicrobial evaluation of novel diethyl (2-...iosrphr_editor
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
Evaluation of antioxidant and antiradical properties of pomegranate (punica g...Pritam Kolge
Evaluation of antioxidant and antiradical properties
of Pomegranate (Punica granatum L.) seed and defatted
seed extracts
This is Journal Club activity Presentation with the reference of various research papers.
This Presentation Contain following...
#Info about Paper
#Abstract
#Materials
#Methods
#Results
#Discussion
#Conclusion
#References
*Important Methods used
#Moisture content
#Fat content
#Acid value
#Peroxide value
#Oxidative stability index
#Total phenols content
#Preparation of Pomegranate seed extracts and calculate extract yield
#Evaluation of antioxidant properties of Pomegranate seed extracts using
-DPPH radicals scavenging activity
-FRAP assay
#Antioxidant efficiency of seed extract (Oxidative stability extract)
#Statistical analysis
Journal Club Presentation at Bharati Vidyapeeth College of Pharmacy, Kolhapur.
Thanks for Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Dr. A. J. Shinde (Assistant Professor, Department of Pharmaceutics)
Polymeric Nanoparticles of Rifampicin were prepared by emulsion solvent evaporation technique using poly methyl methacrylate as polymer matrix and Poly vinyl alcohol as surfactant. Drug entrapped free flowing nanoparticles of Rifampicin were obtained after optimization using 32 factorial design and characterized for entrapment efficiency, particle size distribution, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and in vitro and stability studies. The PMMA nanoparticles had a small size (213 ± 0.72 nm), uniform size distribution. The effects of dependent variables drug-polymer ratio and surfactant concentration on particle size and encapsulation efficiency were studied. The drug and polymer were not interacting with each other. SEM studies revealed the spherical shape of nanoparticles and in vitro release studies showed sustained drug release. RIF-polymeric nanoparticles drug delivery system proved to be promising for anti-tubercular therapy.
Simple and Eco-friendly Synthesis of Glycosides bearing triazolo[3,4-b][1,3,4...IOSRJAC
There is a vast variety of naturally occurring glycosides which have marked pharmacological properties. These glycosides have widely diversed functional groups modifications which result in influencing pharmacological performance of corresponding glycosides. The 3,6-disubstituted-s-triazolo[3,4- b][1,3,4]thiadiazoles were glucosidated with 2,3,4,6tetra-o-acetyl α D glulopryanosyl bromide using simple methodologies. The compounds obtained in good yield in a 80-90 minutes.
Rheological behavior and thermal stability of palmitoyl chitosan varying the ...inventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Synthesis, Characterization and invitro Anti- inflammatory activity of 1, 3, ...SriramNagarajan19
Oxadiazole derivatives have played a vital part in the development of heterocyclic compounds. In this present work, a series of 5-(2-aminophenyl)-1,3,4-oxadiazole-2(3H)-thione derivatives (1-10) have been synthesized by Mannich reaction. The reaction progress of the synthesized compounds was checked by TLC. The structures of the newly synthesized compounds were confirmed by IR and 1H NMR spectral data. The in-vitro anti-inflammatory activity of 1, 3, 4-oxadiazole compounds (1-10) was assessed by HRBC Membrane Stabilization Method. Among the newly synthesized 1,3,4-oxadiazole derivatives, compounds OFP, OAP, OBNP, OPBNP, ORP, OUP, OPClBP, OFD, OAD and OBND possessed highly significant anti-inflammatory activity at a dose of 1000µg/ml when compared with standard, Diclofenac potassium.
Chemical Design, Synthesis and Bio-efficacy Screening of New Growth Inhibitor...CrimsonPublishersACSR
The present work aimed to find new growth inhibitors agents spodoptera littoralis (Boisd.), several
inhibitors structurally relevant to the insect growth regulator, Fenoxycarb and the naturally transpiring
juvenile hormone of insects were chemically designed, prepared and evaluated as anti-proliferative agents.
Epihalohydrins derivatives have been synthesized and their agricultural bio-efficacy as insecticides
against spodoptera littoralis (Boisd.). Insecticidal bio-efficacy data showed that that some compounds are
very active against spodoptera littoralis (Boisd.)
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Solvent Extraction Method for the Separation of Cerium(III) as
Cations From Aqueous Media By use 4-[N-(5-methyl isoxazol-3-
yl)benzene sulfonamide azo]-1- Naphthol Coupled With
Spectroscopic Method For Determination
To Study The Viscometric Measurement Of Substituted-2-Diphenylbutanamide And ...IOSR Journals
Recently in this laboratory the viscometric measurement of 4-[4-(4-chlorophenyl]-4-hydroxy piperidin-1-yl]-N, N-dimethyl-2, 2-diphenylbutanamide[CPHDD] and (2S, 6R)-7-chloro -2, 4, 6-trimethoxy-6'-methyl-3H, 4'H-spiro[1-benzofuran 2, 1’-] cychohex-2-ene]-3,4'-dione[CTMBCD] were carried out at different percentage compositions of solvent to investigate the solute-solvent interactions of drugs with solvent and the effect of dilution of the solvent. The effects of various substituents were also investigated. The results obtained during this investigation gave detail information about pharmacokinetics and pharmacodynamics of these drugs.
Some physicochemical properties such as density, refractive index, solubility, conductance, dissociation constant etc. have been studied for some newly synthesized chalcones in different solvents at 308.15 K.
Synthesis, characterization and antimicrobial evaluation of novel diethyl (2-...iosrphr_editor
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
Evaluation of antioxidant and antiradical properties of pomegranate (punica g...Pritam Kolge
Evaluation of antioxidant and antiradical properties
of Pomegranate (Punica granatum L.) seed and defatted
seed extracts
This is Journal Club activity Presentation with the reference of various research papers.
This Presentation Contain following...
#Info about Paper
#Abstract
#Materials
#Methods
#Results
#Discussion
#Conclusion
#References
*Important Methods used
#Moisture content
#Fat content
#Acid value
#Peroxide value
#Oxidative stability index
#Total phenols content
#Preparation of Pomegranate seed extracts and calculate extract yield
#Evaluation of antioxidant properties of Pomegranate seed extracts using
-DPPH radicals scavenging activity
-FRAP assay
#Antioxidant efficiency of seed extract (Oxidative stability extract)
#Statistical analysis
Journal Club Presentation at Bharati Vidyapeeth College of Pharmacy, Kolhapur.
Thanks for Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Dr. A. J. Shinde (Assistant Professor, Department of Pharmaceutics)
Polymeric Nanoparticles of Rifampicin were prepared by emulsion solvent evaporation technique using poly methyl methacrylate as polymer matrix and Poly vinyl alcohol as surfactant. Drug entrapped free flowing nanoparticles of Rifampicin were obtained after optimization using 32 factorial design and characterized for entrapment efficiency, particle size distribution, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and in vitro and stability studies. The PMMA nanoparticles had a small size (213 ± 0.72 nm), uniform size distribution. The effects of dependent variables drug-polymer ratio and surfactant concentration on particle size and encapsulation efficiency were studied. The drug and polymer were not interacting with each other. SEM studies revealed the spherical shape of nanoparticles and in vitro release studies showed sustained drug release. RIF-polymeric nanoparticles drug delivery system proved to be promising for anti-tubercular therapy.
Simple and Eco-friendly Synthesis of Glycosides bearing triazolo[3,4-b][1,3,4...IOSRJAC
There is a vast variety of naturally occurring glycosides which have marked pharmacological properties. These glycosides have widely diversed functional groups modifications which result in influencing pharmacological performance of corresponding glycosides. The 3,6-disubstituted-s-triazolo[3,4- b][1,3,4]thiadiazoles were glucosidated with 2,3,4,6tetra-o-acetyl α D glulopryanosyl bromide using simple methodologies. The compounds obtained in good yield in a 80-90 minutes.
Rheological behavior and thermal stability of palmitoyl chitosan varying the ...inventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Synthesis, Characterization and invitro Anti- inflammatory activity of 1, 3, ...SriramNagarajan19
Oxadiazole derivatives have played a vital part in the development of heterocyclic compounds. In this present work, a series of 5-(2-aminophenyl)-1,3,4-oxadiazole-2(3H)-thione derivatives (1-10) have been synthesized by Mannich reaction. The reaction progress of the synthesized compounds was checked by TLC. The structures of the newly synthesized compounds were confirmed by IR and 1H NMR spectral data. The in-vitro anti-inflammatory activity of 1, 3, 4-oxadiazole compounds (1-10) was assessed by HRBC Membrane Stabilization Method. Among the newly synthesized 1,3,4-oxadiazole derivatives, compounds OFP, OAP, OBNP, OPBNP, ORP, OUP, OPClBP, OFD, OAD and OBND possessed highly significant anti-inflammatory activity at a dose of 1000µg/ml when compared with standard, Diclofenac potassium.
Chemical Design, Synthesis and Bio-efficacy Screening of New Growth Inhibitor...CrimsonPublishersACSR
The present work aimed to find new growth inhibitors agents spodoptera littoralis (Boisd.), several
inhibitors structurally relevant to the insect growth regulator, Fenoxycarb and the naturally transpiring
juvenile hormone of insects were chemically designed, prepared and evaluated as anti-proliferative agents.
Epihalohydrins derivatives have been synthesized and their agricultural bio-efficacy as insecticides
against spodoptera littoralis (Boisd.). Insecticidal bio-efficacy data showed that that some compounds are
very active against spodoptera littoralis (Boisd.)
Design, Synthesis, and Characterization of New 1,3,5-Trisubstituted-2-pyrazol...BRNSS Publication Hub
Objective: The objective of the paper was to design, synthesis, and characterization of new 1,3,5-trisubstituted-2-pyrazolines derivative and to evaluate for analgesic potential. Materials and Methods: The 1,3,5-tri-substituted-2-pyrazolines derivatives have been synthesized by the reaction of chalcone derivatives with 4-hydrazinylbenzene sulfonamide hydrochloride and phenyl hydrazine hydrochloride. Total 16 compounds have been synthesized and characterized by the IR, 1HNMR, and mass spectral analysis. Proposed compounds have been evaluated for analgesic activity. The synthesized compounds also evaluated for the analgesic activity by the following two methods, that is, hot plate test method and acetic acid induced writhing in mice. Pentazocine and acetyl acetic acid were used as standard drug for compare the efficacy. Results and Discussion: The analgesic activity of the 16 synthesized compound series A1-A8, and B1-B8 has been evaluated using hot plate test method and acetic acid induced writhing in mice. The results of the evaluation have been viewed by taking pentazocine and acetyl acetic acid as the standard drug. In hot plate test, series A1-A8, shown delay the paw withdrawal latency time for compound A2 (10.30 s), A4 (9.45 s), A7 (11.65 s), and A8 (11.26 s) after 90 min. In series, B1-B8 shown delay the paw withdrawal latency time for compound B2 (9.10 s) and B7 (10.42 s) after 90 min, inhibit the pain sensation, and inhibit pain produced by thermal means. Synthesized compounds of series A1-A8, compounds A2, A5, A6, A7, and A8 were shown 83.00, 76.01, 80.34, 86.99, and 88.15 were shown percent inhibition, significantly (p<0.05 and p<0.001, respectively) and reduced the number of wriths induced by 0.6% acetic acid at the dose of 10 mg/kg. Acetylsalicylic acid (10 mg/kg) appears to be better effective in reducing the number of wriths, it significantly (P < 0.001) reduced the number of wriths by 99.0%. The compounds B1, B3, and B4 have shown least active activity. These all finding suggest that these synthesized compounds have the potential as analgesic agent. Conclusion: The 1,3,5-pyrazoline derivatives has been successfully synthesized and evaluated for analgesic activity of mice model and results data indicate that compounds A2, A5, A6, A7, and A8 were shown 83.00, 76.01, 80.34, 86.99, and 88.15%, and compounds B2, B7, and B8 were shown 72.25, 74.27, and 74.56% inhibitions. The presence of SO2NH2 is essential for analgesic activity.
Validation and uncertainty analysis of a multi-residue method for 42 pesticides in made tea, tea infusion and spent leaves using ethyl acetate extraction and liquid chromatography–tandem mass spectrometer
Microwave-assisted synthesis, characterization, and antimicrobial activity of...Pawan Kumar
Nine odorant Schiff bases, namely 2-(4-methoxybenzylideneamino)
benzoic acid, 2-(benzylideneamino) benzoic acid, 2-(3-phenylallylidene
amino) benzoic acid, 2-(3,7-dimethyloct-2,6-enylideneamino) benzoic
acid, 2-(3,7-dimethyloct-6-enylideneamino) benzoic acid, 2-(4-
isopropylbenzylideneamino)benzoic acid, 2-(3,4-dimethoxybenzylideneamino)
benzoic acid, 2-(1-phenylethylideneamino) benzoic acid, and
2-[(4-(2,6,6-trimethylcyclohex-2-enyl)-but-2-enylideneamino)benzoic
acid, were prepared by condensation of anthranilic acid with
corresponding naturally occurring carbonyl compounds (anisaldehyde,
benzaldehyde, cinnamaldehyde, citral, citronellal, cuminaldehyde,
veratraldehyde, acetophenone, and α-ionone) employing conventional
and microwave irradiation methods. These compounds were characterized
with the aid of elemental and spectral (FT-IR, 1H NMR, and
13C NMR) analysis. Microwave irradiation method was efficient in terms
of reduced reaction time, solvent use, and increased yields of these
compounds without affecting their olfactory characteristics. These
Schiff bases also exhibited olfactory characteristics for various
fragrance compositions and varied antimicrobial activity against
Aspergillus niger, Penicillium chrysogenum, Staphylococcus aureus, and
Escherichia coli.
New Schiff base ligand (E)-6-(2-(4-
(dimethylamino)benzylideneamino)-2-phenylacetamido)-3,3-
dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic
acid = (HL) Figure(1) was prepared via condensation of
Ampicillin and 4(dimethylamino)benzaldehyde in methanol
.Polydentate mixed ligand complexes were obtained from 1:1:2
molar ratio reactions with metal ions and HL, 2NA on reaction
with MCl2 .nH2O salt yields complexes corresponding to the
formulas [M(L)(NA)2Cl] ,where M =
Fe(II),Co(II),Ni(II),Cu(II),and Zn(II) and NA=nicotinamide.
The 1H-NMR, FT-IR, UV-Vis and elemental analysis
were used for the characterization of the ligand. The complexes
were structurally studied through AAS, FT-IR, UV-Vis,
chloride contents, conductance, and magnetic susceptibility
measurements. All complexes are non-electrolytes in DMSO
solution. Octahedral geometries have been suggested for each
of the complexes. The Schiff base ligands function as
tridentates and the deprotonated enolic form is preferred for
coordination. In order to evaluate the effect of the bactericidal
activity, these synthesized complexes, in comparison to the un
complexed Schiff base has been screened against bacterial
species, Staphy
Facial and Simple Synthesis of Some New (Pyrazole and Triazole) Coumarin Deri...IOSRJAC
2-oxo-2H-coumarin-3-carbohydrazide (2) which prepared from the reaction of ethyl-2-oxo-2Hcoumarin-3-carboxylate (1) with hydrazine hydrate in ethanol containing a catalytic amount of piperidine mixture consider a good and available starting intermediate for synthesis of series of functionalized coumarins. So, compound (2) was utilized as a key for the synthesis of some new (pyrazole, triazole)-2H- coumarin-2-one derivatives by the reaction with some selected reagents.
An Efficient Synthetic Approach Towards 4-Cyano-3-(Methylthio)-5-Oxo-2H-Pyraz...inventionjournals
ABSTRACT: Synthesis of novel heterocyclic 4-cyano -3-(methylthio)-5-oxo-2H-pyrazole-1(5H)- carbothioamide (3) was prepared by condensing ethyl-2-cyano-3,3-bis (methylthio)acrylate (1) with thiosemicarbazide (2) in DMF and catalytic amount of potassium carbonate. Compound (3) has methylthio group at third position, which is replaced by different nucleophiles such as substituted anilines| phenols| hetryl amines| compounds containing active methylene group to afford 3-substituted derivatives of compound (3). All the newly synthesized compounds were screened for their antimicrobial activity.
Design, synthesis, characterization and biological evaluation of 3- (4-(7-chl...iosrjce
Novel thiazolidinone derivatives TQ-VI(1-10) were designed, synthesized and screened for
antimicrobial activity. Synthesis of 3-(4-(7-chloro-2-(4-chlorophenyl) 4-oxo-quinazolin-3(4H)-yl) phenyl) -
2-arylthiazolidin-4-one TQ-VI(1-10) have been achieved from the starting material 2-amino-4-chlorobenzoic
acid TQ-I on cyclization with p-chlorobenzoyl chloride TQ-II to yield 7-chloro-2-(4-chlorophenyl)-4H-3,1-
benzoxazin-4-one,TQ-III, which on treatment with p-phenylindiamine gave 3-(4-aminophenyl)-7-chloro-2-(4-
chlorophenyl)quinazolin-4(3H)-one, TQ-IV in good yield. Then, TQ-IV on reaction with substituted aromatic
aldehydes converted to TQ-V(1-10), which on cyclization with thioglycolic acid gave TQ-VI (1-10). All the
synthesized compounds have been characterized on the basis of IR,
1
H-NMR and mass spectral data. The
compounds containing 4-OH, 4-OCH3 and 3,4,5-(OCH3)3 showed good activity. The title compounds were
screened for qualitative (zone of inhibition) and quantitative antimicrobial activity (MIC) by agar cup plate
method and serial dilution technique, respectively. Among the synthesized compounds in the series, the
compound TQVI4 and TQVI5 were found to exhibit significant antifungal activity at lower concentration of
31.25 µg/ml, against A.niger. The compound TQVI5 and TQVI4 showed zone of inhibition of 17mm and 15mm
against A.niger and C.albicans respectively which is comparable to that of standard drug. The rest of the
analogues in the series displayed weak to moderate antimicrobial activity when compared to the standard
positive controls Ampicillin and Amphotericin B.
Synthesis of Novel Piperidine Compounds As Anticholinesterase Agentsinventionjournals
Donepezil is a piperidine based agent that is used for treatment of Alzheimer’s diseases. This agent acts as acetylcholine esterase inhibitor and therefore, synthesis of piperidine compounds to evaluate anticholinesterase activity is very popular field in medicinal chemistry. Thus, in this study some novel piperidine derivatives were synthesized in order to observe their probable anticholinesterase effects. Structures of obtained compounds were confirmed by IR, NMR and Mass spectroscopic methods. Anticholinesterase activity of the synthesized compounds were tested by using Ellman’s method. Some of the compounds in the series indicated good enzyme inhibitory activity
A STUDY TO EVALUATE THE IN VITRO ANTIMICROBIAL ACTIVITY AND ANTIANDROGENIC E...Dr. Pradeep mitharwal
The present paper deals with synthesis and characterization
of some new chromium (III) Schiff base complexes using microwave irradiation
technique as well as conventional heating. The S∩N donor benzothiazolines, 1-
(2-furanyl) ethanone benzothiazoline (Bzt1N
∩
SH), 1-(2-thienyl) ethanone
benzothiazoline (Bzt2N
∩
SH) and 1-(2-pyridyl) ethanone benzothiazoline
(Bzt3N
∩
SH) were prepared by the condensation of ortho-aminothiophenol with
respective ketones in ethanol.
Synthesis and Anti-Inflammatory activity of Sulpha/substituted 1,2-Diazolesinventionjournals
A Novel compound namely N1 (3 Nicotinoyl) 3,5 dimethyl-4-(N-4-sulfamoyl-azo)-1,2-diazoles has been synthesized by two step processes. Synthesis of N1 -4-sulfamoylphenylhydrazono-3,5-dimethyl propane-1,3-dione and sulfonamide, which interacting with 3-Nicotinoyl hydrazine to form final compound. The newly synthesized compound N1 -(3-Nicotinoyl)-3,5-dimethyl 4-(N1 -4-sulfamoyl phenyl azo) 1,2-diazoles was screened for antiinflammatory activity
N-alkylation methods, Characterization and Evaluation of antibacterial activi...IJERA Editor
A series of new 5-Chloroisatin derivates have been synthesized by the method of N-alkylation at room temperature, in the presence of a base and a catalyst with good yields. The chemical structures of these compounds were confirmed by NMR (1H &13C), these new compounds obtained were evaluated for their antibacterial activity. The final results revealed that the majority of the compounds exhibited good antimicrobial activity against various organisms
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Na...Pawan Kumar
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Na...Pawan Kumar
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Na...Pawan Kumar
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Solar-Driven Cellulose Photorefining into Arabinose over Oxygen-Doped Carbon ...Pawan Kumar
Biomass photorefining is a promising strategy to address the energy crisis and transition toward carbon carbon-neutral society. Here, we demonstrate the feasibility of direct cellulose photorefining into arabinose by a rationally designed oxygen-doped polymeric carbon nitride, which generates favorable oxidative species (e.g., O2–, •OH) for selective oxidative reactions at neutral conditions. In addition, we also illustrate the mechanism of the photocatalytic cellulose to arabinose conversion by density functional theory calculations. The oxygen insertion derived from oxidative radicals at the C1 position of glucose within cellulose leads to oxidative cleavage of β-1,4 glycosidic linkages, resulting in the subsequent gluconic acid formation. The following decarboxylation process of gluconic acid via C1–C2 α-scissions, triggered by surface oxygen-doped active sites, generates arabinose and formic acid, respectively. This work not only offers a mechanistic understanding of cellulose photorefining to arabinose but also sets up an example for illuminating the path toward direct cellulose photorefining into value-added bioproducts under mild conditions.
Solar-Driven Cellulose Photorefining into Arabinose over Oxygen-Doped Carbon ...Pawan Kumar
Biomass photorefining is a promising strategy to address the energy crisis and transition toward carbon carbon-neutral society. Here, we demonstrate the feasibility of direct cellulose photorefining into arabinose by a rationally designed oxygen-doped polymeric carbon nitride, which generates favorable oxidative species (e.g., O2–, •OH) for selective oxidative reactions at neutral conditions. In addition, we also illustrate the mechanism of the photocatalytic cellulose to arabinose conversion by density functional theory calculations. The oxygen insertion derived from oxidative radicals at the C1 position of glucose within cellulose leads to oxidative cleavage of β-1,4 glycosidic linkages, resulting in the subsequent gluconic acid formation. The following decarboxylation process of gluconic acid via C1–C2 α-scissions, triggered by surface oxygen-doped active sites, generates arabinose and formic acid, respectively. This work not only offers a mechanistic understanding of cellulose photorefining to arabinose but also sets up an example for illuminating the path toward direct cellulose photorefining into value-added bioproducts under mild conditions.
Solar-Driven Cellulose Photorefining into Arabinose over Oxygen-Doped Carbon ...Pawan Kumar
Biomass photorefining is a promising strategy to address the energy crisis and transition toward carbon carbon-neutral society. Here, we demonstrate the feasibility of direct cellulose photorefining into arabinose by a rationally designed oxygen-doped polymeric carbon nitride, which generates favorable oxidative species (e.g., O2–, •OH) for selective oxidative reactions at neutral conditions. In addition, we also illustrate the mechanism of the photocatalytic cellulose to arabinose conversion by density functional theory calculations. The oxygen insertion derived from oxidative radicals at the C1 position of glucose within cellulose leads to oxidative cleavage of β-1,4 glycosidic linkages, resulting in the subsequent gluconic acid formation. The following decarboxylation process of gluconic acid via C1–C2 α-scissions, triggered by surface oxygen-doped active sites, generates arabinose and formic acid, respectively. This work not only offers a mechanistic understanding of cellulose photorefining to arabinose but also sets up an example for illuminating the path toward direct cellulose photorefining into value-added bioproducts under mild conditions.
Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single...Pawan Kumar
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single...Pawan Kumar
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Selective Cellobiose Photoreforming for Simultaneous Gluconic Acid and Syngas...Pawan Kumar
Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O2− during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (~56 μmol g-1 h-1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition.
Selective Cellobiose Photoreforming for Simultaneous Gluconic Acid and Syngas...Pawan Kumar
Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O2− during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (~56 μmol g-1 h-1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition.
Selective Cellobiose Photoreforming for Simultaneous Gluconic Acid and Syngas...Pawan Kumar
Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O2− during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (~56 μmol g-1 h-1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition.
Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single...Pawan Kumar
Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer–Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.
Recent advancements in tuning the electronic structures of transitional metal...Pawan Kumar
The smooth transition from finite non-renewables to renewable energy conversion technologies will require efficient electrocatalysts which can harness intermittent energies to store in the form of chemical bonds. The oxygen evolution reaction (OER) impedes the widespread usage of water electrolyzers to convert H2O into H2 and persists as a bottleneck, including other energy conversion devices with sluggish four H+/e− kinetics. In this context, designing highly active and stable catalysts capable of driving a lower overpotential in the OER to produce continuous hydrogen (H2) is a primary demanded. This chapter discussed the mechanism of the OER in conventional adsorbate oxygen and lattice oxygen participation in transition metal oxides (TMOs). Further, the influences of surface engineering, doping, and defects in the TMOs and understanding the electronic structure to screen electrodes towards the structure–activity relationship are highlighted. Specifically, the adsorption strength of O 2p is understood in detail as its binding ability over the surface of TMOs can be correlated directly to the OER activity. The iterative development of TMOs in terms of understanding electronic structural attributes is essential for the commercial deployment of energy conversion technologies. The comprehensive outlook of this chapter investigates thoroughly how TMOs can be used as significant materials for the OER in the near future.
Hole transport materials (HTMs) have a significant impact on the effectiveness of organic electronic devices; therefore, we present a molecular architecture of pyrazino[2,3-g]quinoxaline (PQ10)-based room-temperature organic liquid crystalline semiconductor (OLCS) as an alternative HTM. The PQ10 compound exhibits three different rectangular columnar (Colr) phases offering an impressive hole mobility of 8.8 × 10−3 cm2V−1s−1 which is found to be dexterous than most of existing polymeric hole transport materials. The charge transport mechanism is governed by the hole polarons hopping through H-aggregates of the PQ10 molecules and the hole mobility remains nearly constant throughout the mesophase range, but it decreases with increasing applied electric field. The current-voltage characteristics of the PQ10 have also been investigated in all three Colr phases and explained via the Poole-Frenkel conduction mechanism. The dielectric spectroscopy has been eventually carried out to understand the nature of dielectric permittivity and conductivity as a function of temperature and a correlation is established between the molecular architecture of the Colr phases and aforementioned physical properties. Solar cell simulation has been additionally performed to demonstrate that the PQ10 material can be a better choice as HTM for organic electronics and photovoltaic applications.
Multifunctional carbon nitride nanoarchitectures for catalysisPawan Kumar
Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated.
Production of Renewable Fuels by the Photocatalytic Reduction of CO2 using Ma...Pawan Kumar
The photo-reductive performance of natural ilmenite was boosted and the production of renewable fuels from the reduction of CO2 was enhanced by doping the natural mineral with magnesium. The doping was achieved by high energy ball milling in the presence of MgO and Mg(NO3)2. The photo-reduction of CO2 in aqueous solution led to the evolution of H2, CH4, C2H4, and C2H6, and the insertion of Mg in the structure of ilmenite enabled increases of up to 1245% in the fuel production yield, reaching total production of 210.9 µmol h-1 gcat-1. Displacements of the conduction band to more negative potentials were evidenced for the samples doped with magnesium. Indirect effects such as increases in the valence band maximum, and the introduction of intermediate energy levels were also evidenced through the measurement of the crystallite size and the determination of the band structure of the materials. Mott-Schottky analyses of the samples showed the n-type nature of the semiconductor materials and enabled the estimation of the density of charge carriers, which strongly influenced the photocatalytic performance. The strong potential of the application of natural ilmenite in gas phase artificial photosynthesis was proved by the evaluation of CO2 reduction in gas conditions, which allowed the enhancement in the selectivity and significantly increased the production of CH4 as compared to aqueous solution, reaching an important yield of CH4 of 16.1 µmol h-1 gcat-1.
Nanoengineered Au-Carbon Nitride Interfaces Enhance PhotoCatalytic Pure Water...Pawan Kumar
Photocatalytic pure water splitting using solar energy is one of the promising routes to produce sustainable green hydrogen (H2). Tuning the interfacial active site density at catalytic heterojunctions and better light management are imperative to steer the structure-activity correlations to enhance the photo-efficiency of nanocomposite photocatalysts. Herein, we report the decoration of nitrogen defects-rich carbon nitride CN(T) with metallic Au nanostructures of different morphologies and sizes to investigate their influence on the photocatalytic hydrogen evolution reactions (HER). The CN(T)-7-NP nano-heterostructure comprises Au nanoparticles (NPs) of ~7 nm and thiourea-derived defective CN exhibits an excellent H2 production rate of 76.8 µmol g–1 h–1 from pure water under simulated AM 1.5 solar irradiation. In contrast to large-size Au nanorods, the high activity of CN(T)-7-NP was attributed to their strong localized surface plasmon resonance (LSPR) mediated visible absorption and interfacial charge separation. The surface ligands used to control Au nanostructures morphology were found to play a major role in the stabilization of NPs and improve interfacial charge transport between Au NPs and CN(T). First-principles calculations revealed that defects in CN and Au-CN interfacial sites in these nanocomposites facilitate the separation of e-/h+ pairs after light excitation and provide lower energy barrier pathways for H2 production by photocatalytic water splitting.
Nanoengineered Au-Carbon Nitride Interfaces Enhance Photo-Catalytic Pure Wate...Pawan Kumar
Photocatalytic pure water splitting using solar energy is one of the promising routes to produce sustainable green hydrogen (H2). Tuning the interfacial active site density at catalytic heterojunctions and better light management are imperative to steer the structure-activity correlations to enhance the photo-efficiency of nanocomposite photocatalysts. Herein, we report the decoration of nitrogen defects-rich carbon nitride CN(T) with metallic Au nanostructures of different morphologies and sizes to investigate their influence on the photocatalytic hydrogen evolution reactions (HER). The CN(T)-7-NP nano-heterostructure comprises Au nanoparticles (NPs) of ~7 nm and thiourea-derived defective CN exhibits an excellent H2 production rate of 76.8 µmol g–1 h–1 from pure water under simulated AM 1.5 solar irradiation. In contrast to large-size Au nanorods, the high activity of CN(T)-7-NP was attributed to their strong localized surface plasmon resonance (LSPR) mediated visible absorption and interfacial charge separation. The surface ligands used to control Au nanostructures morphology were found to play a major role in the stabilization of NPs and improve interfacial charge transport between Au NPs and CN(T). First-principles calculations revealed that defects in CN and Au-CN interfacial sites in these nanocomposites facilitate the separation of e-/h+ pairs after light excitation and provide lower energy barrier pathways for H2 production by photocatalytic water splitting.
Cooperative Copper Single Atom Catalyst in Two-dimensional Carbon Nitride for...Pawan Kumar
Renewable electricity powered carbon dioxide (CO2) reduction (eCO2R) to high-value fuels like methane (CH4) holds the potential to close the carbon cycle at meaningful scales. However, this kinetically staggered 8-electron multistep reduction still suffers from inadequate catalytic efficiency and current density. Atomic Cu-structures can boost eCO2R-to-CH4 selectivity due to enhanced intermediate binding energies (BEs) resulting from favorably shifted d-band centers. Herein, we exploit two-dimensional carbon nitride (CN) matrices, viz. Na-polyheptazine (PHI) and Li-polytriazine imides (PTI), to host Cu-N2 type single atom sites with high density (∼1.5 at%), via a facile metal ion exchange process. Optimized Cu loading in nanocrystalline Cu-PTI maximizes eCO2R-to-CH4 performance with Faradaic efficiency (FECH4) of ≈68% and a high partial current density of 348 mA cm−2 at a low potential of -0.84 V versus RHE, surpassing the state-of-the-art catalysts. Multi-Cu substituted N-appended nanopores in the CN frameworks yield thermodynamically stable quasi-dual/triple sites with large interatomic distances dictated by the pore dimensions. First-principles calculations elucidate the relative Cu-CN cooperative effects between the two matrices and how the Cu-Cu distance and local environment dictate the adsorbate BEs, density of states, and CO2-to-CH4 energy profile landscape. The 9N pores in Cu-PTI yield cooperative Cu-Cu sites that synergistically enhance the kinetics of the rate-limiting steps in the eCO2R-to-CH4 pathway.
Bioinspired multimetal electrocatalyst for selective methane oxidationPawan Kumar
Selective partial electrooxidation of methane (CH4) to liquid oxygenates has been a long-sought goal. However, the high activation energy of C–H bonds and competing oxygen evolution reaction limit product selectivity and reaction rates. Inspired by iron (IV)-oxo containing metalloenzymes’ functionality to activate the C–H bond, here we report on the design of a copper-iron-nickel catalyst for selective oxidation of CH4 to formate via a peroxide-assisted pathway. Each catalyst serves a specific role which is confirmed via electrochemical, in situ, and theoretical studies. A combination of electrochemical and in situ spectroelectrochemical studies revealed that H2O2 oxidation on nickel led to the formation of active oxygen species which trigger the formation of iron (IV) at low voltages. Density functional theory analysis helped reveal the role of iron (IV)-oxo species in reducing the activation energy barrier for CH4 deprotonation and the critical role of copper to suppress overoxidation. Our multimetal catalyst exhibits a formate faradaic efficiency of 42% at an applied potential of 0.9 V versus a reversible hydrogen electrode.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
ISI 2024: Application Form (Extended), Exam Date (Out), EligibilitySciAstra
The Indian Statistical Institute (ISI) has extended its application deadline for 2024 admissions to April 2. Known for its excellence in statistics and related fields, ISI offers a range of programs from Bachelor's to Junior Research Fellowships. The admission test is scheduled for May 12, 2024. Eligibility varies by program, generally requiring a background in Mathematics and English for undergraduate courses and specific degrees for postgraduate and research positions. Application fees are ₹1500 for male general category applicants and ₹1000 for females. Applications are open to Indian and OCI candidates.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...
A facile and efficient synthesis of some odorant Schiff bases using microwave irradiation and their antimicrobial activity
1. Journal of Scientific Research and Advances
J. Sci. Res. Adv. 3 (2016) 334-339
A facile and efficient synthesis of some odorant Schiff bases using microwave irradiation and their
antimicrobial activity
Prasoon Kumar Kaushik1
, V.K. Varshney*1
, Pallavi Bhatia2
, Pawan Kumar3
and S.V. Shukla4
1
Chemistry Division, Forest Research Institute, P.O. New Forest, Dehra Dun-248 006, India
2
Forest Pathology Division, Forest Research Institute, P.O. New Forest, Dehra Dun-248 006, India
3
Chemical Sciences Division, CSIR-Indian Institute of Petroleum, Dehradun- 248005, India
4
Fragrance & Flavor Development Center, Makrandnagar, Kannauj, India
Tel/Fax: +91 135222 4207
Email: vinay.varshney5@gmail.com
Three odorant Schiff bases of methylanthranilate, an aroma constituent of blossom essential oils, with naturally occurring
odorant aldehydes- anisaldehyde, benzaldehyde and cinnamaldehyde employing microwave (MW) irradiation method were
synthesized. Elemental and spectral (FT-IR, 1
H-NMR) analysis of these compounds supported their molecular structures.
Olfactory properties of these Schiff bases indicated their suitability for use in various fragrance compositions. These
compounds also showed varied antimicrobial activity against Aspergillus niger, Penicillium chrysogenum, Staphylococcus
aureus and Escherichia coli.
Keywords: Schiff base, methylanthranilate, aldehydes, microwave irradiation, olfactory property, antimicrobial activity
INTRODUCTION
Schiff bases (azomethines / anils / imines) having
azomethine group (-CH=N-) belong to a group of
compounds which possess varied biological activities
including antimicrobial, anticancer, antineoplastic,
antiviral, antitumour, anti-HIV, antitubercular,
anticonvulsant, anthelmintic, antiplatelet, antimalarial,
antibiotics, anti-inflammatory, diuretic, and analgesic [1-
18]. Besides, Schiff bases are also well known in
flavoring and perfumery due to their odor characteristics
[19]. Several Schiff bases are reported to exhibit floral,
fruity odors, namely of the citrus type and, more
particularly, reminiscent of the odor of the orange-flower
[20-21]. Schiff bases also act as intermediates for
producing other fragrance materials [22-23].
Condensation of carbonyl compounds (aldehydes or
ketones) with primary amines yields Schiff bases with
biological and olfactory properties. Microwave (MW)
irradiation technique being simple, clean, fast, efficient
and economical is in tune with the green chemistry
approach and therefore MW assisted synthesis of organic
compounds has acquired significant importance over
conventional organic synthesis in terms of reduced
solvent consumption and reaction time, improved yields
and easier workup [24-28]. Several Schiff bases have
been synthesized using MW irradiation and characterized
[29-34].
Present paper describes synthesis of three odorant Schiff
bases of methylanthranilate (Figure 1), an aroma
constituent of blossom essential oils of neroli, ylang-
ylang, and citrus [35], with naturally occurring odorant
aldehydes - anisaldehyde, benzaldehyde and
cinnamaldehyde) (Figure 2) using MW irradiation
method. The structures of the synthesized compounds
were confirmed by means of their physical (elemental
analysis) and spectral (FT-IR and 1
H-NMR) data. Their
olfactory and antimicrobial properties were also
evaluated.
Figure 1: Methylanthranilate
Synthesis of these Schiff bases using conventional
method and their odoriferous properties are reported in
334
2. P. K. KAUSHIK et al./ J. Sci. Res. Adv. 3 (2016) 334-339
J. Sci. Res. Adv. 3 (2016) 334-339
literature [36]. To the best of our knowledge synthesis of
these Schiff bases under influence of MW irradiation is
being reported for the first time. This is also first report on
antimicrobial activity of the synthesized Schiff bases.
Figure 2: Reactant aldehydes
MATERIALS AND METHODS
General
All chemicals obtained from commercial suppliers
were of highest purity grade and used without further
purification. These include anisaldehyde (Loba chemie),
benzaldehyde (Merck), cinnamaldehyde (Himedia),
methylanthranilate (Himedia), Nutrient Agar Media
(Himedia) and Potato Dextrose Agar (Himedia).
Elemental analysis of carbon, nitrogen and hydrogen were
carried out on CHN elemental analyser (Thermo
Scientific). Infrared (IR) spectra were recorded at room
temperature from 4000 cm-1
to 500 cm-1
with KBr pellets
at a resolution of 4cm-1
, using Thermo-Nicolet 8700,
Research spectrometer (Thermo Scientific). 1
H-NMR
spectra were recorded on Bruker Avance-II 500 MHz
instrument using CDCl3 as solvent and TMS as an
internal slandered. Chemical shifts (δ) are reported in
ppm. The microwave assisted synthesis was performed in
scientific microwave oven, (SRL-Milestone Start S
Labstation for synthesis, (Operating between 140-
1600W).
General procedure for preparation of Schiff bases
Solvent free MW irradiation method: The equi-molar
ratio of methylanthranilate (0.1mol, 15.11 g) and
aldehyde (0.1mol: anisaldehyde, 13.61 g; benzaldehyde,
10.61g; cinnamladehyde, 13.21g) were mixed in a
reaction flask and irradiated with MW at 300 for 4min.
After completion of the reaction, the mixture was purified
by vacuum distillation. These products were stored at 4ºC
until analysed further.
Methyl- 2-(4-methoxybenzylideneamino)benzoate (Sb1)
C16H15NO3; Intense yellow; Yield: 69% (MW irradiation
method); Fraction condition: 153-155°C/0.0079MPa; IR
(KBr, cm-1
): 1727, 1621, 1492, 1236, 1140; 1
H-NMR
(500 MHz, CDCl3, (δ) ppm): 8.45 (1H, s, HC=N), 6.66-
7.91 (8H, m, Ar-H), 3.91 (3H, s, OCOCH3), 3.89 (3H, s,
OCH3); Anal. Calc. for C16H15NO3: (%) calculated: 71.34,
5.61, 5.20, 17.83, found: 71.39, 5.67, 5.18, 17.76; MW:
269.10
Methyl 2-(benzylideneamino)benzoate (Sb2)
C15H13NO2; intense yellow; Yield: 79% (MW irradiation
method); Fraction condition: 130-132°C/0.0079MPa; IR
(KBr, cm-1
): 1714, 1610, 1504, 1253, 1160; 1
H-NMR
(500 MHz, CDCl3, (δ) ppm): 8.49 (1H, s, HC=N), 6.92-
7.89 (9H, m, Ar-H), 3.89 (3H, s, OCOCH3); Anal. Calc.
for C15H13NO2 (%) calculated: 75.28, 5.47, 5.85, 13.37,
found: 75.33, 5.46, 5.84, 13.46; MW: 239.09
Methyl 2-(3-phenylallylideneamino)benzoate (Sb3)
C17H15NO2; reddish brown; Yield: 69% (MW irradiation
method); Fraction condition: 153-155°C/0.0079MPa; IR
(KBr, cm-1
): 1717, 1613, 1488, 1228, 1139; 1
H-NMR
(500 MHz, CDCl3, (δ) ppm): 7.84 (1H, s, HC=N), 6.61-
7.36 (9H, m, Ar-H), 6.61 (1H, s, vinylic H), 5.79 (1H, s,
vinylic H), 3.82 (3H, s, OCOCH3); Anal. Calc. for
C17H15NO2 (%) calculated: 76.94, 5.70, 5.28, 12.06,
found: 76.93, 5.79, 5.31, 11.98; MW: 265.11
Olfactory evaluation:
Olfactory properties of the Schiff bases were studied
employing standard olfactory method [37]. Sample
solutions (10 wt. % in ethanol) were used to evaluate their
odour properties.
Antimicrobial Properties:
Disc diffusion method
Biological studies of the Schiff bases was evaluated
according to the guidelines of the National Committee for
Clinical Laboratory Standards [38] using the agar disc
diffusion method. The bacterial cultures for
Staphylococcus aureus (ATCC 259235) and Escherichia
coli (ATCC 27853) were obtained from Microbial Type
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J. Sci. Res. Adv. 3 (2016) 334-339
Culture Collection (MTCC), Chandigarh and fungal
cultures of Aspergillus niger and Penicillium
chrysogenum were obtained from National Type Culture
Collection (NTCC), Forest Research Institute, Dehradun.
Exponentially grown cultures of bacteria and fungi were
mixed with sterile 0.85% saline solution to make the final
volume upto 105
- 106
cfu/ml. Petri plates containing 15 ml
of Nutrient Agar Media (NAM) and Potato Dextrose Agar
(PDA) were used for bacteria and fungi respectively. The
inoculum of bacterial and fungal cultures was spread
separately on the surface of their respective solidified
media. Schiff bases (40 μg/ml) were dissolved in
dimethylsulfoxide (DMSO) and whatman no.-1 filter
paper discs (5mm in diameter) impregnated with the test
compound (5 μl/disc) were placed on the plates.
Ciprofloxacin (10μg/disc) was used for bacteria and
griseofulvin was used for the fungi as positive control. A
paper disc impregnated with dimethylsulfoxide (DMSO)
was used as negative control. Plates inoculated with the
bacteria were incubated for 24h at 30±2 ºC and the fungal
cultures were incubated for 5-6 days at 27±2ºC. The
inhibition zone diameters were measured in millimeters.
All the tests were per formed in triplicate and the average
was taken as final reading.
Determination of MIC
MIC values were determined by testing performed
according to the guidelines of NCCLS [39]. Solutions of
the test compounds, and control compounds (antibacterial
– ciprofloxacin and antifungal- griseofulvin) were
prepared in DMSO at different concentrations of 10, 20,
30, 40, 50, 60 μg/ml to determine the MIC. All
determinations were done in triplicate and found the same
result.
RESULTS AND DISCUSSION
Three odorant Schiff bases namely methyl- 2-(4-
methoxy benzylideneamino) benzoate (Sb1), methyl 2-
(benzylideneamino)benzoate (Sb2), methyl 2-(3-phenyl
allylidene amino)benzoate (Sb3) (Figure 3) were prepared
from naturally occurring three aldehydes anisaldehyde,
benzaldehyde, cinnamaldehyde, respectively with
methylanthranilate by microwave (MW) irradiation
method. A large number of experiments were performed
to optimize the irradiation power and its duration and the
optimized conditions are reported. MW irradiation
afforded no solvent consumption, fast reaction (occurred
in 4 minutes) with 69%, 79% and 69%yields,
respectively.
Figure 3: Synthesized odorant Schiff bases
The Schiff bases were characterized by analysis of the
elements (C, H and N), FT-IR and 1
H-NMR spectral data.
Elemental analysis of the Schiff bases was in agreement
to their molecular formula assigned. The FT-IR spectra of
the free aldehydes (anisaldehyde, cinnamaldehyde and
cuminaldehyde) have a strong band at 1690-1700 cm-1
(due to carbonyl stretch), two bands of moderate intensity
in the region 2700-2800 cm-1
(due to H-C=O stretch),
while two sharp bands at 3500 and 3580 cm-1
corresponding to N-H stretch were observed in the IR
spectrum of methylanthranilate. In the IR spectra of the
Schiff bases, these bands disappeared and a new band
appeared in 1621, 1610 and 1613 cm-1 attributed to the
v(C=N) mode of azomethine linkage showing the
condensation between the -CHO group of the aldehydes
and amino group of methylanthranilate resulting in the
formation of the respective Schiff bases.
The 1
H-NMR spectra of the odorant Schiff bases
exhibit singlet of integration intensity equivalent to one
hydrogen at 7.84-8.49 ppm and attributed to (-CH=N-). A
singlet at 3.82-3.91 ppm due to ester protons was
observed in the spectra of all the Schiff bases. A broad
signal at 5.74 ppm due to free NH2 protons in the spectra
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J. Sci. Res. Adv. 3 (2016) 334-339
of methylanthranilate was absent in the observed spectra
of the Schiff bases which indicated the formation of the
azomethine linkage. The multiplets within the 6.61-7.91
ppm range were assigned to protons belonging to
aromatic rings. The spectra of Sb1 showed a singlet with
an integration equivalent to three hydrogens at 3.89 ppm
corresponding to the methoxyl protons. The NMR
spectral assignments of the Schiff bases support the
inferences drawn from the elemental and IR studies.
Olfactory evaluation
Schiff bases were evaluated for their olfactory properties
in terms of their odor profile and odor strength and data
are shown in Table 1. The Schiff bases possessed an
interesting odor profile having contributions of the
characteristic aroma of methyanthranilate and respective
aldehydes which differed in the notes with medium
strength. Sb1 and Sb2 had floral, fruity undertone in their
odor profile with strong sweet, bitter almond notes, while
Sb3 showed spicy, sweet, cinnamon like odor due to their
reactant aldehydes. The olfactory properties of these
Schiff bases indicated their possible use in varied
fragrance and flavour compositions.
Table 1: Olfactory properties of the Schiff bases
Sl. No. Schiff base Odor profile Odor strength
1. Sb1 Strong sweet floral with fruity undertone Medium
2. Sb2 Bitter almond with mild floral fruity tone Medium
3. Sb3 Spicy, sweet, cinnamon like Medium
Antimicrobial activity
Antimicrobial activity of Sb1, Sb2 and Sb3 was
examined against four pathogenic microorganisms which
include one gram positive bacteria (Staphylococcus
aureus), one gram negative bacteria (Escherichia coli)
and two fungi viz; Aspergillus niger and Penicillium
chrysogenum All the Schiff bases showed moderate to
good activity against the pathogenic organisms tested.
The solvent used for the preparation of compound
solutions (DMSO) did not show inhibition against the
tested organisms (negative control). Compared to the
positive control, compounds showing the zones of
inhibition between 9-16 mm and >17 mm were
considered to be moderately active and highly active,
respectively. Zone of inhibition, MIC and % activity
index of the tested compounds are given in Table 2.
The MIC values of the highly active compounds ranged
between 20-30 μg/ml with 66.66-75.00% activity index
while those for moderately active compounds were
40μg/ml with 43.75-53.70% activity index. Compounds
Sb3 found highly active while compounds Sb1 and Sb2
found moderate active against all four microorganisms
tested.
Table 2: Zone of inhibition, MIC and % activity index of odorant Schiff bases
Schiff base Bacteria
Zone of inhibition (MIC)
Fungi
Zone of inhibition (MIC)
*% Activity index
(Bacteria)
% Activity index
(Fungi)
E. coli S. aureus A. niger P. chrysogenum E. coli S. aureus A. niger P. chrysogenum
Sb1 13.0 (40) 14.5 (40) 11.5 (40) 10.5 (40) 52 53.70 47.91 43.75
Sb2 13.0 (40) 12.5 (40) 10.0 (40) 11.00 (40) 52 48 46.29 45.83
Sb3 18.5 (20) 18.0 (20) 18.0 (20) 17.5 (20) 74 66.66 75.00 72.91
Ciprofloxacin 25.0 (20) 27.0 (20) - - - - - -
Griseofulvin - - 24.0 (20) 24.0 (20) - - - -
DMSO - - - - - - - -
1 - 8 mm = less active; 9 - 16 mm = moderate active; >17 mm = highly active
*% Activity index = Zone of inhibition by test compound (diameter) / Zone of inhibition by control compound (diameter) x
100
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5. P. K. KAUSHIK et al./ J. Sci. Res. Adv. 3 (2016) 334-339
J. Sci. Res. Adv. 3 (2016) 334-339
CONCLUSION
MW irradiation technique provided a facile, rapid, clean
and effective synthesis of three Schiff bases namely methyl-
2-(4-methoxy benzylideneamino) benzoate, methyl 2-
(benzylideneamino)benzoate, and methyl 2-(3-phenyl
allylidene amino) benzoate. Olfactory attributes of these
Schiff bases were indicative of their use in various fragrance
compositions. These compounds also displayed moderate to
good antimicrobial activity against bacteria - Staphylococcus
aureus and Escherichia coli, and fungi- Aspergillus niger
and Penicillium chrysogenum.
ACKNOWLEDGEMENTS
Authors are thankful to the Director, Forest Research
Institute, Dehradun, India for providing necessary
facilities to carry out this work.
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