Three symmetrical and two unsymmetrical Schiff bases were synthesized from o-phenylenediamine and substituted salicylaldehydes. The compounds were characterized using various analytical techniques and their antimicrobial activity was tested against bacteria. The symmetrical compounds showed dependence of activity on substituents as H>NO2>Br, while unsymmetrical compounds exhibited higher activity compared to symmetrical ones. The nitro-substituted unsymmetrical compound showed the best antimicrobial properties.
Partial Molar Volumes of Tetra alkyl ammonium salts in 10%(W/W) 2-(Ethoxy) et...Premier Publishers
In this article densities and apparent molar volumes of Tetra alkyl ammonium bromide salts ( ) in 10% (W/W) 2-(Ethoxy) ethanol-water mixture is studied at 30o, 35o and 40oC. Partial molar volumes are divided into ionic components using different methods such as Conway et al. and Jolicoeur et al. The results are compared with the values of partial molar volumes of ions reported in literature for pure water. Decrease in hydrophobic hydration is noticed. This may be due to the addition of co-solvent 2-(Ethoxy) ethanol (confirming the conclusions drawn from our viscosity studies that in 2-(Ethoxy) ethanol-water mixture, the structuredness of water is reduced by the breaking of hydrogen bonds). The values are divided into and . Making use of the Padova’s equation values of salts are calculated. These are also divided into ionic contributions. Dimensions of ions have been calculated to understand solvation behavior. It is shown that the classification of salts into structure makers and structure breakers on the basis of the sign of is not valid for the present water rich mixed solvent system.
Vibrational Characterization and Antioxidant Activity of Newly Synthesized Ga...peertechzpublication
The gallium(III) complex of orotic acid (HOA) was synthesized and its structure was determined
by means of analytical and spectral analyses. Detailed vibrational analysis of HOA, sodium salt of HOA
(NaOA) and Ga(III)-OA systems based on both the calculated and experimental spectra confi rmed the
suggested metal-ligand binding mode. Signifi cant differences in the IR and Raman spectra of the complex
were observed as compared to the spectra of the ligand and confi rmed the suggested metal-ligand
binding mode.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, 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.
Ntioxidant study of usnic acid and its derivative usnic acid diacetateeSAT Journals
Abstract
Currently interest towards the study of antioxidant efficiency of the lichen metabolites was given prior attention in the field of research. As the free radical accumulation in human cells causes several chronic diseases which can be eliminated with the help of antioxidants. In our present study we have isolated the lichen secondary metabolite Usnic acid from Usnea luridorufa and also prepared the acetyl derivative of Usnic acid. The in vitro antioxidant activity of Usnic acid and Usnic acid diacetate under DPPH free radical scavenging, FRAP, Superoxide dismutase activity, Metal chelating activity, Phosphomolybdenum activity, Hydroxyl scavenging activity, Lipid peroxidation inhibiting activity were studied. The antioxidant potential of the Usnic acid and its derivative Usnic acid diacetate were compared. The IC50 value are also determined. Both the test compounds possesses significant antioxidant activity under the studies.
Keywords: Antioxidant efficiency, Usnic acid, diacetate, Tannic acid.
Partial Molar Volumes of Tetra alkyl ammonium salts in 10%(W/W) 2-(Ethoxy) et...Premier Publishers
In this article densities and apparent molar volumes of Tetra alkyl ammonium bromide salts ( ) in 10% (W/W) 2-(Ethoxy) ethanol-water mixture is studied at 30o, 35o and 40oC. Partial molar volumes are divided into ionic components using different methods such as Conway et al. and Jolicoeur et al. The results are compared with the values of partial molar volumes of ions reported in literature for pure water. Decrease in hydrophobic hydration is noticed. This may be due to the addition of co-solvent 2-(Ethoxy) ethanol (confirming the conclusions drawn from our viscosity studies that in 2-(Ethoxy) ethanol-water mixture, the structuredness of water is reduced by the breaking of hydrogen bonds). The values are divided into and . Making use of the Padova’s equation values of salts are calculated. These are also divided into ionic contributions. Dimensions of ions have been calculated to understand solvation behavior. It is shown that the classification of salts into structure makers and structure breakers on the basis of the sign of is not valid for the present water rich mixed solvent system.
Vibrational Characterization and Antioxidant Activity of Newly Synthesized Ga...peertechzpublication
The gallium(III) complex of orotic acid (HOA) was synthesized and its structure was determined
by means of analytical and spectral analyses. Detailed vibrational analysis of HOA, sodium salt of HOA
(NaOA) and Ga(III)-OA systems based on both the calculated and experimental spectra confi rmed the
suggested metal-ligand binding mode. Signifi cant differences in the IR and Raman spectra of the complex
were observed as compared to the spectra of the ligand and confi rmed the suggested metal-ligand
binding mode.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, 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.
Ntioxidant study of usnic acid and its derivative usnic acid diacetateeSAT Journals
Abstract
Currently interest towards the study of antioxidant efficiency of the lichen metabolites was given prior attention in the field of research. As the free radical accumulation in human cells causes several chronic diseases which can be eliminated with the help of antioxidants. In our present study we have isolated the lichen secondary metabolite Usnic acid from Usnea luridorufa and also prepared the acetyl derivative of Usnic acid. The in vitro antioxidant activity of Usnic acid and Usnic acid diacetate under DPPH free radical scavenging, FRAP, Superoxide dismutase activity, Metal chelating activity, Phosphomolybdenum activity, Hydroxyl scavenging activity, Lipid peroxidation inhibiting activity were studied. The antioxidant potential of the Usnic acid and its derivative Usnic acid diacetate were compared. The IC50 value are also determined. Both the test compounds possesses significant antioxidant activity under the studies.
Keywords: Antioxidant efficiency, Usnic acid, diacetate, Tannic acid.
ABSTRACT- L-Ascorbic acid derivatives was synthesized on treatment with acetone and acetyl chloride afforded 5,6-acetal of L-ascorbic acid then benzylation of C-2 and C-3 hydroxyl groups of the lactone ring was accomplished using K2CO3 and benzyl bromide in DMF, then deblocking of the 5,6-O,O-protected derivative of L-Ascorbic acid with acetic acid and methanol gave 2,3-O,O-dibenzyl-L-Ascorbic acid. Subsequently mono-tosylation at 6 position of 2,3-O, O-dibenzyl-L-Ascorbic acid was carried out with addition of p-toluenetosylchloride (PTSC) in Pyridine and MDC solvent medium gave 2,3-O,O-dibenzyl-6-O-tosyl-L-Ascorbic acid. All the structures were characterized by 1H NMR, 13C NMR and Mass Spectroscopy.
Key-words- L-Ascorbic acid, 5,6-Acetal, Benzylation, Hydrolysis, Tosylation
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, Characterization, Spectral (FT-IR, 1H, 13C NMR, Mass and UV) and B...Dr. Pradeep mitharwal
Bio-potent ligands, 2-hydroxy-N-phenylbenzamide hydrazinecarbothioamide(HPHTSCZH2) and 2-hydroxy-N-phenylbenzamide hydrazine carbodithioic benzyl ester (HPHCBESH2) have been synthesized by the condensation of 2-hydroxy-N-phenylbenzamide with hydrazinecarbothioamide and hydrazine carbodithioic benzyl ester, respectively and reacted with hydrated lanthanide chlorides. The coordination moieties of the ligands have been confirmed by various spectral studies. - See more at: http://www.sciencedomain.org/abstract.php?iid=271&id=16&aid=2488#sthash.6v3aFQIi.dpuf
A new Schiff base 4-chlorophenyl)methanimine
(6R,7R)-3-methyl-8-oxo-7-(2-phenylpropanamido)-5-thia-1-
azabicyclo[4.2.0]oct-2-ene-2-carboxylate= (HL)= C23H20
ClN3O4S) has been synthesized from β-lactam antibiotic
(cephalexin mono hydrate(CephH)=(C16H19N3O5S.H2O) and 4-
chlorobenzaldehyde . Figure(1) Metal mixed ligand complexes
of the Schiff base were prepared from chloride salt of
Fe(II),Co(II),Ni(II),Cu(II),Zn(II) and Cd (II), in 50% (v/v)
ethanol –water medium (SacH ) .in aqueous ethanol(1:1)
containing and Saccharin(C7H5NO3S) = sodium hydroxide.
Several physical tools in particular; IR, CHN, 1H NMR, 13C
NMR for ligand and melting point molar conductance, magnetic
moment. and determination the percentage of the metal in the
complexes by flame(AAS). The ligands and there metal
complexes were screened for their antimicrobial activity against
four bacteria (gram + ve) and (gram -ve) {Escherichia coli,
Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus}.
The proposed structure of the complexes using program, Chem
office 3D(2006). The general formula have been given for the
prepared mixed ligand complexes Na2[M(Sac)3(L)], M(II) = Fe
(II), Co(II) , Ni(II), Cu (II), Zn(II) , and Cd(II).
HL= C29H24 ClN3O4S, L= C29H23 ClN3O4S -.
An efficient synthesis, characterization and antibacterial activity of novel ...iosrjce
IOSR Journal of Applied Chemistry (IOSR-JAC) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Synthesis, spectral characterization and bioactivity studies of some S-substi...Jing Zang
A new series of 5-(4-Chlorophenyl)-1,3,4-Oxadiazol-2-thiol derivatives was prepared from 4-chlorobenzoic acid (1) by converting it successively into corresponding ester (2), carbohydrazide (3) and 5-(4-Chlorophenyl)-1,3,4-Oxadiazol-2-thiol (4). Finally the target compounds, 6a-l, were synthesized by stirring 4 with different electrophiles, 5a-l, in DMF using NaH as weak base and activator. The proposed structures of newly synthesized compounds were confirmed by spectroscopic techniques such as 1H-NMR, 13C-NMR, HR-MS and EI-MS. All synthesized compounds were evaluated for their anti-bacterial, antifungal, cytotoxicity and enzyme inhibition activities. The compounds, 6e and 6g exhibited significant inhibition activity against acetyl cholinesterase enzyme (AChE) and 6j moderate activity against butyryl cholinesterase enzyme (BChE). The molecule, 4 exhibited good MIC (minimum inhibitory concentration) value against all the bacterial and fungal strains taken into account.
Synthesis, characterization, antimicrobial, anticancer and antidiabetic activ...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, 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, Biological Evaluation of Some Heterocyclic Oxaze...JohnJulie1
The new serious of pentyloxy and aryloxy benzaldehyde (3ae) were synthesized from the substitution reaction of 4-hydroxy benzaldehyde with different aryl bromide and alkyl bromide, on the basis of Williamson ether synthesis in the presence of Potassium carbonate using absolute ethanol as a solvent. The second step was the synthesis of 2-amino-5-(p-tolyl)1,3,4-thiadiazole.
Synthesis, Characterization, Biological Evaluation of Some Heterocyclic Oxaze...
ogundele journal
1. Available online www.jocpr.com
Journal of Chemical and Pharmaceutical Research, 2014, 6(6):816-819
Research Article
ISSN : 0975-7384
CODEN(USA) : JCPRC5
816
Synthesis and biological properties of N2O2 Schiff bases derived
from o-phenylenediamine and substituted salicylaldehydes
Tolulope M. Fasina*, Olorunfemi O. Ogundele and Isaac Ayeni
Department of Chemistry, University of Lagos, Akoka Lagos State Nigeria
_____________________________________________________________________________________________
ABSTRACT
Three symmetrical and two unsymmetrical N2O2 Schiff bases obtained from the condensation of o-phenylenediamine
with various salicylaldehydes namely salicylaldehyde, 5-nitrosalicylaldehyde and 5-bromosalicylaldehyde were
synthesized and characterized based on elemental analysis, IR, 1
H NMR and electronic absorption spectroscopy.
The antimicrobial activity of the compounds tested against the microorganisms E. coli (ATCC 25922), E. feacalis
(ATCC 29212) and S. aureus (ATCC 25923) using the agar ditch method showed a dependence on the substituent
present in order H>NO2>Br. The unsymmetrical compounds exhibited higher activity compared to the symmetrical
compounds.
Key words: o-phenylenediamine, symmetrical Schiff base, unsymmetrical Schiff base, antimicrobial activity
_____________________________________________________________________________________________
INTRODUCTION
There has been renewed interest in the Chemistry of Schiff bases as a result of the wide variety of potential
applications reported for this class of compounds. These compounds can be used in photochemical, catalytic,
biological and electrochemical applications [1-3]. Schiff bases are also used as ligands to obtain metal complexes
that can serve as models in the understanding of biological systems. The preparative ease and variable geometries of
the metal complexes obtained makes them important stereochemical models in main group and transition metal
coordination Chemistry. Thus, these compounds play an important role in advancement of inorganic biochemistry
[4].
Schiff bases composed of N2O2 donor atoms are important chelating ligands for designing supramolecular synthons,
medicinal and catalytically useful metal complexes [5-6]. Symmetrical Schiff bases derived from aromatic 1,2-
diamines such as o-phenylenediamine have received attention due to their synthetic flexibility, rich coordination
chemistry and application in catalysis [7]. Related unsymmetrical Schiff bases have received less attention, The
unsymmetrical Schiff bases of 1,2-diamines may be of more practical importance due to presence of the different
reactive centres located in the compounds. Unsymmetrical Schiff bases are important in understanding the process
of metal binding in metalloproteins and metalloenzymes in the body [8-9].
We have been interested in understanding the effects of subtle changes in electronic properties of Schiff bases and
metal complexes through substituent and solvent variation [10-11] and metal complex formation [12]. In this paper,
we report the effect of change in substituent on the biological properties of symmetrical and unsymmetrical Schiff
bases derived from o-phenylenediammine and substituted salicyaldehydes.
2. Tolulope M. Fasina et al J. Chem. Pharm. Res., 2014, 6(6): 816-819
______________________________________________________________________________
817
EXPERIMENTAL SECTION
Chemicals and solvents were of reagent or analytical grade and used without further purification.
o-phenylenediamine, salicylaldehyde, 5-nitrosalicylaldehyde and 5-bromosalicylaldehyde, were purchased from
Aldrich Sigma Company Ltd and used as supplied.
Elemental analysis data were obtained on a Perkin Elmer model 2400 series II CHNS/O analyzer. Infrared (IR)
spectra of the compounds were recorded as KBr discs on a Perkin-Elmer Spectrum RX1 spectrophotometer in the
range 4000 to 400 cm–1
.
1
H NMR spectrum of the ligand was recorded in CDCl3 solutions on a Bruker Avance III 400 MHz spectrometer
with chemical shifts reported in ppm relative to TMS as internal standard. The electronic absorption spectra of all
the complexes were recorded in DMSO on a PGT80/T80+
UV-VIS spectrophotometer in 1cm quartz cell at room
temperature immediately after preparing the solution. Melting points (o
C) were determined with aid of Gallenkamp
melting-point apparatus and are uncorrected. The symmetric Schiff bases (L1 - L3) were prepared using literature
method [12].
Synthesis of Unsymmetrical Schiff Bases (L4 –L5)
To a cold stirred solution of o-phenylenediamine (10 mmol.) in absolute ethanol (10 ml) were added ethanolic
solutions (10 ml) of salicylaldehyde (10 mmol.) and the corresponding substituted salicylaldehyde (10 mmol.). The
mixture was refluxed at 70 o
C for 3 h and cooled to room temperature. The yellow solid obtained collected by
filtration dried and re-crystallized from ethanol.
RESULTS AND DISCUSSION
Synthesis
Symmetrical and unsymmetrical Schiff bases (Figure 1) were prepared in good yields from the condensation
reaction of o-phenylenediamine with corresponding aldehydes in 1:2 ratio for the symmetrical compounds L1-L3
and 1:1:1 ratio for the unsymmetrical compounds L4-L5. All the compounds obtained are stable at room
temperature and are non-hygroscopic. The analytical data and physical properties of the compounds are presented in
table 1. The elemental analysis data conform to expected values.
The infrared spectral bands of all the Schiff bases show a band in the region 1602-1619 cm-1
due to azomethine
(HC=N) group. The occurrence of this band along with disappearance of the band at ca 1700 cm-1
for the carbonyl
group and appearance of a band in 1391-1392 cm-1
for the phenolic oxygen in all compounds confirms the formation
of the Schiff base. The 1
HNMR spectra for each compound gave a peak at 8.89-9.24 attributed to the azomethine
protons which further confirms formation of desired product.
3. Tolulope M. Fasina et al J. Chem. Pharm. Res., 2014, 6(6): 816-819
______________________________________________________________________________
818
TABLE 1. Physical and Analytical Data of Schiff bases L1-L5
Compound Empirical Formular
Yield
(%)
M.P
0
C
Colour
Microanalysis,
cald(found)
%C %H %N
L1 C20H16N2O2 79.0 153-154 yellow
75.93 5.10 8.86
(75.31) (5.00) (8.75)
L2 C20H14Br2N2O2 83.3 118-199 yellow
50.66 2.98 5.91
(50.51) (2.86) (5.86)
L3 C20H14N4O6 87.0 >230 yellow
59.12 3.47 13.79
(58.79) (3.48) (13.55)
L4 C20H15N2O2Br 73.3 186-188 yellow
60.78 3.83 7.09
(59.65) (3.42) (6.79)
L5 C20H15N3O4 86.1 192-194 yellow
66.48 4.17 11.63
(65.80) (3.96) (11.49)
TABLE 2. Important IR, UV-vis and 1
HNMR Bands in Schiff bases L1-L5
Compound
ν (OH)
cm-1
ν (C=N)
cm-1
ν (C-O)
cm-1
δ
HC=N
λ max
nm
L1 3674 1606 1373 8.85 269,324
L2 3677 1602 1373 8.89 269,324
L3 3692 1619 1350 9.01 265,332
L4 3567 1608 1371 9.24 329
L5 3624 1611 1349 9.13 336
Electronic Absorption Spectra
The electronic absorption spectra of the ligands were recorded in the range 200-600 nm and are reported in table 2.
Earlier reports indicate that the electronic absorption bands of the salicylaldehyde type Schiff base comprises of
three bands [13]. The band located in the range 230-260 nm in the spectra is assigned to the excitation of the π-
electrons of the aromatic system since these bonds are quite sensitive to substitution at this part of the molecule. The
band observed within the wavelength range 260-310 nm is due to n- π* transition between the π-orbital largely
localized on the central C=N bond, influenced by the charge within the entire molecule.
The third band observed within the wavelength of 320-400 nm is attributed to an intermolecular charge transfer for
interaction based on expected strong intermolecular hydrogen bonding between the hydroxyl group of the
salicylidene part and azomethine nitrogen.
The electronic absorption bands the symmetric compounds exhibit two bands a high energy band between 265-269
nm attributed to n- π* and a low energy band 305-360 nm due to charge transfer transitions. The presence of
electron withdrawing nitro groups results in shift of charge transfer band to higher wavelengths in the compounds.
This suggests that the nitro group is a good charge-transfer acceptor centre as a result of its strong electron
withdrawing power.
Antimicrobial Activity
The antimicrobial activity of the investigated compounds was tested at a concentration of 5 mg mL-1
using the agar
ditch method against the microorganisms E. coli, E. feacalis and S. aureus The diameter of growth inhibition zones
were measured (mm) and results summarized in table 3.
TABLE 3.
Compound
Diameter of inhibition zone of bacteria (mm)
S. aureus E.Feacalis E. coli
L1 20 0 20
L2 15 - -
L3 12 - 16
L4 10 14 11
L5 15 20 11
Streptomycin 12 25 18
4. Tolulope M. Fasina et al J. Chem. Pharm. Res., 2014, 6(6): 816-819
______________________________________________________________________________
819
All the compounds were active against S. aureus in varying degrees. The bis-salicylaldehyde imine L1 exhibited
highest activity comparable to the reference compound against S. aureus and E. coli but no activity against E.
feacalis. Comparison of the results with those of Schiff bases derived from aniline and the corresponding aldehydes
[10] revealed that the presence of N2O2 donor group enhanced activity of the compounds. The bromo substituted
compound L2 was only active against S.aureus. Thus, activity of the symmetric compounds is in order L1>L3>L2.
This reflects a dependence on the substituent present in order H>NO2>Br.
The unsymmetrical compounds L4 and L5, were active against all the bacterial strains studied with highest activity
recorded against E. feacalis. The nitro compound L5 exhibited highest activity, thus the presence of the electron
withdrawing nitro group enhanced antimicrobial activity of the compounds.
CONCLUSION
Three symmetrical and two unsymmetrical Schiff bases containing the N2O2 unit derived from condensation
reaction of o-phenylenediamine with substituted salicyaldehydes have been synthesized and characterized. The
antimicrobial activity of the compounds varied with the nature of substituent in order H>NO2>Br. The symmetrical
Schiff basses exhibited narrow spectrum antimicrobial activity. The unsymmerical compounds compounds can be
further investigated for design of broad spectrum antibiotic compounds.
Acknowledgement
The Authors are grateful to Department of Medical Microbiology, University of Lagos for gift of the bacterial
strains used.
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[13]HH Hammud; A Ghannoum; MS Masoud Spectrochimica Acta A 2006, 63,255-265