This document describes a new method for synthesizing methyl 6-azido-2,3,4-tri-O-benzyl-6-deoxy-α-D-glucopyranoside from methyl-2,3,4-tri-O-benzyl-α-D-glucopyranoside. The method uses diphenyl phosphorazidate (DPPA) and 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) in dry DMF at 127°C to replace the hydroxyl group at position 6 with an azide group, yielding the product in 95% yield without needing to first make
A new road for the synthesis and characterization of new enamino benzodiazepinesAlexander Decker
This document describes the synthesis and characterization of new enamino benzodiazepine derivatives. The synthesis involves two steps: first, N-alkylation of 4-phenyl-1H-1,5-benzodiazepin-2(3H)-one 1 with alkyl bromides to yield compounds 2a-2f. Second, reaction of compounds 2a-2f with N,N-dimethylformamide dimethyl acetal yields compounds 4a-4f. The structures of the products were confirmed using NMR, mass spectroscopy, and X-ray crystallography. This efficient synthetic method provides access to novel enamino benzodiazepine compounds with potential pharmacological activity.
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.
Synthesis of 3-Substituted Coumarins by the Knoevenagel Condensation Reactionmariam1020
The document summarizes a study on the synthesis of 3-substituted coumarins via the Knoevenagel condensation reaction of various 2-hydroxyaldehydes and malonate esters under solvent-free conditions using silica gel or basic alumina as catalyst. The reaction was carried out using microwave irradiation. Various coumarin products were obtained in moderate to good yields and characterized using techniques such as IR, NMR, and GC-MS. The method provides an improvement over traditional Knoevenagel condensation reactions through the use of solvent-free conditions and microwave activation.
A green synthesis of isatoic anhydrides from isatins with urea–hydrogen perox...fer18400
The document describes a green synthesis method for producing isatoic anhydrides from isatins using urea-hydrogen peroxide complex and ultrasound irradiation. Four reaction procedures were tested using urea-hydrogen peroxide as the oxidizing agent and sulfuric acid as a catalyst. The procedures used either acetic anhydride/acetic acid or formic acid as solvents. Ultrasound irradiation was found to dramatically reduce reaction times from 2-24 hours down to 20-135 minutes. The method provides isatoic anhydrides in good yields and with high purity under mild conditions. Combining formic acid and ultrasound yielded the best results for most isatins tested.
This document summarizes the one-pot synthesis of tri- and tetra-substituted imidazoles using 3-picolinic acid as an organocatalyst. A variety of substituted imidazoles were obtained in good yields under mild conditions. The method provides advantages such as short reaction times, high yields, and an easy experimental procedure. The author concludes that this simple method could serve as an effective approach for synthesizing highly substituted imidazole systems.
Novel approach to synthesis of pentofurano nucleoside assisted natural phosph...Alexander Decker
This document describes a novel method for synthesizing various ribonucleosides using natural phosphate doped with CF3SO3H (NP/CF3SO3H) as a catalyst. Several ribonucleosides were prepared from 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranoside and silylated nucleobases under mild conditions using NP/CF3SO3H. The reaction proceeded through an oxonium intermediate to provide the desired nucleosides in good yields ranging from 20-35%. The method was found to be regioselective, stereoselective, simple, efficient and environmentally friendly for synthesizing various D
Synthesis, characterization, in vitro cytotoxic and antioxidant activities of...ijperSS
ABSTRACT
A series of novel (Z)-3-(2-(4-(2-oxo-2H-chromen-3-yl) thiazol-2-yl-)hydrazono)indolin-2-one (8a-8d, 9) were synthesized with various substituted indole derivatives. Structures of the newly synthesized compounds were elucidated by FT-IR, 1H-NMR, 13C-NMR and API-ES Mass spectral data. The in vitro cytotoxic activities of the complexes measurement against the human cancer T-lymphocyte cell lines. In vitro evaluation of these title complexes revealed cytotoxicity from 6.8-18µg/mL against CEM, 9.2-21µg/mL against L1210, 10-19µg/mL against Molt4/C8, 8-12µg/mL against HL60 and 8-16µg/mL against BEL7402. Coumarin derivatives 8c and 8d showed that quite significant anticancer activities. The antioxidant activity of the synthesized compounds was evaluated by DPPH scavenging method. Compounds 8c, 8d and 9 showed significant antioxidant activity compared with that of standard drug, ascorbic acid.
Key words: Coumarin, DPPH, Cytotoxic activity.
A new and efficient synthesis of 1 (4-subtitued phenyl)-3-(1-(6-(substitued-2...Alexander Decker
This document describes a new efficient method for the synthesis of 1-(4-Subtitued phenyl)-3-(1-(6-(Substitued-2-yl)pyrimidin-4-yl)piperidin-4-yl)ureas. Tert-butyl (1-(6-chloropyrimidin-4-yl)piperidin-4-yl)carbamate is coupled with various arylboronic acids using Suzuki coupling to yield intermediates. These intermediates are then deprotected and coupled with various aryl isocyanates using triethylamine to yield the final urea products in good yields. In total, twelve new 4,6-disubstituted
A new road for the synthesis and characterization of new enamino benzodiazepinesAlexander Decker
This document describes the synthesis and characterization of new enamino benzodiazepine derivatives. The synthesis involves two steps: first, N-alkylation of 4-phenyl-1H-1,5-benzodiazepin-2(3H)-one 1 with alkyl bromides to yield compounds 2a-2f. Second, reaction of compounds 2a-2f with N,N-dimethylformamide dimethyl acetal yields compounds 4a-4f. The structures of the products were confirmed using NMR, mass spectroscopy, and X-ray crystallography. This efficient synthetic method provides access to novel enamino benzodiazepine compounds with potential pharmacological activity.
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.
Synthesis of 3-Substituted Coumarins by the Knoevenagel Condensation Reactionmariam1020
The document summarizes a study on the synthesis of 3-substituted coumarins via the Knoevenagel condensation reaction of various 2-hydroxyaldehydes and malonate esters under solvent-free conditions using silica gel or basic alumina as catalyst. The reaction was carried out using microwave irradiation. Various coumarin products were obtained in moderate to good yields and characterized using techniques such as IR, NMR, and GC-MS. The method provides an improvement over traditional Knoevenagel condensation reactions through the use of solvent-free conditions and microwave activation.
A green synthesis of isatoic anhydrides from isatins with urea–hydrogen perox...fer18400
The document describes a green synthesis method for producing isatoic anhydrides from isatins using urea-hydrogen peroxide complex and ultrasound irradiation. Four reaction procedures were tested using urea-hydrogen peroxide as the oxidizing agent and sulfuric acid as a catalyst. The procedures used either acetic anhydride/acetic acid or formic acid as solvents. Ultrasound irradiation was found to dramatically reduce reaction times from 2-24 hours down to 20-135 minutes. The method provides isatoic anhydrides in good yields and with high purity under mild conditions. Combining formic acid and ultrasound yielded the best results for most isatins tested.
This document summarizes the one-pot synthesis of tri- and tetra-substituted imidazoles using 3-picolinic acid as an organocatalyst. A variety of substituted imidazoles were obtained in good yields under mild conditions. The method provides advantages such as short reaction times, high yields, and an easy experimental procedure. The author concludes that this simple method could serve as an effective approach for synthesizing highly substituted imidazole systems.
Novel approach to synthesis of pentofurano nucleoside assisted natural phosph...Alexander Decker
This document describes a novel method for synthesizing various ribonucleosides using natural phosphate doped with CF3SO3H (NP/CF3SO3H) as a catalyst. Several ribonucleosides were prepared from 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranoside and silylated nucleobases under mild conditions using NP/CF3SO3H. The reaction proceeded through an oxonium intermediate to provide the desired nucleosides in good yields ranging from 20-35%. The method was found to be regioselective, stereoselective, simple, efficient and environmentally friendly for synthesizing various D
Synthesis, characterization, in vitro cytotoxic and antioxidant activities of...ijperSS
ABSTRACT
A series of novel (Z)-3-(2-(4-(2-oxo-2H-chromen-3-yl) thiazol-2-yl-)hydrazono)indolin-2-one (8a-8d, 9) were synthesized with various substituted indole derivatives. Structures of the newly synthesized compounds were elucidated by FT-IR, 1H-NMR, 13C-NMR and API-ES Mass spectral data. The in vitro cytotoxic activities of the complexes measurement against the human cancer T-lymphocyte cell lines. In vitro evaluation of these title complexes revealed cytotoxicity from 6.8-18µg/mL against CEM, 9.2-21µg/mL against L1210, 10-19µg/mL against Molt4/C8, 8-12µg/mL against HL60 and 8-16µg/mL against BEL7402. Coumarin derivatives 8c and 8d showed that quite significant anticancer activities. The antioxidant activity of the synthesized compounds was evaluated by DPPH scavenging method. Compounds 8c, 8d and 9 showed significant antioxidant activity compared with that of standard drug, ascorbic acid.
Key words: Coumarin, DPPH, Cytotoxic activity.
A new and efficient synthesis of 1 (4-subtitued phenyl)-3-(1-(6-(substitued-2...Alexander Decker
This document describes a new efficient method for the synthesis of 1-(4-Subtitued phenyl)-3-(1-(6-(Substitued-2-yl)pyrimidin-4-yl)piperidin-4-yl)ureas. Tert-butyl (1-(6-chloropyrimidin-4-yl)piperidin-4-yl)carbamate is coupled with various arylboronic acids using Suzuki coupling to yield intermediates. These intermediates are then deprotected and coupled with various aryl isocyanates using triethylamine to yield the final urea products in good yields. In total, twelve new 4,6-disubstituted
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 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).
IRJET- Development of Heterogeneous Catalyst for Transesterification Reaction...IRJET Journal
This document describes research into developing a heterogeneous catalyst for transesterification of rice bran oil into biodiesel. A catalyst of Mg-SO4-2/ZrO2 was found to achieve over 90% conversion at 800°C. Characterization showed the catalyst could be reused for 1000 hours without loss of activity. The biodiesel produced contained fatty acid methyl esters like methyl palmitate and methyl oleate. Kinetic studies found the reaction to be first order with a rate constant of approximately 1 min-1. The catalyst shows potential for industrial biodiesel production.
Stability studies are important to ensure drugs maintain their efficacy and safety throughout their shelf life. The rate of a chemical reaction determines a drug's stability and can be zero order, first order, or second order. Various factors influence reaction rates, including temperature, pH, moisture, light exposure, and concentration. Understanding reaction kinetics and identifying the order of a reaction allows researchers to predict a drug's shelf life by substituting experimental data into the appropriate rate equation.
A series of novel 5-[2-(4-fluorobenzyl)-6-aryl-imidazo[2,1-b][1,3,4]thiadiazol-5-ylmethylene] thiazolidine-2,4-dione derivatives (4a-d) were synthesized. These final compounds (4a-d) were synthesized by Knoevenagel condensation of 2-(4-fluorobenzyl)-6-arylimidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehydes (3a-d) with thiazolidine-2,4-dione. All the newly synthesized compounds were screened for their invivo hypoglycemic and hypolipidemic activity in male Wister rats. The Structures of all the newly synthesized compounds were established by analytical and spectral data.
1. The document discusses degradation kinetics and mechanisms of drugs. It defines kinetics, order of reaction, and half-life and describes zero, first, second and third order degradation pathways.
2. Common chemical degradation mechanisms for drugs include hydrolysis, dehydration, isomerization, racemization, decarboxylation, elimination, oxidation, and photodegradation. Specific drug examples are provided for each.
3. Amines can also degrade through the Maillard reaction with reducing sugars, browning the products. This document provides an overview of important concepts in drug degradation kinetics and mechanisms.
Mixed Ligand, Palladium(II) and Platinum(II) Complexes of Tertiary Diphosphin...Karwan Omer
This document summarizes a study that synthesized and characterized mixed ligand palladium(II), platinum(II) complexes with tertiary diphosphine and S-1H benzo[d]imidazole-2-yl benzothioate ligands. The complexes were synthesized in two steps, first forming metal complexes with tertiary diphosphines, then adding the S-1H benzimidazole ligand. The complexes were characterized using techniques such as elemental analysis, infrared spectroscopy, UV-Vis spectroscopy, magnetic susceptibility, and X-ray crystallography. The results indicate the ligand bonds to the metal through the nitrogen atom and the complexes have square planar geometries.
Visible Spectrophotometric Determination of Gemigliptin Using Charge Transfer...Ratnakaram Venkata Nadh
A visible spectrophotometric method was developed and validated for the determination of gemigliptin present in bulk drug and tablet formulation. It involves an indirect method of charge transfer complex formation in presence of NBS, metol and suphanilic acid. Gemigliptin was subjected to oxidation with excess amount of oxidant (NBS) and the unconsumed NBS oxidizes metol to give p-N-methylbenzoquinone monoamine (PNMM) which in turn forms a charge transfer complex with sulphanilic acid. Then validated the above developed method as per the current ICH guidelines. An excellent correlation coefficient (> 0.999) was found for the obtained regression equation
(y = –0.0302x + 0.928) in the range of 2.0–30.0 μg mL-1. The method was found to be simple and rapid because it does not involve any solvent extraction. The recovery levels of the drug were in the range 99.92 – 100.08.
This document describes the design, synthesis, and evaluation of benzimidazolo/tetrazolo quinazoline compounds. Specifically, it details the reaction of anthranilic acid with primary amides to form quinazolinones, which were then treated with phosphorus oxychloride and phosphorus pentachloride to form chloroquinazolines. These compounds then reacted with o-phenylenediamine or sodium azide to form the target benzimidazolo or tetrazolo quinazolines. The compounds were evaluated for their antihyperglycemic activity in sucrose-loaded rat models, with the benzimidazolo quinazolines showing better but still low activity
This document discusses the optimization of supercritical carbon dioxide extraction (SCE) conditions for extracting c-linolenic acid (GLA) from Spirulina platensis. Response surface methodology (RSM) was used to optimize three extraction parameters: pressure, time, and ethanol concentration. SCE with ethanol as a co-solvent was found to significantly increase GLA yields compared to SCE alone. RSM analysis identified a pressure of 400 bars, extraction time of 1 hour, and minimum ethanol concentration of 13.7 ml per 16 g of biomass as optimal conditions for extracting 102% of the GLA content compared to conventional solvent extraction.
Effect of Fractionation and Pyrolysis on Fuel Properties of Poultry LitterLPE Learning Center
The document summarizes research on the effect of fractionation and pyrolysis on the fuel properties of poultry litter. Key findings include:
- Pyrolyzing the coarse fraction of poultry litter at 300°C captured the most energy (68.71%) in the charcoal produced and resulted in the highest calorific value (17.39 MJ/kg).
- Pyrolysis above 500°C captured less carbon but produced a light condensate fraction that could be used as a low-grade liquid fuel.
- The medium condensate fraction captured 27.54% of nitrogen and could be used as fertilizer.
- Pyrolysis significantly reduced nutrients like ammonium
N – methyl thiomethylation and n hydroxymethylation of phthalimideAlexander Decker
This document summarizes a study on the N-methyl thiomethylation and N-hydroxymethylation of phthalimide. Phthalimide was refluxed with DMSO and DMSO-acetic anhydride reagent, yielding two new compounds - N-methyl thiomethyl phthalimide (I) and N-hydroxymethyl phthalimide (II). Spectral data including IR, NMR and mass spectrometry were used to determine the structures of compounds I and II. The reactions and mechanisms for the formation of these compounds from the reactions of phthalimide with DMSO and DMSO-acetic anhydride are discussed.
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.
The document summarizes Dr. Anthony Melvin Crasto's work involving Ugi reactions and their derivatives for synthesizing compounds. It provides details on a specific Ugi reaction to synthesize N-allyl-N-(2-(cyclohexylamino)-2-oxo-1-phenylethyl)-3-nitropropanamide including the chemicals used, procedure, and analytical data obtained. It also lists references for Ugi reactions and thanks Dr. Crasto for his contributions through various websites helping millions in the field of organic chemistry.
Study of the Electric Properties of Azo/Hydrazone Tautomeric Mixture of the ...Scientific Review SR
An azo/hydrazone mixture of the phenolic azo dye 4-(9-Anthrylazo)-1-naphthol was obtained in 58%
yield. The product was characterized using spectroscopic techniques such as IR, NMR and ms. The electric
conductivity of the tautomeric mixture was investigated in solid phase at ambient temperature. The electric
measurements revealed that the azo derivative has an electric conductivity equals 0.657 10
7
1
cm
1
and
electric resistivity of 1.521545 10
7
cm which falls within the range of the semiconductors’ electric resistivity that ranges between 10
2 and 109cm.
Graphene oxide is used as an efficient and recyclable catalyst for ultrasound-mediated multi-component reactions to synthesize biologically active α-aminophosphonates and 3,4-dihydropyrimidin-2-ones under solvent-free conditions. Reactions using aromatic and aliphatic aldehydes, amines, and diethyl phosphite or urea provide the products in excellent yields within short reaction times. Optimization studies found the best results using 10 mg of graphene oxide under ultrasonic irradiation for 5 minutes, with yields over 96%. The graphene oxide catalyst can be reused for multiple cycles without significant loss of activity.
This document describes a one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones using 4-nitrophthalic acid as a catalyst under solvent-free conditions. Various aldehydes, 1,3-dicarbonyl compounds, and urea or thiourea reacted smoothly in good to excellent yields. The reaction conditions were optimized to use a 2 mol% catalyst loading at 90°C for 30 minutes. 4-Nitrophthalic acid proved to be an effective and inexpensive catalyst for this Biginelli reaction, providing advantages over other reported catalysts such as higher yields, simpler workup, and an environmentally friendly procedure. The products were characterized
This document describes a study on using a solid silica-based sulfonic acid catalyst for the one-pot synthesis of 2H-indazolo[2,1-b]phthalazine-trione derivatives. Key points:
1) A novel and efficient one-pot method is reported that uses a solid silica-based sulfonic acid heterogeneous and reusable catalyst under thermal and solvent-free conditions.
2) This method has advantages of high yields, a cleaner reaction, simple methodology, easy work-up and greener conditions.
3) The catalyst is easily prepared, stable up to 300°C, reusable and efficient under the reaction conditions studied.
This document describes a study that developed a novel method for synthesizing 2H-indazolo[2,1-b]phthalazine-trione derivatives using solid silica-based sulfonic acid as a heterogeneous reusable catalyst. The method has advantages such as high yields, cleaner reactions, simple methodology, easy work-up, and greener conditions. The catalyst is easily prepared, stable up to 300°C, reusable, and efficient under reaction conditions. The study evaluated different catalysts and reaction temperatures to optimize the process. The optimized method uses dimedone, phthalhydrazide, an aromatic aldehyde, and solid silica-based sulfonic acid at 100°C to produce the desired products in
Heterogeneous solid liquid catalysis of n-glycosylation by natural phosphate ...Alexander Decker
This document describes a study that investigated using natural phosphate doped with potassium iodide (NP/KI) as a heterogeneous solid-liquid catalyst for the one-step synthesis of several β-D-ribonucleosides. The reaction of 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranoside with various nucleobases including uracil, thymine, cytosine, adenine, and N-acetyl-guanine in the presence of NP/KI produced the corresponding ribonucleosides in good yields ranging from 45-55% after refluxing overnight. The use of NP/KI as the catalyst resulted in higher yields
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 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).
IRJET- Development of Heterogeneous Catalyst for Transesterification Reaction...IRJET Journal
This document describes research into developing a heterogeneous catalyst for transesterification of rice bran oil into biodiesel. A catalyst of Mg-SO4-2/ZrO2 was found to achieve over 90% conversion at 800°C. Characterization showed the catalyst could be reused for 1000 hours without loss of activity. The biodiesel produced contained fatty acid methyl esters like methyl palmitate and methyl oleate. Kinetic studies found the reaction to be first order with a rate constant of approximately 1 min-1. The catalyst shows potential for industrial biodiesel production.
Stability studies are important to ensure drugs maintain their efficacy and safety throughout their shelf life. The rate of a chemical reaction determines a drug's stability and can be zero order, first order, or second order. Various factors influence reaction rates, including temperature, pH, moisture, light exposure, and concentration. Understanding reaction kinetics and identifying the order of a reaction allows researchers to predict a drug's shelf life by substituting experimental data into the appropriate rate equation.
A series of novel 5-[2-(4-fluorobenzyl)-6-aryl-imidazo[2,1-b][1,3,4]thiadiazol-5-ylmethylene] thiazolidine-2,4-dione derivatives (4a-d) were synthesized. These final compounds (4a-d) were synthesized by Knoevenagel condensation of 2-(4-fluorobenzyl)-6-arylimidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehydes (3a-d) with thiazolidine-2,4-dione. All the newly synthesized compounds were screened for their invivo hypoglycemic and hypolipidemic activity in male Wister rats. The Structures of all the newly synthesized compounds were established by analytical and spectral data.
1. The document discusses degradation kinetics and mechanisms of drugs. It defines kinetics, order of reaction, and half-life and describes zero, first, second and third order degradation pathways.
2. Common chemical degradation mechanisms for drugs include hydrolysis, dehydration, isomerization, racemization, decarboxylation, elimination, oxidation, and photodegradation. Specific drug examples are provided for each.
3. Amines can also degrade through the Maillard reaction with reducing sugars, browning the products. This document provides an overview of important concepts in drug degradation kinetics and mechanisms.
Mixed Ligand, Palladium(II) and Platinum(II) Complexes of Tertiary Diphosphin...Karwan Omer
This document summarizes a study that synthesized and characterized mixed ligand palladium(II), platinum(II) complexes with tertiary diphosphine and S-1H benzo[d]imidazole-2-yl benzothioate ligands. The complexes were synthesized in two steps, first forming metal complexes with tertiary diphosphines, then adding the S-1H benzimidazole ligand. The complexes were characterized using techniques such as elemental analysis, infrared spectroscopy, UV-Vis spectroscopy, magnetic susceptibility, and X-ray crystallography. The results indicate the ligand bonds to the metal through the nitrogen atom and the complexes have square planar geometries.
Visible Spectrophotometric Determination of Gemigliptin Using Charge Transfer...Ratnakaram Venkata Nadh
A visible spectrophotometric method was developed and validated for the determination of gemigliptin present in bulk drug and tablet formulation. It involves an indirect method of charge transfer complex formation in presence of NBS, metol and suphanilic acid. Gemigliptin was subjected to oxidation with excess amount of oxidant (NBS) and the unconsumed NBS oxidizes metol to give p-N-methylbenzoquinone monoamine (PNMM) which in turn forms a charge transfer complex with sulphanilic acid. Then validated the above developed method as per the current ICH guidelines. An excellent correlation coefficient (> 0.999) was found for the obtained regression equation
(y = –0.0302x + 0.928) in the range of 2.0–30.0 μg mL-1. The method was found to be simple and rapid because it does not involve any solvent extraction. The recovery levels of the drug were in the range 99.92 – 100.08.
This document describes the design, synthesis, and evaluation of benzimidazolo/tetrazolo quinazoline compounds. Specifically, it details the reaction of anthranilic acid with primary amides to form quinazolinones, which were then treated with phosphorus oxychloride and phosphorus pentachloride to form chloroquinazolines. These compounds then reacted with o-phenylenediamine or sodium azide to form the target benzimidazolo or tetrazolo quinazolines. The compounds were evaluated for their antihyperglycemic activity in sucrose-loaded rat models, with the benzimidazolo quinazolines showing better but still low activity
This document discusses the optimization of supercritical carbon dioxide extraction (SCE) conditions for extracting c-linolenic acid (GLA) from Spirulina platensis. Response surface methodology (RSM) was used to optimize three extraction parameters: pressure, time, and ethanol concentration. SCE with ethanol as a co-solvent was found to significantly increase GLA yields compared to SCE alone. RSM analysis identified a pressure of 400 bars, extraction time of 1 hour, and minimum ethanol concentration of 13.7 ml per 16 g of biomass as optimal conditions for extracting 102% of the GLA content compared to conventional solvent extraction.
Effect of Fractionation and Pyrolysis on Fuel Properties of Poultry LitterLPE Learning Center
The document summarizes research on the effect of fractionation and pyrolysis on the fuel properties of poultry litter. Key findings include:
- Pyrolyzing the coarse fraction of poultry litter at 300°C captured the most energy (68.71%) in the charcoal produced and resulted in the highest calorific value (17.39 MJ/kg).
- Pyrolysis above 500°C captured less carbon but produced a light condensate fraction that could be used as a low-grade liquid fuel.
- The medium condensate fraction captured 27.54% of nitrogen and could be used as fertilizer.
- Pyrolysis significantly reduced nutrients like ammonium
N – methyl thiomethylation and n hydroxymethylation of phthalimideAlexander Decker
This document summarizes a study on the N-methyl thiomethylation and N-hydroxymethylation of phthalimide. Phthalimide was refluxed with DMSO and DMSO-acetic anhydride reagent, yielding two new compounds - N-methyl thiomethyl phthalimide (I) and N-hydroxymethyl phthalimide (II). Spectral data including IR, NMR and mass spectrometry were used to determine the structures of compounds I and II. The reactions and mechanisms for the formation of these compounds from the reactions of phthalimide with DMSO and DMSO-acetic anhydride are discussed.
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.
The document summarizes Dr. Anthony Melvin Crasto's work involving Ugi reactions and their derivatives for synthesizing compounds. It provides details on a specific Ugi reaction to synthesize N-allyl-N-(2-(cyclohexylamino)-2-oxo-1-phenylethyl)-3-nitropropanamide including the chemicals used, procedure, and analytical data obtained. It also lists references for Ugi reactions and thanks Dr. Crasto for his contributions through various websites helping millions in the field of organic chemistry.
Study of the Electric Properties of Azo/Hydrazone Tautomeric Mixture of the ...Scientific Review SR
An azo/hydrazone mixture of the phenolic azo dye 4-(9-Anthrylazo)-1-naphthol was obtained in 58%
yield. The product was characterized using spectroscopic techniques such as IR, NMR and ms. The electric
conductivity of the tautomeric mixture was investigated in solid phase at ambient temperature. The electric
measurements revealed that the azo derivative has an electric conductivity equals 0.657 10
7
1
cm
1
and
electric resistivity of 1.521545 10
7
cm which falls within the range of the semiconductors’ electric resistivity that ranges between 10
2 and 109cm.
Graphene oxide is used as an efficient and recyclable catalyst for ultrasound-mediated multi-component reactions to synthesize biologically active α-aminophosphonates and 3,4-dihydropyrimidin-2-ones under solvent-free conditions. Reactions using aromatic and aliphatic aldehydes, amines, and diethyl phosphite or urea provide the products in excellent yields within short reaction times. Optimization studies found the best results using 10 mg of graphene oxide under ultrasonic irradiation for 5 minutes, with yields over 96%. The graphene oxide catalyst can be reused for multiple cycles without significant loss of activity.
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A new approach for preparing methyl 6 azido-2,3,4-tri-o
1. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.8, 2014
1
A New Approach for Preparing Methyl 6-azido-2,3,4-tri-O-
benzyl-6-deoxy-alpha-D-glucopyranoside
Ghassab M. Al-Mazaideh*
and Rasheed M.A.Q. Jamhour
Department of Chemistry and Chemical Technology, Faculty of Science, Tafila Technical University, P.O. Box
179, Tafila 66110, Jordan.
*
E-mail of the corresponding author: gmazideh@ttu.edu.jo
Abstract:
Azide sugars are key intermediates in the synthesis of aminglycosides, which themselves are useful for the
synthesis of glycopeptides. A new method has been achieved by using DPPA and DBU in dry DMF with high
temperature for replacement of the azide group from alcohol (glucoside) on the position 6. The results of this
method are very important for preparing 6-azido sugar without needing to prepare and separate glucosyl halide
completely. The proposed method was successfully applied with direct, simple, and time saving. In addition,
excellent yield of 95% was obtained from azide, which could be used to obtain pharmaceutical active
compounds.
Keywords: Methyl 6-azido-2,3,4-tri-O-benzyl-6-deoxy-α-D-glucopyranoside, DPPA, DBU,
azides.
1. Introduction
Recently, the synthesis of glycosyl azides and their applications has been one of the most important areas of
research in chemistry and biochemistry. Moreover, azides are known as starting materials or a key intermediate
in preparation of a number of biologically active compounds and aminglycosides, which can be used as glycosyl
donors for the synthesis of glycopeptides and construction of heterocycles (Biswajit et al., 2008; de Oliveira et
al., 2006; Wilkinson et al., 2006 & Rokhum and Bez, 2012). Due to their easily performed reduction to amines
and their stability with reaction conditions, they can maintain amines against variety of carbohydrate synthesis
such as ‘click chemistry’ (Lutz, 2007). Moreover, glycoproteins have many important functions like carriers,
hormones, enzymes, lectins, antibodies, and receptors (Karlsson et al., 1993).
A common way for the preparation of
azido sugar is by nucleophilic substitution of the corresponding halides or sulfonates under classical
homogeneous conditions by azide ion at the anomeric center (Alvarez and Alvarez, 1997). While elevated
temperatures are often required in case of homogeneous one-phase reactions in DMF. The phase-transfer
catalysis at milder conditions may cause instability of acetylated halides, which is considered as a major
limitation of this method. These methodologies have been developed to avoid the preparation of glycosyl
halides completely (Beckmann and Wittmann, 2010). Consequently, the direct method is used to convert
acetylated sugars into acetylated 1-azide using trimethylsilyl azide in the presence of lewis acid catalysis. This
method is a useful one, but it has some limitations. For example, the change of the position of halide, this is
commonly axial with the pyranose ring to β-glycosyl halide.
In addition, some spodric and limited direct methods for the said transformation are available in literature.
However, few modifications have been reported by the activation of only acyclic organic alcohol using diphenyl
phosphorazidate (DPPA) and 1,8-Diazabicyclo [5.4.0]undec-7-ene (DBU) (Lal, 1977) and the use of bis(p-
nitrophenyl) phosphorazidate (Mizuno and Shioiri, 1997). Along this line, method based on the work of
Danishefsky group (Chan et al., 2005) is widely applied. They successfully employed DPPA with other reagents
to displace a benzyl alcohol in high yield. DPPA undergoes pseudohalogen replacement of the azide group by
treatment with nucleophilic reagents, such as: butanol, water, ammonia, and various amines. Herein DPPA is
used as an azide source in preparing some organic azide compounds. In addition, DBU is used in organic
synthesis as a catalyst, non-nucleophilic base and also as complexing ligand.
Researchers at Merck Research Laboratories developed a one-pot method to react a secondary alcohol with
DPPA and DBU and that did not involve Mitsunobu conditions (Thompson et al., 1993), where
2. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.8, 2014
2
triphenylphosphine is used as an activator for hydroxyl group and diethyl azadicarboxylate as azide source. But
hydrazoic acid is health hazard. These methods valid only for a secondary organic alcohol and didn’t apply for
primary sugar. Furthermore, similar reaction was performed by Mizuno and Shioiri using bis(p-nitrophenyl)
phosphorazidate instead of DPPA (Mizuno and Shioiri, 1997 & Akhlaghinia and Samiei, 2007).
There is a need for continuous new process that is capable of providing glycosyl azides with the azide group at
position 6 directly from alcohol with high yield, short time and avoiding the formation of glycosyl halide
completely. Therefore, the starting materials utilized by such a method should be very stable.
The object of this work is to provide such a process wherein the use of a novel and cheap reagent for efficient
synthesis of Methyl 6-Azido-2,3,4-tri-O-benzyl-α-D-glucopyranoside from methyl-2,3,4-tri-O-benzyl-α-D-
glucopyranoside using DPPA and DBU in dry DMF with high temperature. This new approach of synthesis gave
an advantage of short time and less preparation steps. The method could be used for preparing pharmaceutical
active compounds.
2. Experimental
2.1 General method and measurements
The starting material and chemicals were purchased from Sigma-Aldrich chemical company (Germany) and used
without further purification. All solvents were dried according to standard procedures (Becker et al., 1974). The
reaction was performed under Argon atmosphere and was monitored by thin-layer chromatography using TLC
sheets coated with silica gel 60 F254 (Merck). The sugar spots were visualized with UV light at a wavelength of
254 nm, followed by spraying with a solution of thymol-sulfuric acid solution (0.5 g of thymol and 5 ml of conc.
H2SO4 in 95 ml of ethanol) (Göllner et al., 2009) heating to 130 °C for 10 minutes, the sugar can be detected as
pink spots. Azide was purified by column chromatography on silica gel 60.
The 1
H NMR and H-H-Cosy spectra were recorded on a Bruker DRX-500 (500 MHz) spectrometer using
deuterated chloroform solvent and TMS as internal standard. Chemical shifts are reported as δ-values in ppm
relative to δH =7.24 ppm for CDCl3. The mass spectrum (MS) was recorded off-line with nano-ESI method. All
the above analyses were carried out at the Department of Medicinal Chemistry, Institute of Pharmacy, Martin-
Luther-University Halle-Wittenberg, Halle (Saale), Germany.
2.2 Synthesis of glucosyl azide from alcohol
In a clean, dry one neck flask fitted with magnetic stirring bar. Methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside
(200 mg, 0.43 mmol) was dissolved in 5 ml dry DMF, with Ar and stirred for 5 minutes. Then 1.5 equivalent of
DBU was added and allowed to stir at room temperature for 10 minutes. After that DPPA (0.118 g, 0.43 mmol, 1
equivalent) was added to the reaction mixture and heated to 127 °C. The same amounts of DBU and DPPA were
added to reaction mixture after two hours to get excellent yield. Once completion by TLC (Chloroform / Ethyl
acetate 9:1), the reaction mixture was co-evaporated with toluene on a rotary evaporator. The residue was
purified by column chromatography to yield azide as high-viscous, colorless oil (250 mg, 95 %).
There was another method for separating the product where ethyl acetate was added to the mixture,
washed two times with 30 ml H2O. Then extracted three times with 30 ml ethyl acetate and the combined ethyl
acetate phases were washed with water and brine, then dried over Na2SO4, filtered and concentrated in vacuo.
The residue was purified by column chromatography to give the desired product (242 mg, 92
1
H NMR (500 MHz, CDCl3):
δ 7.38 – 7.24 (m, 15H, H-Ph), 4.99 (d, J = 10.9 Hz, 1H, -CH2-Ph), 4.90 (d, J = 11.1 Hz, 1H, -CH2-Ph), 4.80 (dd,
2H, -CH2-Ph), 4.67 (d, J = 12.1 Hz, 1H, -CH2-Ph), 4.62 (d, J = 3.5 Hz, 1H, H-1α), 4.58 (d, J = 11.1 Hz, 1H, -
CH2-Ph), 3.98 (t, J = 9.2 Hz, 1H, H-3), 3.78 (ddd, J = 9.7, 5.7, 2.3 Hz, 1H, H-5), 3.54 (dd, J = 9.6, 3.6 Hz, 1H,
H-2), 3.47 – 3.44 (m, 1H, H-6), 3.47 – 3.41 (m, 1H, H-4), 3.40 (s, 3H, -OCH3), 3.33 (dd, J = 13.1, 5.7
Hz, 1H, H-6').
ESI-MS: m/z calculated for [C28H31N3O5+Na] +
: 512.2161, observed: 512.30
3. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.8, 2014
3
3. Results and Discussion
The proposed research was conducted to explore the generalities of the reaction on carbohydrate
system based primary alcohols, while designing a procedure that allowed for excellent conversion of
the hydroxyl sugar to the azide product. This is new method for converting benzylated sugar with
hydroxyl group at position C6 into azide directly without going through to the classical SN2
conditions, which substitutes primary hydroxyl group by a good leaving group like halides or
sulfonates. The second step is converting it to azide. In this work, primary alcohol can be efficiently
and smoothly converted into an azide using DPPA under mild basic conditions using DBU in DMF
as a polar aprotic solvent with heating to 127ºC.
These novel conditions were used for preparing glucosyl azide from commercially
available and inexpensive methyl-2,3,4-tri-O-benzyl-α-D-glucopyranoside 1 directly with high yield
95% and short time. The general reaction conditions are shown in Scheme 1.
Scheme 1: General reaction for synthesis Methyl 6-Azido-2,3,4-tri-O-benzyl-α-D-glucopyranoside
The reaction focuses on use of DBU, which acts as base in the reaction, to activate primary hydroxyl
group at C6 and DPPA as azide source for the SN2 displacement. Use of DPPA allows the in situ
generation of N3
¯
nucleophile via displacement from phosphate group upon alcohol attack. Then,
glucosyl azide is prepared by nucleophilic substitution of the corresponding phosphate by azide ion.
Proposed mechanism for the new azidation step is shown in Scheme 2.
Scheme 2: Proposed mechanism for synthesis glucosyl azide
O
BnO
BnO
OCH3
OBn
OH
+ P
O
O
O
N3
DBU
DMF, 127ºC
N
N
1
DPPA
O
BnO
BnO
OCH3
OBn
N3
O
BnO
BnO
O CH 3
OBn
O
H
D BU
O
BnO
BnO
OC H3
O Bn
O
+
P
O
O
O
N3ph
ph
O
BnO
BnO
OC H3
O Bn
OPO(O ph)2
+ N3
O
BnO
BnO
O CH 3
OBn
N3
N
N
H
1
4. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.8, 2014
4
In order to optimize the reaction conditions, at first the temperature was increased gradually from -7
to 10 ºC in dry DMF. There was only a minimal amount of azide produced, as observed via TLC. The
benzene rings in 1 and azide allow the easy detection of sugars with UV-lamp.
TLC plates were efficient for determining crude reaction completeness by spraying with a solution of
thymol-sulfuric acid solution. This reagent causes any sugar to appear as pink spots against a red
background upon heating. Percentage of conversion was increased with temperature and TLC shows
a good product at 127ºC. The temperature would still be far enough below the boiling point of DMF
to avoid any decomposition in the reaction. These tests showed that DPPA and DBU amounts did not
seem to be enough to afford complete conversion to azide. So that, the same amount of reagents were
added again to the reaction mixture after 2 hours with 127ºC to get reaction completion.
There are two procedures for workup first one by co-evaporated the reaction mixture with toluene on
a rotary evaporator, which then purified by column chromatography. This gave with the best yield
95% of azide as colorless oil. The second method was the extraction of the product by ethyl acetate
and washed with water, and brine. Subsequent purification steps led to losses in overall yield to 92%.
The HNMR spectra (Scheme 3 and 4) were taken for the azide product after column purification. The
spectra gave a clear indication that the azide had been formed in the reaction. The 1
HNMR and H-H-
Cosy spectra were processed with MestReNova software (V6.0.2-5475). NMR clearly indicated a
double beak at 4.62 ppm that α-H is present in the product and further indication that all peaks of
azide product are present in both NMRs. So that, reaction worked excellently as evident from its
NMR for isolated yield and mass spectrometry. It confirmed azide production by detecting an m/z of
512.30, where the calculated m/z is 512.216. Interestingly, HNMR spectra for azide are in excellent
agreement with those reported in the literature (Hansen and Jensen, 2009).
Scheme 3: 1
HNMR spectrum of azide product
5. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.8, 2014
5
Scheme 4: H-H-Cosy spectrum of azide product
4. Conclusion
In summary, we achieved a new strategy with a simple and efficient protocol for direct conversion of
benzylated glucoside into its azide on position 6 avoiding preparing and separating glucosyl halide
completely. While the reaction produced azide and confirmed by NMR and MS. There were no side
products that might be formed during heating. This study clearly showed the ability to prepare the
desired product without changing the stereochemistry of the sugar. This reaction conditions proposed
could, in fact, show excellent selectivity for conversion of primary glucoside to its corresponding
azide in the presence of DPPA and DBU in DMF as solvent with excellent yield and high purity.
Future work will focus on applying these new conditions for conversion of a wide variety of protected and
unprotected sugars with different positions and organic alcohols to their corresponding azides. Another area of
research is to test the ability of the prepared azide to be intercalated in layered hydroxide for further study on
controlled drug release which is currently underway.
5. Acknowledgement
The authors are very grateful to Martin-Luther-University Halle-Wittenberg, Department of Medicinal
Chemistry, Institute of Pharmacy, Halle (Saale), Germany.
6. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.8, 2014
6
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