Background: The 4-thiazolidinone-5-carboxylic acid and its derivatives have diverse applications ... more Background: The 4-thiazolidinone-5-carboxylic acid and its derivatives have diverse applications in agriculture, industrial and pharmaceutical fields. Therefore, the synthesis of this heterocyclic compound attracted much attention from researchers with green chemistry protocols. In this research work, we have introduced the green protocol for the synthesis of 4-thiazolidinone- 5-carboxylic acid by keeping the parameters in mind like cost-effective, environmentally benign, short reaction time and easy work-up procedure. Methods: Initially, we irradiated the mixture of substituted aldehyde, thiosemicarbazide and furan 2-5-dione in the presence of choline chloride-thiourea-based Deep Eutectic Solvent [DES] as a green medium. The reaction optimization was performed in different solvents like ethanol, glycerol, and PEG-400. Results: The DES, which was used as a green solvent, produced an excellent result in context to short reaction time, yield, easy workup, mild reaction condition and c...
A simple and efficient one-pot multicomponent solvent-free protocol developed for the synthesis o... more A simple and efficient one-pot multicomponent solvent-free protocol developed for the synthesis of 3,4-dihydropyrimidine-2-one derivatives from the reaction of various aromatic aldehyde, ethyl acet...
One-pot condensation of pyrazole-4-aldehydes and hydroxylamine hydrochloride to form the correspo... more One-pot condensation of pyrazole-4-aldehydes and hydroxylamine hydrochloride to form the corresponding oxime using formic acid as a medium and further dehydration of oxime using a catalytic amount of orthophosphoric acid to afford novel pyrazole-4-carbonitrile. This protocol serves as an ortho-phosphoric acid-catalyzed one-pot conversion of aldehyde to nitrile. Most remarkable features of this method are metal-free, cost-effective, atom efficiency with excellent yield (98–99%). This process will serve as a robust and scalable tool for the synthesis of valuable and versatile precursor (nitriles). This precursor will pave the way for the synthesis of various medicinally important valuable compounds. H3PO4 catalysed transformation of aldehydes to nitriles H3PO4 catalysed transformation of aldehydes to nitriles
A Facile, ecofriendly, one-pot protocol for the synthesis of substituted 3-phenyl-furo[3,2-c]coum... more A Facile, ecofriendly, one-pot protocol for the synthesis of substituted 3-phenyl-furo[3,2-c]coumarins from in-situ generated α-halo ketones and 4-hydroxy coumarins in PEG-400 and water as a greener solvent. The developed protocol provides the better alternative to the existing method as it involves utilization of in-situ generated α-halo ketones and avoids the use of lachrymatric α-haloketones as well as toxic organic solvents.
Introduction: Quinoxalines show diversified applications in the field of medicinal chemistry. Mat... more Introduction: Quinoxalines show diversified applications in the field of medicinal chemistry. Materials and Methods: Therefore, we have designed a highly efficient, environmentally benign and one-pot protocol for the synthesis of 2-phenylquinoxaline from the reaction of Acetophenone, N-bromosuccinimide and 1,2-phenylenediamine under ultrasound irradiation in glycerol-water. Results and Discussion: We observed that, although the reaction efficiently completed in all of these solvents, the use of glycerol-water with different ratios gives consistently higher yields (89–94%) and decreases reaction times. Conclusion: The main advantages of this protocol are that it is a green method, avoids the use of toxic catalysts and volatile organic medium and the product is obtained with excellent yield.
Background: 1,4-benzothiazine carboxylates show wide application in the field of medicinal chemis... more Background: 1,4-benzothiazine carboxylates show wide application in the field of medicinal chemistry. Therefore, we have designed convenient and efficient method for the synthesis of 1,4-benzothiazine carboxylates. Objective: Synthesis of 1,4-benzothiazine carboxylates and its guanidines by simple and facile method using efficient catalyst. Methods: Derivatives of 1,4-benzothiazine carboxylates were synthesized by cyclocondensing β- keto esters with 2-aminobenzenethiols using CAN as a catalyst at room temperature. 1,4-benzothiazine carboxylate, condensed with guanidine hydrochloride in the presence of sodium methoxide in DMF to obtained new 3-substituted-l-4H-benzo[b][1,4]thiazine-2-carboxyguanidines (88-91%). Results: All the products were obtained with good to excellent yields within 40 min. Here, CAN oxidizes aminothiophenol into disulfide and then nucleophilic attack of enolic form of β-ketoesters on the disulphide and 1, 4-benzothiazine acetates, were obtained with good yields....
Objective: A simple and highly efficient microwave-promoted procedure for the synthesis of imidaz... more Objective: A simple and highly efficient microwave-promoted procedure for the synthesis of imidazo[1,2-a]pyridine derivatives from the reaction of aromatic ketones, N-bromosuccinimide, and 2-aminopyridines in lemon juice was designed. The main advantages of this protocol, such as clean reaction profile, mild reaction condition, high yield, and minimum reaction time, were compared to other previously developed methods. Method: A mixture of aromatic ketones (1a-m) (0.005 m), N-bromosuccinimide (NBS) (0.005 m), and lemon juice (10 ml) was irradiated by microwave at 400-watt power at 85°C, and the formation of α- bromoketones was monitored by Thin Layer Chromatography (TLC). After completion of α-bromination, 2-aminopyridines (0.005 m) was added to the reaction mixture and it was further irradiated at the same reaction condition. After completion of the reaction, the reaction mass was poured in ice-cold water, the solid product obtained was filtered, washed with cold water, and recrysta...
The article has been withdrawn at the request of the authors and editor of the journal "Curr... more The article has been withdrawn at the request of the authors and editor of the journal "Current Organic Synthesis." Bentham Science apologizes to the readers of the journal for any inconvenience this may cause. The Bentham Editorial Policy on Article Withdrawal can be found at https://benthamscience.com/editorial-policies-main.php Bentham Science Disclaimer: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that ...
Background: For the green synthesis of furocoumarins in water, PEG-OSO3H was used as a recyclable... more Background: For the green synthesis of furocoumarins in water, PEG-OSO3H was used as a recyclable catalyst for the one-pot synthesis in water. To avoid the use of toxic lachrymators and unstable phenacyl bromides, we prepared them in-situ and directly condensed with 4-hydroxycoumarins. Objective: PEG-OSO3H was found to be an efficient and reusable catalyst for the microwave irradiated one-pot synthesis of 3-Aryl-furo[3,2-c]coumarins in PEG-water as a greener reaction medium. This method was found to be rapid, simple, eco-friendly and obtained relatively higher yield than other reported methods. Methods: Aromatic ketones (5 mmol), NBS (5mmol) were added in the solution of PEG-OSO3H (10 mol%) in 10 ml water and irradiated under ultrasound at 80-85°C. Then, the solution of 4- hydroxycoumarin (5 mmol) and the solution of acetic acid and ammonium acetate (1 ml) were added into it. The reaction mass was further irradiated for 3 min. From the reaction mixture, ethyl acetate (3 x 10ml) was ...
Almost 20 million tons of solvents are released in the nature per year. Solvents represent about ... more Almost 20 million tons of solvents are released in the nature per year. Solvents represent about 80% of the total volume of chemicals employed in chemical synthesis. Solvents are often flammable or toxic, calling for the replacement of conventional solvents by sustainable solvents. Recent sustainable solvents can be recovered and reused easily, and can efficiently support catalysts. Here we review key synthetic procedure using supercritical liquid CO2, polyethylene glycol, glycerol, ionic liquids and deep eutectic solvents.
Background: The 4-thiazolidinone-5-carboxylic acid and its derivatives have diverse applications ... more Background: The 4-thiazolidinone-5-carboxylic acid and its derivatives have diverse applications in agriculture, industrial and pharmaceutical fields. Therefore, the synthesis of this heterocyclic compound attracted much attention from researchers with green chemistry protocols. In this research work, we have introduced the green protocol for the synthesis of 4-thiazolidinone- 5-carboxylic acid by keeping the parameters in mind like cost-effective, environmentally benign, short reaction time and easy work-up procedure. Methods: Initially, we irradiated the mixture of substituted aldehyde, thiosemicarbazide and furan 2-5-dione in the presence of choline chloride-thiourea-based Deep Eutectic Solvent [DES] as a green medium. The reaction optimization was performed in different solvents like ethanol, glycerol, and PEG-400. Results: The DES, which was used as a green solvent, produced an excellent result in context to short reaction time, yield, easy workup, mild reaction condition and c...
A simple and efficient one-pot multicomponent solvent-free protocol developed for the synthesis o... more A simple and efficient one-pot multicomponent solvent-free protocol developed for the synthesis of 3,4-dihydropyrimidine-2-one derivatives from the reaction of various aromatic aldehyde, ethyl acet...
One-pot condensation of pyrazole-4-aldehydes and hydroxylamine hydrochloride to form the correspo... more One-pot condensation of pyrazole-4-aldehydes and hydroxylamine hydrochloride to form the corresponding oxime using formic acid as a medium and further dehydration of oxime using a catalytic amount of orthophosphoric acid to afford novel pyrazole-4-carbonitrile. This protocol serves as an ortho-phosphoric acid-catalyzed one-pot conversion of aldehyde to nitrile. Most remarkable features of this method are metal-free, cost-effective, atom efficiency with excellent yield (98–99%). This process will serve as a robust and scalable tool for the synthesis of valuable and versatile precursor (nitriles). This precursor will pave the way for the synthesis of various medicinally important valuable compounds. H3PO4 catalysed transformation of aldehydes to nitriles H3PO4 catalysed transformation of aldehydes to nitriles
A Facile, ecofriendly, one-pot protocol for the synthesis of substituted 3-phenyl-furo[3,2-c]coum... more A Facile, ecofriendly, one-pot protocol for the synthesis of substituted 3-phenyl-furo[3,2-c]coumarins from in-situ generated α-halo ketones and 4-hydroxy coumarins in PEG-400 and water as a greener solvent. The developed protocol provides the better alternative to the existing method as it involves utilization of in-situ generated α-halo ketones and avoids the use of lachrymatric α-haloketones as well as toxic organic solvents.
Introduction: Quinoxalines show diversified applications in the field of medicinal chemistry. Mat... more Introduction: Quinoxalines show diversified applications in the field of medicinal chemistry. Materials and Methods: Therefore, we have designed a highly efficient, environmentally benign and one-pot protocol for the synthesis of 2-phenylquinoxaline from the reaction of Acetophenone, N-bromosuccinimide and 1,2-phenylenediamine under ultrasound irradiation in glycerol-water. Results and Discussion: We observed that, although the reaction efficiently completed in all of these solvents, the use of glycerol-water with different ratios gives consistently higher yields (89–94%) and decreases reaction times. Conclusion: The main advantages of this protocol are that it is a green method, avoids the use of toxic catalysts and volatile organic medium and the product is obtained with excellent yield.
Background: 1,4-benzothiazine carboxylates show wide application in the field of medicinal chemis... more Background: 1,4-benzothiazine carboxylates show wide application in the field of medicinal chemistry. Therefore, we have designed convenient and efficient method for the synthesis of 1,4-benzothiazine carboxylates. Objective: Synthesis of 1,4-benzothiazine carboxylates and its guanidines by simple and facile method using efficient catalyst. Methods: Derivatives of 1,4-benzothiazine carboxylates were synthesized by cyclocondensing β- keto esters with 2-aminobenzenethiols using CAN as a catalyst at room temperature. 1,4-benzothiazine carboxylate, condensed with guanidine hydrochloride in the presence of sodium methoxide in DMF to obtained new 3-substituted-l-4H-benzo[b][1,4]thiazine-2-carboxyguanidines (88-91%). Results: All the products were obtained with good to excellent yields within 40 min. Here, CAN oxidizes aminothiophenol into disulfide and then nucleophilic attack of enolic form of β-ketoesters on the disulphide and 1, 4-benzothiazine acetates, were obtained with good yields....
Objective: A simple and highly efficient microwave-promoted procedure for the synthesis of imidaz... more Objective: A simple and highly efficient microwave-promoted procedure for the synthesis of imidazo[1,2-a]pyridine derivatives from the reaction of aromatic ketones, N-bromosuccinimide, and 2-aminopyridines in lemon juice was designed. The main advantages of this protocol, such as clean reaction profile, mild reaction condition, high yield, and minimum reaction time, were compared to other previously developed methods. Method: A mixture of aromatic ketones (1a-m) (0.005 m), N-bromosuccinimide (NBS) (0.005 m), and lemon juice (10 ml) was irradiated by microwave at 400-watt power at 85°C, and the formation of α- bromoketones was monitored by Thin Layer Chromatography (TLC). After completion of α-bromination, 2-aminopyridines (0.005 m) was added to the reaction mixture and it was further irradiated at the same reaction condition. After completion of the reaction, the reaction mass was poured in ice-cold water, the solid product obtained was filtered, washed with cold water, and recrysta...
The article has been withdrawn at the request of the authors and editor of the journal "Curr... more The article has been withdrawn at the request of the authors and editor of the journal "Current Organic Synthesis." Bentham Science apologizes to the readers of the journal for any inconvenience this may cause. The Bentham Editorial Policy on Article Withdrawal can be found at https://benthamscience.com/editorial-policies-main.php Bentham Science Disclaimer: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that ...
Background: For the green synthesis of furocoumarins in water, PEG-OSO3H was used as a recyclable... more Background: For the green synthesis of furocoumarins in water, PEG-OSO3H was used as a recyclable catalyst for the one-pot synthesis in water. To avoid the use of toxic lachrymators and unstable phenacyl bromides, we prepared them in-situ and directly condensed with 4-hydroxycoumarins. Objective: PEG-OSO3H was found to be an efficient and reusable catalyst for the microwave irradiated one-pot synthesis of 3-Aryl-furo[3,2-c]coumarins in PEG-water as a greener reaction medium. This method was found to be rapid, simple, eco-friendly and obtained relatively higher yield than other reported methods. Methods: Aromatic ketones (5 mmol), NBS (5mmol) were added in the solution of PEG-OSO3H (10 mol%) in 10 ml water and irradiated under ultrasound at 80-85°C. Then, the solution of 4- hydroxycoumarin (5 mmol) and the solution of acetic acid and ammonium acetate (1 ml) were added into it. The reaction mass was further irradiated for 3 min. From the reaction mixture, ethyl acetate (3 x 10ml) was ...
Almost 20 million tons of solvents are released in the nature per year. Solvents represent about ... more Almost 20 million tons of solvents are released in the nature per year. Solvents represent about 80% of the total volume of chemicals employed in chemical synthesis. Solvents are often flammable or toxic, calling for the replacement of conventional solvents by sustainable solvents. Recent sustainable solvents can be recovered and reused easily, and can efficiently support catalysts. Here we review key synthetic procedure using supercritical liquid CO2, polyethylene glycol, glycerol, ionic liquids and deep eutectic solvents.
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