A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga（OTf）3 under sol...A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga（OTf）3 under solvent-free conditions is presented. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straight forward procedure, and use of relatively non-toxic catalysts.展开更多
An efficient synthesis of 2-substituted benzoxazoles through RuCl3·3H2O catalyzed, air oxidized tandem reactions of 2-aminophenols and aldehydes in [bmim]BF4 was developed. This synthetic strategy has such advant...An efficient synthesis of 2-substituted benzoxazoles through RuCl3·3H2O catalyzed, air oxidized tandem reactions of 2-aminophenols and aldehydes in [bmim]BF4 was developed. This synthetic strategy has such advantages as mild reaction conditions, cost-free oxidant, readily available starting materials, and recyclable catalyst and solvent. As an application, it was successfully used in the synthesis of the unreported 5-（benzoxazol-2-yl）-2＇-deoxyuridines with potential biological activities.展开更多
New Schiff base liquid crystals containing benzoxazole core and alkanoyloxy chain at the end group of the molecules （C_（n-1）H_（2n-1）COO-,n=14,16,18） was synthesized.The present compounds are enantiotropic smecti...New Schiff base liquid crystals containing benzoxazole core and alkanoyloxy chain at the end group of the molecules （C_（n-1）H_（2n-1）COO-,n=14,16,18） was synthesized.The present compounds are enantiotropic smectic A liquid crystals.It was also found that the end groups of the molecules and polar chloro substituent at the benzoxazole fragment had effect on the mesomorphic properties.展开更多
A series of novel 2-（5-substituted-[ 1,3,4]oxadiazol-2-yl）-benzoxazoles （Ta-h） were synthesized in good yields in two different directions by involving benzoxazole-2-carboxylic acid （1） as raw material and benzo...A series of novel 2-（5-substituted-[ 1,3,4]oxadiazol-2-yl）-benzoxazoles （Ta-h） were synthesized in good yields in two different directions by involving benzoxazole-2-carboxylic acid （1） as raw material and benzoxazole-2-carbonyl chloride （2）, benzoxazole-2-carboxylic acid methyl ester （3）, benzoxazole-2- carboxylic acid hydrazide （4）, benzoxazole-2-carboxylic acid N＇-acetyl hydrazide （Sa-d） and benzoxazole-2-carboxylic acid-ethylidene-hydrazides （6a-d） as reactive intermediates. The chemical structures of all the synthesized compounds were elucidated by their IR, 1H NMR and 13C NMR and mass spectral data. Further, the target compounds were screened for their antimicrobial activity against various Gram-positive and Gram-negative bacteria.展开更多
Benzimidazoles, benzoxazoles, and benzothiazoles derivatives were synthesized from condensation of aldehydes and 1,2-phenylenediamine or ortho-aminophenol or ortho-aminothiophenol in the presence of catalytic amount o...Benzimidazoles, benzoxazoles, and benzothiazoles derivatives were synthesized from condensation of aldehydes and 1,2-phenylenediamine or ortho-aminophenol or ortho-aminothiophenol in the presence of catalytic amount of Fe（Ⅲ）-Schiff base/SBA-15 in water medium. Short reaction times, good to excellent yields, easy availability, reusability, and use of an eco-friendly catalyst are some of the significant attributes of the present method.展开更多
文摘A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga（OTf）3 under solvent-free conditions is presented. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straight forward procedure, and use of relatively non-toxic catalysts.
基金Project supported by the National Natural Science Foundation of China （Nos. 20772025, 20972042）, Innovation Scientists and Technicians Troop Construction Projects of Henan Province （No. 104100510019）, and the Natural Science Foundation of Henan Province （No. 092300410237）.
文摘An efficient synthesis of 2-substituted benzoxazoles through RuCl3·3H2O catalyzed, air oxidized tandem reactions of 2-aminophenols and aldehydes in [bmim]BF4 was developed. This synthetic strategy has such advantages as mild reaction conditions, cost-free oxidant, readily available starting materials, and recyclable catalyst and solvent. As an application, it was successfully used in the synthesis of the unreported 5-（benzoxazol-2-yl）-2＇-deoxyuridines with potential biological activities.
基金Universiti Tunku Abdul Rahman for the research facilities and financial support (UTAR Research Fund)Ministry of Higher Education(MOHE) for funding this project
文摘New Schiff base liquid crystals containing benzoxazole core and alkanoyloxy chain at the end group of the molecules （C_（n-1）H_（2n-1）COO-,n=14,16,18） was synthesized.The present compounds are enantiotropic smectic A liquid crystals.It was also found that the end groups of the molecules and polar chloro substituent at the benzoxazole fragment had effect on the mesomorphic properties.
文摘A series of novel 2-（5-substituted-[ 1,3,4]oxadiazol-2-yl）-benzoxazoles （Ta-h） were synthesized in good yields in two different directions by involving benzoxazole-2-carboxylic acid （1） as raw material and benzoxazole-2-carbonyl chloride （2）, benzoxazole-2-carboxylic acid methyl ester （3）, benzoxazole-2- carboxylic acid hydrazide （4）, benzoxazole-2-carboxylic acid N＇-acetyl hydrazide （Sa-d） and benzoxazole-2-carboxylic acid-ethylidene-hydrazides （6a-d） as reactive intermediates. The chemical structures of all the synthesized compounds were elucidated by their IR, 1H NMR and 13C NMR and mass spectral data. Further, the target compounds were screened for their antimicrobial activity against various Gram-positive and Gram-negative bacteria.
基金Payame Noor University for its financial support of this study
文摘Benzimidazoles, benzoxazoles, and benzothiazoles derivatives were synthesized from condensation of aldehydes and 1,2-phenylenediamine or ortho-aminophenol or ortho-aminothiophenol in the presence of catalytic amount of Fe（Ⅲ）-Schiff base/SBA-15 in water medium. Short reaction times, good to excellent yields, easy availability, reusability, and use of an eco-friendly catalyst are some of the significant attributes of the present method.
