A simple and efficient procedure for the preparation of aryl- 14-H-dibenzo [aj]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes, in the presence of silica supported sodium hydrogen sulfate...A simple and efficient procedure for the preparation of aryl- 14-H-dibenzo [aj]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes, in the presence of silica supported sodium hydrogen sulfate （NaHSO4/SiO2） as a catalyst and in the absence of solvent has been developed. The present method offers several advantages such as excellent yields, short reaction time （10-30min）, mild condition, simple work-up, and the use of a cheap and environmentally friendly catalyst with remarkable reusability.展开更多
A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of ali...A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of aliphatic and aromatic aldehydes,ketones and amines when mixed with NaBH;/silica chloride at room temperature,afforded excellent yield of the corresponding amines.展开更多
Silica triflate, as a new silica-based reagent, can be used for the efficient synthesis of 4-substituted coumarins via a Pechmann reaction under solvent-free reaction conditions. All reactions were performed at 80 ℃ ...Silica triflate, as a new silica-based reagent, can be used for the efficient synthesis of 4-substituted coumarins via a Pechmann reaction under solvent-free reaction conditions. All reactions were performed at 80 ℃ in good to high yields.展开更多
Silica sulfuric acid was developed as a stable and efficient heterogeneous catalyst in organic synthesis. This solid acid catalyzed the regioselective ring opening of epoxides by thiocyanate anion to give thiocyanohyd...Silica sulfuric acid was developed as a stable and efficient heterogeneous catalyst in organic synthesis. This solid acid catalyzed the regioselective ring opening of epoxides by thiocyanate anion to give thiocyanohydrins as key intermediates in agricultural and pharmaceutical chemistry in high yields under solvent-free conditions.展开更多
A one-pot synthesis of some unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles via cyclocondensation of benzoylhydrazines with orthoesters under solvent-free and microwave conditions are described here. The reaction is...A one-pot synthesis of some unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles via cyclocondensation of benzoylhydrazines with orthoesters under solvent-free and microwave conditions are described here. The reaction is efficiently catalyzed by silica- supported sulfuric acid as it provided the title compounds in high yields and relatively short times. The catalyst is reusable and can be applied several times without considerable decrease in the yields and rates of the reactions.展开更多
Application of sulfuric acid immobilized on silica gel as an efficient and benign catalyst has been explored in the syn-thesis of 2,4,5-Triaryl-1H-imidazoles via condensation reaction of benzil or benzoin, aldehyde an...Application of sulfuric acid immobilized on silica gel as an efficient and benign catalyst has been explored in the syn-thesis of 2,4,5-Triaryl-1H-imidazoles via condensation reaction of benzil or benzoin, aldehyde and ammonium acetate. The key advantages of this process are high yields, cost effectiveness of catalyst, easy work-up, purification of products by non-chromatographic method and the reusability of the H2SO4.SiO2 catalyst.展开更多
The symmetric oxidative coupling reactions of 2-naphthol derivatives with both ferric hydrogensulfate in water and silica ferric hydrogensulfate in solvent free conditions were carried out. The advantages of this gree...The symmetric oxidative coupling reactions of 2-naphthol derivatives with both ferric hydrogensulfate in water and silica ferric hydrogensulfate in solvent free conditions were carried out. The advantages of this green procedure are inexpensive catalyst or cocatalyst, reusability of catalyst, organic solvent-free procedures and simple workup.展开更多
Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesi...Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols and β-keto- esters at 80 ℃ under solvent-free conditions.展开更多
研究了无有机胺醇水体系低硅铝比ZSM-5沸石的绿色合成方法。在无有机胺模板剂和不加晶种的醇水体系中,一步合成了形貌均一的小晶粒聚集体低硅铝比ZSM-5沸石,考察了合成体系中各配料的含量以及晶化温度对合成低硅铝比ZSM-5沸石的影响。利...研究了无有机胺醇水体系低硅铝比ZSM-5沸石的绿色合成方法。在无有机胺模板剂和不加晶种的醇水体系中,一步合成了形貌均一的小晶粒聚集体低硅铝比ZSM-5沸石,考察了合成体系中各配料的含量以及晶化温度对合成低硅铝比ZSM-5沸石的影响。利用XRD、FTIR、SEM、N_(2)吸附-脱附、^(27)Al MAS NMR和^(29)Si MAS NMR等方法对合成的ZSM-5沸石进行表征。实验结果表明,当n(Si)∶n(Al)=20,n(Na_(2)O)∶n(SiO_(2))=0.071,n(C_(2)H_(5)OH)∶n(SiO_(2))=1.77,晶化温度为160℃时,可合成具有高结晶度的纯相ZSM-5沸石。^(27)Al MAS NMR表征结果显示,合成的ZSM-5沸石主要含有骨架四配位铝,无非骨架铝。合成的ZSM-5沸石的比表面积和微孔孔体积分别为384 m^(2)/g和0.14 cm^(3)/g,总酸量达到789μmol/g,骨架n(Si)∶n(Al)=14.4。展开更多
基金the K.N.Toosi University of Technology Research Council for financial support.
文摘A simple and efficient procedure for the preparation of aryl- 14-H-dibenzo [aj]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes, in the presence of silica supported sodium hydrogen sulfate （NaHSO4/SiO2） as a catalyst and in the absence of solvent has been developed. The present method offers several advantages such as excellent yields, short reaction time （10-30min）, mild condition, simple work-up, and the use of a cheap and environmentally friendly catalyst with remarkable reusability.
基金support of this work from the Research Council of Mazandaran University gratefully acknowledged.
文摘A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of aliphatic and aromatic aldehydes,ketones and amines when mixed with NaBH;/silica chloride at room temperature,afforded excellent yield of the corresponding amines.
文摘Silica triflate, as a new silica-based reagent, can be used for the efficient synthesis of 4-substituted coumarins via a Pechmann reaction under solvent-free reaction conditions. All reactions were performed at 80 ℃ in good to high yields.
文摘Silica sulfuric acid was developed as a stable and efficient heterogeneous catalyst in organic synthesis. This solid acid catalyzed the regioselective ring opening of epoxides by thiocyanate anion to give thiocyanohydrins as key intermediates in agricultural and pharmaceutical chemistry in high yields under solvent-free conditions.
文摘A one-pot synthesis of some unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles via cyclocondensation of benzoylhydrazines with orthoesters under solvent-free and microwave conditions are described here. The reaction is efficiently catalyzed by silica- supported sulfuric acid as it provided the title compounds in high yields and relatively short times. The catalyst is reusable and can be applied several times without considerable decrease in the yields and rates of the reactions.
文摘Application of sulfuric acid immobilized on silica gel as an efficient and benign catalyst has been explored in the syn-thesis of 2,4,5-Triaryl-1H-imidazoles via condensation reaction of benzil or benzoin, aldehyde and ammonium acetate. The key advantages of this process are high yields, cost effectiveness of catalyst, easy work-up, purification of products by non-chromatographic method and the reusability of the H2SO4.SiO2 catalyst.
文摘The symmetric oxidative coupling reactions of 2-naphthol derivatives with both ferric hydrogensulfate in water and silica ferric hydrogensulfate in solvent free conditions were carried out. The advantages of this green procedure are inexpensive catalyst or cocatalyst, reusability of catalyst, organic solvent-free procedures and simple workup.
文摘Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols and β-keto- esters at 80 ℃ under solvent-free conditions.
文摘研究了无有机胺醇水体系低硅铝比ZSM-5沸石的绿色合成方法。在无有机胺模板剂和不加晶种的醇水体系中,一步合成了形貌均一的小晶粒聚集体低硅铝比ZSM-5沸石,考察了合成体系中各配料的含量以及晶化温度对合成低硅铝比ZSM-5沸石的影响。利用XRD、FTIR、SEM、N_(2)吸附-脱附、^(27)Al MAS NMR和^(29)Si MAS NMR等方法对合成的ZSM-5沸石进行表征。实验结果表明,当n(Si)∶n(Al)=20,n(Na_(2)O)∶n(SiO_(2))=0.071,n(C_(2)H_(5)OH)∶n(SiO_(2))=1.77,晶化温度为160℃时,可合成具有高结晶度的纯相ZSM-5沸石。^(27)Al MAS NMR表征结果显示,合成的ZSM-5沸石主要含有骨架四配位铝,无非骨架铝。合成的ZSM-5沸石的比表面积和微孔孔体积分别为384 m^(2)/g和0.14 cm^(3)/g,总酸量达到789μmol/g,骨架n(Si)∶n(Al)=14.4。
