A compound ethyl(5S,6R)-2-(4-methylphenyl)-6-[(1R)-tert-butyldimethylsilyloxyethy]-penem-3-carboxylate was synthesized through displacement,acylation and Wittig cyclization reaction of optically active material(3R,4R)...A compound ethyl(5S,6R)-2-(4-methylphenyl)-6-[(1R)-tert-butyldimethylsilyloxyethy]-penem-3-carboxylate was synthesized through displacement,acylation and Wittig cyclization reaction of optically active material(3R,4R)-3-[(1R)-tert-butyldimethylsilyloxyethyl]-4-acetoxy-2-azetidi-none(4AA)upon thionocarboxlic acid.The intermediates and the target product were characterized by 1HNMR,IR,elementary analysis and MS.展开更多
The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluene...The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluenesulfonic acid.But the products esters were racemic when（S）-3-（2′-oxocyclohexyl） propionic acid reacts with alcohols in the presence of sulfuric acid or with p-toluenesulfonic acid as catalyst.We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst.The optical compound（S）-methyl-3-（2′-oxocyclohexyl）propionate,（（S）-ethyl-3-）（2′-oxocyclohexyl）propionate and（S）-n-butyl-3-（2′-oxocyclohexyl）propionate were obtained.In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate（R）TTCA·K as the chiral catalyst to afford optically active（S）-3-（2′-oxocy-clohexyl） propionate.The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of（R）TTCA·K as the catalyst would be a complex process.展开更多
文摘A compound ethyl(5S,6R)-2-(4-methylphenyl)-6-[(1R)-tert-butyldimethylsilyloxyethy]-penem-3-carboxylate was synthesized through displacement,acylation and Wittig cyclization reaction of optically active material(3R,4R)-3-[(1R)-tert-butyldimethylsilyloxyethyl]-4-acetoxy-2-azetidi-none(4AA)upon thionocarboxlic acid.The intermediates and the target product were characterized by 1HNMR,IR,elementary analysis and MS.
文摘The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluenesulfonic acid.But the products esters were racemic when（S）-3-（2′-oxocyclohexyl） propionic acid reacts with alcohols in the presence of sulfuric acid or with p-toluenesulfonic acid as catalyst.We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst.The optical compound（S）-methyl-3-（2′-oxocyclohexyl）propionate,（（S）-ethyl-3-）（2′-oxocyclohexyl）propionate and（S）-n-butyl-3-（2′-oxocyclohexyl）propionate were obtained.In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate（R）TTCA·K as the chiral catalyst to afford optically active（S）-3-（2′-oxocy-clohexyl） propionate.The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of（R）TTCA·K as the catalyst would be a complex process.
