2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 w...2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones(5).The entire process represent a demethylation— alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols(4)was discussed.展开更多
采用BH&HLYP/6-311++g(d,p)方法研究了咖啡因N3和N7位水解代谢机理.每个N位的水解代谢机理考察了两种可能的反应路径:分步的路径A和协同的路径B.计算结果表明:对于N3或N7位水解代谢,路径A均优于路径B;N3位水解代谢的路径A所需的活...采用BH&HLYP/6-311++g(d,p)方法研究了咖啡因N3和N7位水解代谢机理.每个N位的水解代谢机理考察了两种可能的反应路径:分步的路径A和协同的路径B.计算结果表明:对于N3或N7位水解代谢,路径A均优于路径B;N3位水解代谢的路径A所需的活化自由能(358.8 k J·mol-1)低于N7位(363.1 k J·mol-1),因而代谢产物副黄嘌呤优于茶碱.展开更多
文摘2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones(5).The entire process represent a demethylation— alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols(4)was discussed.
文摘采用BH&HLYP/6-311++g(d,p)方法研究了咖啡因N3和N7位水解代谢机理.每个N位的水解代谢机理考察了两种可能的反应路径:分步的路径A和协同的路径B.计算结果表明:对于N3或N7位水解代谢,路径A均优于路径B;N3位水解代谢的路径A所需的活化自由能(358.8 k J·mol-1)低于N7位(363.1 k J·mol-1),因而代谢产物副黄嘌呤优于茶碱.
