Methylation of methyl α-d-hexopyranosides with diazo-methane in the presence of a small amount of water
作者:Yuko Inoue、Kinzo Nagasawa
DOI:10.1016/0008-6215(87)80024-1
日期:1987.11
Abstract The long-time reduction of methylα-d -gluco-, α-d -manno-, and α-d -galactopyranosides with excess diazomethane-diethyl ether at 25° in the presence of water gave all partially methylated methylα-d -hexopyranosides which differ in number and position of methyl substitution. The presence of electrolytes, such as potassium or sodium phosphate, in the reaction medium enhanced the degree of methylation
Regioselective methylation of methyl glycopyranosides with diazomethane in the presence of transition-metal chlorides and of boric acid
作者:Evgeny V. Evtushenko
DOI:10.1016/s0008-6215(99)00044-0
日期:1999.3
Abstract Partial methylation of the methyl pyranosides of a number of pentoses, hexoses, 6-deoxyhexoses, methyl uronates and their methyl ethers with diazomethane in the presence of transition-metal chlorides and boric acid was studied. It was found for methyl glycosides of pentoses and 6-deoxyhexoses that tin(II), antimony(III), and titanium(IV) chlorides as well as boric acid promoted substitution