Glycosidation Route to 4''-epi-(Methylamino)-4''-Deoxyavermectin B1 (MK-244, Emamectin Benzoate)
作者:Mallory F. Loewe、Raymond J. Cvetovich、Lisa M. DiMichele、Richard F. Shuman、Edward J. J. Grabowski
DOI:10.1021/jo00104a052
日期:1994.12
A stereocontrolled glycosidation with phenyl 4-epi-[N-(allyloxycarbonyl)-methylamino]-4-deoxy-1-thiooleandroside (10) and 5-O-(allyloxycarbonyl)avermectin B-1 monosaccharide (12) using N-iodosuccinimide gave exclusively the alpha-anomer 13 in 90% yield. Thiophenyl oleandrose derivative 10 was prepared from methyl oleandroside, which was prepared via methanolysis of avermectins. Deprotection and crystallization as the benzoic acid salt gave 4''-epi-(methylamino)-4''-deoxyavermectin B-1 (1a, MK-244, emamectin benzoate).