<i>O</i>-Glycosylation of 4-(Substituted benzyl)-1,2-dihydro-3<i>H</i>-pyrazol-3-one Derivatives with 2,3,4,6-Tetra-<i>O</i>-acyl-α-D-glucopyranosyl Bromide <i>via</i> <i>N</i><sub>1</sub>-Acetylation of the Pyrazole Ring
作者:Masahiro Kobayashi、Hidetoshi Isawa、Junichi Sonehara、Minoru Kubota、Tetsuji Ozawa
DOI:10.1248/cpb.c15-00982
日期:——
2-dihydro-3H-pyrazol-3-one 10 reacted with 2,3,4,6-tetra-O-acyl-alpha-D-glucopyranosyl bromide 5 in the presence of potassium carbonate in acetonitrile to provide the 1-acetyl-4-(substituted benzyl)-3-(2,3,4,6-tetra-O-acyl-beta-D-glucopyranosyloxy)-1H-pyrazole derivative 11 in high yield. When 2,3,4,6-tetra-O-pivaloyl-alpha-D-glucopyranosyl bromide (5b) was used as a glycosyl donor, the resulting O-glycosylated product
描述了4-(取代的苄基)-3-(2,3,4,6-四-O-酰基-β-D-吡喃葡萄糖基氧基)-1H-吡唑衍生物2的实用制备。通过在吡唑的N1位引入吸电子取代基,例如乙酰基,可以促进4-(取代的苄基)-1,2-二氢-3H-吡唑-3-酮衍生物3的O-糖基化。戒指。1-乙酰基-4-(取代的苄基)-1,2-二氢-3H-吡唑-3-酮10与2,3,4,6-四-O-酰基-α-D-吡喃葡萄糖基溴化物5反应在乙腈中存在碳酸钾以提供1-乙酰基-4-(取代的苄基)-3-(2,3,4,6-四-O-酰基-β-D-吡喃葡萄糖基氧基)-1H-吡唑衍生物11高产。当将2,3,4,6-四-O-新戊酰基-α-D-吡喃葡萄糖基溴化物(5b)用作糖基供体时,在甲醇中存在碳酸氢钾的情况下,将所得的O-糖基化产物11 N1-脱乙酰基,而糖基部分的去保护作用不佳,从而以优异的产率提供了2。使用该策略合成了莫格列净依替膦酸酯的合成中间体2b(1b)。