<i>C</i>-Nucleoside studies. Part XI. <i>Cine</i>-substitution in 1,4-dinitropyrazoles; application to the synthesis of formycin via nitropyrazole derivatives
作者:J. Grant Buchanan、Alan Stobie、Richard H. Wightman
DOI:10.1139/v80-419
日期:1980.12.1
Reaction of 1,4-dinitro-3-methylpyrazole with a variety of nucleophiles led to the formation of 5-substituted 3-methyl-4-nitropyrazoles 11–15 by a process of cine-substitution. This reaction has been applied as the key step in a novel synthesis of formycin. Treatment of 1,4-dinitro-3-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)pyrazole (17) with cyanide ion produced 3(5)-cyano-4-nitro-5(3)-(2,3,5-tri-O-
1,4-二硝基-3-甲基吡唑与多种亲核试剂的反应导致通过电影取代过程形成5-取代的3-甲基-4-硝基吡唑11-15。该反应已被用作新合成福尔霉素的关键步骤。用氰化物离子处理 1,4-二硝基-3-(2,3,5-tri-O-乙酰基-β-D-呋喃核糖基)吡唑 (17) 产生 3(5)-氰基-4-硝基-5( 3)-(2,3,5-三-O-乙酰基-β-D-呋喃核糖基)吡唑(19),产率为89%。催化还原为 4-氨基化合物 20 (84%),随后与乙酸甲脒反应产生三乙酸甲霉素 21 (79%)。21 的甲醇分解以 90% 的产率生产了福尔霉素 (1)。