Studies on heterocyclic enaminonitriles. I. Synthesis and aromatization of 2-amino-3-cyano-1-ethoxycarbonyl-4,5-dihydropyrroles.
作者:MIKI SONODA、NOBUTAKA KURIYAMA、YUKIHIKO TOMIOKA、MOTOYOSHI YAMAZAKI
DOI:10.1248/cpb.30.2357
日期:——
The reaction of 1-ethoxycarbonylaziridine with malononitrile in the presence of sodium hydride gave 2-amino-3-cyano-1-ethoxycarbonyl-4, 5-dihydropyrrole (IIa) in 47% yield. Similarly, 1-ethoxycarbonyl-2-methyl (or phenyl) aziridine reacted with malononitrile to give 2-amino-3-cyano-5-methyl (or 4-phenyl)-4, 5-dihydropyrrole (IIb or c). Compounds IIa-c were dehydrogenated to the corresponding pyrroles (IVa-c) when heated with chloranil in benzene. 2-Amino-3-cyano-1-ethoxycarbonyl-4-phenylpyrrole (IVc) was also synthesized from ethyl N-phenacylcarbamate and malononitrile. The 2-benzamido derivatives of IIa-c reacted with N-bromosuccinimide in the presence of 2, 2'-azobisisobutyronitrile to produce the corresponding 2-benzamido-3-cyano-1-ethoxycarbonylpyrroles (Va-c) as major products.
在氢化钠存在下,1-乙氧羰基氮丙啶与丙二腈反应,得到 2-氨基-3-氰基-1-乙氧羰基-4, 5-二氢吡咯(IIa),产率为 47%。同样,1-乙氧羰基-2-甲基(或苯基)氮丙啶与丙二腈反应,得到 2-氨基-3-氰基-5-甲基(或 4-苯基)-4, 5-二氢吡咯(IIb 或 c)。化合物 IIa-c 在苯中与氯苯胺加热后脱氢生成相应的吡咯(IVa-c)。2-Amino-3-cyano-1-ethoxycarbonyl-4-phenylpyrrole (IVc) 也是由 N-苯乙酰氨基甲酸乙酯和丙二腈合成的。IIa-c 的 2-苯甲酰胺基衍生物在 2,2'-偶氮二异丁腈存在下与 N-溴代丁二酰亚胺反应,生成相应的 2-苯甲酰胺基-3-氰基-1-乙氧基羰基吡咯(Va-c)作为主要产物。