Preparation of Pyrazolo[3′,4′ : 4,5]pyrido[2,3-<i>d</i>]pyrimidines by the Intramolecular Reaction of Azomethine Imines in a 2,4(1<i>H</i>,3<i>H</i>)-Pyrimidinedione System
作者:Michihiko Noguchi、Kazuo Yamada
DOI:10.1055/s-1993-25819
日期:——
A facile synthetic route to substituted 6,8-dimethyl-3,3a,4, 5-dihydro-2H-pyrazolo[3′,4′:4,5]pyrido[2,3-d]pyrimidine-] 7,9(6H,8H)-di-ones is described based on an intramolecular azomethine imine cyclization followed by dehydrogenation. The azomethine imine intermediates are given by the thermal 1,2-hydrogen shift of the hydrazones, which are formed from the reaction of 6-allylamino-5-formyl-1, 3-dimethyl-2,4(1H,3H)-pyrimidinediones and hydrazines 2.
基于分子内氮亚胺环化和脱氢反应,描述了取代的 6,8-二甲基-3,3a,4,5-二氢-2H-吡唑并[3′,4′:4,5]吡啶并[2,3-d]嘧啶-]7,9(6H,8H)-二酮的简便合成路线。偶氮亚胺中间体是由 6-烯丙基氨基-5-甲酰基-1,3-二甲基-2,4(1H,3H)-嘧啶二酮和肼 2 反应生成的肼的 1,2-氢热移给出的。