Heteropentalenes. The thermal addition of 1,3-dimethylpyrazolo-[1,2-a]benzotriazole to dimethyl acetylenedicarboxylate
作者:Angelo Albini、Gianfranco Bettinetti、Giovanna Minoli
DOI:10.1039/p19830002491
日期:——
compound (3) reacts with dimethyl acetylenedicarboxylate with addition onto the azomethinimine moiety to give dimethyl 2a,4-dimethyl-4a,8b,8c-triazapentaleno[1,6-ab]indene-1,2-dicarboxylate (7)via a zwitterionic intermediate which can be trapped by protic solvents, e.g. methanol or water to give dimethyl 2-[o-(3,5-dimethylpyrazol-1-yl)anilino]-3-methoxymaleate (8) or tetramethyl 3,3′-bis-[o-(3,5-dimeth
标题化合物(3)与乙炔二羧酸二甲酯反应,并加到偶氮甲亚胺部分上,得到经由(7)的2a,4-二甲基-4a,8b,8c-三氮杂戊烯二烯[1,6- ab ]茚-1,2-二羧酸二甲酯(7)。一种两性离子中间体,可被质子溶剂(例如甲醇或水)捕获,得到2- [ o-(3,5-二甲基吡唑-1-基)苯胺基] -3-甲氧基马来酸二甲酯(8)或四甲基3,3'-双-[邻-(3,5-二甲基吡唑-1-基)苯胺基] -2,2'-氧二马来酸酯(9)。环加合物(7)自发逆向加成至甲基3-甲基吡唑并[1,2- a]苯并三唑-1,2-二羧酸酯(12)和自由基裂解,出乎意料地得到4,5-二氢-2-甲基-4-氧杂吡唑并-[2,3 - a ]喹喔啉-3-羧酸甲酯(17)主要产品,以及少量的两种苯并三唑基戊烯酮(14)和(15)。