A method for the preparation of pyrimido[1,2-a]benzimidazoles containing a 2-hydroxybenzyl or (2-hydroxynaphthalen-1-yl)methyl group at position 3 was proposed based on the reaction of β-carbonyl-substituted 4H-chromenes and their benzo analogs with 2-aminobenzimidazole. In the case of chromenes substituted in the methylene fragment, 7,13a-dihydro-5H-benzo[5',6']chromeno-[3',2':5,6]pyrimido[1,2-a]benzimidazoles were isolated.

中文翻译：

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4H-Chromenes 作为 1,3-双亲电子试剂与 2-氨基苯并咪唑反应：嘧啶并[1,2-a]苯并咪唑的合成

基于β-羰基取代的4 H -反应，提出了一种在3位含有2-羟基苄基或(2-羟基萘-1-基)甲基的嘧啶并[1,2- a ]苯并咪唑的制备方法。色烯及其与 2-氨基苯并咪唑的苯并类似物。在亚甲基片段中取代色烯的情况下，7,13a-二氢-5 H-苯并[5',6']色基-[3',2':5,6]嘧啶并[1,2- a ]苯并咪唑被隔离。