Abstract

A new and convenient approach to functionalized benzimidazopyrimidinones is reported. It is based on a two-step procedure starting from readily available 1-(prop-2-yn-1-yl)-1H-benzo[d]imidazol-2-amines, consisting of a multicomponent palladium-catalyzed oxidative cyclocarbonylation–alkoxycarbonylation process, followed by base-promoted isomerization of the initially formed mixture of isomeric carbonylated products. Fair to good overall yields of the final alkyl 2-(2-oxo-1,2-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-3-yl)acetates are obtained, using different alcohols as solvent and nucleophile in the carbonylation step (carried out in the presence of 0.33–1 mol% PdI₂ in conjunction with 17–50 mol% KI, at 100 °C and under 20 atm of a 4:1 mixture of CO–air) and the corresponding sodium alkoxide as base in the subsequent isomerization step (carried out in the alcoholic solvent at room temperature). The structures of a representative substrate [N-benzyl-1-(prop-2-yn-1-yl)-1H-benzo[d]imidazol-2-amine] and a representative product [methyl 2-(1-isopentyl-2-oxo-1,2-dihydrobenzo-[4,5]imidazo[1,2-a]pyrimidin-3-yl)acetate] were confirmed by X-ray diffraction analysis.

A new and convenient approach to functionalized benzimidazopyrimidinones is reported. It is based on a two-step procedure starting from readily available 1-(prop-2-yn-1-yl)-1H-benzo[d]imidazol-2-amines, consisting of a multicomponent palladium-catalyzed oxidative cyclocarbonylation–alkoxycarbonylation process, followed by base-promoted isomerization of the initially formed mixture of isomeric carbonylated products. Fair to good overall yields of the final alkyl 2-(2-oxo-1,2-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-3-yl)acetates are obtained, using different alcohols as solvent and nucleophile in the carbonylation step (carried out in the presence of 0.33–1 mol% PdI₂ in conjunction with 17–50 mol% KI, at 100 °C and under 20 atm of a 4:1 mixture of CO–air) and the corresponding sodium alkoxide as base in the subsequent isomerization step (carried out in the alcoholic solvent at room temperature). The structures of a representative substrate [N-benzyl-1-(prop-2-yn-1-yl)-1H-benzo[d]imidazol-2-amine] and a representative product [methyl 2-(1-isopentyl-2-oxo-1,2-dihydrobenzo-[4,5]imidazo[1,2-a]pyrimidin-3-yl)acetate] were confirmed by X-ray diffraction analysis.

中文翻译：

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钯催化羰基化合成功能化苯并咪唑并嘧啶酮

摘要

报道了一种新的方便的方法来官能化苯并咪唑并嘧啶酮。它基于两步程序，从容易获得的1-（prop-2-yn-1-yl）-1 H-苯并[ d ]咪唑-2-胺开始，由多组分钯催化的氧化环羰基化反应-烷氧基羰基化过程，然后对最初形成的异构体羰基化产物混合物进行碱促进的异构化。使用不同的醇类作为溶剂，最终得到2-（2-氧代-1,2-二氢苯并[4,5]咪唑并[1,2 - a ]嘧啶-3-基）乙酸烷基酯的总体收率相当好。羰基化步骤中的亲核试剂（在0.33–1 mol％PdI ₂的存在下进行在随后的异构化步骤中（在室温下于醇类溶剂中）与17–50 mol％KI，在100°C和20 atm的4–1 CO-空气混合物中与相应的醇钠作为碱结合使用，作为碱温度）。代表性底物[ N-苄基-1-（丙-2-炔-1-基）-1 H-苯并[ d ]咪唑-2-胺]的结构和代表性产物[甲基2-（1-异戊基）通过X射线衍射分析确认了-2-氧代-1,2-二氢苯并-[4,5]咪唑并[1,2 - a ]嘧啶-3-基）乙酸酯。

报道了一种新的方便的方法来官能化苯并咪唑并嘧啶酮。它基于两步程序，从容易获得的1-（prop-2-yn-1-yl）-1 H-苯并[ d ]咪唑-2-胺开始，由多组分钯催化的氧化环羰基化反应-烷氧基羰基化过程，然后对最初形成的异构体羰基化产物混合物进行碱促进的异构化。使用不同的醇类作为溶剂，最终得到2-（2-氧代-1,2-二氢苯并[4,5]咪唑并[1,2 - a ]嘧啶-3-基）乙酸烷基酯的总体收率相当好。羰基化步骤中的亲核试剂（在0.33–1 mol％PdI ₂的存在下进行在随后的异构化步骤中（在室温下于醇类溶剂中）与17–50 mol％KI，在100°C和20 atm的4–1 CO-空气混合物中与相应的醇钠作为碱结合使用，作为碱温度）。代表性底物[ N-苄基-1-（丙-2-炔-1-基）-1 H-苯并[ d ]咪唑-2-胺]的结构和代表性产物[甲基2-（1-异戊基）通过X射线衍射分析确认了-2-氧代-1,2-二氢苯并-[4,5]咪唑并[1,2 - a ]嘧啶-3-基）乙酸酯。