I₂/CHP‐Mediated Oxidative Coupling of 2‐Aminobenzamides and Isocyanides: Access to 2‐Aminoquinazolinones

Abstract

An oxidative coupling of 2‐aminobenzamides 1 and isocyanides 2 mediated by I2 and cumyl hydroperoxide (CHP) leads to the formation of 2‐aminoquinazolinones 3 in moderate to excellent yields. This method provides an efficient approach to 2‐aminoquinazolinones with high atom economy under metal‐free conditions through two C–N bond‐formation reactions. The products can be further transformed to give benzo[4,5]imidazo[2,1‐b]quinazolin‐12(6H)‐one (4).

Synthesis of N-Alkyl Substituted Benzimidazoquinazolinones

“…In 2009, Molina and co-workers reported the synthesis of benzimidazoquinazolinones using an aza-Wittig reaction . Wang and co-workers demonstrated C–N bond formation on benzimidazoquinazolinones using CuI as a catalyst, a strategy similar to that employed by Chien and co-workers. , Mamedov and co-workers described a method involving the reduction of the nitro group using Na 2 S 2 O 4 and Zn in AcOH. , Recently, Borggrave reported the synthesis of benzimidazoquinazolinones using a Pd catalyst with ex situ generation of CO (Scheme ). To the best of our knowledge, there are few reports on the alkylation of benzimidazoquinazolinone’s imidazole nitrogen. , These compounds exhibit high biological activities. − Our group has been contributing to copper-catalyzed amination reactions for over a decade. − …”

“…29a Wang and co-workers demonstrated C−N bond formation on benzimidazoquinazolinones using CuI as a catalyst, a strategy similar to that employed by Chien and co-workers. 30,31 Mamedov and coworkers described a method involving the reduction of the nitro group using Na 2 S 2 O 4 and Zn in AcOH. 32a,b Recently, Borggrave reported the synthesis of benzimidazoquinazolinones 33 using a Pd catalyst with ex situ generation of CO (Scheme 1).…”