Synthesis of 3-Benzo[d]imidazol-2(3H)-ylidene Substituted Pyrano-[3,2-c]chromen-2-ones via Three-Component Reaction

Both benzimidazoles and pyranochromenes exhibit a variety of important biological activities. However, the effective preparation of compounds incorporating both pyranochromene and benzoimidazole moieties is very rare. In this paper, a HOAc-promoted three-component annulation reaction of aromatic aldehydes with 2-(1H-benzo[d]imidazol-2-yl)acetonitrile and 4-hydroxy-2H-chromen-2-one is reported, leading to the formation of a series of 3-benzo[d]imidazol-2(3H)-ylidene substituted pyrano[3,2-c]chromen-2-ones in 58%similar to 84% yields. The current reaction could tolerate aromatic aldehydes with diverse functional groups such as chloro, bromo, cyano, methoxy and heteroaryl aldehydes, and HOAc served as the reaction media as well as the Bronsted acid catalyst, thereby providing an effective synthetic method for the construction of N,O-containing heterocyles.

Automated summary

The study reported a HOAc-promoted three-component annulation reaction leading to the synthesis of a series of compounds with two different active moieties, providing an effective synthetic method for N,O-containing heterocycles construction.