Silica sulfuric acid / ethylene glycol: An Efficient Eco-friendly Catalyst for One-pot Synthesis of Tricyclic and Tetarcyclic Dihydropyrimidine Derivatives.

Document Type : Review Articles

Authors

1 Organometallic and Organometalloid Chemistry Department, National Research Centre, Cairo, Egypt.

2 Chemistry Department, Faculty of Science, Ain Shams University

Abstract

A simple and efficient eco-friendly chemical procedures were developed for the synthesis of series of tricyclic and tetarcyclic dihydropyrimidine derivatives in excellent yields via a one-pot, multi-component reaction in the presence of silica sulfuric acid / ethylene glycol catalyst. The Tricyclic dihydropyrimidine derivatives 1a-g (benzo[4,5]imidazo[1,2-a]pyrimidine derivatives) were synthesized in high yields and high purity with short reaction times by reacting 2-aminobenzimidazole, aldehydes and ethyl acetoacetate. Also, the tetracyclic dihydropyrimidine derivatives 3a-f (benzo[4,5]imidazo[1,2-a]pyrimido[4,5-d]pyrimidin-4(1H)-one derivatives) were synthesized by the reaction of 2-aminobenzimidazole, aldehydes and cyanoacetamide. This present new protocol offers shorter reaction time, high yields and low cost. This method provides much improved protocol over the existing methods.

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