Domino synthesis of pyrimido and imidazoquinazolinones

A simple method for the synthesis of N-alkyl-2-arylquinazolin-4-amines, methyl 4-((2-arylquinazolin-4-yl)amino) butanoates, 6-aryl-2,3-dihydro-4H-pyrimido1,2-c]quinazolin-4-ones, and 5-arylimidazo1,2-c]quinazolin-3(2H)-ones has been described. It involves a simple reaction of N-(2-cyanophenyl)-substitutedbenzimidoyl chlorides with alkylamine, γ-aminobutyric acid, β-alanine, l -alanine, and glycine methyl esters hydrochloride in acetonitrile to afford the desired compounds after a series of instantaneous reactions that include Dimroth rearrangement. The reaction involves reflux for 12 hours, simple addition of reagents to an in situ generated benzimidoyl chloride, and simple workup, to form 21 examples of pure compounds in high yields. The active intermediate N-(2-cyanophenyl)-substitutedbenzimidoyl chlorides were formed by the reaction of N-(2-cyanophenyl)-substitutedbenzamides with thionyl chloride in a one-pot strategy. The alternative method described for this preparation deals with an exhausting multistep reactions starting from anthranilic acid.