N-(2-Carboxyphenyl)oxalamides in the synthesis of the quinazoline central nervous system depressant methaqualone and fused biheterocyclic systems.

A synthesis of the quinazolin-4-one pharmacological agent methaqualone from N-(2-carboxyphenyl)oxalamide was developed. A new method for the reductive cyclization of 3-(2-nitrophenyl)quinazolin-4-ones to benzimidazo[2,1-b]quinazolin-12(6H)-ones, the 6-deoxo-6-aza analogs of natural alkaloid tryptanthrine, was suggested and new derivatives of poorly available quinoxalinoquinazolinone fused system were synthesized. [ABSTRACT FROM AUTHOR]