Preparation of a useful synthetic precursor, 2-substituted 4(3H)-quinazolinone: directed lithiation and N~3-deprotection of 3-t-butoxycarbonyl-4(3H)-quinazolinone

摘要

Directed lithiation of 3-t-butoxycarbonyl-4(3H)-quinazolinone using LDA was accomplished to afford 2-substituted 3-t-butoxycarbonyl-4-(3H)-quinazolinones. The t-butoxycarbonyl group of these products was easily deprotected to give key intermediates for the synthesis of quinazoline derivatives, 2-substituted 4(3H)-quinazolinones, in good yield