Synthesis of some 5-azaflavones

Within a plan of researches concerning drugs with anti-ulcer activity, a series of 5-azaflavones has been prepared. In this first communication we report the relevant synthesis obtained by cyclization of appropriate beta-diketones in HCOOH at the boiling point. The beta-diketones have been obtained by Claisen condensation, starting from methyl 3-hydroxypicolinate and from appropriate aromatic or heterocyclic methylketone, using NaH as base.