Synthèse de L'hydroxy-9 pyrimido[1,6-a]pyrimidine one-4 et dérivés

Condensation of 5-alkoxy-4-aminopyrimidines with diethyl ethoxy-methylenemalonate and with isopropylidene methoxymethylenemalon-ate, followed by thermal cyclization of the resulting enaminoesters intermediates yielded 9-alkoxypyrimido[l,6-a]pyrimidin-4-ones which were substituted in the 3 position by an ethoxycarbonyl group in the first case. Subsequent hydrogenolysis of the corresponding benzylic ethers afforded new heterocyclic phenols 9-hydroxypyrimido[l,2-a]pyrimidin-4-one and its 3-ethoxycarbonyl derivative.