AMINO-ACIDS IN THE SYNTHESIS OF HETEROCYCLIC-SYSTEMS - THE SYNTHESIS OF 4-OXO-4H-PYRIDO[1,2-A]PYRIDINES AND 4-OXO-4H-PYRIDO[1,2-A]PYRIMIDINES

The pyridine and quinoline derivatives 2, 3, and 6 with an activated methylene group at alpha-position in respect to the ring nitrogen atom were converted with 1, 8, or 9 into fused pyrido[1,2-a]pyridine derivatives 4, 5, 7, and 10. In an analogous manner were the aminopyridines 16 and 17 transformed with thiazolone 9 into pyrido[1,2-a]pyrimidine derivatives 20, 21, 25, and 26.