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

Abstract

AbstractThe pyridine and quinoline derivatives 2, 3, and 6 with an activated methylene group atα‐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.