Studies on Pyrimidine Derivatives. XXVIII. Synthesis of Pyridopyrimidine Derivatives by Cross-coupling of Halopyrimidines with Olefins and Acetylenes

Abstract

Three kinds of pyridopyrimidines were synthesized from appropriate pyrimidine derivatives. Cross-coupling of 4-amino-5-iodopyrimidines with α, β-unsaturated carboxylic esters followed by ring-closure afforded pyrido [2, 3-d] pyrimidines. Ammonolysis of 4-ethoxycarbonyl-5-phenylethynyl-and 5-ethoxycarbonyl-4-phenyl-ethynyl-pyrimidines which were obtained by cross-coupling of the corresponding halopyrimidines with phenylacetylene, gave pyrido [3, 4-d]-and pyrido [4, 3-d]-pyrimidines, respectively.