A novel method was successfully demonstrated towards the synthesis of
pyrido[1,2-a]pyrimidines having chloroethyl as an
intractable side chain, through dihydrofuranone intermediates. The dihydrofuranone intermediates
were synthesized by condensation of 2-aminopyridines with
α-acetyl-γ-butyrolactone, which upon cyclization using phosphorus
oxychloride or ethanol in sodium ethoxide furnished the
pyrido[1,2-a]pyrimidines in good yield.
