Pyrido[1,2-a]pyrimidinium salt derivatives 2a–f were prepared in good
yields by condensation of 2-aminopyridine with 2-substituted
vinamidinium salt derivatives 1a–f. The purity and the structure of
the synthetized compounds were ascertained by elemental analysis,
mass spectrometry, infrared, and NMR (¹H and ¹³C 400 MHz)
spectroscopy.