title: Pyrido(1,2-a)pyrimidinium salts. I. Synthesis from 2-aminopyridines and interconversion with 2-(2-acylvinylamino)pyridines.
mesh_terms: D000215:Acylation; D008722:Methods; D011725:Pyridines / Q000138:chemical synthesis; D011743:Pyrimidines / Q000138:chemical synthesis*; D000644:Quaternary Ammonium Compounds / Q000138:chemical synthesis*; D014753:Vinyl Compounds
chemical_list: D011725:Pyridines; D011743:Pyrimidines; D000644:Quaternary Ammonium Compounds; D014753:Vinyl Compounds