1-CHLORO-2-AZAPROPENYLIUM AND 1-CHLORO-2,4-DIAZABUTENYLIUM SALTS - INTERMEDIATES FOR THE SYNTHESIS OF PYRIDO[1,2-A]-1,3,5-TRIAZINIUM SALTS

1-Chloro-1,3-bis(dimethylamino)-3-phenyl-2-azaprop-2-en-1-ylium perchlorate obtained from the reaction of phosphorus oxychloride-N,N-dimethylbenzamide complex and dimethylcyanamide reacts with 2-amino-4-methylpyridine to yield 8-methyl-4-dimethylamino-2-phenylpyrido[1,2-a]1,3,5-triazinium perchlorate (8). The structure is established by X-ray crystallography. Various suitably substituted pyridines react similarly to afford the corresponding pyrido[1,2-a]-1,3,5-triazinium salts. The intermediates obtained from several secondary amides give identical products when treated with the same pyridines. The limitations of this procedure are investigated.