Synthesis and Reaction of Novel Spiro Pyrimidine Derivatives

Abstract

2‐Mercapto‐6‐[(pyridin‐4‐ylmethylene)‐amino]‐3H‐pyrimidin‐4‐one 1 was synthesized from Schiff base reaction of 6‐amino‐2‐thiouracil with isonicotinaldehyde. The reaction of 1 with hydrazonyl chloride 2a, 2b, 2c, 2d afforded the novel pyrimidin‐4‐one 3a, 3b, 3c, 3d. Compounds 3a, 3b, 3c, 3d reacted with methyl iodide to give 4a, 4b, 4c, 4d. Subsequently, reaction of 4a, 4b, 4c, 4d with triethylamine as a catalyst in dry chloroform yielded tetraaza‐spiro[4.5]deca‐2, 8‐dien‐7‐one 5a, 5b, 5c, 5d. In addition, reaction of 1 with acrylonitrile gave pyrimidin‐propionitrile 6. The cyclization of 6 by reacting with sodium ethoxide to give pyrimido [2, 1‐b] [1,3] thiazin‐6‐one 7. The refluxing of 1 with bromine in acetic acid yielded 2‐bromo‐pyrimidin‐4‐one 8. The latter compound 8 reacted with sodium azide gave tetrazolo‐pyrimidine 10. The chemical structures of the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, and mass spectral analysis.