Synthesis of A Novel Heterocyclic System of 3,8-Disubstituted-5H-Pyrimido[5’,4’:5,6][1,4]Thiazino[3,2-e][1,2,4]Triazine

Abstract

The new compounds 6-methyl-8-morpholino-2H pyrimido[5’,4’:5,6][1,4]thiazino[3,2e][1,2,4]triazin-3(5H)-one (3a) and 6-methyl-8-(piperidin-1-yl)-2Hpyrimido[5’,4’:5,6][1,4]thiazino[3,2-e][1,2,4]triazin-3(5H)-one (3b) were obtained from cyclocondensation of 6-bromo-1,2,4-triazine-3,5(2H,4H)-dione (1) with appropriate 5-amino-6methylpyrimidine-4-thiol (2a, b) in dimethylformamide and in the presence of potassium carbonate under reflux. Reaction of compounds (3a, b) with phosphorous oxychloride gave 4-(3-chloro-6-methyl-5H-pyrimido[5’,4’:5,6][1,4]thiazino[3,2-e][1,2,4]triazin-8-yl)morpholine (4a) and 3-chloro-6-methyl-8-(piperidin-1-yl)-5H-pyrimido[5’,4’:5,6][1,4]thiazino[3,2-e][1,2,4]triazine (4b). Nucleophilic substitution of chlorine atom of compounds (4a, b) with typical secondary amines in DMF and K₂CO₃ produced the new derivatives of the 3,8-disubstituted-5H-pyrimido[5’,4’:5,6][1,4]thiazino[3,2-e][1,2,4]triazine ring systems (5a–f). All the synthesized products were characterized and confirmed by their spectroscopic and microanalytical data.

Keywords:

• Fused heterocyclic
• pyrimidine
• thiazine
• triazine

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge the Research Council of the University of Gonabad for financial support.