Acta Pharm. 56 (2006) 231-244[ Full paper in PDF ]
4,6-Diamino-1H-pyrimidine-2-thione (1) was used for the preparation of the pyrimidine derivatives 2-5. Compound 5 was cyclized to produce pyrimido[2,1-b][1,3]thiazine derivatives 6a,b which were condensed with p-chlorobenzaldehyde to give compound 7. The latter compound was reacted with hydroxylamine to give isoxazolo[4,5-d]thiazino[2,3-a]pyrimidines 8a,b. Compound 8b was treated with 2-chloroethyl methyl ether to afford compound 9. Similarly, compound 3 reacted with chloroacetic acid to give thiazolo[3,2-a]pyrimidine 10, which was condensed with p-chlorobenzaldehyde to give compound 11. Compound 11 was condensed with hydroxylamine to give isoxazolo[4,5-d]thiazolo[2,3-a]pyrimidine 12. Compound 12b was treated with 2-chloroethyl methyl ether to afford compound 13. The biological evaluation of some prepared products showed that many of them revealed promising antimicrobial activity.
Keywords: pyrimidine, pyrimidothiazine, thiazolopyrimidine, antimicrobial activity