Synthesis of thieno, pyrazolo and isothiazolo-pyrimidine derivatives based on o-mercaptoacetylpyrimidine derivative

Mercaptopyrimidine 4 was prepared and transformed into methylmercaptopyrimidine 5. Compound 5 was transformed into pyrazolopyrimidine 6, and cinnamoylpyrimidine 7. Compound 4 reacted with halomethylene to produce thienopyrimidines 9, 10. Pyrimidine 4 was converted into pyrimidine derivative 12a,b, upon treatment with H2O2 in acetic acid and NaOH, respectively. Oxidation of 4 leads to disulfide 13. Heterocyclization of 4 using NaOCL in the presence of NaOH/NH [4]OH afforded isothiazolopyrimidine 15. Heterocyclization of 4 using aromatic aldehydes gives thiopyranopyrimidines 17a,b. Chlorination of 4 afforded chloropyrimidine 18, which was transformed into pyrrolopyrimidine 20 and pyrimidine derivatives 21a,b,c,d