Purine studies. Part V. Formation and aminolysis of some methylthiopurines

Abstract

Syntheses of 6,7- and 6,9-dimethyl-2-methylthiopurine, 2,9-dimethyl-6-methylthiopurine, 9-benzyl-8-methyl-and 2,9-dimethyl-8-methyl-thiopurine, and related compounds are described. The 2-methylthiopurines are unaffected by butylamine at 200°, but the dimethyl-6(and 8)-methylthiopurines undergo apparent first-order-butylaminolysis under preparative conditions at rates comparable with simple 4-methylthiopyrimidines; 9-benzyl-8-methylthiopurine is decomposed by such treatment. The recorded ionisation constants and ultraviolet spectra are used to confirm some of the structures involved.