Potentiell tumorhemmende wirkstoffe. IX. 4,5,6-trialkylierte 2-methoxy- und 2-(methylthio)pyrimidine

The interaction of O-methylisourea sulfate ( 1a ) or S-methyl-isothiourea sulfate ( 1b ), respectively, with 3-methyl-2,4-pentanedi-one ( 2a ) yields 2-methoxy-( 3a )and 2-methylthio-4,5,6-trimethyl-pyrimidine ( 3b ). The 5-ethylpyrimidines ( 3c and 3d ) obtained by the analogous reactions with 3-ethyl-2,4-pentanedione ( 2b ), in contact with air exhibit a tendency to cleave off the 5-ethyl group and give 4,6-dimethyl-2-methoxypyrimidine ( 4a ) and 4,6-dimethyl-2-(melhylthio)pyrimidine ( 4b ).