Über Tetrahydro-6-methyl- bzw. 6-phenyl-2-oxopyrimidin-5-carbonsäuren und ihre Derivate Über Heterocyclen, 48 Mitt

Tetrahydro-6-methyl- and-6-phenyl-2-oxopyrimidine-5-carboxylic acids5, 8 resp are obtained on hydrogenolysis of the corresponding benzyl esters4, 7; 1-methyl compounds (5, 8) are also formed by hydrolysis of the ethyl and benzyl esters (3, 4, 6, 7) in alcoholic KOH. Benzyl esters4 which are unsubstituted at position1 are converted by alcoholic KOH into ethyl esters3. Phenols convert3, 4, 5, depending on the substituent in position 1, into 6-hydroxyphenyltetrahydro-2(1H)-pyrimidinones (10) or di(tri)phenylalkanes11, 12. Bromination of the pyrimidine-carboxylic acids5 or of the tert butyl esters18 leads to the 6-bromomethyl- and dibromomethyl derivatives15, 16, which are easily transformed into furo-3,4-d]pyrimidines17. Thermal decarboxylation of carboxylic acids5 c, f, g lead to dihydro-2(1H)-pyrimidinones13 a, c, d.