Verfahren zur Herstellung substituierter 4-Hydroxypyrimidine

摘要

1,244,075. Preparation of 4-hydroxypyrimidines. BYK-GULDEN LOMBERG CHEMISCHE FABKIK G.m.b.H. 31 Get., 1969 [4 Nov., 1968], No. 53473/69. Heading C2C. Hydroxypyrimidines (5H-pyrimidinones) of the formula in which R is -CN, -COOR 1 or -CONR 1 R 2 , where R 1 and R 2 are C 1-4 alkyl groups, are prepared by reacting an amide R-CH 2 CONH 2 with an O,O- or O,N-acetal of a dialkyl formamide of the formula H.CONR 1 R 2 'to obtain a formamidine of the formula and reacting this compound, or the perchlorate addition salt thereof, with an aqueous NH 4 Cl solution. Preferred acetals are dimethylformamide dimethylacetal and methoxy-bis (dimethylamino) methane. The process may be effected using a molar ratio of amide : acetal of 1: 2 to 1: 4 at temperatures up to 100‹ C. in the first step and completing the reaction with a saturated NH 4 Cl solution containing free ammonia. Examples describe the preparation of 5-cyano- and 5-ethoxycarbonyl-4-hydroxy pyrimidine via the intermediates N-[(α-dimethylaminomethylene)-cyano (or carbethoxy) acetyl]- N1,N1-dimethyl formamidine.