5,6-di:ethyl-4-pyrimidinol prodn. - from alkyl 2-ethyl -3-oxo-pentanoate and formamidine salt in the presence of alkali metal ethoxide

摘要

Prodn. of (I) is effected by reacting an alkyl 2-ethyl-3-oxopentanoate of formula (II) Et-CO-CH(Et)-COOR with a formamidine salt of formula (III) HN-CH-NH2R1 in the presence of an alkali metal ethoxide in a low-boiling aliphatic alcohol at room temp. and pH 3-6. In formulae, R = 1-4C alkyl; and R1 = HOAc or HCl. USE/advantage - (I) is an intermediate for 4-chloro-5,6-diethylpyrimidine, whose use is not disclosed. The process gives high yields (e.g. 60%) of high purity (I) (cf. EP276406). A mixt. of 3.25 g ethyl 2-ethyl-3-oxopentanoate, 2.4 g formamidine acetate and 20 g EtOH was treated with 3.09 g NaOEt at 12-15 deg. C, stirred at room temp. for 21 hrs. adjusted to pH 5.5 with 18% HCl, and evaporated. The residue was suspended in EtOAc, filtered, evaporated and recrystallised from H2O to give a 60% yield of more than 99% pure (I), m.pt. 153-154 deg. C.