反应详情

Saponification of 9.5 g. of this ester with an aqueous-alcoholic solution of sodium hydroxide (N NaOH, 15 cm3 + water, 30 cm3 + ethanol, 30 cm3) is complete in 1 hour at ordinary temperature. After acidification, the precipitate is filtered off and recrystallised from 160 cm3 of a mixture of dimethylformamide (1 volume) and ethanol (1 volume). 6.8 g. of 2-(4'-benzyl-piperazino)-5-oxo-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine-6-carboxylic acid are obtained; melting point 207° C.

1. filtrationAfter acidification, the precipitate is filtered off
2. customrecrystallised from 160 cm3 of a mixture of dimethylformamide (1 volume) and ethanol (1 volume)