Barbital → 1,3-Di-(4'-methoxycarbonylbenzyl)-5,5-diethylbarbituric acid

Participants

Reaction Steps

A mixture of 46.05 g (0.25 mol) of diethylbarbituric acid, 96.9 g (0.525 mol) of 4-chloromethylbenzoic acid methyl ester and 38 g (0.275 mol) of finely ground, anhydrous potassium carbonate in 450 ml of dimethylformamide is stirred at room temperature and is heated to 100° C over the course of 2 hours. The reaction solution is kept at 100° C for one hour and the temperature is then raised to 135° C, whilst stirring. Stirring is continued for a further 4 hours at 135° C and the reaction mixture is then filtered, while still hot. 77.8 g of colourless crystals can be isolated from the cooled filtrate and concentrating the mother liquor gives a further 42 g of a syrup which crystallises (total yield of crude material: 119.8 g; theory: 120.1 g).

Provenance & Evidence