GB435480A - Improvements in or relating to the manufacture of barbituric acid derivatives - Google Patents

Abstract

N-Mono- or di-alkylated barbituric acids substituted in the 5-position by a methyl group and a group X are prepared by known methods. The group X comprises a saturated cycloalkyl group, or a saturated alkyl group which may be substituted by a cycloalkyl residue, or an unsaturated alkyl group or halogen derivative thereof, provided the group contains at least three carbon atoms. Methods involving the treatment of 1-cyano-2-imino-barbituric acids are, however, excluded. The products possess therapeutic properties, and in the case of the N-monoalkyl compounds may be converted into their salts with inorganic and organic bases. According to the examples: (1) n-butyl-methyl-malonic acid diethyl ester is treated with methylurea to give N-methyl-C : C-methyl - n - butyl - barbituric acid; N - methyl-C : C-methyl-n-hexyl-barbituric acid may be similarly prepared; (2) N-methyl-C : C-methyl-allyl-barbituric acid is prepared from methyl-allyl-malonic acid diethyl ester and methyl-urea; N - methyl - C : C - bromallyl - methyl-barbituric acid is similarly prepared, whilst from allylurea and methyl-isoamyl-malonic acid diethyl ester, N-allyl-C : C-methyl-isoamyl-barbituric acid is obtained. Specifications 1664/03, 14014/04, 11219/05, [all in Class 2], and 391,741 are referred to. The Specification as open to inspection under Sect. 91 also describes the alkylation of cyanimino derivatives of barbituric acid and the saponification of the resulting N-alkyl compounds. It contains an example of the preparation of N-methyl-C : C-cyclohexyl-methyl-barbituric acid by reacting cyclohexyl-methyl-malonic acid diethylester with dicyandiamide, treating the product with dimethyl sulphate and then saponifying. N - Methyl - C : C, isopropyl-methyl- and N-methyl-C : C-b -ethylhexyl-methyl-barbituric acids are stated to be-prepared in the same way. This subject-matter does not appear in the Specification as accepted. Malonic acid esters. Methyl-n-hexyl-malonic acid diethyl ester is obtained by reacting sodium n-hexyl-malonic acid diethyl ester with methyl iodide. The Specification as open to inspection under Sect. 91 also describes the preparation of cyclohexyl-methyl-malonic acid diethyl ester by treating sodium malonic acid diethyl ester with cyclohexyl bromide and methylating with methyl iodide, and of b -ethylhexyl-methyl-malonic acid diethyl ester in the same way using b -ethylhexyl bromide. This subject-matter does not appear in the Specification as accepted.