GB770344A - Novel heterocyclic compounds - Google Patents

Abstract

The invention comprises 1-alkyl-5-dialkyl or -5-dialkenyl- or -5-alkyl-5-alkenyl-thiobarbituric acids (wherein the alkyl group in position 1 contains 3 to 5 carbon atoms and the alkyl or alkenyl groups in position 5, which may be the same or different, contain not more than 6 carbon atoms), their salts (e.g. sodium salts), and their preparation by condensing an appropriately disubstituted malonic acid di-(1-4C)-alkyl ester with an N-alkyl thiourea, or by condensing an appropriately disubstituted cyanacetic acid (1-4C)-alkyl ester with an N-alkyl thiourea with subsequent dilute mineral acid hydrolysis of the resultant 4-iminothiobarbituric acid. The condensations may be effected by refluxing the reactants in a solution of a sodium alkoxide in a 1-4C aliphatic alcohol. Examples describe the preparation by the first of the above methods of thiobarbituric acids in which the 1-substituent is selected from n- and iso-propyl, n-, iso- and sec.-butyl and isoamyl, and the 5-substituents are selected from 2-methyl-n-butyl, allyl, ethyl, sec.-butyl, n-propyl, iso-butyl and methyl, and by the second of the above methods of 5-(isobutyl)-5-allyl-1-n-propylthiobarbituric acid via the intermediate 5 - (isobutyl) - 5 - allyl - 1 - n - propyl - 4 - iminothiobarbituric acid. In a further example, 5-isobutyl-5-methyl-1-n-propylthiobarbituric acid is converted into its sodium salt by the action of sodium ethoxide in ethanol. The products are useful as general an sthetics. According to the Provisional Specification, the 1-substituent may be any alkyl group containing more than two carbon atoms.