GB802628A - New thiobarbituric acid derivatives - Google Patents

Abstract

The invention comprises thiobarbituric acid derivatives of the formula <FORM:0802628/IV (b)/1> where R is ethyl or allyl, and the sodium salts thereof, also processes for their preparation by condensation of N-methyl-thiourea with either a sec-butyl-R-substituted-cyanoacetic acid alkyl ester, followed by acid hydrolysis of the resulting 4-imino-thiobarbituric acid, or with an R-substituted-malonic acid di-alkyl ester, the alkyl groups containing not more than three carbon atoms. In examples: (1) ethyl sec-butyl-ethyl-cyanoacetate and N-methylthiourea are refluxed in ethanolic sodium ethoxide, the cooled mixture diluted with water and acidified yielding 5 - sec - butyl - 5 - ethyl - 1 - methyl - 4-imino-thiobarbituric acid which on hydrolysis with dilute HCl gives 5-sec-butyl-5-ethyl-1-methyl-thiobarbituric acid; (2) as in (1) using ethyl sec-butyl-allyl-cyanoacetate to produce 5 - sec - butyl - 5 - allyl - 1 - methyl - thiobarbituric acid, which, (3), is dissolved in ethanolic sodium ethoxide and the solution distilled in vacuo to give the corresponding sodium salt; (4) diethyl sec-butyl-allyl-malonate and N-methylthiourea are refluxed in ethanolic sodium ethoxide, the cooled mixture poured on to solid carbon dioxide and treated with water yielding the product of (2).