GB748801A - Improvements in or relating to new chemical compounds - Google Patents

Abstract

The invention comprises lactones of aliphatic epsilon-hydroxy saturated straight-chain carboxylic acids containing 9 to 14 carbon atoms. They may be prepared by dehydrating the appropriate acid or de-alcoholating the alkyl ester. The acid or ester may be formed by reducing the epsilon-keto acid or an alkyl ester thereof with, for example, aluminium isopropylate. The lactones may also be prepared by directly oxidizing the a -alkylcyclohexanone by use of Caro's acid or a mixture of sulphuric acid and hydrogen peroxide. In the example: cyclohexanone is condensed with butanal and the product is dehydrated by heating with oxalic acid to give butylidene cyclohexanone. This is reduced with hydrogen in the presence of palladized charcoal to give butyl cyclohexanone which is oxidized with Caro's acid and the product saponified with alcoholic KOH to give epsilon-hydroxy decanoic acid. This is lactonized in boiling benzene in the presence of p-toluenesulphonic acid. The compounds are used to impart a butter-like flavour to foodstuffs. The epsilon-keto-acids may be prepared by the following methods:-(1) By hydrogenating the condensation product of a di-alkyl ester of sodium malonic acid and adipic acid anhydride. (2) Condensing a di-ester of sodium malonic acid with an alkyl gamma-halogenated butyrate, condensing the product with an acid halide, hydrogenating, saponifying and acidifying. (3) Condensing the butyrate of (2) with an alkyl acyl-acetate, saponifying &c. (4) Condensing a dialkyl sodium malonate with a monohalogenated methyl ether, reacting with an alkyl acyl-acetate, saponifying &c. (5) The condensation product of an alkyl-acetyl acetate and an alkyl-gamma-chloro-butyrate is condensed with an acid halide, followed by reaction with ammonia and hydrolysis. (6) Condensing an adipic alkyl imide with an alkyl magnesium halide, saponifying &c. (7) Treating a 2-alkylcycloheptanedione with an alkaline solution. (8) Oxidizing an alkylcyclohexene obtained by dehydrating the alkylcyclohexanol. (9) Oxydizing an a -alkylcyclohexanone with chromic acid in sulphuric acid. (10) Replacing the halogen atom in adipic acid mono-alkyl estermonoacid halide with an alkyl group and saponifying &c. The epsilon-hydroxy acids may be prepared, in addition to the reduction of the keto-acids, by (1) condensing a 1-halogenated-4-hydroxyalkane with a dialkyl sodium malonate to form an epsilon-hydroxyalkyl malonic ester which is saponified and acidified; and (2) subjecting the oxime of an a -alkylcyclohexanone to a Beckmann conversion to form a lactam, hydrolysing to an epsilon-amino-acid and treating with nitrous acid. The a -alkylcyclohexanone may be prepared as in the example or by transforming a dialkyl pimelate into carbalkoxy-cyclohexanone which is converted via its alkyl derivative and saponification. Specification 748,764, [Group VI], is referred to.