GB378088A - Process for the production of ª†-lactones of decahydronaphthalene - Google Patents

Abstract

g -Lactones of decahydronaphthalene, of the general formula--<FORM:0378088/IV/1> where R represents hydrogen or alkyl, are manufactured by the action of mineral acids, such as sulphuric or hydrobromic acid, in the warm, on b -oxyacid esters of the general formula-- <FORM:0378088/IV/2> where R represents hydrogen or alkyl and R<1> alkyl, which are obtainable by the Reformatsky reaction from a -halogen fatty acid esters, b -ketodecahydronaphthalene and zinc. Alternatively the b -oxyacid esters are converted with water-eliminating agents into the corresponding b -g -unsaturated acid esters, which are then converted, with or without first being saponified, into the g -lactones by heating with mineral acids. The products may be employed as agents against animal parasites, e.g. as anthelmintics. They may be split up by lyes and converted by careful acidification into the corresponding g -oxyacids, from which the g -lactones can be regenerated. In an example, a -(2-oxy-2-decahydronaphthyl)-propionic acid methyl ester (from b -keto-decahydronaphthalene, a -bromopropionic acid methyl ester and zinc) is treated with potassium bisulphate to yield a - (2 - octahydronaphthalene) - propionic acid methyl ester, which is saponified with aqueous alcoholic alkali and the acid obtained is warmed with 70 per cent sulphuric acid, producing the g -lactone of a -(1-oxy-2-decahydronaphthyl)-a -methylacetic acid. Alternatively the oxyacid ester or the unsaturated ester is directly converted into the lactone by the action 70 per cent sulphuric acid. The product is converted by barium hydroxide into the barium salt of the corresponding acid, from which the lactone is regenerated by acid.