Unsaturated aliphatic compounds and process for the manufacture thereof

Abstract

Abstract The invention comprises acetylenically unsaturated acids and esters of general formula: <FORM:0859897/IV(b)/1> where c is an integer from 2 to 5 and d an integer from 0 to 8, but where c is 2, d is other than 6 and the corresponding ethylencially unsaturated acids or esters other than linoleic, homolinoleic, y-linoleic, and arachidonic acids and those compounds in which c and d are 2 and 8, 3 and 5, 4 and 6, 4 and 4, and 5 and 1, and a process for the preparation thereof which comprises condensing a halogen compound of general formula: CH3-(CH2)4-(C­CH2)s-X with an acid or ester of formula <FORM:0859897/IV(b)/2> group, s and t being integers from 0 to 4 but totalling 4, and X being a chlorine, bromine or iodine atom, in a Grignard reaction, in th presence of a copper or cuprous salt, hydrolysing the adamantyl group if present esterifying if desired, or selectively hydrogenating to the ethylenically unsaturated acid or alkyl ester. Specified compounds are 1-ethyloxy-carbonyloctadecadiyne-(9, 12), and -nonadecadiyne-(10, 13), 1-methoxycarbonyl-octadecatriyne -(6, 9, 12), docosapentayn- (4, 7, 10, 13, 16)-oic acid, octadecatriyne- (6, 9, 12)-oic-(1) acid, eicosatetrayn -(5, 8, 11, 14)-oic-(1) acid, and examples describe, their preparation and hydrogenation to the ethylenically unsaturated compounds such as linoleic, homolinoleic, y-linoleic, docosapentaen- (4, 7, 10, 13, 16)-oic, and arachidonic acids and esters. The acetylenic halogeno compounds are prepared in repeated stages from pentyl bromide by condensing with a dimagnesium bromide derivative of propargyl alcohol in the presence of cuprous chloride and brominating the resulting octyn-(2)-ol-(1) with phosphorus tribromide to form octyn-(2)-yl bromide. The 1-bromo-octyne -(2) may also be prepared by reacting acetylene with amyl bromide in loquid ammonia and condensing the resulting heptyne- (1) with formaldehyde in a Grignard reaction and hydrolysing the resulting magnesium bromide derivative of octyn-(2)-ol-1. The acetylenic acids are prepared by the condensation of an acid of general formula: <FORM:0859897/IV(b)/3> with propargyl halide in a Grignard reaction with copper or a cuprous salt; and the adamantyl hindered esters are prepared in stages from a nitrile of general formula: CH ­ C-CH2-(CH2)b-C ­ N byconverting into an imino ether hydrochloride with ethanol and hydrogen chloride, and reacting with ethanol and ether to yield ortho-ester which is reacted with cis 1, 3, 5-trihydroxycyclohexane in the presence of boron trifluoride etherate to give the hindered ortho ester which is condensed if necessary with propargyl halide in a Grignard reaction until the required chain length is obtained. The hydrogenation to the ethylenically unsaturated compounds is preferably by lead inhibited palladium catalysts. Specification 859,898 is referred to.

Inventors

• 👤 Osbond John Mervyn
• 👤 Philpott Peter George
• 👤 Wickens James Charles

Bibliographic Details