GB935412A - Production of ionine compounds - Google Patents

Abstract

Ionone compounds of the formulae <FORM:0935412/IV(a)/1> in which R1 is hydrogen or a methyl group, are prepared by a four-stage process in which (1) an unsaturated ketone of the formula <FORM:0935412/IV(a)/2> is ethinylated to yield an unsaturated ethinyl carbinol of the formula <FORM:0935412/IV(a)/3> (2) the ethinyl carbinol is treated with aliphatic, cycloaliphatic or araliphatic alcohol to yield a product of the formula <FORM:0935412/IV(a)/4> in which R2 is an aliphatic, cycloaliphatic or araliphatic radical, which (3) is reacted with an acetoacetio ester or with diketene to yield, after decarboxylation, a product of either of the formula <FORM:0935412/IV(a)/5> which (4) is then cyclicized to yield products of the first two formulae above. Reaction (1) may be effected with acetylene at a temperature between -60 and +120 DEG C. at atmospheric or raised pressure in the presence of a basic catalyst and optionally in a solvent, a number of catalysts and solvents being specified. Reaction (2) may be carried out at 0-120 DEG C. under acidic conditions, preferably in an excess of the alcohol. Specified alcohols for use in the reaction are methanol, ethanol, n- or iso-propyl, n- or iso-butyl alcohol, n- or iso-amyl alcohol, hexanol, allyl alcohol, crotyl alcohol, hexanediol-1,6, butanetriol-1,2,4-, glycol, methyl glycol, butyl glycol, glycerol, trimethylolpropane, cyclopentanol, cyclohexanol, benzyl alcohol and b -phenylethyl alcohol. Reaction (3) may be effected at 0-30 DEG C. and the decarboxylation of the intermediately formed acetoacetic ester may be effected in the liquid phase at 150-250 DEG C. Acid or alkaline substances and an inert solvent may be present during the decarboxylation, a number of acid or alkaline substances and inert solvents being specified. Alternatively, the decarboxylation may be effected in the vapour phase at 300-500 DEG C. The mixed isomers of the last two formulae above may be used as such or may be separated by distillation or by chromatography. Reaction (4) may be effected at a temperature of -80 to +80 DEG C. in an acid medium in the presence of a solvent, a number of acid media and solvents being specified. The reaction sequences may be modified by interchanging stages (1) and (2). The final products, and also the intermediates of the last three formulae above, are useful as perfumes. In examples of reactions (1) and (2), (a) 2-methylheptene-2-one-6 yields, successively, 2-methoxy-2-methylheptanone-6 and 2-methoxy-2,6-dimethyloctine-7-ol-6; (b) 2,6-dimethyloctene-2-ine-7-ol-6 yields 2-methoxy-2,6-dimethyloctine-7-ol-6. The corresponding 2-ethoxy, 2-n-butoxy, 2-(b -methoxyethoxy), 2-isopropoxy, 2-(b -hydroxyethoxy), 2-allyloxy and 2-(b -phenylethoxy) compounds are also described. In examples of reaction (3), 2,6-dimethyloctene-2-ine-7-ol-6 and methyl or ethyl acetoacetate or diketene yield a mixture of 2-methoxy-2,6-dimethylundecanediene- 6,7-one-10 and 2-methoxy-2,6-dimethylundecanediene-6,8-one-10, which may be fractionated. Mixtures of the corresponding 2-(b -hydroxyethoxy), 2-n-butoxy, 2-allyloxy and 2-(b -phenylethoxy) compounds are also described. In examples of reaction (4), (a) 2-methoxy-2,6-dimethyundecadiene-6,8-one-10 yields b -ionone, which is similarly obtainable from an isomeric mixture of 2-(b -hydroxyethoxy)-2,6-dimethylundecadiene-6,7-one-10 and 2-(b -hydroxyethoxy- 2,6-dimethylundecadiene-6,8-one-10; the corresponding isomers substituted with an allyloxy, a b -phenylethoxy, a b -methoxyethoxy or a butoxy group in the 2-position are similarly obtainable; (b) 2-methoxy- 2,3,6-trimethylundecadiene- 6,7-one-10 to yield b -irone.