Verfahren zur Herstellung von sekundären Alkoholen

摘要

The invention comprises compounds of formula I in which R1 represents a C1-C10 hydrocarbon group, R2 represents a C1-C6 alkyl group or R1 and R2 together with the carbon atom to which they are attached form a carbocyclic ring, R3 represents a C1-C6 alkyl group, R4 represents a C1-C8 hydrocarbon group and R5 represents the acyl residue derived from a C1-C8 aliphatic or aromatic carboxylic acid, and wherein the broken lines denote that the substituents attached thereby are optional; and the corresponding compounds which are progressively more saturated commencing at the ethynyl group, with the proviso that R1 and R4 do not represent unsaturated groups when the ethynyl group and the 6,7-double bond are completely saturated. The compounds are obtained by ethynylating by known methods an aldehyde of formula V and, where required, subjecting the product to catalytic hydrogenation and/or esterification. In the formulae above R1 may be alkyl, particularly C1-C6 alkyl, or aromatic or araliphatic groups such as phenyl, benzyl or phenethyl; R4 may be alkyl, cycloalkyl, aryl, aralkyl or alkenyl; and R1 and R2 may form with the carbon atom to which they are attached a carbocyclic ring, e.g. cyclopentyl or a cyclohexyl ring. The acyl residue R5 may be derived, for example, from formic, acetic, propionic, butyric, isobutyric, benzoic, anthranilic, salicylic or phenylacetic acid. The preferred compounds are 3-hydroxy-7-methyl-octen-6-yne-(1); 3-hydroxy - 4,7 - dimethyl - octen - (6) - yne - (1); 3 - hydroxy - 4 - ethyl - 7 - methyl - octen - (6) - yne - 1; 3 - hydroxy - 6,7 - dimethyl - octen - (6) - yne - (1); 3 - hydroxy - 7 - isobutyl - octen -(6) - yne - (1); 3 - hydroxy - 6 - cyclohexylidine - hexyne - (1); 3 - hydroxy - 7 - methyl - octadiene - (1,6); 3 - hydroxy - 4 - ethyl - 7 - methyl - octadiene - (1,6); 3 - hydroxy - 6,7 - dimethyl - octadiene - (1,6); 3 - hydroxy - 7 - isobutyl - octadiene - (1,6); 3 - hydroxy - 6 - cyclohexylidine - hexene - (1); 3 - hydroxy - 4 - ethyl - 7 - methyl - octane - (6); 3 - hydroxy - 4 - ethyl - 7 - methyl octane and their acetates; 3-hydroxy-4,7 - dimethyl - octadiene - (1,6) and its acetate, propionate, isobutyrate and benzoate and 3-hydroxy - 4,7 - dimethyl - octene - (6) and its acetate, propionate and isobutyrate. The ethynylation of the starting aldehyde may be conveniently carried out by reaction with an acetylene reactant in liquid ammonia in the presence of sodium or lithium or by reacting the starting aldehyde with an acetylene-Grignard compound. The acetylene-carbinols obtained as products of the ethynylation step can be hydrogenated on the triple band by using a palladium/calcium carbonate catalyst partially deactivated with lead, a palladium(carbon catalyst deactivated by absorption of quinoline, colloidal palladium or Raney iron. The double bond may conveniently be hydrogenated using a palladium on carbon catalyst. The acetylene-carbinols or the more saturated carbinols may be esterified by reaction with an acid anhydride in the presence of an acid esterification catalyst such as sulphuric acid, phosphoric acid or p-toluene-sulphonic acid or with an acid chloride in the presence of a tertiary base such as pyridine or picoline. Ketene may also be used as the esterification agent for production of acetates. The new alcohols and esters are useful as odorants in scented compositions.