GB807616A - Products having ambergris aroma and a process of making same - Google Patents

Abstract

Oxygen-containing products having ambergris aroma are produced by a process comprising (a) gradually adding while stirring a solution of chromium trioxide in acetic acid to a solution of sclareol in acetic acid at a temperature not substantially exceeding 60 DEG C., e.g. between about 40 DEG and 60 DEG C., the amounts of chromium trioxide added being equivalent to an amount not exceeding about 6 atoms of oxygen per 1 mol. of sclareol, or (b) gradually adding, while stirring, an aqueous acid solution of an alkali metal dichromate in an amount corresponding to not more than 7 atoms of oxygen per 1 mol. of sclareol in a substantially non-oxidizable organic solvent at a temperature not substantially exceeding 60 DEG C., or (c) gradually adding, while stirring, a solution of chromium trioxide in mineral acid to a solution of sclareol in benzene at a temperature between about 40 DEG and 60 DEG C., the amount of chromium trioxide being equivalent to an amount between about 3 and about 7 atoms of oxygen per 1 mol. of sclareol and recovering the odoriferous oxidation product having ambergris aroma from the oxidation mixture. Alternatively derivatives of 2,5,5,9-tetramethyldecahydronaphthalene, other than sclareol, which have an hydroxyl group in the 2-portion or dehydration products thereof wherein the hydroxyl group is split off to form a double bond in the 1,2-position or a methylene group in the 2-position, for example manool, may be employed as starting materials instead of sclareol in the above process. The starting material may have a hydrocarbon substituent in the 1-position as in ambrein. In examples: sclareol is oxidized with chromium trioxide in acetic acid solution, the oxidation products are extracted from the reaction mixture and distilled under vacuum in the presence of copper bronze and fractionated; a fraction containing carbonyl groups is isolated (1); sclareol is oxidized with a solution of sodium dichromate in aqueous sulphuric acid and the product is worked up similarly (2); sclareol is oxidized in a process similar to (1), (3); sclareol is oxidized in a process similar to (2), carbonyl compounds are separated from the product with Girard's carbonyl reagent T, and a residue containing an hydroxy compound is obtained; acids are also extracted from the crude oxidation, optionally after distillation, with potash or soda solution, the extract is acidified and the acids obtained, or the esters thereof e.g. obtained by esterification with diazomethane are reduced to primary alcohols with lithium aluminium hydride or sodium and isoamyl alcohol (4); sclareol is oxidized in processes similar to (2), (5) and (6); sclareol in benzene solution is oxidized with chromic acid in aqueous sulphuric acid and the products are worked up as in (2), (7); and manool is oxidized instead of sclareol in processes otherwise similar to (1)-(6), (8). In general the ambergris odour of the product is increased by splitting off acetic acid, e.g. by storage in air or by vacuum distillation other catalysts for optional use being sebacic and myristic acids, brass, bronze and aluminium oxides, which may be active. Other inert organic solvents mentioned are toluene xylene, petroleum ether, hexane, gasoline, dioxane and tetrahydrofuran. The reduction of the acid fraction may also be carried out with sodium under benzene, toluene or xylene in alcohol.