2,4-Dihydroxy-3-Methyl-Benzaldehyde Perfume Compositions

This invention relates to 2,4-dihydroxy-3-methyl-benzaldehyde perfume compositions. In the art of perfumery, the extracts of lichens such as those marketed under the name of "Oak Moss" have become indispensable and are widely used as materials for perfumes. The natural extracts of Oak Moss, however, have limited availability and are very expensive. Applicants have discovered that when 2,4-dihydroxy-3-methyl-benzaldehyde is combined with other perfume components, it serves as a substitute for "Oak Moss" in the combination of components which determine the odor note of various perfume compositions. In addition, this chemical not only simulates with great fidelity the characteristic odor note of Oak Moss, it is much less expensive than natural oak Moss or its synthetic simulations, and can be prepared from readily available materials in a one step synthesis. The discovery of the unexpected odor note imparted by this chemical when combined with other perfume components becomes even more significant since its value in perfumery could not be predicted from the knowledge of a closely related chemical such as 2,6-dihydroxy4-methyl-benzaldehyde (ATRENOL) which, for all practical purposes, is odorless and therefore valueless in perfumery.

In accordance with this invention, at least 1% by weight of 2,4-dihydroxy-3-methyl-benzaldehyde is mixed with at least 1% by weight of one or more other perfume components. Desirably, the amount of 2,4-dihydroxy-3-methyl-benzaldehyde is 0.1 to 15% by weight; preferably 0.5 to 10% by weight; and most advantageously 1 to 9% by weight of the perfume composition.

The other perfume component or components comprise in their entirety at least 1% by weight and preferably at least 10% by weight of the total perfume composition.

The 2,4-dihydroxy-3-methyl-benzaldehyde perfume compositions of this invention may be used in soaps, creams, sachets and other cosmetic or household products.

The 2,4-dihydroxy-3-methyl-benzaldehyde having the following chemical structure: ##SPC1##

Was prepared by Elfeed Thomas Jones and Alexander Robertson [Journal of the Chemical Society, London, page 1691 (1932)] by the condensation of 2,6-dihydroxytoluene with zinc cyanide and excess hydrogen chloride. It may be produced by placing 496 g of 2-methyl-resorcinol, 712 g of n-methyl-formanilide and 300 ml of benzene in a 3-necked five liter flask fitted with an agitator, reflux condenser, dropping funnel and thermometer. After a homogeneous solution is obtained by agitation at room temperature, 808 g of phosphorus oxychloride are added over a period of 2 hours, maintaining the reaction temperature at 25.degree.-30.degree.C. After the addition is completed, agitation is continued for about 4 hours at 25.degree.-30.degree.C with occasional cooling. During the reaction, 600 ml of benzene are added to the reaction mixture.

The reaction mixture is cooled in an isopropanol-dry ice bath. 100 ml of ice water are added in one portion to the reaction mixture, followed by the addition with agitation of 2000 ml of a 50% aqueous sodium acetate solution over a period of 50 minutes (exothermic) allowing the reaction temperature to rise to a maximum of 65.degree.C. The reaction mixture is cooled to 20.degree.C and 1000 ml of a 50% aqueous acetate solution (precooled to 25.degree.C) are added under agitation in one portion. 800 ml of ethyl acetate (solvent) are added. The mixture is agitated for about 5 minutes and permitted to separate into an aqueous part and an organic layer, which is washed with 200 ml of water. The solvent (ethyl acetate) is removed by distillation under vacuum from a steam bath. The crude reaction product is cooled to 20.degree.C and the formed crystals are filtered on a Buchner funnel. The crystals are recrystallized from a solution of 1000 ml of water and 600 ml of methanol.

To the mother liquor are added 300 ml of benzene and 100 ml of ether. The reaction mixture separates into two layers. The organic layer is washed three times with 200 ml portions of water and neutralized with a 10% aqueous solution of sodium bicarbonate. The solvent is removed by distillation from a steam bath under an ejector vacuum. The formed crystals are collected on a Buchner funnel and recrystallized from a solution of 200 ml of benzene and 100 ml of hexane.

The combined Crops (I and II) are placed in a 3 liter 3-necked flask with an agitator and 1500 ml of water are added. The product is steam distilled for approximately 1 hour. The steam distillation is necessary to remove traces of contaminants which give an off-odor to the product. From 426 g of the product, 420 g of 2,4-dihydroxy-3-methyl-benzaldehyde having a melting point of 151.5.degree.-152.5.degree.C result after distillation.

A more comprehensive understanding of this invention is obtained by reference to the following examples of perfume compositions: CHYPRE PERFUME COMPOSITIONS EXAMPLE I Parts by Weight ______________________________________ 2.5 Oak Moss Extract (Evernia) 2.5 2,4-Dihydroxy-3-Methyl Benzaldehyde 22.5 Oil of Bergamot 7.5 Oil Vetiver Bourbon 5.0 Oil of Lavender 7.0 Oil Sandalwood 1.0 Oil Patchouli 3.5 Oil of Cloves 10.0 Extract of Jasmine 8.0 Oil of Rose 7.0 Isobutyl Salicylate 5.0 Cinnamyl Alcohol 10.0 Heliotropin 5.0 Coumarin 2.0 Oleoresin Tonka Beans 1.5 Methyl Nonyl Acetaldehyde 100.0 ______________________________________

2,4-Dihydroxy-3-methyl benzaldehyde can replace partially or completely natural "Oak Moss" extract or any of the synthetic replacements of "Oak Moss". By adding any quantity of the chemical of this invention, the odor quality of natural "Oak Moss" may be achieved with great fidelity but with great reduction in cost.