METHOD FOR PREPARING OPTICALLY ACTIVE 5-METHYL-2- (1-METHYL-BUTYL)-5-PROPYL-1,3-DIOXAN

• Main Authors: MERKEL, DIRK, MARKERT, THOMAS, ALTENBACH, HANS-JOSEF
• Format: Patent
• Language: English; French; German
• Published: 09.06.2004
• Edition: 7
• Subjects: ANIMAL AND VEGETABLE OILS, FATS, FATTY SUBSTANCES AND WAXES; CANDLES; CHEMISTRY; DETERGENTS; ESSENTIAL OILS; FATTY ACIDS THEREFROM; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY; PERFUMES; PRODUCING (PRESSING, EXTRACTION), REFINING AND PRESERVINGFATS, FATTY SUBSTANCES (e.g. LANOLIN), FATTY OILS AND WAXES,INCLUDING EXTRACTION FROM WASTE MATERIALS

The present invention relates to a method for preparing optically active 5-methtyl-2-(1-methtyl-butyl)-5-propyl-1,3-dioxan, wherein said method comprises the following steps: converting lactic acid methylic ester into the corresponding N,N-disubstituted amid (aminolysis with piperidine and/or pyrrolidine); protecting its free OH function by a reaction with ethylvinylether in the presence of p-pyridiniumtosylate as a catalyst; submitting the N-pentamethylen- or N-tetramethylenlactamide thus obtained to a Grignard reaction in a conventional way so as to produce the corresponding alpha, beta-unsaturated ketone; further separating in a conventional way (e.g. agitation with acetic acid) the protection group introduced during the second step; acetalating in a conventional way the ketone function (e.g. by reaction with 2-methyl-2-propyl-1,3-propanediol); mesylating the free OH function by reaction with methansulfonic acid chloride in pyridine; submitting the intermediate thus obtained to a reducing 1,2-transposition in the presence of trimethylammonium and diisobutylaluminum hydride while maintaining the sterochemistry; and converting by catalytic hydrogenation the dehydro compound thus abtained into optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan. The optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan of the present invention exhibits a remarkable scent profile as well as a high scent intensity and may be used as perfume.