Process for the preparation of timberone

#This application is the U.S. national phase of International Application No. PCT/EP2008/002120, filed 17 Mar. 2008, which designated the U.S., and claims priority to EP 07005910.0, filed 22 Mar. 2007, the entire contents of each of which are hereby incorporated by reference.

#This invention relates to a novel process for the preparation of timberone useful for perfume or cosmetics.

#Timberone is known to have a woody/amber-like odour which is highly appreciated by the fragrance industry.

#In a typical procedure for the aldol condensation citral (50 g, 91.4%, 300 mmol) and 2-pentanone (180 g, 90.0%, 1881 mmol) were stirred under argon in a 2-neck-flask at −10° C. Over 30 min a mixture of sodium (3.7 g, 161 mmol) in 68 ml ethanol was added. After the addition the mixture was stirred for 30 min at −10 to −5° C. A solution of tartaric acid (12.0 g, 99.5%, 80 mmol) in 60 ml of water was added. The aqueous phase was separated and the organic phase three times washed with a saturated aqueous NaCl solution (3×70 ml), dried with Na2SO4 and the solvent evaporated in vacuum. The raw product (81.2 g) was vacuum distilled. 8,12-Dimethyl-5,7,11-tridecatrien-4-one boils at 120-122° C. (3.1×10−1 mbar). Yield: 65.7% (50.3 g, 86.7%, determined by GC, E/Z-mixture).

#Alternative Procedure

#Citral (2.0 g, 95.0%, 12.5 mmol) and 2-pentanone (20 g, 99.0%, 229.9 mmol) were stirred under argon in a 2-neck-flask at 80° C. Afterwards, Ca/Na on silica (360 mg, 18 wt % on citral) was added. The mixture was stirred for 4 h at 80° C. After cooling to room temperature the mixture was filtered, the heterogeneous catalyst washed with 2-pentanone and all volatiles of the liquid phase were removed in vacuum (20 mbar, 40° C.). Yield: 87.5% (3.81 g, 63.3%, determined by GC, E/Z-mixture).