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A Grignard reagent was prepared by the dropwise addition of a solution of 25 g of 3,4-difluorobromobenzene in 100 ml of tetrahydrofuran to 3.5 g of magnesium. The reagent mixture was filtered through a glass filter, and following the addition of 150 ml of toluene to the filtrate, approximately 100 ml of solvent was removed under reduced pressure, at room temperature. The mixture was then heated to 60° C., and a solution of 27 g of 6-bromo-1,2,3,4-tetrahydronaphthalen-2-one in 50 ml of toluene was added dropwise over a period of 20 minutes. The resulting mixture was stirred for a further 30 minutes, returned to room temperature, and then poured into a 10% hydrochloric acid solution. The organic layer was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, and then concentrated. The thus obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=6/1) and yielded 29 g of 6-bromo-2-(3,4-difluorophenyl)-2-hydroxy-1,2,3,4-tetrahydronaphthalene. To this product was added 100 ml of toluene and 3 g of p-toluenesulfonic acid, and the resulting mixture was stirred with heating for one hour. The reaction solution was then cooled and concentrated, and the residue purified by silica gel column chromatography (hexane) to obtain 26 g of 6-bromo-2-(3,4-difluorophenyl)-3,4-dihydronaphthalene. To this product was added 50 ml of ethanol, 50 ml of ethyl acetate and 3 g of 5% rhodium-carbon, and the resulting mixture was stirred under an atmosphere of hydrogen for 2 hours at room temperature. The reaction mixture was then filtered through celite, and the filtrate concentrated by removal of the solvent. The residue was purified by silica gel column chromatography (hexane), and yielded 26 g of 6-bromo-2-(3,4-difluorophenyl)-1,2,3,4-tetrahydronaphthalene. A Grignard reagent was then prepared by the dropwise addition of a solution of this 26 g of 6-bromo-2-(3,4-difluorophenyl)-1,2,3,4-tetrahydronaphthalene in 70 ml of tetrahydrofuran to 2.3 g of magnesium. A solution of 13.5 g of 4-propylcyclohexanone in 30 ml of tetrahydrofuran was then added dropwise to this reagent. The resulting mixture was stirred for a further 30 minutes, and then poured into a 10% hydrochloric acid solution. The organic layer was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, and then concentrated. The thus obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=6/1) and yielded 23 g of 2-(3,4-difluorophenyl)-2-hydroxy-6-(trans-4-propylcyclohexyl)-1,2,3,4-tetrahydronaphthalene. To this product was added 80 ml of toluene and 2 g of p-toluenesulfonic acid, and the resulting mixture was stirred with heating for one hour. The reaction solution was then cooled and concentrated, and the residue purified by silica gel column chromatography (hexane) to obtain 26 g of 2-(3,4-difluorophenyl)-6-(trans-4-propylcyclohexyl)-3,4-dihydronaphthalene. To this product was added 30 ml of ethanol, 50 ml of ethyl acetate and 2 g of 5% palladium-carbon, and the resulting mixture was stirred under an atmosphere of hydrogen for 2 hours at room temperature. The reaction mixture was then filtered through celite, and the filtrate concentrated by removal of the solvent. 50 ml of dimethyl formamide and 5.5 g of potassium t-butoxide were then added to the residue, and the mixture was stirred for 2 hours at 70° C. 10% hydrochloric acid was then added to the reaction mixture, which was then extracted with toluene, and the extracted organic layer was then washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate and concentrated by removal of the solvent. The residue was purified by silica gel column chromatography (hexane), and then recrystallized from ethanol, and yielded 20 g of 2-(3,4-difluorophenyl)-6-(trans-4-propylcyclohexyl)-1,2,3,4-tetrahydronaphthalene. This compound displayed a purity of 99.8% when analyzed by gas chromatography, and had a molecular weight of 368.

1. washThe organic layer was washed with a saturated aqueous solution of sodium chloride
2. dry with materialdried over anhydrous sodium sulfate
3. concentrationconcentrated
4. customThe thus obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=6/1)