Hydrochloric Acid → HCID 178466299, compound

Participants

Reaction Conditions

Reaction Steps

4-Ethoxy-2,3-difluorobenzyltriphenylphosphonium chloride (11) (dried; 24.9 g) and THF (100 ml) were mixed under a nitrogen atmosphere and cooled to −10° C. Then, potassium t-butoxide (t-BuOK) (5.4 g) was added thereto in twice in the temperature range of −10° C. to −5° C. The stirring was continued at −10° C. for 60 minutes, and then the compound (18) (10.0 g) dissolved in THF (30 ml) was added thereto dropwise in the temperature range of −10° C. to −5° C. The stirring was continued at 0° C. for 30 minutes, and then the reaction mixture was poured into a mixture of water (100 ml) and toluene (50 ml), and mixed. The mixture was then allowed to separate into organic and aqueous phases, and the extraction into an organic phase was carried out. The organic phase obtained was washed with water and dried over anhydrous magnesium sulfate. The solution obtained was concentrated under reduced pressure and the residue obtained was purified with a fractional operation by means of column chromatography (silica gel; toluene). The eluent obtained was concentrated under reduced pressure. Sodium benzenesulphinate dihydrate (2.6 g) was added, with stirring, to obtained light yellow crystals in Solmix A-11 (20 ml) and then 6N-hydrochloric acid (2.2 ml) was added, and the mixture was heated under reflux for 5 hours. The reaction mixture was cooled to 30° C., and water (100 ml) and toluene (100 ml) were added to the mixture obtained, and mixed. The mixture was then allowed to separate into organic and aqueous phases, and the extraction into an organic phase was carried out. The obtained organic phase were washed sequentially with water, aqueous 0.5 N-sodium hydroxide solution, a saturated aqueous solution of sodium hydrogencarbonate, and dried over anhydrous magnesium sulfate. The solution obtained was concentrated under reduced pressure and the residue obtained was purified by means of column chromatography (silica gel; heptane: toluene=2:3 by volume), and the eluent was concentrated under reduced pressure. The residue obtained was purified by means of recrystallization (heptane: Solmix=3:2 by volume), giving 10.6 g of 2,3-difluoro-4-ethoxy-[trans-4-(2,3-difluoro-4-ethoxyphenylethenyl)cyclohexyl]benzene (No. 228). The yield based on the compound (18) was 67.5%.

Provenance & Evidence