Dodecylbenzenesulphonic acid → 2,3-dimethoxy-7,7-dimethyl-9-trifluoromethyl-7H-benzo[C]fluoren-5-ol

Participants

Reaction Steps

The products from Step 4 (1-(4-trifluoromethylphenyl)-2-(dimethylhydroxymethyl)-4-hydroxy-6,7-dimethoxynaphthalene and 1-(3,4-dimethoxyphenyl-2-(dimethylhydroxymethyl)-4-hydroxy-6-trifluoromethylnaphthalene, 51.7 grams) were placed in a reaction flask equipped with a Dean-Stark trap and 775 mL of toluene was added. The reaction mixture was stirred under a nitrogen atmosphere and dodecylbenzene sulfonic acid (8.3 grams) was added. The reaction mixture was heated to reflux for 5 hours. Upon cooling to room temperature the reaction mixture was concentrated by rotary evaporation. The resulting brown solid was slurried in 300 mL of 15% ethyl acetate/85% hexanes. The solid was collected by vacuum filtration yielding 35.1 grams of 2,3-dimethoxy-7,7-dimethyl-9-trifluoromethyl-7H-benzo[C]fluoren-5-ol. This material was not purified further but was used directly in the next step.

Provenance & Evidence