Sodium Hydroxide → [1R*,8S*,9aR*]5,6-Dimethoxy-8-phenyl-2,3,7,8,9,9a-hexahydrophenalene-1-carboxylic acid

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Reaction Steps

Crude [1R,8S,9aR]-1-carbomethoxy-5,6 dimethoxy 2,3,7,8,9,9a-hexahydro-8-phenyl-phenalene (0.8 g, 2.1 mmol) from Step 4, was dissolved in 100 mL of methanol and 8 mL of 1N aqueous sodium hydroxide was added. After stirring for 3 days at ambient temperature, the methanol was removed from the reaction mixture under reduced pressure. The residue was partitioned between 50 mL of diethyl ether and 75 mL of water. The aqueous phase was acidified to pH 2 with 6M hydrochloric acid solution and extracted with 3×25 mL of 1:1 ethyl acetate:diethyl ether. The combined organic layers were washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to give 0.74 g (100% yield) of the title compound as an oil. DCI MS: (M+H)+ 253. 1H NMR (CDCl3) delta 2.0-2.3 (m, 2H), 2.65-2.85 (m, 2H), 2.9-3.1 (m, 6H), 3.2-3.3 (m, 1H), 3.73 (s, 3H), 3.83 (s, 3H), 6.56 (s, 1H), 7.2-7.4 (m, 5H).

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