Hydrochloric Acid → 2-[4-(2-Hydroxycyclohexylidenemethyl)phenyl]propionic acid

Participants

Reaction Steps

2.0 g of (+)-2-[4-(2-oxocyclohexylidenemethyl)phenyl]-propionic acid and 0.6 g of sodium cyanoborohydride were dissolved in 50 ml of methanol. The pH of the mixture was adjusted to a value of 3 with 6N hydrochloric acid, whilst ice-cooling. The mixture was then stirred, with heating, for 40 minutes. Ice-water was added to the reaction mixture, which was then extracted with diethyl ether. The extract was washed with water and dried over anhydrous sodium sulphate, and the solvent was distilled off, to give 350 mg of (±)-2-[4-(2-hydroxycyclohexylidenemethyl)phenyl]propionic acid as crystals [compound of formula (VI)]. These crystals were dissolved in 10 ml of ethyl acetate, 50 mg of palladium chloride were added, and the mixture was subjected to catalytic reduction whilst bubbling hydrogen through the mixture. After the theoretical amount of hydrogen had been absorbed, the catalyst was removed by filtration and the solvent was distilled off, to give 330 mg of a mixture of the cis- and trans-isomers. This mixture was treated in the same manner as in Example 1, affording crystals of the cis- and trans-isomers of the title compound, having the same properties as the product of Example 1.

Provenance & Evidence