Potassium Cyanide → 3-Cyano-3-phenylpropanoic acid

Participants

Reaction Steps

A solution of benzalmalonate (124 g., 0.5 mole) in ethanol (560 ml.) and water (240 ml.) was heated at reflux for 60 hours with potassium cyanide (45 g., 0.7 mole). The solution was cooled, concentrated to remove ethanol, and then acidified with concentrated hydrochloric acid. The product was extracted with dichloromethane, and the extracts were washed with brine, dried over anhydrous sodium sulfate, and concentrated. The residue was dissolved in ethyl acetate (500 ml.) and treated with dicyclohexylamine (82 ml.) to yield 118 g. (67%) of white crystals which were collected by filtration and washed sequentially with ethyl acetate and ether and dried. A suitable cation-exchange resin in the acid form, such as Dowex® 50x8-100 ion-exchange resin, (20 g.) was washed with acetone and suspended in methanol (130 ml.) with dicyclohexylammonium salt (15 g.). After stirring at ambient temperature for 1 hour, the cation exchange resin was removed by filtration and the filtrate was concentrated to yield 3-cyano-3-phenylpropionic acid as an oil.

Provenance & Evidence