Dichloromethane → (1)-4-Fluorophenylglycine

Participants

Reaction Conditions

Reaction Steps

800 ml. of saturated ammonium hydroxide solution is slowly added to 67.6 g. (1.59 mmoles) of lithium chloride, 268.8 g. (4.79 moles) of potassium hydroxide is slowly added portionwise (the addition being exothermic), and a solution of 18.4 g. (0.81 mole) of benzyltriethylammonium chloride in 400 ml. of methylene chloride is added, the reaction mixture being stirred at 20°-25° C. under nitrogen throughout. The reaction mixture is cooled to 0° C., ammonia is bubbled in for 30 minutes with vigorous stirring, and, over a period of 1 hour, a solution of 99.2 g. (0.80 mole) of 4-fluorobenzaldehyde in a mixture of 400 ml. of methylene chloride and 102 ml. of chloroform is added dropwise while simultaneously bubbling in ammonia, the reaction mixture being stirred at 0° C. throughout. Ammonia is bubbled in for 5 hours with stirring at 0° C., and the reaction mixture is allowed to warm to 20°-25° C. and stirred at 20°-25° C. for 16 hours. The aqueous phase is separated, washed three times with 150 ml. portions of methylene chloride, concentrated to one half of its volume at reduced pressure and filtered. The filtrate is acidified to pH 6.5 with concentrated hydrochloric acid, and the resulting fine precipitate is collected by filtration, washed with 1.5 l. of water, washed with 500 ml. of ethanol, washed with 200 ml. of diethyl ether and dried to obtain the product as a fine white solid (40 g.). A previous batch melted at about 280° C. (softened at about 260° C.).

Provenance & Evidence