The general procedure for the synthesis of (R)-2-amino-2-(2-chlorophenyl)acetic acid from sodium cyanide and o-chlorobenzaldehyde is as follows: 2-chlorophenylglycine was prepared according to the synthetic method described in Scheme 1. This was done as follows: 2-chlorobenzaldehyde, ammonium bicarbonate (NH4HCO3; 23.7 g) and sodium cyanide (NaCN; 14.7 g) were dissolved in a mixed solution of 500 ml of methanol and 500 ml of water, and the reaction was stirred for 5 hours at 65-70 °C. Upon completion of the reaction, the solution was concentrated and transferred to an autoclave, where 45% sodium hydroxide (NaOH) solution was added and refluxed at 120°C for 4 hours. After the reaction mixture was cooled, 2 g of activated carbon was added and stirred for 10 minutes for decolorization. The activated carbon was removed by filtration and the pH of the filtrate was adjusted to 7-8 with 50% sulfuric acid (H2SO4).Subsequently, the precipitate was collected by filtration and washed with distilled water to give a final product of 27 g (58% yield) of 2-chlorophenylglycine. The compound had a specific optical rotation of +0.16 (C=1, 1N HCl) and a melting point of 185.4-186.8 °C.
