Benzyl chloroformate → N-Cbz-d-alanine

Participants

Reaction Conditions

Reaction Steps

To a solution of 12.5 g. of D-alanine in 70 ml. of 2N sodium hydroxide, with ice cooling and stirring, is added in simultaneous dropwise addition 24 g. of benzyloxycarbonyl chloride and 35 ml. of 4N sodium hydroxide. The pH is maintained at 10 to 12 using a pH electrode in the reaction vessel. The reaction is stirred for one hour further at 4° C. and then extracted with 100 ml. of ethyl ether and acidified to pH 3 with concentrated hydrochloric acid. The product precipitates and is separated by filtration and dried in air; 23.5 g., m.p. 82°-85° C.; [α]D25 30 14.8° (c 1, 1N acetic acid). A second cup can be obtained from the filtrate by concentration and cooling.

Provenance & Evidence