Benzene → L-Aspartic acid, 1,4-bis(phenylmethyl) ester, 4-methylbenzenesulfonate (1:1)

Participants

Reaction Steps

A stirred mixture of L-aspartic acid (1197 g.; 9.000 moles), benzyl alcohol (5850 g.; 54.00 moles), p-toluenesulfonic acid monohydrate (1746 g.; 9.180 moles), and benzene (3.6 l.) was heated at reflux for 12 hours. The water formed in the reaction (480 ml.) was removed by means of a Dean-Stark trap. The reaction solution was cooled to room temperature then diluted with benzene (3.6 l.) and ether (10.8 l.). The resulting solid was collected on a filter, washed with ether (12.0 l.), and air dried; yield, 3646 g. (83.4%). Recrystallization of this material from methanol (6.0 l.) afforded purified (I); m.p., 158.5°-160.5°; literature m.p., 158°-160°. Four additional esterifications and recrystallizations were carried out on the same scale. The material from the five runs was combined to give 10,310 g. (57.6% recovery) of product suitable for further transformation.

Provenance & Evidence