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

Participants

Reaction Steps

A stirred mixture of L-aspartic acid (399 g.; 3.00 moles), benzyl alcohol (1.95 kg.; 18.0 moles), p-toluenesulfonic acid monohydrate (582 g.; 3.06 moles), and dry benzene (1.2 l.) was heated at reflux for 16 hours. The water formed in the reaction (145 ml.) was removed by means of a Dean-Stark trap. The resulting solution was cooled to room temperature, then diluted with benzene (1.2 l.) and ether (3.6 l.). The resulting solid was collected on a filter, washed with ether (7.0 l.), and dried; yield, 1195 g. (82%). The crude product was recrystallized from methanol (1720 ml.) to give 959 g. (80% recovery) of purified (I); m.p., 158°-159.5°; literature m.p., 158°-160°. Additional reactions were carried out to give a total of 4.27 kg. of product suitable for further transformation.

Provenance & Evidence