Unprecedented crystallization and X-ray crystal structure of racemic N(alpha)-(t-butyloxycarbonyl)-L-L-phenylalanine N-methoxy-N-methylamide.

X Zheng, I O Donkor, D D Miller, C R Ross

Index: Chirality 12(1) , 2-6, (2000)

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Abstract

Weinreb amide 3 was synthesized using isobutyl chloroformate, carbonyldiimidazole, or ethylcarbodiimide as the coupling agent in the reaction of Boc-phenylalanine with O,N-dimethylhydroxylamine hydrochloride. An optically active oil was isolated along with an optically inactive solid irrespective of the type of coupling agent used. Single crystal X-ray analysis of the solid revealed that it is a racemate. The molecular packing of the crystals reflect the stability of the racemate as opposed to an enantiomerically pure solid.Copyright 2000 Wiley-Liss, Inc.