Unprecedented crystallization and X-ray crystal structure of racemic N(alpha)-(t-butyloxycarbonyl)-L-L-phenylalanine N-methoxy-N-methylamide.
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.
Zheng
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Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee, Memphis, TN 38163, USA.
Donkor
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Miller
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Ross
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D002154:Calpain / Q000037:antagonists & inhibitors; D002234:Carbodiimides / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D018360:Crystallography, X-Ray; D015853:Cysteine Proteinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry*; D005561:Formates / Q000737:chemistry; D008970:Molecular Weight; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism
D002234:Carbodiimides; D003432:Cross-Linking Reagents; D015853:Cysteine Proteinase Inhibitors; D005561:Formates; C403673:N-butyloxycarbonyl-phenylalanine N-methoxy-N-methylamide; D010649:Phenylalanine; C039311:isobutyl chloroformate; D002154:Calpain