37784-23-9Relevant articles and documents
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Touet, Joel,Faveriel, Laurent,Brown, Eric
, p. 1709 - 1720 (2007/10/02)
Treatment of the readily available (S)-(+) and (R)-(-) enantiomers of 2-aminobutan-1-ol 1 with sodium hydride followed by benzyl chloride, or a substituted benzyl halide, afforded the corresponding O-benzyl bases 4-7 in good yields. These new bases are recommended for the large scale resolution of racemic acids. For instance, they proved efficient for the practical resolutions of α-methylsuccinic acid (±)-9, N-acetylphenylglycine (±)-11, N-acetyl-(4-hydroxyphenyl) glycine (±)-14 and N-chloroacetyl-(4-hydroxyphenyl) glycine (±)-15.
Racemization of Optically Active Aromatic N-Acetylamino Acids and Asymmetric Transformation of N-Acetyl-2-(4-hydroxyphenyl)glycine via Salt Formation with Optically Active α-Methylbenzylamine
Shiraiwa, Tadashi,Sakata, Shinji,Natsuyama, Hisashi,Fujishima, Keiko,Miyazaki, Hideya,et al.
, p. 965 - 970 (2007/10/02)
The racemization rates of N-acetyl-(S)-tyrosine, N-acetyl-(S)-phenylalanine, N-acetyl-(R)-2-(4-hydroxyphenyl)glycine , N-acetyl-(R)-2-phenylglycine, and N-acetyl-(S)-alanine were measured by use of (RS)-α-methylbenzylamine as base-catalyst.The first-order rate constant for racemization tended to increase with an increase in the polar substituent constant of the N-acetylamino acid side chain.The racemization appeared to be subject to the inductive effect by the side chain.An asymmetric transformation of (RS)-AcHpg by using (R)-MBA, based on the result of racemization, gave an optically pure salt of (R)-AcHpg with (R)-MBA by successive use of the filtrate as the solvent.Optically pure (R)-2-(4-hydroxyphenyl)glycine was separated from the salt in 87-90percent yield based on the starting (RS)-AcHpg.In addition, the asymmetric transformation of (R)-AcHpg was achieved by using (S)-MBA to give optically pure (S)-Hpg in 80percent yield after purification of the salt of (S)-AcHpg with (S)-MBA followed by hydrolysis.
