Optical Resolution and Asymmetric Transformation of (RS)-N-Alkyl- and (RS)-N,N-Dialkyl-2-phenylglycines

• Published in: Bulletin of the Chemical Society of Japan Vol. 66; no. 5; pp. 1430 - 1437
• Main Authors: Shiraiwa, Tadashi, Baba, Yoshihisa, Miyazaki, Hideya, Sakata, Shinji, Kawamura, Seiko, Uehara, Masashi, Kurokawa, Hidemoto
• Format: Journal Article
• Language: English
• Published: Tokyo The Chemical Society of Japan 01.05.1993; Chemical Society of Japan
• Subjects: Chemistry; Exact sciences and technology; Noncondensed benzenic compounds; Organic chemistry; Preparations and properties; Solvent effect; Substituent effect; α-Aminoacid; Optical resolution; Racemization; Benzenic compound; Tartaric acid; Butyric acid
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.66.1430

Optical resolution of (RS)-N-methyl-2-phenylglycine [(RS)-Mpg] and (RS)-N-ethyl-2-phenylglycine [(RS)-Epg] was carried out by using (1S)-10-camphorsulfonic acid [(S)-CS] as resolving agents, and that of (RS)-N-ethyl-N-methyl-2-phenylglycine [(RS)-Emp] by (R)- and (S)-1-phenylethylamine. Racemization rates of optically active Mpg, Epg, Emp, N,N-dimethyl-2-phenylglycine [Dmp], and six α-amino acids were measured by heating in carboxylic acids. The electron-donating amino acid side chain and N-substituted alkyl group decreased the rate to inhibit the formation of intermediary carbanions, whereas the electron-withdrawing side chain increased it. Asymmetric transformation of (RS)-Mpg, (RS)-Epg, and (RS)-Dmp was carried out on the basis of the results of optical resolution and racemization to give the corresponding enantiomers of approximately 100% optical purities in over 70% yield based on the starting racemates.