Reference

Optically active

Optically active .alpha.-alkyl-.alpha.-amino acid derivatives. Yamada, Shunichi; Shioiri, Takayuki; Oguri, Tomei (Japan ). Japan. Kokai JP 51110502 30 Sep 1976 Showa,9 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C07B029-00. APPLICATION: JP 75-35211 24 Mar 1975. DOCUMENT TYPE: Patent CA Section: 34 (Synthesis of Amino Acids, Peptides, and Proteins) Section cross-reference(s): 30 Optically active .alpha.-alkyl-.alpha.-amino acid derivs. were prepd. by the reaction of optically active carbonyl compds. with .alpha.-amino acid alkyl esters, treatment of the resulting .alpha. 1845-25-6 and 338-69-2 which are cas registry numbers are also used here.-amino acid alkyl ester derivs. with alkali metal amides, and alkylation. Thus, a mixt. of (1S,2S,5S)-(-)-2-hydroxy-3-pinanone, H-Gly-OCMe3, and BF3-Et2O in benzene was refluxed for 4 h to give 83% N-[(1S,2S,5S)-2-hydroxy-3-pinanylidene]glycine tert-butyl ester (I). I in THF was added to Li diisopropylamide in THF at -74.degree. and the mixt. was stirred for 30 min. MeI was added to the resulting mixt. and it was kept at -74.degree. for 2.75 h to give, after treatment with Bz/pyridine, 52% Bz-D-Ala-OCMe3. Analogously, prepd. were N-benzoyl-D-leucine tert-Bu ester, D-phenylalanine tert-Bu ester, D-3,4-dimethoxyphenylalanine tert-Bu ester, N-benzoyl-D-alanine Et ester, (S)-N-acetyl-.alpha.-methylphenylanine tert-Bu ester, and (S)-N-acetyl-.alpha.-methyl-.beta.-(3,4-dimethoxyphenyl)alanine tert-Bu ester. .