Enzymatic resolution of Cα-fluoroalkyl substituted amino acids
作者:Beate Koksch、Peter J.L.M. Quaedflieg、Thomas Michel、Klaus Burger、Quirinus B. Broxterman、Hans E. Schoemaker
DOI:10.1016/j.tetasy.2004.02.027
日期:2004.5
A methodology for the enzymatic resolution of sterically constrained C-alpha-fluoroalkyl substituted amino acids has been developed. Racemic H-(alphaTfm)Ala-NH2, H-(alphaCF(2)Cl)Ala-NH2 and H-(alphaCF(2)Br)Ala-NH2 was separated with very high enantio-selectivity (E >200) into their enantiomers using amidase from Mycobacterium neoaurum yielding the corresponding (R)-acids. Furthermore, the first example of an enzymatic resolution of a C-alpha-fluoroalkyl substituted Phe derivative has been established using amidase from Ochrobactrum anthropi. (C) 2004 Published by Elsevier Ltd.
Peptide Synthesis with α-(Difluoromethyl)-Substituted α-Amino Acids
作者:Thomas Michel、Beate Koksch、Sergei N. Osipov、Alexander S. Golubev、Joachim Sieler、Klaus Burger
DOI:10.1135/cccc20021533
日期:——
Methodology for the incorporation of α-(difluoromethyl)-substituted α-amino acids into N- and C-terminal positions of dipeptides as well as into position 2 of tri- and tetrapeptides is described.
A New Strategy for the Synthesis of α-Difluoromethyl-Substituted α-Hydroxy and α-Amino Acids
作者:Sergey N. Osipov、Alexander S. Golubev、Norbert Sewald、Thomas Michel、Alexey F. Kolomiets、Alexander V. Fokin、Klaus Burger
DOI:10.1021/jo9608331
日期:1996.1.1
A newmethod for the preparation of alpha-chlorodifluoromethyl-, alpha-bromodifluoromethyl-, and alpha-difluoromethyl-substituted alpha-hydroxy and alpha-amino acid esters 11, 19-21 is described. The key step of the synthesis is the regioselective alkylation of ketones 5, 7-9 and imines 16-18 with C-nucleophiles. The ketones 7-9 are readily available from 3,3,3-trifluorolactate 1 by a five-step procedure