title: Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution.
abstract: Both epimers of the naturally occurring nonproteinogenic amino acid L-cyclopentenylglycine, (2S,1'S)- and (2S, 1'R)-2-(cyclopent-2'-enyl)glycine, were obtained via a procedure involving condensation of 3-chlorocyclopentene with diethyl acetylaminomalonate, deethoxycarbonylation, chromatographic separation of the resulting two pairs of enantiomers, and enzymatic resolution of the racemates employing enantioselective hydrolysis of the ethyl ester group with alpha-chymotrypsin. The method was used for preparation of (13)C-labeled compounds of interest for biosynthetic tracer experiments. Enantiomeric purity of the products was determined by chiral HPLC on a Crownpak CR(+) column. The biologically active (2S,1'R) isomer was obtained as a pure compound and characterized for the first time. The (2R,1'R) and (2R,1'S) isomers were obtained as N-acetyl ethyl ester derivatives.
authors.affiliation: Department of Medicinal Chemistry, The Royal Danish School of Pharmacy, Copenhagen, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Andersen
authors.forename: B
authors.initials: B
authors.lastname: Nielsen
authors.forename: J W
authors.initials: JW
authors.lastname: Jaroszewski
mesh_terms: D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin; D005998:Glycine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism
chemical_list: D002247:Carbon Isotopes; C026228:cyclopentenylglycine; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; D005998:Glycine