Determination ofD-amino acids. II. Use of a bifunctional reagent, 1,5-difluoro-2,4-dinitrobenzene

Abstract

Keywords: D-amino acids, bifunctional reagent, diastereomers l-fluoro-2,4-dinitrophenyl-5-L-alanine amide has been synthesized in high yield (76%) from 1,5-difluoro-2,4-dinitrobenzene and L-AIa-NH2. This compound contains a reactive fluorine atom which can be used for the reaction with a mixture of L-and D-amino acids. The resulting diastereomers which are obtained in quantitative yield can be separated and estimated by HPLC. With the five amino acids studied (Ala, Asp, Glu, Met and Phe), L-diastereomers were eluted from the reverse-phase column before D-diastereomers. This behavior can be explained by a stronger i ntramolecular hydrogen bonding in the latter diastereomer. When artificial mixtures of the five amino acids containing known proportions of L-and D-isomers were derivatized with the reagent and the reaction products analyzed by HPLC, it was possible to determine the relative content of each isomer in a nanomole range.

Isolation and characterization of a new iturinic lipopeptide, mojavensin A produced by a marine-derived bacterium Bacillus mojavensis B0621A

“…As described for Marfey's method, 29 lipopeptides (1 mg) were hydrolyzed with 6 N HCl (1 ml) at 110 1C for 24 h, and were then dried in a vacuum. The hydrolyzes were added to H 2 O (50ml), 1% (w/v) FDAA (Marfey's reagent, 100 ml) in acetone and 1 M NaHCO 3 (20 ml).…”

Bioactive Cyclic Peptides from the Psychrotolerant Fungus Penicillium algidum

“…The absolute stereochemistry of 1 was determined by hydrolysis and HPLC comparison of the Marfey's [5] derivative with standards derived from authentic R-and Sleucine. This revealed the leucine moiety to have the Sconfiguration.…”

A new cytotoxic indole-3-ethenamide from the halotolerant fungus Aspergillus sclerotiorum PT06-1

“…The absolute configuration of N-methylvaline unit was determined as L-by Marfey's method. 14 The FDAA derivatives of the acid hydrolysates of 1 gave the same retention time as that prepared from authentic N-Me-L-Val in HPLC analysis (Supplementary Figure S1). Thus, structure of 1 was determined to be (S,E)-…”