Amino-acids and peptides. Part X. Characterisation of the monamycins, members of a new family of cyclodepsipeptide antibiotics
作者:K. Bevan、J. S. Davies、C. H. Hassall、R. B. Morton、D. A. S. Phillips
DOI:10.1039/j39710000514
日期:——
N-methyl-D-leucine, L-proline (or trans-4-methyl L-proline), D-isoleucine (or D-valine), (3R)-piperazic acid [or (3R,5S)-5-chloropiperazicacid, or (3R)-4,5 (or 5,6)-dehydropiperazic acid], and (3S,5S)-5-hydroxypiperazicacid. The name piperazic acid is assigned to hexahydropyridazine-3-carboxylic acid.
Twonovelcyclichexapeptides, designated NW‐G08 (1) and NW‐G09 (2), were isolated from the fermentation broth of Streptomycesalboflavus313. Their structures were elucidated on the basis of extensive spectroscopic analysis, MS experiments, and chemical analysis. Their antibacterial activities against several strains of bacteria were evaluated by micro‐broth dilution method. NW‐G08 (1) and NW‐G09
The short-step synthesis of the unsubstituted, 5-hydroxy- and 5-chloropiperidazine-3-carboxylic acids using an aza Diels-Alder reaction between the 1,3-diene and azodicarboxylate was described. This synthetic methodology could be used for the preparation of the optically active piperazic acid in a 35% overall yield.
Improved Synthesis of Cyclic <font>α</font>-Hydrazino Acids of Five- to Nine-Membered Rings and Optical Resolution of 5,6,7-Membered Ring Hydrazino Acids
to the diastereomers either via the formation of peptides with L-phenylalanine methyl ester or via the formation of esters (for five- to seven-memberedrings) with L-2-phenylalaninol. All diastereomers were separated except the nine-membered ring by flash chromatography. Hydrolysis of diastereomeric esters generated the optically pure five-, six- and seven-membered cyclic α-hydrazino acids. In this process