Thioester analogues of peptidoglycan fragment MurNAc-L-Ala-γ-D-Glu as substrates for peptidoglycan hydrolase MurNAc-L-Ala amidase
作者:Ross L. Harding、Joanne Henshaw、Joannah Tilling、Timothy D. H. Bugg
DOI:10.1039/b200921h
日期:2002.7.11
MurNAc-L-amidase is one of a family of peptidoglycan hydrolases which catalyses the breakdown of bacterial peptidoglycan. Analogues of the peptidoglycan fragment MurNAc-L-Ala-γ-D-Glu containing S-thiolactic acid in place of L-alanine were synthesised as thioester substrates for this enzyme. Triphenylmethanethiol was used to develop a stereoselective synthesis of S-thiolactic acid, which was elaborated synthetically into MurNAc-dipeptide analogues. MurNAc-S-thioacetyl-N-propylamide 13 and MurNAc-S-thiolactyl-2R-alaninamide 16 were found not to be substrates for recombinant MurNAc-L-Ala amidases CwlA from Bacillus subtilis and Ply21 from bacteriophage TP21, however, turnover of tripeptide thioester S-propionylthiolactyl-γ-D-Glu-L-Lys-OMe 21 was observed using amidase Ply21. Therefore, recognition of the amino acid at position 3 of the pentapeptide sidechain appears to be important for enzymatic turnover.
[EN] METHOD OF CONVERTING ALCOHOL TO HALIDE<br/>[FR] PROCÉDÉ DE CONVERSION D'UN ALCOOL EN HALOGÉNURE
申请人:UNIV SAARLAND
公开号:WO2016202894A1
公开(公告)日:2016-12-22
The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
Catalytic Phosphorus(V)-Mediated Nucleophilic Substitution Reactions: Development of a Catalytic Appel Reaction
作者:Ross M. Denton、Jie An、Beatrice Adeniran、Alexander J. Blake、William Lewis、Andrew M. Poulton
DOI:10.1021/jo201085r
日期:2011.8.19
from stoichiometric waste products into catalysts and a new concept for catalytic phosphorus-based activation and nucleophilicsubstitution of alcohols has been validated. The present study has focused on a full exploration of the scope and limitations of phosphine oxide catalyzed chlorination reactions as well as the development of the analogous bromination reactions. Further mechanistic studies, including