Synthesis and Structural Investigation of Internally Coordinated α-Amidoboronic Acids
摘要:
Six new N-acyl-boroGly derivatives, along with their N-acyl-boroSar analogues, have been synthesized by modification of conventional procedures. Structural characterization of these alpha-amidoboronic acids was accomplished by extensive use of B-11 and H-1 NMR spectroscopy. These compounds were prepared to determine the extent of intramolecular B-O dative bond formation within the context of a five-membered (:O=C-N-C-B) ring motif. It is shown that the formation of such dative bonds depends on the nature of the substituents at both the acyl carbon and the nitrogen atoms. Computational evidence from second-order Moller-Plesset perturbation theory is provided in support of these findings.
In response to the widespread use of beta-lactam antibiotics bacteria have evolved drug resistance mechanisms that include the production of resistant Penicillin Binding Proteins (PBPs). Boronic acids are potent beta-lactamase inhibitors and have been shown to display some specificity for soluble transpeptidases and PBPs, but their potential as inhibitors of the latter enzymes is yet to be widely explored. Recently, a (2,6-dimethoxybenzamido) methylboronic acid was identified as being a potent inhibitor of Actinomadura sp. R39 transpeptidase (IC50: 1.3 mu M). In this work, we synthesized and studied the potential of a number of acylaminomethylboronic acids as inhibitors of PBPs from different classes. Several derivatives inhibited PBPs of classes A, B and C from penicillin sensitive strains. The (2-nitrobenzamido) methylboronic acid was identified as a good inhibitor of a class A PBP (PBP1b from Streptococcus pneumoniae, IC50 = 26 mu M), a class B PBP (PBP2xR6 from Streptococcus pneumoniae, IC50 = 138 mu M) and a class C PBP (R39 from Actinomadura sp., IC50 = 0.6 mu M). This work opens new avenues towards the development of molecules that inhibit PBPs, and eventually display bactericidal effects, on distinct bacterial species. (C) 2012 Elsevier Ltd. All rights reserved.
Synthesis and Structural Investigation of Internally Coordinated α-Amidoboronic Acids
作者:Jack H. Lai、Yuxin Liu、Wengen Wu、Yuhong Zhou、Hlaing H. Maw、William W. Bachovchin、Krishna L. Bhat、Charles W. Bock
DOI:10.1021/jo051757h
日期:2006.1.1
Six new N-acyl-boroGly derivatives, along with their N-acyl-boroSar analogues, have been synthesized by modification of conventional procedures. Structural characterization of these alpha-amidoboronic acids was accomplished by extensive use of B-11 and H-1 NMR spectroscopy. These compounds were prepared to determine the extent of intramolecular B-O dative bond formation within the context of a five-membered (:O=C-N-C-B) ring motif. It is shown that the formation of such dative bonds depends on the nature of the substituents at both the acyl carbon and the nitrogen atoms. Computational evidence from second-order Moller-Plesset perturbation theory is provided in support of these findings.