Synthesis of Transition-State Inhibitors of Chorismate Utilizing Enzymes from Bromobenzene cis-1,2-Dihydrodiol

J Org Chem. 2017 Apr 7;82(7):3432-3440. doi: 10.1021/acs.joc.6b02801. Epub 2017 Mar 17.

Abstract

In order to survive in a mammalian host, Mycobacterium tuberculosis (Mtb) produces aryl-capped siderophores known as the mycobactins for iron acquisition. Salicylic acid is a key building block of the mycobactin core and is synthesized by the bifunctional enzyme MbtI, which converts chorismate into isochorismate via a SN2″ reaction followed by further transformation into salicylate through a [3,3]-sigmatropic rearrangement. MbtI belongs to a family of chorismate-utilizing enzymes (CUEs) that have conserved topology and active site residues. The transition-state inhibitor 1 described by Bartlett, Kozlowski, and co-workers is the most potent reported inhibitor to date of CUEs. Herein, we disclose a concise asymmetric synthesis and the accompanying biochemical characterization of 1 along with three closely related analogues beginning from bromobenzene cis-1S,2S-dihydrodiol produced through microbial oxidation that features a series of regio- and stereoselective transformations for introduction of the C-4 hydroxy and C-6 amino substituents. The flexible synthesis enables late-stage introduction of the carboxy group and other bioisosteres at the C-1 position as well as installation of the enol-pyruvate side chain at the C-5 position.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bromobenzenes / chemical synthesis
  • Bromobenzenes / chemistry
  • Bromobenzenes / pharmacology*
  • Cyclohexenes / chemical synthesis
  • Cyclohexenes / chemistry
  • Cyclohexenes / pharmacology*
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Lyases / antagonists & inhibitors*
  • Lyases / metabolism
  • Molecular Structure
  • Mycobacterium tuberculosis / enzymology*
  • Structure-Activity Relationship

Substances

  • Bromobenzenes
  • Cyclohexenes
  • Enzyme Inhibitors
  • 3-bromo-3,5-cyclohexadiene-1,2-diol
  • Lyases
  • salicylate synthetase