Referenced in: none

Automatically associated channels: TRP , TRPV , TRPV1

Title: Synthesis of Redshifted Azobenzene Photoswitches by Late-Stage Functionalization.

Authors: David B Konrad, James A Frank, Dirk Trauner

Journal, date & volume: Chemistry, 2016 Feb 17 , ,

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/26889884

Abstract
Azobenzenes are versatile photoswitches that can be cycled between their trans- and cis-configuration with light. The wavelengths required for this isomerization are substantially shifted from the UV to the visible range through tetra-ortho-chlorination. These halogenated azobenzenes display unique photoswitching characteristics, but their syntheses remain limited and inefficient. A new general method for the synthesis of tetra-ortho-chloro azobenzenes has been developed, which relies on direct palladium(II)-catalyzed C-H activation of pre-existing standard azobenzenes. This late-stage functionalization has a broad substrate scope and can be used to create a variety of useful building blocks for the construction of more elaborate redshifted photopharmaceuticals. This method is used to prepare red-AzCA-4, a photoswitchable vanilloid that enables optical control of the cation channel TRPV1 with visible light.