A Cyanine Photooxidation/ β‐Elimination Sequence Enables Near‐infrared Uncaging of Aryl Amine Payloads

Chemical optimization leads to a novel reaction sequence —cyanine photooxidation followed byβ‐elimination—for near‐infrared uncaging. AbstractUncaging strategies that use near ‐infrared wavelengths can enable the highly targeted delivery of biomolecules in complex settings. Many methods, including an approach we developed using cyanine photooxidation, are limited to phenol‐containing payloads. Given the critical role of amines in diverse biological processes, we sough t to use cyanine photooxidation to initiate the release of aryl amines. Heptamethine cyanines substituted with an aryl amine at the C4′ position undergo only inefficient release, likely due electronic factors. We then pursued the hypothesis that the carbonyl products derived from cyanine photooxid ation could undergo efficientβ‐elimination. After examining both symmetrical and unsymmetrical scaffolds, we identify a merocyanine substituted with indolenine and coumarin heterocycles that undergoes efficient photooxidation and aniline uncaging. In total, these studies provide a new scheme—cyanine photooxidation followed b yβ‐elimination—through which to design photocages with efficient uncaging properties.

Source: Photochemistry and Photobiology - July 18, 2019 Category: Science Authors: Tsuyoshi Yamamoto, Donald R. Caldwell, Albert Gandioso, Martin J. Schnermann Tags: Research Article Source Type: research