Competing pathways in the photo-Favorskii rearrangement and release of esters: studies on fluorinated p-hydroxyphenacyl-caged GABA and glutamate phototriggers.

ABSTRACT: Three new trifluoromethylated p-hydroxyphenacyl (pHP)-caged gamma-aminobutyric acid (GABA) and glutamate (Glu) derivatives have been examined for their efficacy as photoremovable protecting groups in aqueous solution. Through the replacement of hydrogen with fluorine, e.g., a m-trifluoromethyl or a m-trifluoromethoxy versus m-methoxy substituents on the pHP chromophore, modest increases in the quantum yields for the release of amino acids GABA and glutamate as well as improved lipophilicity were realized. The pHP triplet undergoes a photo-Favorskii rearrangement with concomitant release of the amino acid substrate. Deprotonation competes with the rearrangement from the triplet excited state and yields the pHP conjugate base that, upon reprotonation, regenerates the starting ketoester, a ch

SUBMITTER: Stensrud K 

PROVIDER: S-EPMC3422889 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature