engleski

Chromo-orthogonal deprotection of carboxylic acids by aminonaphthalene and aminoaniline photocages

Photoremovable protecting groups (photocages) 6b-6i based on 1-amino-2- hydroxymethylnaphthalene were developed and their applicability to release alcohols and carboxylic acids in photohydrolysis was investigated. Compound 6b cannot release alcohol since the N- demethylation takes place instead. However, photorelease of carboxylic acids from 6c-6i was demonstrated on caged substrates including some nonsteroidal drugs and a neurotransmitter. A simultaneous use of aniline and aminonaphthalene cages allows for the chromatic orthogonality and selective deprotection by UV-B or near visible and UV-A light, respectively. The photochemical reaction mechanism of decaging was investigated by fluorescence measurements and laser flash photolysis, indicating that the heterolysis and elimination of carboxylic acids take place in the singlet excited state delivering carbocation as intermediate. The photoheterolysis in singlet excited state which directly releases caged substrates is highly applicable for the photocages and has advances to hitherto used nitrobenzyl derivatives.

photocages ; aminonaphthalenes ; aniline ; chromatic orthogonality

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