2,5-Dihydroxybenzyl and (1,4-Dihydroxy-2-naphthyl)methyl, Novel Reductively Armed Photocages for the Hydroxyl Moiety
摘要:
[Graphics]Irradiation of alcohols, phenols, and carboxylic acids "caged" with the 2,5-dihydroxybenzyl group or its naphthalene analogue results in the efficient release of the substrate. The initial byproduct of the photoreaction, 4-hydroxyquinone-2-methide, undergoes rapid tautomerization into methyl p-quinone. The UV spectrum of the latter is different from that of the caging chromophore, thus permitting selective irradiation of the starting material in the presence of photochemical products. These photoremovable protecting groups can be armed in situ by the reduction of photochemically inert p-quinone precursors.
Selective deprotection of alkyl esters using magnesium methoxide
作者:Xu Yao-Chang、Amsalu Bizuneh、Clint Walker
DOI:10.1016/0040-4039(95)02197-3
日期:1996.1
The use of magnesium methoxide for the deprotection of alkyl esters is described. This mild reagent provides a good method to cleave esters efficiently and more importantly, allows for effective differentiation between two different esters. The order of the reactivity of this reagent towards acyl cleavages was found to be: p-nitrobenzoate>acetate>benzoate>pivaloate>>acetamide.