Two new classes of near-infrared molecular probes were prepared and shown to exhibit “turn on” fluorescence when cleaved by the nitroreductase enzyme, a well-known biomarker cell hypoxia. The fluorescent are heptamethine cyanine dyes with central 4‘-carboxylic ester group on chain that is converted self-immolative fragmentation mechanism 4‘-caboxylate greatly enhances brightness. Each compound ...

The chemistry of the reaction of 2-hydroxy&nitrobenzyl bromide (HNB-Br) with tryptophan ethyl ester to form monosubstitution adducts has been elucidated. The initial compounds are formed by addition at position 3 of the indole ring to form two diastereomeric indolenines. These compounds can then cyclize and rearrange in a number of ways. The absolute stereochemistries of the products have been ...

We report the intermolecular palladium-catalyzed reaction of tert-butyl propargyl carbonate with tryptamine derivatives or other indole-containing bis-nucleophiles. The reaction proceeds under mild conditions and with low catalyst loadings to afford novel spiroindolenine products in good to high yields.