A temporary marker for biological applications

Having in mind the development Of new colour labelled amino acid derivative s. a carboxyl azo dye was coupled to amino acid esters to give the correspo nding orange N-acyl derivatives, which were in turn further acylated at the ir N-terminus with Boc for investigation of the conditions of possible clea vage of the chromophore by electrolysis or with nucleophiles. While difficu lties were met with electrolysis owing to competitive reduction of the azo group, cleavage with N,N-diethylaminoethylamine (DEAEA) gave satisfactory r esults. This allows the use of the chromophore as a temporary marker. (C) 2 001 Elsevier Science Ltd. All rights reserved.