A Facile Two-Step Synthesis of Novel Ring-A Double Substituted Tryptophan Building Blocks for Combinatorial Chemistry
24 July 2003 (online)
A fast synthesis of ring-A disubstituted Fmoc and Boc protected l-tryptophan analogs was achieved starting from the appropriate 2,4- or 2,3-disubstituted phenylhydrazines and optically active N,N-diprotected l-glutamic acid γ-aldehydes, utilizing a Fischer-indole synthesis as a key step. Unlike most of the previously reported methods, that required the multistep stereoselective generation of a chiral carbon, this fast methodology is useful for generating optically active ring-A disubstituted protected tryptophans starting from a simple and common chiral precursor. These building blocks have a wide application scope in peptide and combinatorial chemistry fields.
Boc strategy - combinatorial chemistry - Fischer indole synthesis - Fmoc strategy - orthogonal protection - tryptophan