SYNTHESIS OF AN ALPHA-CH2CO2H FUNCTIONALIZED TRYPTOPHAN AND ITS INCORPORATION INTO AN ANALOG OF CHOLECYSTOKININ

The synthesis of an alpha, alpha-disusbtituted tryptophan derivative (2) predicted by computer assisted molecular modelling to have close structural and conformational analogy to the endogenous neuropeptide cholecystokinin (CCK) is described. Central to the synthesis of (2) is the alkylation of an isonitrile derivative of tryptophan

THE RATIONAL DESIGN AND SYNTHESIS OF NONPEPTIDE RHEGNYLOGUES OF CCK-26-33 - A NOVEL SERIES OF CCK-A SELECTIVE LIGANDS

A novel series of CCK-A receptor ligands has been prepared based on the appendage of modified amino acid side chain mimetics onto the alpha-carbon atom of tryptophan

ENANTIOSPECIFIC SYNTHESIS WITH AMINO-ACIDS .1. TRYPTOPHAN AS A CHIRON FOR THE SYNTHESIS OF ALPHA-SUBSTITUTED TRYPTOPHAN DERIVATIVES

N-alpha-Methoxycarbonyl-(S)-tryptophan methyl ester is cyclised with 85% phosphoric acid to give (2S,3aR,8aS)-1,2-bis(methoxycarbonyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole which on reaction with toluene-p-sulphonyl chloride gives (2S,3aR,8aS)-1,2-bis(methoxycarbonyl)-8-(p-tolylsulphonyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole. This compound undergoes deprotonation with lithium diisopropylamide to the corresponding enolate which is quenched with a variety of alkylating agents resulting in alkylation, with retention of configuration, at C-2 of the pyrroloindole system. Subsequent treatment with trifluoroacetic acid brings about cycloreversion affording essentially optically pure alpha-alkylated tryptophan derivatives. The process is also applied in the R-series

A new phase-switch method for application in organic synthesis programs employing immobilization through metal-chelated tagging

A new phase-switch method for application in organic synthesis is reporte