Facile Synthesis of Reagents Containing a Terminal Maleimido Ligand Linked to an Active Ester

Abstract

Condensation of ω-amino acids with maleic anhydride to yield maleamino acids and subsequent esterification with N-hydroxysuccinimide, 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine, or pentafluorophenol to give the corresponding esters in a one pot procedure are described. The reagents can be isolated and purified without chromatography in 7-55% yields.