S-trityl protection of bis-amino bis-thiol (BAT) chelator enables flexible derivatisation and facile labelling with technetium-99m

We have coupled S,S'-bis-trityl N-BOC protected 1,2-ethylenedicysteamine, a bis-amino bis-thiol (BAT) tetraligand, via a propylene or ethylene spacer to several biologically active molecules including 2-nitroimidazole, desethylflumazenil, a beta-CIT analogue, glucose and 2-(2'-hydroxy-4'-aminophenyl)-1,3-benzothiazole. The conjugates were efficiently labelled with technetium-99m by consecutive heating of the S,S'-bis-trityl protected ligand in hydrochloric acid followed by neutralisation and heating in the presence of Tc-99m-tartrate. The S,S'-bis-trityl BAT chelator is an interesting synthon that allows both flexible derivatisation with various biologically active molecules and facile labelling with technetium-99m. (C) 2003 Elsevier Science Ltd. All rights reserved.