N,N,N',N'-tetramethylchloroformamidinium hexafluorophosphate (TCFH), a powerful coupling reagent for bioconjugation

Prodrugs are increasingly used as delivery vehicles for pharmaceutical agents that present solubility and/or pharmacokinetic/metabolic issues. In the course of the development of prodrugs for the antitumoral agent thiocoraline, standard coupling reagents and procedures failed to provide the desired target derivatives because of the lack of reactivity of its quinolinic alcohol. In contrast, the use of N,N,N',N'-tetramethylchloroformamidinium hexafluorophosphate (TCFH) resulted in good yields of ester prodrugs of thiocoraline and could be applicable to other drugs with similar limitations.