Synthesis, crystal structure, and protonation behaviour in solution of the recently-discovered drug metabolite, N1,N10-diacetyltriethylenetetramine
作者:Kathrin A. Wichmann、Tilo Söhnel、Garth J.S. Cooper
DOI:10.1016/j.molstruc.2011.12.020
日期:2012.3
N-1,N-10-diacetyltriethylenetetramine (DAT) is a recently-discovered major in vivo metabolite of triethylenetetramine (TETA), a highly-selective Cu-II chelator currently under clinical development as a novel first-in-class therapeutic for the cardiovascular, renal and retinal complications of diabetes mellitus. Characterisation of DAT is an integral aspect of the pharmacological work-up required to support this clinical development programme and, to our knowledge, no previous synthesis for it has been published. Here we report the synthesis of DAT dihydrochloride (DAT.2 HCl): its crystal structure as determined by X-ray single-crystal (XRD) and powder diffraction (XRPD); and protonation constants and species distribution in aqueous solution, which represents the different protonation states of DAT at different pH values. The crystal structure of DAT.2 HCl reveals 3D-assemblies of alternating 2D-layers comprising di-protonated DAT strands and anionic species, which form an extensive hydrogen-bond network between amine groups, acetyl groups, and chloride anions. Potentiometric titrations show that HDAT(+) is the physiologically relevant state of DAT in solution. These findings contribute to the understanding of TETA's pharmacology and to its development for the experimental therapeutics of the diabetic complications. (C) 2011 Elsevier B.V. All rights reserved.