Synthesis and σ1 Receptor Binding of Halogenated N,NÂ´-DiphenethylethylenediaminesJonathan M. Fitzsimmons1,5, John R. Lever2,3,5 and Susan Z. Lever1,4*
- *Corresponding Author:
- Dr. Susan Z Lever
PhD, Room 125 Chemistry Building
University of Missouri – Columbia
601 South College Avenue, Columbia, MO 65211 USA
Tel: (573) 882-8395
Fax: (573) 882-2754
E-mail: [email protected]
Received date: September 22, 2011; Accepted date: November 08, 2011; Published date: December 25, 2011
Citation: Fitzsimmons JM, Lever JR, Lever SZ (2011) Synthesis and σ1 Receptor Binding of Halogenated N,N´-Diphenethylethylenediamines. Medchem 1:102. doi:10.4172/2161-0444.1000102
Copyright: © 2011 Fitzsimmons JM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Eight halogenated N,N´-diphenethylethylenediamines were synthesized, characterized and evaluated for ?1 receptor binding affinity in vitro. Measurements of lipophilicity also were obtained. The substitution pattern on one of the aromatic rings remained constant as 3,4-dichloro, while the substituents on the other aromatic ring were varied to include fluorine, bromine or iodine in either the 2-, 3- or 4- positions. Two main structure activity relationships were observed. First, halogen substitution on the 3- or 4-positions of the aromatic ring conferred higher binding affinities (Ki values 6.35 - 15.82 nM) than the corresponding substitutions at the 2-position (Ki values 12.08 - 43.15 nM). Second, derivatives containing either a bromo or fluoro substituent at a given position showed higher ?1 receptor binding affinities than derivatives with a corresponding iodo substituent. The data indicate that ?1 receptor affinity for this structural series is sensitive to steric bulk at the 2-position. Log k´w measurements for the halogenated N,N´- diphenethylethylenediamines were determined by high performance liquid chromatography, and varied from 2.54 - 3.71. In particular, the 3-fluoro analog exhibited a log k´w = 2.54 accompanied by a ?1 receptor Ki = 7.8 nM. These novel N,N´-diphenethylethylenediamines warrant further investigation in behavioral assays, and radiolabeled versions may prove suitable for in vivo studies of ?1 receptors.