Crystal structure of the hydrobromide of 1-p-(2-dimethylaminoethoxyphenyl)-1,2-cis-diphenylbut-1-ene, a compound with oestrogenic activity

Abstract

The crystal structure of the hydrobromide of 1-p-(2-dimethylaminoethoxyphenyl)-1,2-cis-diphenylbut-1-ene, a compound with oestrogenic activity, has been determined from diffractometer data and refined to R 0·101 for 3082 planes. The compound crystallizes in the triclinic system with Z= 4; the structure has refined satisfactorily in the space group P. There are two crystallographically distinct conformational isomers of the cation in the crystal, differing mainly in the torsion angle in the O–CH₂–CH₂–N⁺ chain [+60° and –176°, syn-clinal-(gauche) and anti-periplanar(trans) conformations respectively]. The average dihedral angle between the planes of the aromatic rings and the plane of the ethylenic double bond is 54°. The identification of the isomers of similar related tri-aryl ethylenes from their n.m.r. spectra can now be made with confidence by reference to this known structure.