Crystal structure of the di-Mannich base 4,4′-dichloro-3,3′,5,5′-tetramethyl-2,2′-[imidazolidine-1,3-diylbis(methylene)]diphenol

Abstract

The title compound, C21H26Cl2N2O2, was prepared in a solvent-free microwave-assisted synthesis, and crystallizes in the orthorhombic space groupPna21. The imidazolidine ring adopts an envelope conformation and its mean plane is almost perpendicular to the two pendant aromatic rings [dihedral angles = 84.61 (9) and 86.54 (9)°]. The molecular structure shows the presence of two intramolecular O—H...N hydrogen bonds between the phenolic hydroxy groups and imidazolidine N atoms. The two 3-chloro-6-hydroxy-2,4-dimethylbenzyl groups are located in acisorientation with respect to the imidazolidine fragment. As a result, the lone pairs of electrons on the N atoms are presumed to be disposed in asynconformation. This is therefore the first example of an exception to the `rabbit-ears' effect in such 2,2′-[imidazolidine-1,3-diylbis(methylene)]diphenol derivatives.