Anomalous OH and +NH stretching frequencies in some diastereoisomeric 1,2-diaryl-4-dimethylamino-3-methylbutan-2-ol hydrochlorides

Abstract

The OH and ⁺NH absorption bands of certain (±)-α-1,2-diaryl-4-dimethylamino-3-methylbutan-2-ol hydrochlorides (as Nujol mulls) occur at lower and higher frequencies, respectively, than those of corresponding β-diastereiosomers. These differences are interpreted in terms of an intermolecular interaction between OH and ⁺NH groups in the α-isomers. Anomalous OH and ⁺NH bands are not observed in hydrochlorides of α-1,2-diphenylbutanols with bulky substituents in the ortho position of the 1-phenyl group or ortho and para positions of the 2-phenyl group, and in butanols lacking a 3-methyl group.