The Crystal and Molecular Structure of N-methylephedrinium 4-nitrobenzoate (I, II). Racemic Mimics Part 5

Ephedrine is an ancient Chinese medicine drug used on patients with asthma, bronchitis and hay fever. In more recent times, it is used to prevent low blood pressure during anesthesia and to treat narcolepsy and obesity. It seemed important to understand the interaction of this drug with as large a variety of substrates as possible to get hints as to its modus operandi. It was, therefore, of interest that it appeared to crystallize as a Racemic Mimic in the form of its 4-nitrobenzoate derivative as determined by the cell parameters of that salt when it crystallized in both racemic and Sohncke space groups. Below, we describe the procedure used to prove that ephedrine belongs in that class and to illustrate the nature of the intra- and inter-molecular interactions between the constituent moieties in that monoclinic (P2₁ and P2₁/c) pair. Both crystal structures, obtained from the literature, were determined at 123 K and refined, respectively, to R-factors of 3.73 and 5.51%.