Struktur-Wirkungs-Beziehungen bei Nefopamhydrochlorid

Structure-Activity Relationships of Nefopam Hydrochloride An X-ray study of (?)-nefopam hydrochloride ( 1 ) (P2₁/c, a = 1176.1, b = 773.9, c = 1689.7 pm, β = 97.43°, Z = 4) shows that the heterocyclic ring has two structurally simple features: Five atoms (2–6) form the C₅ fragment of a cyclohexane ring, while another five atoms (2, 1, 10a, 6a and 6) lie within the plane of the fused benzene ring. The two benzene rings are almost perpendicular to each other, which is remarkably different from the structurally related benzodiazepines. The structure of 1 is practically identical with that found for (-)-nefopam hydrochloride monohydrate, a fact which is discussed under the aspect of conformational rigidity. Nefopam can be taken as a model substance for serotonin agonists and antagonists. As a common structural feature these compounds have an aliphatic amino group which lies (or can be easily placed) at a distance of about 600 pm from the center of the aromatic system and nearly within the plane of the system.