Mescaline hydrobromide

At least eighteen phenylethylamines have been examined by x-ray crystallography. Among these are phenylethylamine hydrochloride (3 ), ephedrine hydrochloride (31), ephedrine monohydrogen phosphate monohydrate (32), ephedrine dihydrogen phosphate (33), dopamine hydrochloride (34), 5-hydroxydopamine hydrochloride (35), 6-hydroxydopamine hydrochloride (36), epinephrine hydrogen tartrate (37), norepinephrine hydrochloride (38), isoproterenol sulfate (39), 2,4,5-trimethoxyamphetamine hydrochloride (40), 4-ethyl-2,5-dimethoxyamphetamine (41), mescaline hydrobromide (42), and mescaline hydrochloride (43). 

In the case of catecholamines, the functional groups of particular interest include the nitrogen atom, the C-2 oxygen atom, the aromatic ring and the aromatic oxygen substituents (see Figures 2 and 7). For compounds I-VIII, the interatomic distances are tabulated in Table VI. These may readily be compared to the corresponding values from x-ray studies of three representative conformationally mobile phenyl-ethylamines, norepinephrine hydrochloride (IX), amphetamine sulfate (X) and mescaline hydrobromide (XI). 

Conformational results are often sensitive to the input geometry used. For instance, Pullman at at. (68) carried out two PCILO calculations for mescaline, using the x-ray crystal geometries obtained for the hydrobromide and hydrochloride salts these salts exist in gauche and extended conformations, respectively. 

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