The crystal structure of pyridoxine hydrochloride. A comparison of the symbolic addition procedure and the heavy atom method

Abstract

The crystal structure of pyridoxine hydrochloride was determined directly by means of the heavy atom method and by the symbolic addition procedure from three-dimensional data, and the efficiency of both methods was compared. The space group is P i and the cell dimensions are: a = 9.52, b = 5-803, c = 9.56 A; ~ = 93-9, fl = 115"4, 7, = 98.6 °. The pyridoxine molecule is truly planar with the exception of the oxygen atom from the CH2OH group participating in an intramolecular hydrogen bond. The increase of the C-N-C bond angle in the pyridine ring is discussed. The pyridoxine ions are connected by intermolecular hydrogen bonds of the type O-H..-O, N-H..-C1, O-H-.. C1. The estimated standard deviations for bond lengths and angles are 0-005 A and 0.3 ° respectively.

Pyridoxamine monohydrochloride

“…Diseussion. The bond distances and angles are similar to those observed in other vitamin B 6 derivatives (Hanic, 1966;K. J. Franklin & Richardson, 1978Mosset, Nepveu-Juras, Haran & Bonnet, 1978;Thompson et al, 1980).…”

“…The bond angle at the pyridine N(1) is 125.1 (3) °, as has been observed for other compounds with a protonated ring N atom (Singh, 1965). The C(4)-O(2) distance of 1.298 (4)A is 0.06 A less than the corresponding distance in pyridoxine PYRIDOXAMINE MONOHYDROCHLORIDE hydrochloride (Hanic, 1966), but is close to the values observed for vitamin B 6 compounds whose phenolic group is deprotonated (Mosset et al, 1978;K. J. Franklin & Richardson, 1980;Thompson et al, 1980).…”

Pyridoxine

“…J. Franklin & Richardson, 1980;Hanic, 1966;Longo & Richardson, 1980;Mosset et al, 1978;Thompson et al, 1980). There is a fairly strong intramolecular hydrogen bond from the phenolic OH group to the adjacent CH2OH group (Table 3), which in turn is a hydrogenbond donor to the pyridine N atom in a glide-related molecule.…”

Benzotriazolium hydrogensulphate

“…hydrochloride (Hanic, 1966), but is close to the values observed for vitamin B 6 compounds whose phenolic group is deprotonated (Mosset et al, 1978;K. J. Franklin & Richardson, 1980;Thompson et al, 1980).…”