Chemistry and biology of vitamin B6. 33. General method for modifying the 2-methyl group of pyridoxol. Synthesis and biological activity of 2-vinyl- and 2-ethynylpyridoxols and related compounds

Deuterium-labeled 2′-Hydroxypyridoxol

“…mp 110°C, 15 116°C, 16 (b) From 2¢-hydroxypyridoxol hydrochloride (2). 15,16 Hydrogen chloride gas was passed into a suspension of 2¢-hydroxypyridoxol hydrochloride (2, 4.44 g, 20.0 mmol) in dry acetone (250 mL) until the solid dissolved. The solution was then stirred 30 min at r.t. and was kept in the freezer overnight.…”

“…Since commercially available labeled starting materials that would have been required for de novo synthesis of 13 C or 15 N-labeled samples of the desired substrates would have been very expensive, we chose deuterium as the tracer. Starting with the readily available pyridoxol hydrochloride, the synthesis was carried out of samples of 2¢-hydroxypyridoxol in which the protons at positions 2¢ and 5¢ were replaced quantitatively by deuterium.…”

Theoretical and experimental study on cyclic 6-methyl-2,3,4-tris(hydroxymethyl)pyridin-5-ol acetonides

“…The formation, stability, and conformational specificity of cyclic acetals derived from pyridoxine attract both practical and considerable theoretical interest [4]. Pyridoxine can be converted into two cyclic six-and seven-membered acetonides, depending on the concentration of acid catalyst [5,6].At low concentration of hydrogen chloride or p-toluenesulfonic acid, kinetically controlled product is obtained, whereas at higher concentration of the acid catalyst the product is thermodynamically more stable six-membered acetonide.We previously developed a new and convenient procedure for the synthesis of 2,3,4-tris(hydroxymethyl)-6-methylpyridin-5-ol (I) [7]. Unlike pyridoxine, compound I could give rise to four cyclic acetonides: three monoacetonides II-IV and tricyclic bisacetonide V. We calculated the energies of formation…”

“…The formation, stability, and conformational specificity of cyclic acetals derived from pyridoxine attract both practical and considerable theoretical interest [4]. Pyridoxine can be converted into two cyclic six-and seven-membered acetonides, depending on the concentration of acid catalyst [5,6].…”

“…To obtain crystals suitable for X-ray analysis, cyclic acetonides of compound I were isolated as the corresponding p-toluenesulfonates according to the procedure described in [6]. By reaction of acetone with compound I in the presence of an equimolar amount of p-toluenesulfonic acid we obtained p-toluenesulfonate VI of seven-membered acetal II.…”