The natural abundance deuterium NMR characterization of four commercially available samples(Kahlbaum, Aldrich, Fluka, and Extrasynthèse) of salicin
1 in comparison with two extractive samplesfrom
Salix humboldiana and
Salix purpurea L. and with a synthetic material, performed on thepentaacetate derivative
2 and on diacetyl salicyl alcohol
4, is reported. Product
2 from
S. humboldianaand the sample from salicin Kahlbaum show mean (D/H)
aromatic values of 117 and 121 ppm, whereas,for the remaining, values of 146, 154, 153, and 150 ppm are observed, thus suggesting that salicinKahlbaum is from extractive origin. The (D/H) values at positions 5' and 6' of the sugar moiety suggesta hypothesis on the origin of the glucose residue discriminating between those deriving from C3 orC4 plants. The analysis of
4, obtained from
3, formed in the
-glucosidase hydrolysis of salicin
1,reveals in the natural samples from
S. purpurea and from Kahlbaum the trend (D/H)
4(para) > (DH)
3(meta) ~ (D/H)
5(meta) > (D/H)
6(ortho), the first example of deuterium pattern of an ortho-oxygen-substituted phenylpropanoid. The three samples derived from commercial
1 (Aldrich, Fluka, andExtrasynthèse) and the synthetic sample show almost identical deuterium content at positions 4 and6 (around 153 ppm), whereas for the two meta positions (D/H)
3 > (D/H)
5 (ca. 162 and 140 ppm,respectively). Product
4, obtained from
3 submitted to acid-catalyzed deuteration, shows differentdeuterium incorporations in the two meta positions (which are ortho/para to the activating phenolichydroxyl group), suggesting that possibly the deuterium abundance at the two meta positions maybe affected by exchange phenomena with the medium.Keywords: Salicin; salicyl alcohol; phenylpropanoid; isotope ratio; deuterium pattern