NUCLEAR MAGNETIC RESONANCE SPECTRAL OBSERVATIONS ON THE GLYCOL-SCISSION OF DEUTERATED D-GLUCOSE
The positions of formyl ester groups in products obtained on oxidative glycol-scission of specifically deuterated D-glucose and its 3-O-methyl ether have been determined by n.m.r. spectroscopy. These structural assignments are based on the effect of deuteration on the signal given by the proton located α to the formyloxy group in the undeuterated compound. Thus, mono-O-formyl-2-O-methyl-D-arabinose-4-d (IV) produced by lead tetraacetate oxidation of 3-O-methyl-D-glucose-5-d (I) shows a modified resonance signal for this proton, whereas the signal is absent from the spectrum of the monoformate (III) obtained by periodate oxidation of I. Therefore, IV is a 3-formate and III a 4-formate. According to these findings a furanose form (II) of I is involved in the lead tetraacetate reaction, whereas periodate degrades the pyranose form of the sugar directly.Oxidation of D-glucose-6,6′-d2 with lead tetraacetate is shown in similar fashion to yield 2,3-di-O-formyl-D-erythrose-4,4′-d2, evidence that this degradation involves two successive pyranose-to-furanose interconversions.The preparation of I, and of some other derivatives of D-glucose-5-d, is described.
Constituents of the leaves of Woodfordia fruticosa Kurz. I. Isolation, structure, and proton and carbon-13 nuclear magnetic resonance signal assignments of woodfruticosin (woodfordin C), an inhibitor of deoxyribonucleic acid topoisomerase II.