SYNTHESIS OF L-(4-2H)ERYTHROSE, L-(1-13C, 5-2H)ARABINOSE AND L-(2-13C, 5-2H)ARABINOSE AND IDENTIFICATION OF THE INTERMEDIATES BY 2H AND 13C-N.M.R. SPECTROSCOPY

Article abstract of DOI:10.1016/S0008-6215(00)90635-9

L-(1-13C, 5-2H)Arabinose (6D) and L-(2-13C, 5-2H)arabinose (8D) have been synthesized by degradation of 2,3-O-isopropylidene-β-L-rhamnofuranose (2) to L-(4-2H)erythrose (5β, 5αD), with subsequent chain elongation to 6D plus L-(1-13C, 5-2H)ribose (7D), the latter being converted into 8D.Intermediates were identified by complete assignment of the 13C chemical shifts employing carbon-carbon and carbon-deuterium coupling constants, deuteration shifts, differential isotope-shifts, and deuterium spectra.The anomeric carbon atoms of 2 and 2,3-O-isopropylidene-L-(1-2H)erythrose (4D) gave only single 13C resonances, suggesting that these two compounds exists in only one major anomeric configuration, clarifying previously reported work.The synthesis of 2,3-O-isopropylidene-L-(1-2H)rhamnitol (3D) facilitated the assignment of the signals in the 13C spectra of the nondeuterated analog.Specific deuterium-enrichment and the observed carbon-deuterium coupling (¹J_C,D ca. 22 Hz) not only served to identify the deuterated carbon atom unambiguously in 3 but also permitted assignment of closely spaced resonances.The deuterium spectrum of 2,3-O-isopropylidene-L-(4-2H)erythrofuranose (4D) showed only a single resonance, indicating preponderance of one anomer, in accord with the observation of a single C-1 resonance in the 13C spectrum.