70849-21-7Relevant academic research and scientific papers
Phosphate-catalyzed degradation of d-glucosone in aqueous solution is accompanied by C1-C2 transposition
Zhang, Wenhui,Serianni, Anthony S.
experimental part, p. 11511 - 11524 (2012/08/28)
Pathways in the degradation of the C6 1,2-dicarbonyl sugar (osone) d-glucosone 2 (d-arabino-hexos-2-ulose) in aqueous phosphate buffer at pH 7.5 and 37 °C have been investigated by 13C and 1H NMR spectroscopy with the use of singly and doubly 13C-labeled isotopomers of 2. Unlike its 3-deoxy analogue, 3-deoxy-d-glucosone (3-deoxy-d-erythro-hexos-2-ulose) (1), 2 does not degrade via a 1,2-hydrogen shift mechanism but instead initially undergoes C1-C2 bond cleavage to yield d-ribulose 3 and formate. The latter bond cleavage occurs via a 1,3-dicarbonyl intermediate initially produced by enolization at C3 of 2. However, a careful monitoring of the fates of the sketetal carbons of 2 during its conversion to 3 revealed unexpectedly that C1-C2 bond cleavage is accompanied by C1-C2 transposition in about 1 out of every 10 transformations. Furthermore, the degradation of 2 is catalyzed by inorganic phosphate (Pi), and by the Pi-surrogate, arsenate. C1-C2 transposition was also observed during the degradation of the C5 osone, d-xylosone (d-threo-pentose-2- ulose), showing that this transposition may be a common feature in the breakdown of 1,2-dicarbonyl sugars bearing an hydroxyl group at C3. Mechanisms involving the reversible formation of phosphate adducts to 2 are proposed to explain the mode of Pi catalysis and the C1-C2 transposition. These findings suggest that the breakdown of 2 in vivo is probably catalyzed by Pi and likely involves C1-C2 transposition.
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
Han, Chung H.,Sillerud, Laurel O.
, p. 247 - 264 (2007/10/02)
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 (1JC,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.
