139657-63-9Relevant articles and documents
Successive C1-C2 bond cleavage: The mechanism of vanadium(v)-catalyzed aerobic oxidation of d-glucose to formic acid in aqueous solution
Niu, Muge,Hou, Yucui,Wu, Weize,Ren, Shuhang,Yang, Ru
, p. 17942 - 17951 (2018/07/14)
Vanadium(v)-catalyzed aerobic oxidation in aqueous solution shows high selectivity in the field of C-C bond cleavage of carbohydrates for chemicals with less carbon atoms. However, the pathway of C-C bond cleavage from carbohydrates and the conversion mechanism are unclear. In this work, we studied the pathway and the mechanism of d-glucose oxidation to formic acid (FA) in NaVO3-H2SO4 aqueous solution using isotope-labeled glucoses as substrates. d-Glucose is first transformed to FA and d-arabinose via C1-C2 bond cleavage. d-Arabinose undergoes similar C1-C2 bond cleavage to form FA and the corresponding d-erythrose, which can be further degraded by C1-C2 bond cleavage. Dimerization and aldol condensation between carbohydrates can also proceed to make the reaction a much more complicated mixture. However, the fundamental reaction, C1-C2 bond cleavage, can drive all the intermediates to form the common product FA. Based on the detected intermediates, isotope-labelling experiments, the kinetic isotope effect study and kinetic analysis, this mechanism is proposed. d-Glucose first reacts with a vanadium(v) species to form a five-membered-ring complex. Then, electron transfer occurs and the C1-C2 bond weakens, followed by C1-C2 bond cleavage (with no C-H bond cleavage), to generate the H3COO-vanadium(iv) complex and d-arabinose. FA is generated from H3COO that is oxidized by another vanadium(v) species. The reduced vanadium species is oxidized by O2 to regenerate to its oxidation state. This finding will provide a deeper insight into the process of C-C bond cleavage of carbohydrates for chemical synthesis and provide guidance for screening and synthesizing new highly-efficient catalyst systems for FA production.
Analysis of metabolic pathways via quantitative prediction of isotope labeling patterns: A retrobiosynthetic 13C NMR study on the monoterpene loganin
Eichinger, Dietmar,Bacher, Adelbert,Zenk, Meinhart H.,Eisenreich, Wolfgang
, p. 223 - 236 (2007/10/03)
The monoterpene loganin serves as a precursor in the biosynthetic pathways of numerous indole alkaloids. In contrast to earlier studies, we present evidence that the biosynthesis of loganin in Rauwolfia serpentina cells proceeds mainly via the deoxyxylulose pathway and not by the mevalonate pathway. This conclusion is based on experiments using a R. serpentina cell culture supplied with 13C-labeled samples of glucose, ribose/ribulose, pyruvate or glycerol. Loganin was isolated from biomass, and the hydrolysis of cellular protein afforded amino acids. The isolated metabolites were analyzed by NMR spectroscopy. The 13C-labeling patterns of isolated amino acids were then used to reconstruct the labeling patterns of phosphoenol pyruvate, pyruvate and acetyl CoA. These labeling patterns were subsequently used to predict labeling patterns for dimethylallyl pyrophosphate and isopentenyl pyrophosphate via the mevalonate and deoxyxylulose pathway, respectively. The observed labeling patterns of the terpenoid moieties in loganin were in excellent agreement with the deoxyxylulose prediction. The minor incorporation of mevalonate into loganin observed in earlier studies can be attributed to metabolite exchange between the two terpenoid pathways. The possibility of crosstalk between the two pathways in plants and plant cell cultures stresses the need for a quantitative analysis of general carbon metabolism in order to determine the partitioning between the mevalonate and deoxyxylulose pathway. The present study shows that a wide variety of general metabolic precursors can fulfill this task in conjunction with the retrobiosynthetic concept.
Multiply 13C-substituted monosaccharides: Synthesis of D-(1,5,6-13C3)glucose and D-(2,5,6-13C3)glucose
Wu,Serianni,Bondo
, p. 261 - 269 (2007/10/02)
D-(1,5,6-13C3)Glucose (7) has been synthesized by a six-step chemical method. D-(1,2-13C2)Mannose (1) was converted to methyl D-(1,2-13C2)mannopyranosides (2), and 2 was oxidized with Pt-C and O2 to give methyl D-(1,2-13C2)mannopyranuronides (3). After purification by anion-exchange chromatography, 3 was hydrolyzed to give D-(1,2-13C2)mannuronic acid (4), and 4 was converted to D-(5,6-13C2)mannonic acid (5) with NaBH4. Ruff degradation of 5 gave D-(4,5-13C2)arabinose (6), and 6 was converted to D-(1,5,6-13C3) glucose (7) and D-(1,5,6-13C3)mannose (8) by cyanohydrin reduction. D-(2,5,6-13C3)Glucose (9) was prepared from 8 by molybdate-catalyzed epimerization.
