5155-45-3

Upstream product

• 119418-01-8 C₄₄H₆₄O₁₆ 
• 118536-87-1 licorice-saponin D₃ 
• 118325-22-7 licorice-saponin A₃ 
• 709-50-2 methyl beta-D-glucopyranoside 
• 67-56-1 methanol 
• 78693-94-4 soyasaponin A₁ 
• 82801-38-5 azukisaponin III 
• 78693-93-3 soyasaponin A₂ 
• 143519-29-3 Cloversaponin IV methyl ester 
• 100201-60-3 sophoraflavoside I 
• 82793-03-1 3-O-[β-D-glucopyranosyl(1->2)-β-D-glucuronopyranosyl]olean-12-en-3β,22β,24-triol 
• 55319-36-3 astragaloside VIII 
• 82793-05-3 3-O-[α-L-rhamnopyranosyl(1->2)-β-D-glucopyranosyl(1->2)-β-D-glucuronopyranosyl]olean-12-en-3β,22β,24-triol 
• 97-30-3 methyl-alpha-D-glucopyranoside 

Downstream Products

• 6556-12-3 D-glucuronic acid 
• 18486-38-9 methyl β-D-glucuronopyranoside methyl ester 
• 87-99-0 XYLITOL 
• 18486-51-6 1-O-methyl-α-D-glucopyranuronic acid methyl ester 

Relevant academic research and scientific papers

Bromide-free TEMPO-mediated oxidation of primary alcohol groups in starch and methyl α-D-glucopyranoside

TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)-mediated oxidation of potato starch and methyl α-D-glucopyranoside (MGP) was performed in the absence of sodium bromide (NaBr) as co-catalyst, solely using sodium hypochlorite (NaOCl) as the primary oxidant. The low reaction rate associated with a bromide-free process was increased by performing the oxidation at increased temperatures. The reaction proceeded stoichiometrically and with high selectivity and with only minor depolymerisation, provided that temperature and pH were kept ≤20°C and a corresponding oxidation catalysed by NaBr at 2°C. Consequently, this is a simple approach to raise the TEMPO/NaOCl reaction rate under bromide-free conditions while still maintaining good product properties. At higher oxidation temperatures (≥25°C) and under more alkaline conditions (pH ≥ 9.0) degradation of the starch skeleton occurred. Simultaneously, side-reactions of the nitrosonium ion lowered the yield of the oxidation. Despite the absence of the NaBr catalyst, the reaction rate-controlling step was found to be the oxidation of the primary hydroxyl groups with the nitrosonium ion. The reaction was first- order in MGP and in TEMPO. (C) 2000 Elsevier Science Ltd.

Structure of the unusual Sinorhizobium fredii HH103 lipopolysaccharide and its role in symbiosis

Rhizobia are soil bacteria that form important symbiotic associations with legumes, and rhizobial surface polysaccharides, such as K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS), might be important for symbiosis. Previously, we obtained a mutant of Sinorhizobium fredii HH103, rkpA, that does not produce KPS, a homopolysaccharide of a pseudaminic acid derivative, but whose LPS electrophoretic profile was indistinguishable from that of the WT strain. We also previously demonstrated that the HH103 rkpLMNOPQ operon is responsible for 5-acetamido-3,5,7,9-tetradeoxy-7-(3-hydroxybutyramido)-L-glyc-ero-L-manno-nonulosonic acid [Pse5NAc7(3OHBu)] production and is involved in HH103 KPS and LPS biosynthesis and that an HH103 rkpM mutant cannot produce KPS and displays an altered LPS structure. Here, we analyzed the LPS structure of HH103 rkpA, focusing on the carbohydrate portion, and found that it contains a highly heterogeneous lipid A and a peculiar core oligosaccharide composed of an unusually high number of hexuronic acids containing b-configured Pse5NAc7(3OHBu). This pseudaminic acid derivative, in its a-configuration, was the only structural component of the S. fredii HH103 KPS and, to the best of our knowledge, has never been reported from any other rhizobial LPS. We also show that Pse5NAc7(3OHBu) is the complete or partial epitope for a mAb, NB6-228.22, that can recognize the HH103 LPS, but not those of most of the S. fredii strains tested here. We also show that the LPS from HH103 rkpM is identical to that of HH103 rkpA but devoid of any Pse5NAc7(3OHBu) residues. Notably, this rkpM mutant was severely impaired in symbiosis with its host, Macroptilium atropurpureum.

Toward glucuronic acid through oxidation of methyl-glucoside using PdAu catalysts

The production of glucuronic acid via enzyme catalysis from biomass is slow. Here we studied the oxidation of methoxy-protected glucose (MG) using Pd-on-Au nanoparticle model catalysts to generate methoxy-protected glucuronic acid (MGA), a precursor to glucuronic acid. Pd-on-Au showed volcano-shape activity dependence on calculated Pd surface coverage (sc). The 80 sc% Pd-on-Au catalyst composition showed maximum initial turnover frequency (413 mol-MG mol-surface-atom?1 h?1) that was 5× higher than that of Au/C, while Pd/C was inactive. This Pd-on-Au composition gave the highest MGA yield (46%), supporting a bimetallic approach to glucuronic acid production.

Characterization of ulvan extracts to assess the effect of different steps in the extraction procedure

An effective application development of the polysaccharide ulvan requires a comprehensive knowledge about the influence of the extraction process on composition of the extracts and in ulvan itself. In this context, the two main objectives of the present work are (1) the establishment of an efficient extraction process for ulvan and (2) development of an accurate characterization methodology to evaluate the extract composition and ulvan content. Three ulvan-rich extracts obtained by different schemes of extraction were studied. The methodology for the analysis was improved and a detailed analysis of extracted ulvan was provided. The polysaccharide is rich in ulvanobiuronic acid 3-sulfate type A [→4)-β-d-GlcAp-(1 → 4)-α-l-Rhap 3S-(1→], with minor amounts of ulvanobiuronic acid 3-sulfate type B [→4)-α-l-IdoAp-(1 → 4)-α-l-Rhap 3S-(1→]. The extract with the higher degree of purification is a high molecular weight polysaccharide (790 kDa) composed of rhamnose (22.4%), glucuronic acid (22.5%), xylose (3.7%), iduronic acid (3.1%) and glucose (1.0%). It is highly sulfated (32.2%) and contains 1.3% of proteins and 10.3% of inorganic material. Applying simple extraction scheme it was possible to obtain an extract from green algae with high content of ulvan without affecting the overall chemical structure of the polysaccharide.

Process for oxidizing primary alcohols

Primary hydroxyl groups in a substrate having both primary and secondary hydroxyl groups can be selectively oxidized to carbaldehyde and/or carboxyl groups by contacting the substrate with a cyclic nitroxyl compound in the presence of a peroxosulfate as a co-oxidant and by carrying out the reaction at a temperature below 30° C. and at a pH below 9. The process is halogen-free and metal-free and is especially suitable for oxidizing polysaccharides.

Process of oxidizing primary alcohols

In a new process for oxidizing a primary and/or secondary alcohol, an oxidizing agent is used in the presence of a di-tertiary-alkyl nitroxyl, in an aqueous reaction medium at a pH of below 7. The di-tertiary-alkyl nitroxyl is especially 4-hydroxy-TEMPO, and the process is particularly advantageous for oxidizing carbohydrates such as starch.

Medicinal foodstuffs. XIII.1 saponin constituents with adjuvant activity from hyacinth bean, the seeds of Dolichos lablab L. (2) : Structures of lablabosides D, E, and F

Following the characterization of lablabosides A, B, and C, new oleanane-type triterpene bisdesmosides, lablabosides D, E, and F, were isolated from the glycosidic fraction with adjuvant activity obtained from the seeds of Dolichos lablab L. (Leguminosae). Their chemical structures were elucidated on the basis of chemical and physicochemical evidence as follows : 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[6-O-(3-hydroxy-3-methylglutaroyl)-β-D-glucopyranosyl] 24-epi-hederagenin (lablaboside D), 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[α-L-rhamnopyranosyl (1→4)-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranosyl] 24-epi-hederagenin (lablaboside E), 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[α-L-rhamnopyranosyl (1→4)-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranosyl] oleanolic acid (lablaboside F).

Oxidation of methyl and n-octyl α-D-glucopyranoside over graphite-supported platinum catalysts: Effect of the alkyl substituent on activity and selectivity

The oxidation of methyl and n-octyl α-D-glucopyranoside to methyl and n-octyl α-D-glucopyranosiduronate with molecular oxygen over a graphite-supported platinum catalyst was investigated. An increase of the length of the n-alkyl substituent from methyl to n-octyl resulted in a ten-fold decrease of the catalyst activity and an increase of the selectivity at pH 8.0 and 323 K. The selectivity decreased with increasing pH. The lower activity for a longer n-alkyl substituent is attributed to steric effects upon adsorption on the platinum surface and not to internal diffusion limitations. A tentative reaction scheme is presented, which describes the formation of side products through oxidation of secondary hydroxyl groups, ring cleavage and hydrolysis. Major side products are mono- and di-carboxylates with 2, 4, and 6 carbon atoms and mono-carboxylates, resulting from the oxidation of the alkyl substituent. C-C-Bond cleavage mainly occurs between C-2 and C-3 or C-4 and C-5, the former being less important for a longer alkyl substituent. The higher selectivity for a longer alkyl substituent is attributed to its protecting ability against hydrolysis and the exposition of neighboring hydroxyl groups to the platinum surface.

Saponin and sapogenol. XLVIII. On the constituents of the roots of Glycyrrhiza uralensis FISCHER from Northeastern China. (2). Licorice-saponins D3, E2, F3, G2, H2, J2, and K2

Following the characterization of licorice-saponins A3 (2), B2 (3), and C2 (4), the chemical structures of licorice-saponins D3 (5), E2 (6), F3 (7), G2 (8), H2 (9), J2 (10), and K2 (11), seven of the ten oleanane-type triterpene oligoglycosides isolated from the air-dried roots of Glycyrrhiza uralensis FISCHER collected in the northeastern part of China, were investigated. On the basis of chemical and physicochemical evidence, the structures of licorice-saponins D3, E2, F3, G2, H2, J2, and K2 have been determined to be expressed as 3β-[α-L-rhamnopyranosyl(1 → 2)-β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyloxy]-22β-acetoxyolean-12-en-30-oic acid (5), 3-O- [β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyl]glabrolide (6), 3- O-[α-L-rhamnopyranosyl(1 → 2)-β-D-glucuronopyranosyl(1 → 2)-β-D- glucuronopyranosyl]-11-deoxoglabrolide (7), 24-hydroxyglycyrrhizin (8), 3-O- [β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyl]liquiritic acid (9), 24-hydroxy-11-deoxoglycyrrhizin (10), and 3β-[β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyloxy]-24-hydroxyoleana-11,13(18)-dien-30-oic acid (11), respectively.