10030-80-5Relevant articles and documents
Kinetics of reactions of manganese(III) pyrophosphate with some hexitols
Fadnis, Anand G.,Kulshrestha, Sudhir K.
, p. 137 - 140 (1983)
Alditols are acyclic, polyhydric alcohols that are derived from aldoses and ketoses by reduction.Their wide-spread occurance in Nature, particularly in the lower forms of life, points to their biological importance.Compared to studies of the metal-ion oxidation of sugars, it seems that the oxidation of alditols has received little attention.Earlier, the oxidation of hexitols with cerium(IV) (ref. 1), cobalt(III) (ref. 2), and vanadium(V) (ref. 3) was reported, and we now describe oxidations with manganese(III) pyrophosphate.
Productive sugar isomerization with highly active Sn in dealuminated β zeolites
Dijkmans, Jan,Gabriels, Dries,Dusselier, Michiel,De Clippel, Filip,Vanelderen, Pieter,Houthoofd, Kristof,Malfliet, Annelies,Pontikes, Yiannis,Sels, Bert F.
, p. 2777 - 2785 (2013)
A water-tolerant Lewis acid catalyst was synthesized by grafting Sn IV in isopropanol under reflux onto dealuminated zeolites with the BEA (β) topology. This synthesis method allows the production of highly active Snβ-type catalysts without the need for long hydrothermal syntheses or hydrogen fluoride, while using cheap Sn-precursors, industrially available β zeolites and standard catalyst synthesis unit operations. Extensive characterization of the best catalyst shows highly dispersed Sn in the zeolite matrix (XRD, 29Si MAS NMR and 1H MAS NMR) without the formation of SnO2 (XRD and UV-Vis). The catalyst was tested for the model isomerization of sugars such as glucose to fructose. The catalytic activity proved to be purely heterogeneous and the catalyst was recycled and reused without significant loss in activity. Isomerization productivities above 4 kg product per kg of catalyst per hour are reported with appreciably low Sn loadings, corresponding to exceptionally high turnover frequencies, viz. 500 cycles per Sn per hour at 110 °C, which surpass the activity per Sn of the original hydrothermally synthesized Snβ.
Development of a chemical strategy to produce rare aldohexoses from ketohexoses using 2-aminopyridine
Hasehira, Kayo,Miyanishi, Nobumitsu,Sumiyoshi, Wataru,Hirabayashi, Jun,Nakakita, Shin-Ichi
, p. 2693 - 2698 (2011)
Rare sugars are monosaccharides that are found in relatively low abundance in nature. Herein, we describe a strategy for producing rare aldohexoses from ketohexoses using the classical Lobry de Bruyn-Alberda van Ekenstein transformation. Upon Schiff-base formation of keto sugars, a fluorescence-labeling reagent, 2-aminopyridine (2-AP), was used. While acting as a base catalyst, 2-AP efficiently promoted the ketose-to-aldose transformation, and acting as a Schiff-base reagent, it effectively froze the ketose-aldose equilibrium. We could also separate a mixture of Sor, Gul, and Ido in their Schiff-base forms using a normal-phase HPLC separation system. Although Gul and Ido represent the most unstable aldohexoses, our method provides a practical way to rapidly obtain these rare aldohexoses as needed.
STUDY OF THE EFFECT OF ORGANIC SOLVENTS ON THE SYNTHESIS OF LEVAN AND THE HYDROLYSIS OF SUCROSE BY Bacillus subtilis LEVANSUCRASE
Chambert, Regis,Petit-Glatron, Marie-Francoise
, p. 117 - 124 (1989)
The equilibrium between the hydrolase and synthetase activities of levansucrase was determined by progressively substituting water with various organic solvents in the enzymic reaction medium.In the presence of high concentrations of these solvents, the enzyme displayed anly synthetase activity.The levan obtained under such conditions had Mr-106 and presented a low molecular dipersity.In the presence of solvent, the Km values for sucrose and raffinose remained unchanged, but the kcat values were five times higher in comparison to the same constants determined for an aqueous medium.
Saponins isolated from Allium chinense G. DON and antitumor-promoting activities of isoliquiritigenin and laxogenin from the same drug
Baba, Masaki,Ohmura, Masayoshi,Kishi, Naoki,Okada, Yoshihito,Shibata, Shoji,Peng, Jeng,Yao, Shin-Sen,Nishino, Hoyoku,Okuyama, Toru
, p. 660 - 662 (2000)
Investigation of the Chinese crude drug 'Xiebai,' the bulbs of Allium chinense G. DON (Liliaceae), led to the isolation of 2 saponins, xiebai- saponin I (laxogenin 3-O-β-xylopyranosyl (1→4)-[α-arabinopyranosyl (1→6)]-β-glucopyranoside) (1) and laxogenin 3-O-α-arabinopyranosyl (1→6)- β-glucopyranoside (2), and the aglycone, laxogenin (3), together with 2 chalcones, isoliquiritigenin (4) and isoliquiritigenin-4-O-glucoside (5), and β-sitosterol glucoside (6). Compounds 15 were tested in vitro for their inhibitory effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA)- stimulated 32Pi-incorporation into phospholipids of HeLa cells. In addition to this, laxogenin (3) was proven to have an antitumor-promoting activity in a two-stage lung carcinogenesis experiment.
Anti-inflammatory active components of the roots of Datura metel
Qin, Ze,Zhang, Jin,Chen, Liang,Liu, Shu-Xiang,Zhao, Hai-Feng,Mao, Hui-Min,Zhang, Hong-Yang,Li, De-Fang
, p. 392 - 398 (2020/03/30)
One new phenolic glycoside, methyl 3,4-dihydroxyphenylacetate-4-O-[2-O-β-D-apisoyl-6-O-(2-hydroxybenzoyl)]-β-D-glucopyranoside (1), together with 10 known compounds (2–11), were isolated from the roots of Datura metel. The structures of these compounds we
Orthogonal Active-Site Labels for Mixed-Linkage endo-β-Glucanases
Jain, Namrata,Tamura, Kazune,Déjean, Guillaume,Van Petegem, Filip,Brumer, Harry
, p. 1968 - 1984 (2021/05/26)
Small molecule irreversible inhibitors are valuable tools for determining catalytically important active-site residues and revealing key details of the specificity, structure, and function of glycoside hydrolases (GHs). β-glucans that contain backbone β(1,3) linkages are widespread in nature, e.g., mixed-linkage β(1,3)/β(1,4)-glucans in the cell walls of higher plants and β(1,3)glucans in yeasts and algae. Commensurate with this ubiquity, a large diversity of mixed-linkage endoglucanases (MLGases, EC 3.2.1.73) and endo-β(1,3)-glucanases (laminarinases, EC 3.2.1.39 and EC 3.2.1.6) have evolved to specifically hydrolyze these polysaccharides, respectively, in environmental niches including the human gut. To facilitate biochemical and structural analysis of these GHs, with a focus on MLGases, we present here the facile chemo-enzymatic synthesis of a library of active-site-directed enzyme inhibitors based on mixed-linkage oligosaccharide scaffolds and N-bromoacetylglycosylamine or 2-fluoro-2-deoxyglycoside warheads. The effectiveness and irreversibility of these inhibitors were tested with exemplar MLGases and an endo-β(1,3)-glucanase. Notably, determination of inhibitor-bound crystal structures of a human-gut microbial MLGase from Glycoside Hydrolase Family 16 revealed.
Method for preparing lactic acid through catalytically converting carbohydrate
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Paragraph 0029-0040, (2020/11/01)
The invention relates to a method for preparing lactic acid through catalytically converting carbohydrate, and in particular, relates to a process for preparing lactic acid by catalytically convertingcarbohydrate under hydrothermal conditions. The method disclosed by the invention is characterized by specifically comprising the following steps: 1) adding carbohydrate and a catalyst into a closedhigh-pressure reaction kettle, and then adding pure water for mixing; 2) introducing nitrogen into the high-pressure reaction kettle to discharge air, introducing nitrogen of 2 MPa, stirring and heating to 160-300 DEG C, and carrying out reaction for 10-120 minutes; 3) putting the high-pressure reaction kettle in an ice-water bath, and cooling to room temperature; and 4) filtering the solution through a microporous filtering membrane to obtain the target product. The method can realize high conversion rate of carbohydrate and high yield of lactic acid, and has the advantages of less catalyst consumption, good circularity, small corrosion to reaction equipment and the like.
Formation of Chiral Structures in Photoinitiated Formose Reaction
Stovbun,Skoblin,Zanin,Tverdislov,Taran,Parmon
, p. 108 - 116 (2018/04/05)
The possibility to synthesize biologically important sugars and other chiral compounds without any initiators in the UV-initiated reaction of formaldehyde in aqueous solution has been shown for the first time. An optically active condensed phase due to an
Shape-selective Valorization of Biomass-derived Glycolaldehyde using Tin-containing Zeolites
Tolborg, S?ren,Meier, Sebastian,Saravanamurugan, Shunmugavel,Fristrup, Peter,Taarning, Esben,Sádaba, Irantzu
, p. 3054 - 3061 (2016/11/17)
A highly selective self-condensation of glycolaldehyde to different C4 molecules has been achieved using Lewis acidic stannosilicate catalysts in water at moderate temperatures (40–100 °C). The medium-sized zeolite pores (10-membered ring framework) in Sn-MFI facilitate the formation of tetrose sugars while hindering consecutive aldol reactions leading to hexose sugars. High yields of tetrose sugars (74 %) with minor amounts of vinyl glycolic acid (VGA), an α-hydroxyacid, are obtained using Sn-MFI with selectivities towards C4 products reaching 97 %. Tin catalysts having large pores or no pore structure (Sn-Beta, Sn-MCM-41, Sn-SBA-15, tin chloride) led to lower selectivities for C4 sugars due to formation of hexose sugars. In the case of Sn-Beta, VGA is the main product (30 %), illustrating differences in selectivity of the Sn sites in the different frameworks. Under optimized conditions, GA can undergo further conversion, leading to yields of up to 44 % of VGA using Sn-MFI in water. The use of Sn-MFI offers multiple possibilities for valorization of biomass-derived GA in water under mild conditions selectively producing C4 molecules.
