2492-87-7Relevant academic research and scientific papers
Single-crystal and powder X-ray diffraction and solid-state 13C NMR of p-nitrophenyl glycopyranosides, the derivatives of d-galactose, d-glucose, and d-mannose
Gubica, Tomasz,Temeriusz, Andrzej,Paradowska, Katarzyna,Ostrowski, Andrzej,Klimentowska, Paulina,Cyranski, Michal K.
, p. 1734 - 1744 (2009)
The X-ray diffraction patterns, 13C CP MAS NMR spectra, and powder X-ray diffraction analyses were obtained for selected p-nitrophenyl glycosides: α- and β-d-galactopyranosides (1 and 2), α- and β-d-glucopyranosides (3 and 4), and α- and β-d-mannopyranosides (5 and 6). In X-ray diffraction analysis of 1 and 2, characteristic shortening and lengthening of selected bonds were observed in the molecules of 1 due to anomeric effect, and in the crystal lattice of 1 and 2, hydrogen bonds of complex network were detected. In the crystal asymmetric unit of 1 there were two independent molecules, whereas in 2 there was one molecule. For 1 and 3-6 the number of resonances in solid-state 13C NMR spectra exceeded the number of the carbon atoms in the molecules, while for 2 there were distinct singlet resonances in its solid-state NMR spectrum. Furthermore, the powder X-ray diffraction (PXRD) performed for 1-3 and 5 revealed that 1, 3, and 5 existed as single polymorphs proving that the doublets observed in appropriate solid-state NMR spectra were connected with two non-equivalent molecules in the crystal asymmetric unit. On the other hand 2 existed as a mixture of two polymorphs, one of them was almost in agreement with the calculated pattern obtained from XRD (the difference in volumes of the unit cells), and the subsequent unknown polymorph existed in small amounts and therefore it was not observed in solid-state NMR measurements.
Controllable Iterative β-Glucosylation from UDP-Glucose by Bacillus cereus Glycosyltransferase GT1: Application for the Synthesis of Disaccharide-Modified Xenobiotics
Jung, Jihye,Nidetzky, Bernd,Schachtschabel, Doreen,Speitling, Michael
, p. 14630 - 14642 (2021/12/09)
Glycosylation in natural product metabolism and xenobiotic detoxification often leads to disaccharide-modified metabolites. The chemical synthesis of such glycosides typically separates the glycosylation steps in space and time. The option to perform the two-step glycosylation in one pot, and catalyzed by a single permissive enzyme, is interesting for a facile access to disaccharide-modified products. Here, we reveal the glycosyltransferase GT1 from Bacillus cereus (BcGT1; gene identifier: KT821092) for iterative O-β-glucosylation from uridine 5′-diphosphate (UDP)-glucose to form a β-linked disaccharide of different metabolites, including a C15 hydroxylated detoxification intermediate of the agricultural herbicide cinmethylin (15HCM). We identify thermodynamic and kinetic requirements for the selective formation of the disaccharide compared to the monosaccharide-modified 15HCM. As shown by NMR and high-resolution MS, β-cellobiosyl and β-gentiobiosyl groups are attached to the aglycone's O15 in a 2:1 ratio. Glucosylation reactions on methylumbelliferone and 4-nitrophenol involve reversible glycosyl transfer from and to UDP as well as UDP-glucose hydrolysis, both catalyzed by BcGT1. Collectively, this study delineates the iterative β-d-glucosylation of aglycones by BcGT1 and demonstrates applicability for the programmable one-pot synthesis of disaccharide-modified 15HCM.
Applications of Shoda's reagent (DMC) and analogues for activation of the anomeric centre of unprotected carbohydrates
Fairbanks, Antony J.
, (2020/12/07)
2-Chloro-1,3-dimethylimidazolinium chloride (DMC, herein also referred to as Shoda's reagent) and its derivatives are useful for numerous synthetic transformations in which the anomeric centre of unprotected reducing sugars is selectively activated in aqueous solution. As such unprotected sugars can undergo anomeric substitution with a range of added nucleophiles, providing highly efficient routes to a range of glycosides and glycoconjugates without the need for traditional protecting group manipulations. This mini-review summarizes the development of DMC and some of its derivatives/analogues, and highlights recent applications for protecting group-free synthesis.
Scope of the DMC mediated glycosylation of unprotected sugars with phenols in aqueous solution
Fairbanks, Antony J.,Qiu, Xin
, p. 7355 - 7365 (2020/10/13)
Activation of reducing sugars in aqueous solution using 2-chloro-1,3-dimethylimidazolinium chloride (DMC) and triethylamine in the presence of para-nitrophenol allows direct stereoselective conversion to the corresponding 1,2-Trans para-nitrophenyl glycosides without the need for any protecting groups. The reaction is applicable to sulfated and phosphorylated sugars, but not to ketoses or uronic acids or their derivatives. When applied to other phenols the product yield was found to depend on the pKa of the added phenol, and the process was less widely applicable to 2-Acetamido sugars. For 2-Acetamido substrates an alternative procedure in which the glycosyl oxazoline was pre-formed, the reaction mixture freeze-dried, and the crude product then reacted with an added phenol in a polar aprotic solvent system with microwave irradiation proved to be a useful simplification.
Direct Synthesis of para-Nitrophenyl Glycosides from Reducing Sugars in Water
Fairbanks, Antony J.,Qiu, Xin
supporting information, (2020/03/24)
Reducing sugars may be directly converted into the corresponding para-nitrophenyl (pNP) glycosides using 2-chloro-1,3-dimethylimidazolinium chloride (DMC), para-nitrophenol, and a suitable base in aqueous solution. The reaction is stereoselective for sugars with either a hydroxyl or an acetamido group at position 2, yielding the 1,2-trans pNP glycosides. A judicious choice of base allows extension to di-and oligosaccharide substrates, including a complex N-glycan oligosaccharide isolated from natural sources, without the requirement of any protecting group manipulations
Preparation of salidroside with n-butyl β-D-glucoside as the glycone donor via a two-step enzymatic synthesis catalyzed by immobilized β-glucosidase from bitter almonds
Wang, Feng,Huang, Dengfa,Ma, Yong,Zhang, Fuming,Linhardt, Robert J.
, p. 246 - 260 (2019/02/03)
β-Glucosidase from bitter almonds was immobilized on epoxy group-functionalized beads for catalyzing salidroside synthesis in a two-step process with n-butyl-β-D-glucoside (BG) as the glucosyl donor. The formation of salidroside ((0.59 ± 0.02) M) at a yield of 39.04%±1.25% was accomplished in 8 h by the transglucosylation of immobilized β-glucosidase at pH?8.0 and 50 °C when the ratio of BG to tyrosol was 1:2 (mol/mol). A study on the influence of different glycosyl acceptors demonstrated that the yield of the glucosylation reaction of phenylmethanol and cyclohexanol was higher than that of either phenol or cyclohexanol. This may account for the selectivity of the immobilized enzyme towards the alcoholic hydroxyl group of tyrosol in the salidroside synthesis reaction. A study on the synthesis of BG via the reverse hydrolysis of immobilized β-glucosidase showed that a yield of 78.04%±2.2% BG can be obtained with a product concentration of (0.23 ± 0.015) M.
A new look at acid catalyzed deacetylation of carbohydrates: A regioselective synthesis and reactivity of 2-O-acetyl aryl glycopyranosides
Stepanova, Elena V.,Nagornaya, Marina O.,Filimonov, Victor D.,Valiev, Rashid R.,Belyanin, Maxim L.,Drozdova, Anna K.,Cherepanov, Victor N.
, p. 60 - 66 (2018/02/20)
In the present work we report that acetyl groups of per – acetylated aryl glycosides have different reactivity during the acidic deacetylation using HCl/EtOH in CHCl3, which leads to preferential deacetylation at O-3, O-4 and O-6. Thereby, the one-step preparation of 2-O-acetyl aryl glycosides with simple aglycon was accomplished for the first time. It was proved that the found reagent is to be general and unique for the preparation of series of 2-О-acetyl aryl glycosides. We have determined the influence of both carbohydrate moiety and the aglycon on the selectivity of deacetylation reaction by kinetic experiments. Using DFT/B3LYP/6-31G(d,p) and semi-empirical АМ1 methods we have found that the highest activation barrier is for 2-О-acetyl group. This completely explains the least reactivity of 2-О-acetyl group.
PHENOL GLYCOSIDES AND THEIR USE IN THE TREATMENT OF UROLITHIASIS
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Page/Page column 26; 27; 31, (2017/01/26)
The present invention relates to novel derivatives of polyphenol glycoside or polyalcohols of formula (1), wherein R1, R2, R3 is selected from the group consisting of H, OH, C(O)R4, C(0) OR4, 0 (Gly H3)n, wherein n = 0 1, 2, 3, and R4 is selected from the group consisting of H, alkyl, and Gly is a mono- or disaccharide residue. The present invention also relates to novel derivatives of glycoside polyphenols or polyalcohols, as pharmaceutical composition comprising a novel polyphenol glycoside or polyalcohols and the use of novel polyphenol glycoside or polyalcohols for the treatment of urolithiasis.
Glycosynthase with broad substrate specificity-an efficient biocatalyst for the construction of oligosaccharide library
Wei, Jinhua,Lv, Xun,Lue, Yang,Yang, Gangzhu,Fu, Lifeng,Yang, Liu,Wang, Jianjun,Gao, Jianhui,Cheng, Shuihong,Duan, Qian,Jin, Cheng,Li, Xuebing
supporting information, p. 2414 - 2419 (2013/05/23)
A versatile glycosynthase (TnG-E338A) with strikingly broad substrate scope has been developed from Thermus nonproteolyticus β-glycosidase (TnG) by using site-directed mutagenesis. The practical utility of this biocatalyst has been demonstrated by the facile generation of a small library containing various oligosaccharides and a steroidal glycoside (total 25 compounds) in up to 100 % isolated yield. Moreover, an array of eight gluco-oligosaccharides has been readily synthesized by the enzyme in a one-pot, parallel reaction, which highlights its potential in the combinatorial construction of a carbohydrate library that will assist glycomic and glycotherapeutic research. Significantly, the enzyme provides a means by which glycosynthase technology may be extended to combinatorial chemistry.
The kinetics of p-nitrophenyl-β-d-cellobioside hydrolysis and transglycosylation by Thermobifida fusca Cel5Acd
Dingee, John W.,Anton, A. Brad
scheme or table, p. 2507 - 2515 (2011/01/04)
The hydrolysis of p-nitrophenyl-β-1,4-cellobioside (pNP-G2) by the catalytic domain of the retaining-family 5-2 endocellulase Cel5A from Thermobifida fusca (Cel5Acd) was studied. The dominant reaction pathway involves hydrolysis of the aglyconic bond, producing cellobiose (G2) and a 'reporter' species p-nitrophenol (pNP), which was monitored spectrophotometrically to track the reaction. We also detected the production of cellotriose (G3) and p-nitrophenyl-glucoside (pNP-G1), confirming the presence of a competing transglycosylation pathway. We use a mechanistic model of hydrolysis and transglycosylation to derive an expression for the rate of pNP-formation as a function of enzyme concentration, substrate concentration, and several lumped kinetics parameters. The derivation assumes that the quasi-steady-state assumption (QSSA) applies for three intermediate species in the mechanism; we determine conditions under which this assumption is rigorously justified. We integrate the rate expression and compare its integral form to pNP-versus-time data collected for a range of enzyme and substrate concentrations. The integral comparison gives a stringent test of the mechanistic model, and it serves to quantify the lumped kinetics parameters with good statistical precision, particularly a previously unidentified parameter that determines the selectivity of hydrolysis versus transglycosylation. The integrated rate expression accounts well for pNP-versus-time data under all circumstances we have investigated.
