583-50-6Relevant academic research and scientific papers
Permanganate oxidation revisited: Synthesis of 3-deoxy-2-uloses via indium-mediated chain elongation of carbohydrates
Schmoelzer, Christoph,Fischer, Michael,Schmid, Walther
, p. 4886 - 4892 (2010)
Application of the Barbier-type indium-mediated allylation method to suitable substrates offers access to carbohydrates bearing a terminal olefin moiety. The C-C bond, forming reaction generates a defined stereochemistry of the new chiral center and tolerates a wide variety of starting aldehydes thus allowing modifications in the carbohydrate backbone. Further transformations of the alkene moiety via an environmentally benign and subtle controlled protocol using potassium permanganate gives rise to the structural motif of 3-deoxy-2-uloses in good yields. The final part of the reaction sequence focuses on the deprotection of the acetyl groups essential for the success of the oxidation step. The acidic and labile 3-deoxy position of the target molecule is prone to elimination applying standard deacetylation conditions and therefore demands derivatisation of the molecule. The introduction of a thioketal moiety using microwave conditions shows promising results and subsequent standard transformations are applicable leading to the desired products.
Combined effect of promoter and surfactant on the chromium(VI) oxidation of D-ribose in aqueous media at room temperature
Sar, Pintu,Ghosh, Aniruddha,Malik, Susanta,Saha, Bidyut
, p. 86 - 105 (2016)
Effect of polypyridine derivatives on chromium(VI) oxidation of D-ribose in aqueous media was studied spectrophotometrically. The oxidized product D-erythrose was detected by paper chromatography. The promoters 1,10-phenanthroline, 2,2-bipyridine, 2-picolinic acid, and 2,3-dipicolinic acid accelerated the oxidation, whereas isomeric 4,7-phenanthroline, 4,4-bipyridine, 4-picolinic acid, and 2,6-dipicolinic acid did not influence the oxidation. Formation of Cr(VI)-promoter complex was identified through fluorescence spectroscopy. Rate constants depended on promoter concentration. SDS and TX-100 enhanced the D-ribose oxidation, while CPC retarded the reaction. Location of D-ribose inside micelles was observed through 1H NMR. DLS study showed that the relative size of SDS and TX-100 micelles expanded in presence of chromium(VI).
Catalytic Action of Iron and Manganese Ions in the Photochemically-Induced Oxidation of D-Fructose with Atmospheric Oxygen
Araki, Koji,Shiraishi, Shinsaku
, p. 229 - 234 (1986)
D-fructose is susceptible to photochemically-induced oxidation by atmospheric oxygen in the presence of a catalytic amount of iron or manganese cations in a neutral to weakly basic pH range.Metal hydroxide does not precipitate from a solution in this pH range because of the high sequestering ability of D-fructose.Upon irradiation of Pyrex-filtered light, D-fructose degraded into D-erythrose and other fragments.This reaction is shown to proceed by coupling with an oxidation-reduction cycle involving a metal cation, i.e., the photooxidation of D-fructose by M(III) and the subsequent reoxidation of the resultant M(II) by atmospheric oxygen.
PHOTOOXIDATION OF MONOSACCHARIDES WITH METAL CATALYSIS. OXIDATION WITH ATMOSPHERIC OXYGEN BY COUPLING WITH THE OXIDATION-REDUCTION CYCLE OF METAL IONS
Araki, Koji,Shiraishi, Shinsaku
, p. 267 - 270 (1984)
D-Fructose was oxidatively degraded to D-erythrose by atmospheric oxygen with irradiation of a Pyrex-filtered light in the presence of catalytic amount of FeCl3 at near neutral pH range.The reaction proceeded by coupling with the oxidation-reduction cycle of iron ion.D-Glucose-FeCl3 and D-fructose-MnCl2 systems were also found to be susceptible to the catalytic photooxidation.
Anomerization of Furanose Sugars: Kinetics of Ring-Opening Reactions by 1H and 13C Saturation-Transfer NMR Spectroscopy
Serianni, Anthony S.,Pierce, John,Huang, Shaw-Guang,Barker, Robert
, p. 4037 - 4044 (1982)
With the tetroses D-threose and D-erythrose, kinetic and thermodynamic parameters for the interconversion of α- and β-furanoses and the acyclic hydrate with the intermediate aldehyde form have been obtained from 1H and 13C NMR measurements.Unidirectional rate constants for the various equilibria involving the aldehyde have been determined, and from them the overall rate constants for interconversion of the abundant species.The approach can be applied to systems in which only solutions at tautomeric equilibrium are available or in which interconversions are too rapid to observe by other methods.Analyses by 13C NMR were facilitated by the use of tetroses.Aqueous solutions of the tetroses were examined at 17-81 deg C by 13C and 1H NMR spectroscopy to evaluate tautomeric composition.Solutions of D-threose contain ca. 51percent α-furanose and ca. 38percent β-furanose at all temperatures, while the amount of aldehyde (a) increases from 0.7 to 4.7percent and the amount of hydrate (h) decreases from 10.2 to 7.1percent. ΔG (kcal mol-1), ΔH (kcal mol-1), and ΔS (cal mol-1 K-1) at 25 deg C were estimated for the reaction a -> α, -2.4, -6.0, and -12; a -> β, -2.2, -6.0, -13; a -> h, -1.4, -7.3, -20, respectively.Rate constants for ring opening of the tetroses in 2H2O were obtained by 1H and 13C saturation-transfer NMR spectroscopy by saturating H-1 or C-1 of the aldehyde, respectively, and observing the transfer of saturation to the α- and β-furanose and hydrate resonances.Rate constants (+/-10percent) for the ring-opening reactions of D-threose (unbuffered) are as follows: α-furanose, 0.034 s-1 (51 deg C), 0.10 s-1 (66 deg C); β-furanose, 0.083 s-1 (38 deg C), 0.53 s-1 (66 deg C).Ring-closing rate constants (+/-18percent), determined from equilibrium constants, and ring-opening rate constants are as follows: α-furanose, 0.74 s-1 (51 deg C), 1.5 s-1 (66 deg C); β-furanose, 2.0 s-1 (38 deg C), 5.9 s-1 (66 deg C).Activation energies were estimated for β-threofuranose ring-opening (14 +/- 3 kcal mol-1) and ring-closing (8 +/- 2 kcal mol-1) reactions.From the unidirectional rate constants, overall rate constants at 66 deg C for the conversion of α- and β-threofuranose were calculated as follows: kαβ = 0.08 +/- 0.01 s-1, kβα = 0.11 +/- 0.01 s-1.Rate constants for ring-opening of D-threose and D-erythrose in 50 mM sodium acetate (p2H 5.0) were compared.At 55 deg C, α-erythrose (0.40 s-1) > β-threose (0.36 s-1) > β-erythrose (0.19 s-1) > α-threose (0.11 s-1).Rate constants obtained by 13C and 1H ST NMR spectroscopy were in good agreement.
Synthesis, structure, and conformation of anti-tumor agents in the solid and solution states: Hydroxyl derivatives of ftorafur
Stokes, David M.,Paul, Brajeswar,Alderfer, James L.,Wollman, Robert M.,Srikrishnan, Thamarapu
, p. 863 - 882 (2002)
The pyrimidine antimetabolite Ftorafur [FT; 5-fluoro-1-(tetrahydro-2-furyl)uracil] has shown significant antitumor activity in several adenocarcinomas with a spectrum of activity similar to, but less toxic than, 5-fluorouracil (5-FU). It is considered as a prodrug that acts as a depot form of 5-FU, and hence the two drugs exhibit a similar spectrum ofchemotherapeutic activity. Ftorafur is metabolized in animals and humans when hydroxyl groups are introduced into the tetrahydrofuran moiety. These metabolites are also thought to be as active as ftorafur but less toxic than 5-FU. Hydroxyl derivatives: 2′-hydroxyftorafur (III), 3′-hydroxyftorafur (IV) and 2′,3′-dihydroxyftorafur (II) were synthesized and X-ray and NMR studies of these hydroxyl derivatives were undertaken in our laboratories to study the structural and conformational features of Ftorafur and its metabolites in the solid and solution states. X-ray crystallographic investigations were carried out with data collected on a CAD-4 diffractometer. The structures were solved and refined using the SDP crystallographic package of Enraf-Nonius on PDP 11/34 and Microvax computers. All of the compounds studied had the base in the anti conformation. The glycosidic torsion angles varied from -20 to 60 degrees. There is an inverse correlation between the glycosyl bond distances and the χ angle. Molecules with a lower χ angle have a larger bond distance and vice versa. The sugar rings show a wide variation of conformations ranging from C2′-endo through C3′-endo to C4′-exo. The crystal structures are stabilized by hydrogen bonds involving the base nitrogen atom N3 and the hydroxyl oxygen atoms of the sugar rings as donors and the keto oxygens O2 and O4 of the base and the hydroxyl oxygen atoms O2′ and O3′ as acceptors. The NMR studies were carried out on Brueker 400 and 600MHz instruments. Simulated proton spectra were obtained through Laocoon, and pseudorotational parameters were solved by Pseurot. Presence of syn or anti forms was demonstrated with the use of NOE experiments. The glycosyl conformations in solution vary more widely than in the solid state. The conformations of the sugar molecules are in agreement with the values obtained in the solid state. The studies of the structure and conformation in the solid and solution states give a model for the Ftorafur molecule that could be used in structure, function and biological activity correlation studies.
Photothermal strategy for the highly efficient conversion of glucose into lactic acid at low temperatures over a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide catalyst
Duo, Jia,Jin, Binbin,Jin, Fangming,Shi, Xiaoyu,Wang, Tianfu,Ye, Xin,Zhong, Heng
, p. 813 - 822 (2022/02/09)
The conversion of carbohydrates into lactic acid has attracted increasing attention owing to the broad applications of lactic acid. However, the current methods of thermochemical conversion commonly suffer from limited selectivity or the need for harsh conditions. Herein, a light-driven system of highly selective conversion of glucose into lactic acid at low temperatures was developed. By constructing a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide composite catalyst (CNT/LDHs), the highest lactic acid yield of 88.6% with 90.0% selectivity was achieved. The performance of CNT/LDHs for lactic acid production from glucose is attributed to the following factors: (i) CNTs generate a strong heating center under irradiation, providing heat for converting glucose into lactic acid; (ii) LDHs catalyze glucose isomerization, in which the photoinduced OVs (Lewis acid) in LDHs under irradiation further improve the catalytic activity; and (iii) in a heterogeneous-homogeneous synergistically catalytic system (LDHs-OH-), OH- ions are concentrated in LDHs, forming strong base sites to catalyze subsequent cascade reactions.
Selective Reductive Dimerization of CO2into Glycolaldehyde
Zhang, Dan,Jarava-Barrera, Carlos,Bontemps, Sébastien
, p. 4568 - 4575 (2021/05/04)
The selective dimerization of CO2 into glycolaldehyde is achieved in a one-pot two-step process via formaldehyde as a key intermediate. The first step concerns the iron-catalyzed selective reduction of CO2 into formaldehyde via formation and controlled hydrolysis of a bis(boryl)acetal compound. The second step concerns the carbene-catalyzed C-C bond formation to afford glycolaldehyde. Both carbon atoms of glycolaldehyde arise from CO2 as proven by the labeling experiment with 13CO2. This hybrid organometallic/organic catalytic system employs mild conditions (1 atm of CO2, 25 to 80 °C in less than 3 h) and low catalytic loadings (1 and 2.5%, respectively). Glycolaldehyde is obtained in 53% overall yield. The appealing reactivity of glycolaldehyde is exemplified (i) in a dimerization process leading to C4 aldose compounds and (ii) in a tri-component Petasis-Borono-Mannich reaction generating C-N and C-C bonds in one process.
Glucose oxidation to formic acid and methyl formate in perfect selectivity
Albert, Jakob,Bukowski, Anna,Kumpidet, Chiraphat,Maerten, Stephanie,Vo?, Dorothea,Wasserscheid, Peter
, p. 4311 - 4320 (2020/07/14)
We report the highly remarkable discovery that glucose oxidation catalysed by polyoxometalates (POMs) in methanolic solution enables formation of formic acid and methyl formate in close to 100percent combined selectivity, thus with only negligible sugar oxidation to CO2. In detail, we report oxidation of a methanolic glucose solution using H8[PV5Mo7O40] (HPA-5) as catalyst at 90 °C and 20 bar O2 pressure. Experiments with 13C-labelled glucose confirm unambiguously that glucose is the only source of the observed formic acid and methyl formate formation under the applied oxidation conditions. Our results demonstrate a very astonishing solvent effect for the POM-catalysed glucose oxidation. In comparison to earlier work, a step-change in product yield and selectivity is achieved by applying an alcoholic reaction medium. The extremely high combined yields of formic acid and methyl formate greatly facilitate product isolation as low-boiling methyl formate (bp = 32 °C) can simply be isolated from the reaction mixture by distillation.
Catalytic Gels for a Prebiotically Relevant Asymmetric Aldol Reaction in Water: From Organocatalyst Design to Hydrogel Discovery and Back Again
Hawkins, Kirsten,Patterson, Anna K.,Clarke, Paul A.,Smith, David K.
supporting information, p. 4379 - 4389 (2020/03/05)
This paper reports an investigation into organocatalytic hydrogels as prebiotically relevant systems. Gels are interesting prebiotic reaction media, combining heterogeneous and homogeneous characteristics with a structurally organized active solid-like catalyst separated from the surrounding environment, yet in intimate contact with the solution phase and readily accessible via liquid-like diffusion. A simple self-assembling glutamine amide derivative 1 was initially found to catalyze a model aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, but it did not maintain its gel structure during reaction. In this study, it was observed that compound 1 could react directly with the benzaldehyde to form a hydrogel in situ based on Schiff base 2 as a low-molecular-weight gelator (LMWG). This new dynamic gel is a rare example of a two-component self-assembled LMWG hydrogel and was fully characterized. It was demonstrated that glutamine amide 1 could select an optimal aldehyde component and preferentially assemble from mixtures. In the hunt for an organocatalyst, reductive conditions were applied to the Schiff base to yield secondary amine 3, which is also a highly effective hydrogelator at very low loadings with a high degree of nanoscale order. Most importantly, the hydrogel based on 3 catalyzed the prebiotically relevant aldol dimerization of glycolaldehyde to give threose and erythrose. In buffered conditions, this reaction gave excellent conversions, good diastereoselectivity, and some enantioselectivity. Catalysis using the hydrogel of 3 was much better than that using non-assembled 3 - demonstrating a clear benefit of self-assembly. The results suggest that hydrogels offer a potential strategy by which prebiotic reactions can be promoted using simple, prebiotically plausible LMWGs that can selectively self-organize from complex mixtures. Such processes may have been of prebiotic importance.
