Aldehydo Sugars Research Articles

Acyclic Aldehydo Sugars: 1,3-dimethyl-4,5-diamino Uracil as Recoverable Carbonyl Protecting Group

Abstract: 1,3-dimethyl-4,5-diaminouracil has been used as an efficient protecting group for the carbonyl moiety in sugars by the formation of the imine group. The protection reaction is carried out under mild conditions, the yields are quantitative in most of the cases, and the protecting group is completely recovered and reused. After per-acetylation, deprotection is accomplished at room temperature with aqueous formic acid to produce acyclic acetylated sugars in good global yield.

Synthesis and anticancer activity of new [(Indolyl)pyrazolyl]-1,3,4-oxadiazole thioglycosides and acyclic nucleoside analogs

ABSTRACTNew [(Indolyl)pyrazolyl]-1,3,4-oxadiazole compounds and their derived thioglycosides as well as the corresponding sugar hydrazones were synthesized. The acyclo C-nucleoside analogs of the oxadiazoline base system were also prepared by reaction of acid hydrazides with aldehydo sugars followed by one pot process encompassing acetylation and cyclization of the synthesized hydrazones. The anticancer activity of the newly synthesized compounds was studied against colorectal carcinoma (HCT116), breast adenocarcinoma (MCF7) and prostate cancer (PC3) human tumor cell lines and a number of compounds showed moderate to high activities.

Stereoselective Synthesis of Ketoses by Aldol Reaction Using Water-­Compatible Prolinamide Catalysts in Aqueous Media

Prolinamido-glycosides, water-compatible organocatalysts, are capable of catalyzing the stereoselective aldol reaction in aqueous media. The aldol reaction of 2,2-dimethyl-1,3-dioxan-5-one with aldehydo sugars in the isopropylidene form gave ketoses stereoselectively. The stereochemistry of these aldol reactions has been investigated in terms of the influence of conformational effects, and the results demonstrate that the configuration of the catalysts and the conformation of substrates are a determining factor in the stereochemical outcome of the reaction. Each of d -psicose and d -tagatose was selectively obtained from 2,3-O-isopropylidene- d -glyceraldehyde. Likewise, d -glycero- d -glucooctulose, whose structure was established by X-ray crystallography, was obtained from 2,3:4,5-di-O-isopropylidene-aldehydo- d -arabinose.

VO(acac) 2/H 2O 2/NaI: a mild and efficient combination for the cleavage of dithioacetal derivatives of sugars

A wide variety of dithioacetal derivatives of sugars can be cleaved easily into the corresponding open-chain aldehydo sugars using an efficient combination of VO(acac) 2/H 2O 2/NaI at 0–5 °C. Some of the salient features of this protocol are mild reaction conditions, good yields, short reaction times, easy work-up procedures, and non-involvement of toxic chemicals.

Diastereoselective Synthesis of 5‐(Alditol‐1‐C‐yl)‐hydantoins and Their Use as Precursors of Polyhydroxylated‐α‐amino Acids.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Diastereoselective synthesis of 5-(alditol-1- C-yl)-hydantoins and their use as precursors of polyhydroxylated-α-amino acids

The synthesis of 5-(alditol-1- C-yl)-hydantoin derivatives was performed via diastereoselective aldol-type addition of 1,3-dibenzyl-hydantoin to enantiopure aldehydo sugars. Starting from the d- ribo-configured 5-(alditol-1- C-yl)-hydantoin template, the synthesis of (2 R,3 S,4 R)-3,4,5-trihydroxynorvaline was carried out.

Sugar hydrazone–metal complexes: transition- and non-transition metal complexes of monosaccharide S-alkylhydrazonecarbodithioates and dehydro- l-ascorbic acid bis( S-alkylhydrazonecarbodithioates)

Copper(II), nickel(II) and palladium(II) complexes with aldehydo- d-arabinose-, l-arabinose-, d-galactose-, d-glucose- and d-mannose- S-methyl- and S-benzylhydrazonecarbodithioates were synthesized and characterized by elemental analyses, infrared and UV–Vis. In these complexes the aldehydo sugar hydrazone acts as a mononegative NS bidentate ligand. The reaction of Cu(II) chloride, however, proceeded with reduction, and copper(I) complexes were isolated. The hydrazone molecule in these Cu(I) complexes acts as neutral NS bidentate ligand. Dehydro- l-ascorbic acid bis( S-methylhydrazinecarbodithioate) and bis(hydrazinecarbothioamide), as well as their corresponding Cu(II), Ni(II), zinc(II) and Pd(II) complexes were prepared and characterized. Electrospray (ES) and field desorption (FD) mass spectra suggest that the Cu(II), Ni(II), and Pd(II) complexes are monomeric (square planar), whereas the Zn(II) are dimeric and pentacoordinate.

Synthesis of 1‐(2‐Naphthylsulfonyl)pyrazole‐C‐glycosides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

SYNTHESIS OF 1-(2-NAPHTHYLSULFONYL)PYRAZOLE-C-GLYCOSIDES

ABSTRACT 2-Naphthylsulfonylhydrazine was reacted with aromatic aldehydes or aldehydo sugars to give the corresponding hydrazones which undergo Michael addition reactions with malononitrile or ethyl cyanoacetate to form pyrazole derivatives.

Higher acyclic nitrogen containing deoxy sugar derivatives: A new lead in the generation of antimycobacterial chemotherapeutics

Syntheses of higher acyclic nitrogen containing deoxy sugar derivatives via nitroaldol reaction of different nitroalkanes with 2,3-dideoxy-α,β-unsaturated aldehydo sugars obtained from glycals namely acetylated glucal and galactal and their in vitro antimycobacterial activity are presented.

β-Oxy-α-diazo-carbonyl compounds. Part 5: An improved synthesis of β-hydroxy-α-diazo esters derived from monosaccharides and synthetic applications in the chemistry of 3-deoxy-2-ulosonic acids

Reactions of ethyl 2-diazoacetate with aldehydo sugars and monosaccharide derivatives in their hemiacetal form are reported. The use of diethyl zinc led to an improvement of yields and shorter reaction times compared with neutral conditions as previously described. The resulting products represent potentially useful substrates for the synthesis of 3-deoxy-2-keto-ulosonic acid derivatives. Thus, diazo derivatives from d-mannose were transformed into Ko and 3-epimer Ko derivatives in a straightforward process by reaction with mCPBA.

Diastereoselective Cycloadditions of Nitroalkenes as an Approach to the Assembly of Bicyclic Nitrogen Heterocycles.

A three-component coupling for the rapid assembly of nitrogenated bicycles has been developed that employs the sequential cycloaddition of nitroalkenes as 4pi components and both an electron-rich vinyl ether and electron-withdrawing alkenes. Given the distinct electronic character of nitroalkenes and the intermediate nitronates, the coupling represents an atom-economy strategy without side products resulting from competitive reactions. Either with a racemic nitroalkene or an enantiopure nitroalkenyl sugar, these processes were regiospecific leading to the formation of bicyclic nitrosoacetals with high facial diastereoselectivity. The stereochemistry of the cycloadducts was assigned by NMR spectroscopic techniques, and those of 2 and 15 were corroborated by X-ray crystallographic analysis. The unmasking of the nitrosoacetal moiety under mild conditions represents a homologation route for higher aldehydo sugars.

Kinetics and mechanism of the oxidation of reducing sugars by osmium tetroxide in alkaline medium

A general mechanism for oxidizing reducing sugars (pentoses, hexoses and disaccharides) by OsO4 in alkaline medium is proposed. The reactions exhibit pseudounimolecular kinetics with respect to OsO4, are first order with respect to lower [sugar] and [OH−], but tend towards zeroth order with respect to both higher [sugar] and [OH−]. These results suggest the formation of an activated complex between the enediol andd osmium tetroxide, which slowly disproportionates to give osmium(VI) species and the intermediate products. The reaction products were identified. When an aldehydo sugar is treated with alkali, structural changes occur and an equilibrium is set up, mainly involving a keto sugar product and the starting aldehydo sugar consumed. This process is reversible. These changes are mainly due to the well-known Lobry-de-Bruyn-Alberda Van Ekenstein transformations.

Preparation of Aldehydo Sugars and Sugar Acids via Ozonolysis of Sugar Hydrazones.

Preparation of Aldehydo Sugars and Sugar Acids via Ozonolysis of Sugar Hydrazones.

1H and13C NMR Spectra of Alditolyl Derivatives of 3-Hydrazino-5-Methyl[1,2,4]triazino[5,6-b]indole and Their Cyclized Products.

Abstract The 1H and 13C NMR spectra of sugar (5-methyl [1, 2, 4]-triazino [5, 6-b] indol-3-yl) hydrazones (1), per-0-acetyl aldehydo sugar 1-acetyl-1-(5-methyl [1, 2, 4] triazino [5, 6-b]-indol-3-yl) hydrazones (2), l- (penta-0-acetyl-pentitol-1-yl)-10-methyl [l, 2, 4] triazolo [3′, 4′:3, 4] [l, 2, 4] triazino [5, 6-b]-indoles (3) have been investigated. The 2 D NMR (H, C COSY) spectrum of 2a has been studied.

General approach to hydroxylated α-amino acids exploiting N-(tert-butoxycarbonyl)-2-(tert-butyldimethylsiloxy)pyrrole

Racemic β-hydroxy-α-amino acids 7a, 7b and 10 of either threo or erythro configuration have been efficiently synthesized from simple aldehydes, utilizing N-(tert-butoxycarbonyl)-2-(tert- butyldimethylsiloxy)pyrrole (TBDMSOP) as a glycine-anion equivalent. Similar methodology, employing readily available aldehydo sugar precursors, has been successfully applied to syntheses of enantiomerically pure polyhydroxylated α-amino acids 14a–14f possessing diverse constitution and chirality.

Lengthening of the carbon chain of sugars by the Ch(NO 2·CH(OEt) 2 fragment a route to higher 2-amino-2-deoxyaldoses

Nitroaldol (Henry) reactions promoted by trialkylsilyl chlorides have been applied to the preparation of chain-extended nitro and amino sugars. The one-pot reaction of 1,2:3,4-di O-isopropylidine-α- d- galacto-hexodialdo-1, 5-pyranose ( 1) with 1,1-diethoxy-2-nitroethane in the presence of Et 3N, Bu 4NF ·3H 2O, and tBuMe 2SiCl yielded 7-deoxy-1,2:3,4-di- O-isopropylidene-7-nitro- l- threo-α- d-galacto -octodialdo-1, 5-pyranose diethyl acetal ( 3a) and a diastereoisomer in the ratio 4:1. The structure of 3a was established by a single crystal X-ray diffraction study. Hydrogenation of 3a (Ni, H 2) afforded the corresponding 7-amino-7deoxyl-1,2:3,4-di- O-isoprpylidene- l- threo-α- d-galacto -octodialdo-1,5-pyranose diethyl acetal 4a). Conversion of the latter compound into a trans-oxazoline derivative demonstrated that the l- threo configuration had been retained. Likewise, reaction of the aldehydo sugar 1 with 1-nitropropane was carried out in order to compare the efficiency of the new nitroaldol procedure here applied with that reported using trialkylsilyl nitronic esters as intermediates.

ChemInform Abstract: Synthesis of Pyrazole C‐Glycosides by 1,3‐Dipolar Cycloaddition of Nitrilimines Formed by Lead Tetraacetate Oxidation of p‐ Nitrophenylhydrazones of Aldehydo Sugars.

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Synthesis of Pyrazole C-Glycosides by 1,3-Dipolar Cycloaddition of Nitrilimines Formed by Lead Tetraacetate Oxidation of p-Nitrophenylhydrazones of Aldehydo Sugars

Aldehydo sugars p-nitrophenylhydrazones upon treatment with lead tetraacetate in the presence of an excess of methyl acrylate afforded, besides N'-acetylhydrazide derivatives, methyl 3-glycosyl-1-p-nitrophenylpyrazoline-5-carboxylates which were readily oxidized to the corresponding pyrazoles. The methyl pyrazole-5-carboxylates were converted to 5-carboxamides

Synthetically useful transformations of a branched-chain, deoxynitro-1-thio- d-glucitol, including a novel mode of 1-thioglycoside formation

2-Deoxy-3,4;5,6-di- O-isopropylidene-2- C-(nitromethyl)-1- S-phenyl-1-thio- d-glucitol ( 2), obtainable from d-mannose in several steps with good overall yield, was converted into the corresponding sulfoxide, α-chlorosulfide, α-acetoxysulfide, and analogous 2- C-(acetamido)methyl derivatives. Mild hydrolysis of the 1-chloro derivative of 2 gave a 2-deoxy-2- C-methylene- aldehydo sugar 3,4;5,6-diacetal by concomitant elimination of nitrous acid, whereas a 2-deoxy-2- C-(nitromethyl)- d-glucitol 3,4;5,6-diacetal was obtained under reducing conditions. Pummerer rearrangement of the sulfoxide derived from 2 gave, depending on the reaction conditions, the corresponding α-acetoxysulfide or phenyl 2-deoxy-2- C-(nitromethyl)-1-thio-β- d-glucopyranoside 3,4,6-triacetate.