O-Isopropylidene derivatives of D-allulose (D-psicose) and D-erythro-hexopyranos-2,3-diulose

1968 ◽  
Vol 46 (8) ◽  
pp. 765-770 ◽  
Author(s):  
G. M. Cree ◽  
A. S. Perlin
Keyword(s):  
Deuterium Oxide ◽  
Spectral Characteristics ◽  
High Yield ◽  
Partial Acid Hydrolysis ◽  
Hydride Reduction ◽  
Sodium Amalgam ◽  
Isopropylidene Derivatives ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Sole Product

Oxidation of 1,2: 4,5-di-O-isopropylidene-β-D-fructopyranose (2) with ruthenium tetroxide affords crystalline 1,2: 4,5-di-O-isopropylidene-β-D-erythro-hexopyranos-2,3-diulose (3) in high yield. The latter, on reduction with metal hydrides or on catalytic hydrogenation over platinum, yields 1,2: 4,5-di-O-isopropylidene-β-D-allulopyranose (4) as virtually the sole product. By contrast, sodium amalgam reduction of 3 yields only the D-fructose derivative (2), although in low yield. Also, metal hydride reduction of impure 3, obtained by oxidation of 2 with dimethyl sulfoxide – acetic anhydride, yields equal amounts of both isomers (2 and 4). The stereochemistry of these reductions is complicated by uncertainty as to the conformation of 4 (and possibly of 2), owing to anomalous proton magnetic resonance spectral characteristics observed.Ketone 3, which is unstable in the presence of deuteroxide ion, is smoothly deuterated at C-4 by exchange in hot deuterium oxide – pyridine.Mono-O-isopropylidene derivatives have been prepared by partial acid hydrolysis of 2 and 4.

Bromination of Tetralin. Short and Efficient Synthesis of 1,4-Dibromonaphthalene

2000 ◽  
Vol 65 (11) ◽  
pp. 1791-1804 ◽  
Author(s):  
Osman Çakmak ◽  
Ismail Kahveci ◽  
Íbrahim Demirtaş ◽  
Tuncer Hökelek ◽  
Keith Smith
Keyword(s):  
High Temperature ◽  
Major Product ◽  
High Yield ◽  
Efficient Synthesis ◽  
Secondary Products ◽  
Derivatives Of ◽  
Sole Product

High-temperature bromination of tetralin (1,2,3,4-tetrahydronaphthalene) with bromine resulted in benzylic bromination to give 1,4-dibromo-1,2,3,4-tetrahydronaphthalene (4) as a major product and several secondary products. Photolytic bromination of tetralin and subsequent double dehydrobromination of 1,1,4,4-tetrabromo-1,2,3,4-tetrahydronaphthalene (10) gave 1,4-dibromonaphthalene (11) as the sole product in a high yield. 1,4-Dibromonaphthalene is efficiently converted to the corresponding methoxy (12 and 13) and cyano (14 and 15) derivatives of naphthalene.

DERIVATIVES OF DEHYDROABIETIC AND PODOCARPIC ACIDS

1963 ◽  
Vol 41 (8) ◽  
pp. 1924-1936 ◽  
Author(s):  
Ernest Wenkert ◽  
Peter Beak ◽  
Richard W. J. Carney ◽  
James W. Chamberlin ◽  
David B. R. Johnston ◽  
...  
Keyword(s):  
Methyl Esters ◽  
Resin Acid ◽  
Aluminum Hydride ◽  
Resin Acids ◽  
Lithium Aluminum ◽  
Hydride Reduction ◽  
Rate Of Hydrolysis ◽  
Keto Derivative ◽  
Hydrolysis Of ◽  
Derivatives Of

The lithium aluminum hydride reduction of nitriles in the aromatic resin acid series to aldimines and the conversion of the products to other derivatives are described. The effect of the stereochemistry of the nitriles on the rate of reduction is noted. The transformation of dehydroabietane into a dehydro product is indicated. The syntheses of a desoxydecarboxy-5,6-dehydro-7-keto derivative of podocarpic acid and its optical antipode are discussed. The stereochemistry of hydrogenation of 5,6-dehydro derivatives of podocarpic acid is reported. The effect of a 7-keto group on the rate of hydrolysis of methyl esters of aromatic resin acids is illustrated. The reactions of 6-bromo-7-keto derivatives of methyl podocarpate with bases are portrayed.

New syntheses of isopropylidene derivatives of d-gluco-, d-xylo-, and d-ribo-furanose by hydrolysis of related glycofuranosylamines

1991 ◽  
Vol 218 ◽  
pp. 233-236 ◽  
Author(s):  
David F. Ewing ◽  
Robert W. Humble ◽  
Grahame Mackenzie ◽  
Anthony Raynor ◽  
Gordon Shaw
Keyword(s):  
Isopropylidene Derivatives ◽  
Hydrolysis Of ◽  
Derivatives Of

scholarly journals Further studies on the glycerol teichoic acid of walls of Staphylococcus lactis I3. Location of the phosphodiester groups and their susceptibility to hydrolysis with alkali

1971 ◽  
Vol 125 (1) ◽  
pp. 353-359 ◽  
Author(s):  
A. R. Archibald ◽  
J. Baddiley ◽  
J. E. Heckels ◽  
S. Heptinstall
Keyword(s):  
Acid Hydrolysis ◽  
Teichoic Acid ◽  
Hydroxyl Group ◽  
High Yield ◽  
Selective Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
Structural Types ◽  
Phosphodiester Group ◽  
Hydrolysis Of ◽  
Alcoholic Hydroxyl

1. The teichoic acid from walls of Staphylococcus lactis I3 is readily degraded in dilute alkali. 2. Degradation proceeds by selective hydrolysis of that phosphodiester group attached to an alcoholic hydroxyl group of the N-acetylglucosamine and gives a repeating unit in high yield. 3. Further studies on a different repeating unit isolated by partial acid hydrolysis have shown that the glycerol diphosphate is attached to the 4-hydroxyl group of the N-acetylglucosamine and not to the 3-hydroxyl group as was proposed earlier. 4. The susceptibility towards hydrolysis by alkali of other structural types of teichoic acid has been examined and found to vary markedly according to their structure.

Septanose Carbohydrates. VII. Preparation of Mono-O-isopropylidene Derivatives of Methyl β-D-Glucoseptanoside and Preparation of Methyl α-L-idoseptanoside and its Derivatives

2002 ◽  
Vol 55 (2) ◽  
pp. 171 ◽  
Author(s):  
T. Q. Tran ◽  
J. D. Stevens
Keyword(s):  
Isopropylidene Derivatives ◽  
Hydrolysis Of ◽  
Derivatives Of

Three mono-O-isopropylidene derivatives of methyl β-D-glucoseptanoside have been prepared by acid-catalysed hydrolysis of methyl 2,3 : 4,5-di-O-isopropylidene-β-D-glucoseptanoside or by acetonation of methyl β-D-glucoseptanoside. Two of these derivatives have been used for the preparation of methyl 2,3-O-isopropylidene-α-L-idoseptanoside (8a) and methyl 3,4-O-isopropylidene-α-L-idoseptanoside (10a). Hydrolysis of (10a) yielded methyl α-L-idoseptanoside (12a) and acetonation of (8a) and (12a) yielded methyl 2,3 : 4,5-di-O-isopropylidene-α-L-idoseptanoside. Possible conformations of these compounds are discussed.

Cycloaddition reactions of acetylenic iminium salts and diazoacetates leading to pyrazole iminium salts

2019 ◽  
Vol 74 (4) ◽  
pp. 347-355
Author(s):  
Holger Gerster ◽  
Michael Keim ◽  
Gerhard Maas
Keyword(s):  
General Formula ◽  
Michael Addition ◽  
Equimolar Amount ◽  
High Yield ◽  
Cycloaddition Reactions ◽  
Iminium Salts ◽  
Iminium Salt ◽  
Hydride Reduction ◽  
High Yields ◽  
Hydrolysis Of

AbstractAcetylenic iminium triflates with the general formula [R–C≡ C–C(Ar)=N+R2 TfO−] were found to be excellent dipolarophiles in [3+ 2] cycloaddition reactions with diazoacetates leading to (1H-pyrazol-3(5)-yl)methanaminium triflates in high yields. The terminal acetylenic iminium salt (propyne iminium salt) [HC≡C–C(Ph)=N+Me2 TfO−] reacted with an equimolar amount of methyl diazoacetate instantaneously at 20°C to form the expected pyrazole in almost quantitative yield. When a 2:1 stoichiometry was applied, subsequent Michael addition of the pyrazole at the alkyne occurred and the bis(iminium) ditriflate 4 was obtained in high yield. By hydride reduction or hydrolysis of the iminium group, some of the highly hygroscopic pyrazole iminium salts were converted into neutral, twofold functionalized, di- and tri-C-substitued 1H-pyrazoles.

Theoretical Study of the Process of Passage of Glycoside Amides through the Cell Membrane of Cancer Cell

2020 ◽  
Vol 20 ◽  
Author(s):  
Vasil Tsanov ◽  
Hristo Tsanov
Keyword(s):  
Cell Membrane ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Quantum Chemical ◽  
Density Functional ◽  
Enzyme Regulation ◽  
Amide Derivatives ◽  
Pass Through ◽  
Hydrolysis Of ◽  
Derivatives Of

Background:: This article concentrates on the processes occurring in the medium around the cancer cell and the transfer of glycoside amides through their cell membrane. They are obtained by modification of natural glycoside-nitriles (cyano-glycosides). Hydrolysis of starting materials in the blood medium and associated volume around physiologically active healthy and cancer cells, based on quantum-chemical semi-empirical methods, is considered. Objective:: Based on the fact that the cancer cell feeds primarily on carbohydrates, it is likely that organisms have adapted to take food containing nitrile glycosides and / or modified forms to counteract "external" bioactive activity. Cancers, for their part, have evolved to create conditions around their cells that eliminate their active apoptotic forms. This is far more appropriate for them than changing their entire enzyme regulation to counteract it. In this way, it protects itself and the gene sets and develops according to its instructions. Methods:: Derived pedestal that closely defines the processes of hydrolysis in the blood, the transfer of a specific molecular hydrolytic form to the cancer cell membrane and with the help of time-dependent density-functional quantum- chemical methods, its passage and the processes of re-hydrolysis within the cell itself, to forms causing chemical apoptosis of the cell - independent of its non-genetic set, which seeks to counteract the process. Results:: Used in oncology it could turn a cancer from a lethal to a chronic disease (such as diabetes). The causative agent and conditions for the development of the disease are not eliminated, but the amount of cancer cells could be kept low for a long time (even a lifetime). Conclusion:: The amide derivatives of nitrile glycosides exhibit anti-cancer activity, the cancer cell probably seeks to displace hydrolysis of these derivatives in a direction that would not pass through its cell membrane and the amide- carboxyl derivatives of nitrile glycosides could deliver extremely toxic compounds within the cancer cell itself and thus block and / or permanently damage its normal physiology.

Cyclization and acid-catalyzed hydrolysis of O-benzoylbenzamidoximes

1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský
Keyword(s):  
Reaction Rate ◽  
Kinetic Isotope ◽  
Acid Base Equilibrium ◽  
Mineral Acids ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Ph Scale ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media. It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1% solutions of mineral acids. Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed. From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid. The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.

scholarly journals Novel Amino Acid Derivatives of Quinolines as Potential Antibacterial and Fluorophore Agents

2020 ◽  
Vol 88 (4) ◽  
pp. 57
Author(s):  
Oussama Moussaoui ◽  
Rajendra Bhadane ◽  
Riham Sghyar ◽  
El Mestafa El Hadrami ◽  
Soukaina El Amrani ◽  
...  
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Amino Acid Derivatives ◽  
Bacterial Strains ◽  
Fluorescent Properties ◽  
Topoisomerase Iv ◽  
Microdilution Method ◽  
Hydrolysis Of ◽  
Derivatives Of

A new series of amino acid derivatives of quinolines was synthesized through the hydrolysis of amino acid methyl esters of quinoline carboxamides with alkali hydroxide. The compounds were purified on silica gel by column chromatography and further characterized by TLC, NMR and ESI-TOF mass spectrometry. All compounds were screened for in vitro antimicrobial activity against different bacterial strains using the microdilution method. Most of the synthesized amino acid-quinolines show more potent or equipotent inhibitory action against the tested bacteria than their correspond esters. In addition, many of them exhibit fluorescent properties and could possibly be utilized as fluorophores. Molecular docking and simulation studies of the compounds at putative bacterial target enzymes suggest that the antimicrobial potency of these synthesized analogues could be due to enzyme inhibition via their favorable binding at the fluoroquinolone binding site at the GyrA subunit of DNA gyrase and/or the ParC subunit of topoisomerase-IV.

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