- Deoxyribonolactone formation in photoirradiation of 5-bromouracil-containing oligonucleotides by direct C1′ hydrogen abstraction
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Mechanistic studies on the formation of deoxyribonolactone by UV irradiation of hexamer d(GC1BrUGC)2 (ODN 2a) containing 1′-deuterio-2′-deoxyadenosine 1 was examined. The kinetic isotope effect (kH/kD) for the f
- Fujimoto, Kenzo,Ikeda, Yutaka,Ishihara, Shigenori,Saito, Isao
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- A Novel Synthesis of Protoanemonin by the Catalytic Vapour-phase Oxidation of Silvan
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The vapour-phase oxidation of 2-methylfuran (silvan) in air over vanadium-molybdenum oxide catalysts under specific conditions was unexpectedly found to afford 5-methylenefuran-2(5H)-one (protoanemonin) which is otherwise difficult to obtain.
- Iovel, Irina,Goldberg, Yuri,Shymanska, Mariya
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- HETEROORGANIC FURAN DERIVATIVES. 61. TRIMETHYL(5-METHYL-2-FURYL)SILANE AND TRIMETHYL(5-METHYL-2-FURYL)GERMANE
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The transformations of trimethyl(5-methyl-2-furyl)silane and trimethyl(5-methyl-2-furyl)germane were studied upon vapor-phase oxidation by atmospheric oxygen on a V-Mo-Ag-O catalyst.Under these conditions, trimethyl(5-formyl-2-furyl)silane and trimethyl(5-formyl-2-furyl)germane are formed albeit in only 5-7percent yield.This low yield is a consequence of the thermal instability of the starting compounds and the aldehydes formed.The oxidation of 2-methyl-5-tert-butylfuran was studied under comparable conditions.The corresponding aldehyde was obtained in 30percent yield.A scheme was proposed for the catalytic oxidation of 5-substituted 2-methylfurans.
- Lukevits, E.,Ignatovich, L. M.,Iovel', I. G.,Gol'dberg, Yu. Sh.,Shimanskaya, M. V.
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- A Convenient Synthesis of Protoanemonin
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A new convenient synthesis of protoanemonin (1) starting from 2-deoxy-D-ribose (3) is described. A key step in the sequence is the successive β- and δ-eliminations of 3,5-di-O-p-toluoyl-2-deoxy-D-ribono-1,4-lactone (6).
- Crey, Caroline,Dumy, Pascal,Lhomme, Jean,Kotera, Mitsuharu
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- A palladium catalyzed efficient synthesis of γ-methylene-α, β-unsaturated γ-lactones via cyclization of 3,4-alkadienoic acids
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An efficient method was developed for the synthesis of γ-methylene- α,β-unsaturated γ-lactones from the Pd-catalyzed cyclization of 3,4-alkadienoic acids. Control experiment shows that the reaction should be carried out under a N2 atmosphere to ensure the high purity of the products.
- Ma, Shengming,Yu, Fei
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- A Facile Synthesis of γ-Alkylidene-α,β-unsaturated γ-Lactones
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Treatment of β-allenic acid with KI3 gave directly γ-alkylidene-α,β-unsaturated γ-lactones in moderate yields.
- Tsuboi, Sadao,Wada, Hiroshi,Mimura, Shigetoshi,Takeda, Akira
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- Pd/C-Cu mediated direct and one-pot synthesis of γ-ylidene butenolides
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10% Pd/C in combination with CuI, PPh3, and Et3N has been identified as an effective catalyst system for the coupling of (Z)-3-iodoacrylic acid with terminal alkynes in 1,4-dioxane leading to the one-pot synthesis of γ-ylidene butenolides. The methodology showed remarkable regio- and stereoselectivity as only the five-membered lactone ring products were formed with an exocyclic double bond possessing Z-geometry.
- Rambabu,Bhavani,Nalivela, Kumara Swamy,Mukherjee, Soumita,Rao, M.V. Basaveswara,Pal, Manojit
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- Acid-mediated coupling of γ-hydroxybutenolides and aldehydes: Synthesis of a new class of spirocyclic ketal-lactones
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In the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf), γ-methyl-γ-hydroxybutenolide reacts with aromatic aldehydes to generate a new class of stereochemically rich spirocyclic ketal-lactones in good yields and with excellent stereoselectivities. We believe that this process takes place through the in situ generation of protoanemonin followed by a Prins reaction. Herein, we describe this discovery, along with substrate scope and preliminary mechanistic studies.
- Munoz, Alberto,Murelli, Ryan P.
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- Intramolecular Photocycloaddition of 2(5 H)-Furanones to Temporarily Tethered Terminal Alkenes as a Stereoselective Source of Enantiomerically Pure Polyfunctionalyzed Cyclobutanes
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Allyloxymethyloxymethyl and 4-pentenoyloxymethyl substituents have been used as tethering groups to study the intramolecular [2 + 2] photocycloaddition of chiral 5-substituted 2(5H)-furanones. The photoreactions proceed in good yield and provide the expected regio- and diastereoselective tricyclic compounds with complementary regioselectivity, which depends on whether the vinyl chain is attached to the furanone by an acetal or an ester linkage. Computational simulations agree with experimental observations and indicate that the origin of the different observed regioselectivity in the intramolecular photochemical reaction of lactones 5 and 6 arises from the relative stability of the initial conformers. The synthetic potential of the enantiomerically pure photoadducts is illustrated by preparing an all-cis 1,2,3-trisubstituted cyclobutane bearing fully orthogonally protected hydroxyl groups.
- Xin, Yangchun,Rodríguez-Santiago, Luís,Sodupe, Mariona,álvarez-Larena, Angel,Busqué, Félix,Alibés, Ramon
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- Chemistry of the 2-deoxyribonolactone lesion in oligonucleotides: Cleavage kinetics and products analysis
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Deoxyribonolactone in DNA is an oxidized abasic site damage that is produced by a variety of physical and chemical agents such as γ-irradiation and ene-diyne antibiotics. The extent and biological significance of the lesion are poorly documented due to the high lability of the damaged DNA. The chemistry of degradation of deoxyribonolactone-containing DNA was investigated using oligonucleotides of different length (5-, 11-, 23-, 34-mers) in which the lactone was photochemically generated, as already reported, from oligonucleotide precursors containing a photoactive nitroindole residue. The procedure was successfully extended to double-strand synthesis by irradiation of the preformed duplex in which one strand contained the nitroindole residue. The degradation kinetics were investigated as a function of pH, temperature, length, and ionic strength. The cleavage fragments resulting from β- and δ-eliminations were isolated and identified by 1H NMR. It was found that the lesion is extremely sensitive to pH and temperature while slightly dependent upon ionic strength, length, and sequence. The cleavage rates for the β- and δ-elimination steps are of the same order of magnitude. The deoxyribonolactone site leads to greater instability of DNA than the regular deoxyribose abasic site.
- Roupioz, Yoann,Lhomme, Jean,Kotera, Mitsuharu
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- Efficacy and site specificity of hydrogen abstraction from DNA 2-deoxyribose by carbonate radicals
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The carbonate radical anion CO3?- is a potent reactive oxygen species (ROS) produced in vivo through enzymatic one-electron oxidation of bicarbonate or, mostly, via the reaction of CO2 with peroxynitrite. Due to the vitally essential role of the carbon dioxide/bicarbonate buffer system in regulation of physiological pH, CO3?- is arguably one of the most important ROS in biological systems. So far, the studies of reactions of CO3?- with DNA have been focused on the pathways initiated by oxidation of guanines in DNA. In this study, low-molecular products of attack of CO3?- on the sugar-phosphate backbone in vitro were analyzed by reversed phase HPLC. The selectivity of damage in double-stranded DNA (dsDNA) was found to follow the same pattern C4′ > C1′ > C5′ for both CO3?- and the hydroxyl radical, though the relative contribution of the C1′ damage induced by CO3?- is substantially higher. In single-stranded DNA (ssDNA) oxidation at C1′ by CO3?- prevails over all other sugar damages. An approximately 2000-fold preference for 8-oxoguanine (8oxoG) formation over sugar damage found in our study identifies CO3?- primarily as a one-electron oxidant with fairly low reactivity toward the sugar-phosphate backbone.
- Roginskaya, Marina,Moore,Ampadu-Boateng,Razskazovskiy
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- THERMAL ANALYSIS OF 1-DEOXY-1-GLYCINO-D-FRUCTOSE AND 1-β-ALANINO-1-DEOXY-D-FRUCTOSE
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Aspects of the pyrolysis of 1-deoxy-1-glycino-D-fructose and 1-β-alanino-1-deoxy-D-fructose are reported.Thermal analysis and parallel chemical investigations demonstrate that formation of these Amadori compounds provides a low-energy route to the thermal degradation of their amino acid and sugar moieties.Furthermore, the pathway leads to the production of increased quantities of various aroma compounds as compared with controls.Pyrolysis of the 1-amino-1-deoxyketoses also produces the toxic compound protoanemonin; a degradation pathway leading to its formation is proposed.
- Birch, Edward J.,Lelievre, John,Richards, Edward L.
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- Synthetic method for protoanemonin
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The invention provides a synthetic method for protoanemonin. The method is characterized in that 2-methylfuran is used as a starting raw material, an oxidizing reaction is performed to obtain 5-methyl-5-hydroxyfuran-2-one, a dehydration reaction is performed on the 5-methyl-5-hydrofuran-2-one, and therefore the product is obtained. The synthetic method provided by the invention only needs a two-step reaction, is easy to operate, and does not use toxic and harmful substances such as bromine, and reduces poisoning and pollution; and a total yield of the two steps can reach 65% or more, the yieldis high, the raw materials are easy to obtain, and the costs are low.
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Paragraph 0039-0040; 0041-0042
(2019/05/15)
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- Acid-mediated coupling of γ-hydroxybutenolides and aldehydes: Synthesis of a new class of spirocyclic ketal-lactones
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In the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf), γ-methyl-γ-hydroxybutenolide reacts with aromatic aldehydes to generate a new class of stereochemically rich spirocyclic ketal-lactones in good yields and with excellent stereoselectivi
- Munoz, Alberto,Murelli, Ryan P.
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supporting information
p. 6779 - 6781
(2013/01/15)
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- Stepwise cross-couplings of a dibromo-γ-methylenebutenolide as an access to Z-configured α-alkenyl-γ-alkylidenebutenolides. Straightforward synthesis of the antibiotic lissoclinolide
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The Z-isomer of α-bromo-γ-(bromomethylene)butenolide was prepared from α-angelica lactone or levulinic acid in three and four steps, respectively. Successive Stille-couplings with an unsaturated stannane, with the potential to use a different second unsaturated stannane, involved the a?-substituent first and the a?-substituent thereafter. Thereby, α-alkenyl-γ-alkylidenebutenolides and their arene analogs were obtained Z-selectively.
- Sorg, Achim,Blank, Frederik,Bruckner, Reinhard
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p. 1286 - 1290
(2007/10/03)
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- Identification of Sugar Degradation Intermediates in a Metalloporphyrin-mediated DNA Cleavage Resulting from Hydroxylation at C-5'
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Hydroxylation of poly(dA)-poly(dT) at the 5' position of the deoxyribose units by the chemical nuclease Mn-TMPyP-KHSO5 followed by an additional thermal step provides 5'-aldehyde-3',4'-unsaturated nucleosides which can be reduced by sodium borohydride and then hydrogenated with palladium on charcoal giving 2',3'-dideoxyribonucleosides having the natural β or the non-natural α configuration at 4'.
- Pratviel, Genevieve,Pitie, Marguerite,Perigaud, Christian,Gosselin, Gilles,Bernadou, Jean,Meunier, Bernard
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p. 149 - 151
(2007/10/02)
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- Studies on Structurally Simple α,β-Butenolides. XI. A New and Convenient Synthesis of Protoanemonin
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En efficient three-steps synthesis of protoanemonin from 5-hydroxymethylfurfural is presented.
- Alibes, Ramon,Font, Josep,Mula, Anna,Ortuno, Rosa M.
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p. 2607 - 2615
(2007/10/02)
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- Oxidative Substitution Reactions of Organotin Compounds with Lead Tetra-acetate
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A new oxidative substitution reaction where an organotin group is replaced by an acetoxy group has been investigated; this reaction has been successfully applied to the synthesis of 4-ylidenebutenolides.
- Yamamoto, Makoto,Izukawa, Hiroyoshi,Saiki, Masaru,Yamada, Kazutoshi
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p. 560 - 561
(2007/10/02)
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- Synthesis of the Dideoxynucleosides ddC and CNT from Glutamic Acid, Ribonolactone, and Pyrimidine Bases
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2,3-Dideoxyribose in suitably protected form was prepared from glutamic acid and coupled with silylated cytosine to give a mixture of the α-and β-anomers of 2',3'-dideoxycitidine.The anomer ratio depended on the Lewis acid used in the coupling, with EtAlCl2 favoring the β-anomer ddC, a potent anti-HIV drug.Conjugate addition of cyanide to a 4-butenolide prepared from D-ribonolactone gave a mixture of (racemic) α- and β-3-cyanobutyrolactones.Both isomers were reduced to lactols and coupled with thymine to give α/β-anomer pairs.The α-cyano lactone, the struct ure of which was established by X-ray crystallography, afforded an authentic sample of the putative (but in fact inactive) anti-HIV substance known in AIDS research as CNT.
- Okabe, Masami,Sun, Ruen-Chu,Tam, Steve Y.-K.,Todaro, Louis J.,Coffen, David L.
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p. 4780 - 4786
(2007/10/02)
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- STUDIES ON STRUCTURALLY SIMPLE α,β-BUTENOLIDES. III. BEHAVIOUR OF (-)-(S)-δ-HETEROSUBSTITUTED γ-METHYL-α,β-BUTENOLIDES TOWARDS NUCLEOPHILES. PROTOANEMONIN AS INTERMEDIATE IN AN ELIMINATION-ADDITION MECHANISM.
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The reactivity of the title compounds with different nucleophiles has been checked and it was shown that products from reaction with sodium phenylthiolate result from an elimination-addition process in which protoanemonin is the key intermediate.The synthesis of (-)-(R)-β-angelica lactone is reported for the first time.
- Camps, P.,Cardellach, J.,Corbera, J.,Font, J.,Ortuno, R. M.,Ponsati, O.
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p. 395 - 400
(2007/10/02)
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- STUDIES ON STRUCTURALLY SIMPLE α,β-BUTENOLIDES-II (-)-(S)-γ-HYDROXYMETHYL-α,β-BUTENOLIDE AND DERIVATIVES FROM D-RIBONOLACTONE EFFICIENT SYNTHESIS OF (-)-RANUNCULIN
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A short synthesis of the title compound, 16, from D-ribonolactone is described.Two alternative approaches differing in the timing of the C=C double bond creation are used to prepare some chiral derivatives of 16. (-)-Ranunculin, a glycoside present in Ranunculaceae, has been synthetized for the first time.
- Camps, P.,Cardellach, J.,Font, J.,Ortuno, R. M.,Ponsati, O
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p. 2395 - 2402
(2007/10/02)
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- STUDIES ON STRUCTURALLY SIMPLE α,β-BUTENOLIDES-I NEW SYNTHESIS OF RACEMIC γ-HYDROXYMETHYL-α,β-BUTENOLIDE AND DERIVATIVES
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Exhaustive approaches to the synthesis of racemic γ-heterosubstituted γ-methyl-α,β-butenolides are presented, starting from C3 synthons (glyceraldehyde, glycidaldehyde, acrolein and 2,3-epoxypropyl ethers).Good general methods for the preparation of γ-hydroxymethyl-α,β-butenolide 2, several of its ether derivatives, as well as of γ-bromomethyl-α,β-butenolide 5, are given.The reactivities of these structurally simple but highly functionalized compounds, convenient synthons for more complex molecules, are preliminarily explored.
- Cardellach, J.,Estopa, C.,Font, J.,Moreno-Manas, M.,Ortuno, R. M.,et al.
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p. 2377 - 2394
(2007/10/02)
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- A SHORT SYNTHESYS OF (S)-5-HYDROXYMETHYL-(5H)-FURAN-2-ONE AND DERIVATIVES FROM D-RIBONOLACTONE
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We describe a short synthesis of (S)-5-hydroxymethyl-(5H)-furan-2-one and some 5-O-derivatives, which are being used as key starting products for the synthesis of several antileukaemic lignan lactones, from D-ribonolactone.
- Camps, P.,Font, J.,Ponsati, O.
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p. 1471 - 1472
(2007/10/02)
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