- AN EFFICIENT SYNTHESIS OF (S)-5-HYDROXYMETHYL-2(5H)-FURANONE
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A three step synthesis of the title compound 1a from D-ribono-1,4-lactone in 48percent yield is described.The concept centers on a novel NaHSO3-induced trans-Br-OAc elimination of the readily prepared bromo-acetate mixture 3a,b to the corresponding butenolides 1e and 1f, the former of which, on hydrolysis and purification, yields pure 1a.
- Vekemans, Jozef A. J. M.,Franken, Gabriel A. M.,Chittenden, Gordon J. F.,Godefroi, Erik F.
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Read Online
- 1,3-Dipolar cycloaddition reaction of α,β-unsaturated esters and lactones with diazomethane
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1,3-Dipolar cycloaddition of diazomethane to the α,β-unsaturated esters and lactones such as 2-4, 6-8, 10 and 13 occurs in a stereoselective manner affording conjugated Δ2-pyrazolines. E and Z isomers of D-mannitol lead to identical product which was cyclised to investigate the absolute stereochemistry of the product. The regiospecificities of all the reactions are consistent with FMO coefficients obtained through AM1 calculations.
- Baskaran,Vasu,Prasad, Ram,Kodukulla,Trivedi, Girish K.,Chandrasekhar
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Read Online
- Metal-containing zeolites as efficient catalysts for the transformation of highly valuable chiral biomass-derived products
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Metal-containing zeolites, especially Sn-Beta, perform as very efficient heterogeneous catalysts in the selective oxidation of levoglucosenone, which is considered as a platform chemical for the production of highly-valuable chemicals, towards the synthesis of the optically pure γ-lactone (S)-γ-hydroxymethyl-α,β-butenolide (HBO) using H 2O2 as an oxidizing agent. Using Sn-Beta as a catalyst, yields up to 75% of (S)-γ-hydroxymethyl-α,β-butenolide are achieved in a one-pot cascade reaction. When Sn-Beta is combined with an acid resin, such as Amberlyst-15, the two-step process allows yields up to 90%.
- Paris, Cecilia,Moliner, Manuel,Corma, Avelino
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Read Online
- Stereoselectivity of N-benzyl-C-ethoxycarbonyl nitrone cycloaddition to (S)-5-hydroxymethyl-2(5H)-furanone and its derivatives
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Stereoselectivity of the reaction of N-benzyl-C-ethoxycarbonyl nitrone (3) with (S)-5-hydroxymethyl-2(5H)-furanone (2a) and its 5-alkoxy substituted derivatives 2b-f was investigated. The reaction proceeds in a highly face- selective manner, the products 4-6 resulting from approach anti to the hydroxymethyl or alkoxymethyl group of the dipolarophile. The exo- stereoselectivity increases as the size of protective group attached to lactone (2b-f) increases. Endo-exo diastereoselectivity is affected significantly by the solvent. Microwave irradiation strongly accelerates the reaction with little effect on the diastereoselectivity to give the syn adduct 8a in addition to anti cycloadducts 4a-6a.
- Ondrus, Vladimir,Orsag, Michal,Fisera, L'ubor,Pronayova, Nad'a
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Read Online
- Stereoselective Construction of the Methylcyclopentane Core of Peditithins B-H with Five Continuous Stereocenters
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A stereoselective construction of the methylcyclopentane core (3) of jatrophane diterpenoids peditithins B-H was achieved in 14 steps from commercially available d-(+)-ribono-1,4-lactone (9). The linear 5-ene-heptanal derived from 9 was cyclized to the five-membered ring by an intramolecular carbonyl ene reaction, and five continuous stereocenters on 3 were stereoselectively introduced via a successive substrate-controlled manner, involving diastereoselective 1,4-addition, MoOPH-induced hydroxylation, and stereospecific epoxidation.
- Li, Qingjiang,Li, Wei,Ni, Fu-Qiang,Wu, Shu-Qi,Yin, Sheng
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supporting information
p. 9360 - 9364
(2020/12/21)
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- Synthesis and fungicidal activity of methylsulfanylmethyl ether derivatives of levoglucosenone
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[Figure not available: see fulltext.] A series of derivatives were synthesized on the basis of levoglucosenone that contained hydroxy groups at the С-4 atom or С-2 and С-4 atoms or a hydroxy and methyl group at the С-4 atom. In addition, 4-hydroxymethylbutanolides were synthesized. Derivatives containing hydroxy groups were obtained as methylsulfanylmethyl ethers. It was established that compounds containing a 6,8-dioxabicyclo[3.2.1]-octane ring exhibited fungicidal activity against Rhizoctonia solani. It was shown that the presence of a methylsulfanylmethyl moiety in the ring could increase the fungicidal activity of compounds.
- Sharipov, Bulat T.,Davidova, Anna N.,Ryabova, Alena S.,Galimzyanova, Nailya F.,Valeev, Farid A.
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- High-Yielding Diastereoselective syn-Dihydroxylation of Protected HBO: An Access to D-(+)-Ribono-1,4-lactone and 5-O-Protected Analogues
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A diastereoselective chemoenzymatic synthetic pathway to D-(+)-ribono-1,4-lactone, a versatile chiral sugar derivative widely used for the synthesis of various natural products, has been designed from cellulose-based levoglucosenone (LGO). This route involves a sustainable Baeyer-Villiger oxidation of LGO to produce enantiopure (S)-γ-hydroxymethyl-α,β-butenolide (HBO) that is further functionalized with various protecting groups to provide 5-O-protected γ-hydroxymethyl-α,β-butenolides. The latter then undergo a diastereoselective and high-yielding syn-dihydroxylation of the α,β-unsaturated lactone moiety followed by a deprotection step to give D-(+)-ribono-1,4-lactone. Through this 4-step synthetic route from LGO, D-(+)-ribono-1,4-lactone is obtained with d.r. varying from 82:18 to 97:3 and in overall yields between 32 and 41 % depending on the protecting group used. Moreover, valuable synthetic intermediates 5-O-tert-butyldimethylsilyl-, 5-O-tert-butyldiphenylsilyl- as well as 5-O-benzyl-ribono-1,4-lactones are obtained in 3 steps from LGO in 58, 61 and 40 %, respectively.
- Moreaux, Maxime,Bonneau, Guillaume,Peru, Aurélien,Brunissen, Fanny,Janvier, Marine,Haudrechy, Arnaud,Allais, Florent
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supporting information
p. 1600 - 1604
(2019/01/14)
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- METHOD FOR CONVERTING LEVOGLUCOSENONE INTO 4-HYDROXYMETHYL BUTYROLACTONE AND 4-HYDROXYMETHYL BUTENOLIDE WITHOUT USING ANY ORGANIC SOLVENT AND CATALYST
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The invention relates to a method for converting levoglucosenone into 4-hydroxymethyl butyrolactone and 4-hydroxymethyl butenolide without using any solvent or catalyst, wherein the oxidation and hydrolysis of the levoglucosenone or hydrogenated levoglucosenone are carried out in a single step using an aqueous solution of H2O2.
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Paragraph 0052-0056; 0057-0058; 0081-0084; 0085-0086
(2019/07/23)
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- Assignment of the relative and absolute stereochemistry of two novel epoxides using NMR and DFT-GIAO calculations
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Considering the potential biological application of isobenzofuranones, especially as agrochemical defensives, two novel epoxides, (1aR,2R,2aR,5S,5aS,6S,6aS)-5-(hydroxymethyl)hexahydro-2,6-methanooxireno[2,3-f]isobenzofuran-3(1aH)-one (9), and (1aS,2S,2aR,5S,5aS,6R,6aR)-5-(hydroxymethyl)hexahydro-2,6-methanooxireno[2,3-f]isobenzofuran-3(1aH)-one (10), were synthesized from the readily available D-mannitol in six steps. The multiplicities of the hydrogens located at the bridge of the bicycle are distinct for epoxides 9 and 10 due to W coupling, and this feature was employed to confirm the assignment of these nuclei. Besides analyses of the 2D NMR spectra, the assignments of the nuclei at the epoxide ring were also inferred from information obtained by theoretical calculations. The calculated 1H and 13C NMR chemical shifts for eight candidate structures were compared with the experimental chemical shifts of 9 and 10 by measuring the mean absolute errors (MAE) and by the DP4 statistical analysis. The structures and relative configurations of 9, and 10 were determined via NMR spectroscopy assisted with theoretical calculations. As consequence of the enantioselective syntheses starting from a natural polyol, the absolute configurations of the epoxides 9 and 10 were also defined.
- Moraes,Alvarenga,Demuner,Viana
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p. 109 - 115
(2018/05/03)
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- Organic solvent- and catalyst-free Baeyer-Villiger oxidation of levoglucosenone and dihydrolevoglucosenone (Cyrene): A sustainable route to (: S)-γ-hydroxymethyl-α,β-butenolide and (S)-γ-hydroxymethyl-γ-butyrolactone
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A straightforward and sustainable route to (S)-γ-hydroxymethyl-α,β-butenolide (HBO) and (S)-γ-hydroxymethyl-α,β-butyrolactone (2H-HBO), two valuable chemical platforms for the synthesis of fine chemicals such as drugs, pheromones, flavors and fragrances, has been optimized using renewable cellulose-based levoglucosenone (LGO) and Cyrene as starting materials and aqueous H2O2 as both a solvent and an oxidizing agent. Combined with short-path distillation, this procedure provides enantiopure HBO and 2H-HBO in yield as high as 72% at the kilo scale.
- Bonneau, Guillaume,Peru, Aurélien A. M.,Flourat, Amandine L.,Allais, Florent
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supporting information
p. 2455 - 2458
(2018/06/11)
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- Guiding a divergent reaction by photochemical control: Bichromatic selective access to levulinates and butenolides
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Allylic and acrylic substrates may be efficiently transformed by a sequential bichromatic photochemical process into derivatives of levulinates or butenolides with high selectivity when phenanthrene is used as a regulator. Thus, UV-A photoinduced cross-metathesis (CM) couples the acrylic and allylic counterparts and subsequent UV-C irradiation initiates E-Z isomerization of the carbon-carbon double bond, followed by one of two competing processes; namely, cyclization by transesterification or a 1,5-H shift and tautomerization. Quantum chemical calculations demonstrate that intermediates are strongly blue-shifted for the cyclization while red-shifted for the 1,5-H shift reaction. Hence, delaying the double bond migration by employing UV-C absorbing phenanthrene, results in a selective novel divergent all-photochemical pathway for the synthesis of fundamental structural motifs of ubiquitous natural products.
- Sutar, Revannath L.,Sen, Saumik,Eivgi, Or,Segalovich, Gal,Schapiro, Igor,Reany, Ofer,Lemcoff, N. Gabriel
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p. 1368 - 1374
(2018/02/09)
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- METHOD FOR SYNTHESIZING A PRECURSOR OF A SINGLE DAIRY-LACTONE ISOMER
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This disclosure provides a method for preparing a precursor of a single dairy-lactone isomer, methods of preparing a single dairy-lactone isomer, and to the organoleptic uses thereof.
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Paragraph 0045; 0046; 0052; 0053; 0054; 0055
(2018/03/25)
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- Unconventional Fragment Usage Enables a Concise Total Synthesis of (-)-Callyspongiolide
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An asymmetric synthesis of (-)-callyspongiolide is described. The route builds the macrolide domain atypically from a disaccharide and a monoterpene without passing through a seco-acid. Chiral iridium catalysis selectively joins fragments. Subsequent degradation of an imbedded butyrolactone via perhemiketal fragmentation affords a stereo- and regio-defined homoallylic alcohol that is engaged directly in a carbonylative macrolactonization. Further elaboration of the polyunsaturated appendage provides the natural product in a particularly direct and flexible manner.
- Manoni, Francesco,Rumo, Corentin,Li, Liubo,Harran, Patrick G.
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supporting information
p. 1280 - 1284
(2018/02/09)
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- Diastereoselective Weitz-Scheffer epoxidation of levoglucosenone for the synthesis of isolevoglucosenone and derivatives
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High-yielding epoxidation conditions for the cellulose pyrolysis product (?)-levoglucosenone (LGO) and 3-aryl derivatives of LGO have been developed. The reaction of LGO with hydrogen peroxide/base is known to give a Baeyer-Villiger reaction, however, it was found that the reactions of LGO or derivatives with tert-butylhydroperoxide/base affords solely epoxides through the Weitz-Scheffer reaction. A critical parameter in the successful isolation of the epoxide from LGO was to avoid all contact with water or alcohols during the reaction and workup. The epoxide products were reacted under Wharton conditions affording allylic alcohols and subsequent oxidation led to isolevoglucosenone or 3-arylisolevoglucosenone derivatives. Previously unreported reactions on isolevoglucosenone were then investigated.
- Ledingham, Edward T.,Greatrex, Ben W.
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p. 6107 - 6115
(2018/09/14)
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- NOVEL 3-SUBSTITUTED 5-AMINO-6H-THIAZOLO[4,5-D]PYRIMIDINE-2,7-DIONE COMPOUNDS FOR THE TREATMENT AND PROPHYLAXIS OF VIRUS INFECTION
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The present invention relates to compounds of formula (I), wherein R1, R2 and R3 are as described herein, and their prodrugs or pharmaceutically acceptable salt, enantiomer or diastereomer thereof, and compositions including the compounds and methods of using the compounds.
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Paragraph 0592; 0593; 0594
(2016/08/07)
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- NOVEL SUBSTITUTED AMINOTHIAZOLOPYRIMIDINEDIONE FOR THE TREATMENT AND PROPHYLAXIS OF VIRUS INFECTION
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The present invention relates to compounds of formula (I), wherein R1 to R5 are as described herein, and their prodrugs or pharmaceutically acceptable salt, enantiomer or diastereomer thereof, and compositions including the compounds and methods of using the compounds.
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Page/Page column 25
(2016/11/28)
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- Chemo-enzymatic synthesis of chiral epoxides ethyl and methyl (S)-3-(Oxiran-2-yl)propanoates from Renewable levoglucosenone: An access to enantiopure (S)-dairy lactone
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Chiral epoxides-such as ethyl and methyl (S)-3-(oxiran-2-yl)propanoates ((S)-1a/1b)-are valuable precursors in many chemical syntheses. Until recently, these compounds were synthesized from glutamic acid in four steps (deamination, reduction, tosylation and epoxide formation) in low to moderate overall yield (20%-50%). Moreover, this procedure requires some harmful reagents such as sodium nitrite ((eco)toxic) and borane (carcinogen). Herein, starting from levoglucosenone (LGO), a biobased chiral compound obtained through the flash pyrolysis of acidified cellulose, we propose a safer and more sustainable chemo-enzymatic synthetic pathway involving lipase-mediated Baeyer-Villiger oxidation, palladium-catalyzed hydrogenation, tosylation and treatment with sodium ethoxide/methoxide as key steps. This route afforded ethyl and methyl (S)-3-(oxiran-2-yl)propanoates in 57% overall yield, respectively. To demonstrate the potentiality of this new synthetic pathway from LGO, the synthesis of high value-added (S)-dairy lactone was undertaken from these epoxides and provided the target in 37% overall yield from LGO.
- Peru, Aurélien A. M.,Flourat, Amandine L.,Gunawan, Christian,Raverty, Warwick,Jevric, Martyn,Greatrex, Ben W.,Allais, Florent
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- Chemo-enzymatic synthesis of key intermediates (S)-γ-hydroxymethyl-α,β-butenolide and (S)-γ-hydroxymethyl-γ-butyrolactone via lipase-mediated Baeyer-Villiger oxidation of levoglucosenone
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Levoglucosenone (LGO), a valuable chiral platform chemical that can be efficiently produced from catalytic fast pyrolysis of cellulose, has been efficiently converted into optically pure (S)-γ-hydroxymethyl-α,β-butenolide (HBO) using a two-step sequence involving a lipase-mediated Baeyer-Villiger oxidation and an acid hydrolysis. In the same fashion, (S)-γ-hydroxymethyl-γ-butyrolactone (2H-HBO) was successfully obtained through a three-step sequence (Baeyer-Villiger, palladium-catalysed hydrogenation and acid hydrolysis). The use of solid buffers in the lipase-mediated Baeyer-Villiger oxidation has proved beneficial in two ways: not only the reaction time and the enzymatic load were both reduced four-fold (from 8 to 2 hours and 464 to 113 U mmol?1) to reach conversions ≥83%, but solid buffers also prevented lipase from denaturation, thus preserving its enzymatic activity and allowing its use for further oxidation cycles.
- Flourat,Peru,Teixeira,Brunissen,Allais
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p. 404 - 412
(2018/04/16)
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- The conversion of levoglucosenone into isolevoglucosenone
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Levoglucosenone (1), a compound that will soon be available in tonne quantities through the pyrolysis of acid-treated lignocellulosic biomass, has been converted into isolevoglucosenone (2) using Wharton rearrangement chemistry. Treatment of compound 1 with alkaline hydrogen peroxide gave the γ-lactones 5 and 6 rather than the required epoxy-ketones 3 and/or 4. However, the latter pair of compounds could be obtained by an initial Luche reduction of compound 1, electrophilic epoxidation of the resulting allylic alcohol 8 and oxidation of the product oxiranes 9 and 10. Independent treatment of compounds 3 and 4 with hydrazine then acetic acid followed by oxidation of the ensuing allylic alcohols finally afforded isolevoglucosenone (2). Details of the single-crystal X-ray analyses of epoxy-alcohols 9 and 10 are reported.
- Ma, Xinghua,Anderson, Natasha,White, Lorenzo V.,Bae, Song,Raverty, Warwick,Willis, Anthony C.,Banwell, Martin G.
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p. 593 - 599
(2015/04/27)
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- Synthesis of γ- and δ-lactone natural products by employing a trans-cis isomerization/lactonization strategy
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Alkaline hydrolysis of 4-hydroxy- or/and 5-hydroxy-(2E)-alkenoate followed by acid treatment gave the corresponding (2E)-alkenoic acids which were subjected to lactone formation reaction without further purification. The crude acids were treated with 2,4,6-trichlorobenzoyl chloride in pyridine to afford ?-lactone or d-lactone, respectively, accompanied by trans-cis isomerization. By this procedure, (±)-(4,5)-trans-5-benzyloxy- 2-hexen-4-olide (90% overall yield), (S)-5-hydroxy-2-penten-4-olide (86% overall yield), (4S,5R)-5- hydroxy-2-hexen-4-olide (86% overall yield), (4R,5S)-5-hydroxy-2-hexen-4-olide (82% overall yield), (S)- parasorbic acid (58% overall yield) and natural product, (5R,7S)-7-hydroxy-2-octen-5-olide (euscapholide: 20% overall yield) were synthesized.
- Ono, Machiko,Kato, Keisuke,Akita, Hiroyuki
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p. 464 - 470
(2013/06/05)
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- Expanding the scope of biomass-derived chemicals through tandem reactions based on oxorhenium-catalyzed deoxydehydration
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New modes of DODH: Oxorhenium compounds act as deoxydehydration(DODH)/acid dual-purpose catalysts to transform biomass-derived diol substrates into a variety of commodity chemical precursors. The power of this approach is highlighted by a tandem [1,3]-OH shift/DODH of 2-ene-1,4-diols and 2,4-diene-1,6-diols, and by a DODH/esterification sequence of sugar acids to unsaturated esters for the production of polymers and plasticizers. Copyright
- Shiramizu, Mika,Toste, F. Dean
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supporting information
p. 12905 - 12909
(2014/01/06)
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- HALOGENATED 2-DEOXY-LACTONES, 2'-DEOXY--NUCLEOSIDES, AND DERIVATIVES THEREOF
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Disclosed are halogenated 2-deoxy-lactone, 2'-deoxy-nucleosides, and derivatives thereof, for example, a compound of formula (I). Also disclosed are a composition comprising a pharmaceutically acceptable carrier and at least one compound or salt of the invention, and a method of treating a disorder is selected from the group consisting of an abnormal cellular proliferation, a viral infection, and an autoimmune disorder.
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Page/Page column 40
(2011/02/24)
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- Synthesis and anti-HIV activity of conformationally restricted bicyclic hexahydroisobenzofuran nucleoside analogs
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A chiral synthesis of a series of hexahydroisobenzofuran (HIBF) nucleosides has been accomplished via glycosylation of a stereo-defined (syn-isomer) sugar motif 16 with the appropriate silylated bases. All nucleoside analogs were obtained in 52-71% yield as a mixture of α- and β-anomeric products increasing the breadth of the novel nucleosides available for screening. The structure of the novel bicyclic HIBF nucleosides was established by a single crystal X-ray structure of the β-HIBF thymine analog 22b. Furthermore, the sugar conformation for these nucleosides was established as N-type. Among the novel HIBF nucleosides synthesized, twenty-five compounds were tested as inhibitor of HIV-1 in human peripheral blood mononuclear (PBM) cells and seven were found to be active (EC50 = 12.3-36.2 μM). Six of these compounds were purine analogs with β-HIBF inosine analog 22o being the most potent (EC50 = 12.3 μM) among all compounds tested. The striking resemblance between didanosine (ddI) and 22o may explain the potent anti-HIV activity.
- Diaz-Rodriguez, Alba,Sanghvi, Yogesh S.,Fernandez, Susana,Schinazi, Raymond F.,Theodorakis, Emmanuel A.,Ferrero, Miguel,Gotor, Vicente
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scheme or table
p. 1415 - 1423
(2009/10/24)
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- QUINOLONE ANTIBACTERIAL AGENTS
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Compounds of formula I and methods for their preparation are disclosed. Further disclosed are methods of making biologically active compounds of formula I as well as pharmaceutically acceptable compositions comprising compounds of formula I. Compounds of formula I as disclosed herein can be used in a variety of applications including use as antibacterial agents.
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Page/Page column 68; 131
(2010/02/11)
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- Stereoselective photochemical 1,3-dioxolane addition to 5-alkoxymethyl-2(5H)-furanone: Synthesis of bis-tetrahydrofuranyl ligand for HIV protease inhibitor UIC-94017 (TMC-114)
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A convenient synthesis of (3R,3aS,6aR)-3-hydroxyhexahydrofuro[2,3-b]furan, a high-affinity non-peptidal ligand for HIV protease inhibitor UIC-94017, is described. This inhibitor is undergoing advanced clinical trials. The synthesis utilizes a novel stereoselective photochemical 1,3-dioxolane addition to 5(S)-benzyloxymethyl-2(5H)-furanone as the key step. The requisite furanone derivative was prepared in high enantiomeric excess by an immobilized lipase-catalyzed selective acylation of (±)-1-(benzyloxy)-3-buten-2-ol and a ring-closing olefin metathesis with Grubbs' catalyst. Optically active bis-THF was converted to protease inhibitor 2 (UIC-94017).
- Ghosh, Arun K.,Leshchenko, Sofiya,Noetzel, Marcus
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p. 7822 - 7829
(2007/10/03)
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- Direct access to furanosidic eight-membered ulosonic esters from cis-α,β-epoxy aldehydes
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Direct access to bicyclic precursors of octulosonic acids is achieved by treatment of differentially (or not) protected γ,δbis(silyloxy) cis-α,β-epoxy aldehydes with ethyl 2-(trimethylsilyloxy)-2-propenoate in the presence of boron trifluoride-diethyl ether. An X-ray crystallographic structure of a bicycle (compound 33a) was obtained and used to determine the absolute configurations of the different stereogenic centers and thus the diastereoselective preference of the aldol reaction (syn) and the regioselectivity of the epoxide ring-opening (C-6 atom). Functionalization and opening of the bicyclic compound to afford octulosonic analogues in their furanoside forms was studied. An octulosonic 8-phosphate analogue has been synthesized. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Sugisaki, Claudia H.,Ruland, Yvan,Baltas, Michel
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p. 672 - 688
(2007/10/03)
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- Synthetic study on gymnodimine: Highly stereoselective construction of substituted tetrahydrofuran and cyclohexene moieties
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The synthetic studies on gymnodimine, a shellfish toxin, are described. This marine toxin consists of 16-membered carbocycle, tetrahydrofuran, and spiro-imine moieties. Our synthetic strategy involves the stereoselective allylation of tetrahydrofuran compound and the exo-selective intramolecular Diels-Alder reaction.
- Ishihara, Jun,Miyakawa, Jun,Tsujimoto, Takashi,Murai, Akio
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p. 1417 - 1419
(2007/10/03)
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- Synthesis of Optically Active Butenolides and γ-Lactones by the Sharpless Asymmetric Dihydroxylation of β,γ-Unsaturated Carboxylic Esters
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Keywords: asymmetric synthesis; butenolides; dihydroxylations; furanones; lactones
- Harcken, Christian,Brueckner, Reinhard
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p. 2750 - 2752
(2007/10/03)
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- Cycloaddition Reaction of 2,2-Dimethyl-3,4-dihydro-2H-pyrrole N-Oxide With Unsaturated Sugar Lactones and Esters
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Intermolecular asymmetric 1,3-dipolar cycloaddition of 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide with optically active α,β-unsaturated esters 1,2 gave the diastereomers 8,9,10 and with sugar lactones 3 and 6 gave stereoselectively the cycloadduct 11 and 12.The stereochemistry of the products has been established using high field nmr techniques.The major adducts 11 and 12 arise from an exo transition state and anti-approach, indicating the dominance of steric factors over secondary orbital interactions.
- Baskaran, S.,Trivedi, Girish.K.
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p. 1853 - 1864
(2007/10/03)
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- Enantioselective total synthesis of (+)-stoechospermol via stereoselective intramolecular (2+2) photocycloaddition of the chiral butenolide
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Enantioselective total synthesis of (+)-stoechospermol 2, a representative of spatane diterpenes having a cis,anti,cis-tricyclo[5.2.0.02,6]decane skeleton, was achieved by employing a stereo- and regioselective intramolecular (2+2) photocycloaddition of (S)-γ-hydroxymethyl-γ-butenolide-derived ester 10.
- Tanaka, Masahide,Tomioka, Kiyoshi,Koga, Kenji
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p. 12829 - 12842
(2007/10/02)
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- Stereoselective synthesis of 3-azido-2,3-dideoxy-D-ribose derivatives and its utilization for the synthesis of anti-HIV nucleosides [1]
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Detail account of the synthesis of 3'-azido nucleosides utilizing 3- azido-2,3-dideoxy-D-ribose derivative 7 as the key intermediate was described. The key intermediate 7 was synthesized from D-mannitol in 8 steps in a preparative scale. The Michael reaction of the azide group with α,β- unsaturated-γ-butyrolactone 4 was affected by the steric bulkiness of the substituent at the 5-O position. A bulky t-butyldiphenylsilyl substitution at 5-O gave almost exclusively the α-azido adduct 5b, while unsubstitution at 5-O produced I:1 mixture of α-and β-adducts. The ratio of α to β anomers in the condensation between azido acetate 7a and pyrimidine bases for the preparation of AZT and AZDU was greatly influenced by the solvent and the Lewis acid catalyst used. In the synthesis of 12(AZDU, CS-87), the combination of dichloroethane and trimethylsilyl triflate gave an optimal result, while in the case of 14(AZT), various conditions gave similar ratio of α,β anomers. The azido intermediate 7b was also utilized for the synthesis of several 3'-azido purine-like nucleosides 16-27. The glycosylation was also affected by the Lewis acid catalyst. Boron trifluoride etherate gave the desired N1-glycosylated compounds in which the α-anomer was major, but other catalysts such as trimethylsilyl triflate or stannic chloride produced N2-glycosylated compounds as the major products. The newly synthesized purine-like compounds have been tested against HIV, however, none of them showed any significant activity.
- Jeong,Beach,Chu
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p. 1445 - 1452
(2007/10/02)
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- SYNTHESIS OF A USEFUL CHIRAL BUILDING BLOCK, (S)-5-ACETOXY-2-PENTEN-4-OLIDE FROM D-GLUCOSE
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A new method for preparation of (S)-5-acetoxy-2-penten-4-olide starting from D-glucose with 5 steps is described.
- Honda, Ichiro,Shibagaki, Makoto,Koseki, Koshi,Kuno, Hideyuki,Takahashi, Kyoko,Matsushita, Hajime
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p. 149 - 155
(2007/10/02)
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- A NEW SYNTHESIS OF (S)-5-HYDROXYMETHYL-2(5H)-FURANONE - A MULTIPURPOSE SYNTHON
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The multipurpose chiral synthons (S)-5-hydroxymethyl-2(5H)-furanone and its tert-butyldimethylsilyl ether were synthesized from 2,3-O-isopropylidene-D-glyceraldehyde in four or five stages through derivatives of 2-deoxy-D-ribonolactone.
- Danilova, G. A.,Mel'nikova, V. I.,Pivnitskii, K. K.
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p. 1905 - 1908
(2007/10/02)
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- A METHOD FOR EASY PREPARATION OF OPTICALLY PURE (S)-5-HYDROXY-2-PENTEN-4-OLIDE AND (S)-5-HYDROXYPENTAN-4-OLIDE
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A new method for preparation of (S)-5-hydroxy-2-penten-4-olide 1 and (S)-5-hydroxypentan-4-olide 8 starting from levoglucosenone 2 is described.
- Koseki, Koshi,Ebata, Takashi,Kawakami, Hiroshi,Matsushita, Hajime,Naoi, Yoshitake,Itoh, Kazuo
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p. 423 - 426
(2007/10/02)
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- Vitamin C and Isovitamin C Derived Chemistry. 3. Chiral Butenolides via Efficient 2,3-Didehydroxylations of L-Gulono-, D-Mannono-, and D-Ribono-1,4-lactones
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Efficient, operationally simple procedures for preparing the chiral butenolides 3a, 4a, 13a,b, and 16a-d from the commercial L-ascorbic acid (L-threo-hex-2-enono-1,4-lactone) and D-isoascorbic acid (D-erythro-hex-2-eno-no-1,4-lactone) are described.The concept centers on the novel NaHSO3-induced regiospecific trans-β-bromo-acetoxy elimination of the readily accessible O-acetylated bromodeoxyaldono-1,4-lactones 10a,b to compounds 13a,b.These, on deacetylation and treatment of the resulting bromohydrins 16a,b with Ag2O, afford the enantiomerically pure epoxides 16c,d and thence, in boiling water, the corresponding diols 3a and 4a.In a similar manner NaHSO3 causes the D-ribono-1,4-lactone-derived bromo acetate mixture 17a,b to undergo elimination to the corresponding butenolides 18a,b, which, on subsequent hydrolysis and chromatographic purification, has given compound 1a in 48percent overall yield.
- Vekemans, Josef A. J. M.,Franken, Gabriel A. M.,Dapperens, Cornelis W. M.,Godefroi, Erik F.,Chittenden, Gordon J. F.
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p. 627 - 633
(2007/10/02)
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- AN EFFICIENT TOTAL SYNTHESIS OF 3'-AZIDO-3'-DEOXYTHYMIDINE (AZT) AND 3'-AZIDO-2',3'-DIDEOXYURIDINE (AZDDU, CS-87) FROM D-MANNITOL
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An efficient stereoselective total synthesis of 3'-azido-3'deoxythymidine (AZT) and 3'-azido-2',3'-dideoxyuridine (AZDDU, CS-87) from readily available and inexpensive starting material, D-mannitol has been achieved.
- Chu, Chung K.,Beach, J. Warren,Ullas, Giliyar V.,Kosugi, Yoshiyuki
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p. 5349 - 5352
(2007/10/02)
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- A Short Synthesis of (S)-5-Hydroxy-2-penten-4-olide from D-Mannitol via 2,3-O-Isopropylidene-D-glyceraldehyde
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(S)-5-Hydroxy-2-penten-4-olide (5) was synthesized in three steps starting from D-mannitol bis(acetonide) (1), via D-glyceraldehyde acetonide (2) by Z-selective Wittig reaction, acid-catalyzed lactonization and crystallization with a total yield of 40percent.
- Haefele, Brigitte,Jaeger, Volker
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- Practical Synthesis of Some Versatile Chiral Building Blocks from (D)-Mannitol
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The three chiral building blocks ethyl 4,5-O-isopropylidene-(E)-(S)-4,5-dihydroxy-2-pentenoate , (S)-5-hydroxy-4-pentanolide , and (S)-5-hydroxy-2-penten-4-olide are conveniently prepared from 1,2:5,6-di-O-isopropylidene-D-mannitol (4) via a glycol cleavage and Horner-Emmons reaction sequence.
- Takano, Seiichi,Kurotaki, Ayako,Takahashi, Michiyasu,Ogasawara, Kunio
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p. 403 - 406
(2007/10/02)
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- EFFICIENT SYNTHESIS OF (S)-5-HYDROXYMETHYL-5(H)-FURAN-2-ONE FROM D-MANNITOL
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Chiral synthons - (S)-5-hydroxymethyl-5(H)-furan-2-one and its t-butyldimethylsilyl ether - were synthsized from D-mannitol in 6-7 steps via 2-desoxy-D-ribonolactone derivatives.
- Danilova, G. A.,Mel'nikova, V. I.,Pivnitsky, K. K.
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p. 2489 - 2490
(2007/10/02)
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- Preparation of Some 2,3-Dideoxylactones by an Unusual Catalytic Hydrogenolysis
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Hydrogenolysis of 2-bromo-2-deoxyaldono-1,4-lactones in ethanol solution with palladium as catalyst gives good yields of the corresponding 2,3-dideoxylactones with removal of not only the bromine atom but also the C-3 hydroxy group.
- Lundt, Inge,Pedersen, Christian
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p. 1052 - 1054
(2007/10/02)
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- ASYMMETRIC TOTAL SYNTHESIS OF STOECHOSPERMOL USING INTRAMOLECULAR (2+2) PHOTOCYCLOADDITION REACTION
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The first asymmetric total synthesis of stoechospermol, a representative spatane diterpene having cis, anti, cis-tricyclo2,6>decane ring system, was achieved.Using the intramolecular asymmetric (2+2) photocycloaddition reaction of the diastereomeric ester 11, the readily available butenolide 9 was transformed into the optically active dilactone 12a and 12b.Subsequent construction of tricyclic carbon ring system and introduction of substituents in a right stereochemistry gave rise to optically pure stoechospermol 1.
- Tanaka, Masahide,Tomioka, Kiyoshi,Koga, Kenji
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p. 3035 - 3038
(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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- 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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