- Renewable production of phthalic anhydride from biomass-derived furan and maleic anhydride
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A route to renewable phthalic anhydride (2-benzofuran-1,3-dione) from biomass-derived furan and maleic anhydride (furan-2,5-dione) is investigated. Furan and maleic anhydride were converted to phthalic anhydride in two reaction steps: Diels-Alder cycloaddition followed by dehydration. Excellent yields for the Diels-Alder reaction between furan and maleic-anhydride were obtained at room temperature and solvent-free conditions (SFC) yielding 96% exo-4,10-dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione (oxanorbornene dicarboxylic anhydride) after 4 h of reaction. It is shown that this reaction is resistant to thermal runaway because of its reversibility and exothermicity. The dehydration of the oxanorbornene was investigated using mixed-sulfonic carboxylic anhydrides in methanesulfonic acid (MSA). An 80% selectivity to phthalic anhydride (87% selectivity to phthalic anhydride and phthalic acid) was obtained after running the reaction for 2 h at 298 K to form a stable intermediate followed by 4 h at 353 K to drive the reaction to completion. The structure of the intermediate was determined. This result is much better than the 11% selectivity obtained in neat MSA using similar reaction conditions.
- Mahmoud, Eyas,Watson, Donald A.,Lobo, Raul F.
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p. 167 - 175
(2014/01/06)
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- From Spanish fly to room-temperature ionic liquids (RTILs): Synthesis, thermal stability and inhibition of dynamin 1 GTPase by a novel class of RTILs
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In a series of simple synthetic manipulations the active component of the aphrodisiac Spanish fly has resulted in the generation of a new family of room-temperature ionic liquids (RTILs). These RTILs are synthesized in high yield from readily attainable starting materials and can be generated in either meso or chiral forms dependant on the starting furan analogue. Substituted furans (2-methyl and 2-ethyl) afford chiral RTILs, furan affords a family of meso RTILs. In all cases the counterion was crucial, with CH3SO 3- consistently displaying the lowest melting points. Of the RTILs synthesized, TGA plots showed most to be stable up to at least 250°C. We had sought to use these RTILs in a series of dynamic combinatorial chemistry (DCC) assembly reactions via solubulisation of dynamin GTPases pleckstrin homology (PH) domain, as such all analogues were screened as potential inhibitors. Screening reveals that these RTILs display varying levels of dynamin GTPase inhibition with a number amongst the most potent inhibitors of dynamin GTPase yet discovered, e.g.13 IC50 = 2.3 ± 0.3 μM (4-(N,N-dimethyl-N-octadecyl-N-ethyl)-4-aza-10-oxatricyclo[5.2.1]decane-3, 5-dione bromide. Accordingly these RTILs have limited utility for DCC assembly with dynamin GTPase, but may be of use with other proteins or in other fields of study. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Zhang, Jie,Lawrance, Geoffrey A.,Chau, Ngoc,Robinson, Phillip J.,McCluskey, Adam
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- The molecular and crystal structure of (+/-)-1-methyl-7-oxa-norborn-5-ene-2exo,3exo-dicarboxylic acid-anhydride and its enantiodifferentiation in 1H NMR spectroscopy.
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The Diels-Alder reaction between 2-methylfuran and maleic anhydride leads to the formation of known racemic title adduct 3. The structure of this compound was confirmed by X-ray crystallography. An efficient enantiodifferentiation of 3 in 1H NMR spectroscopy was observed upon treatment with Eu(hfc)3.
- Maurin,Czarnocki,Wojtasiewicz,Matuszewka,Ziolkowski
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p. 347 - 351
(2007/10/03)
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- Heavy atom effects reveal diradical intermediates. I. An aqueous Diels- Alder reaction
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The aqueous Diels-Alder reaction between 2-methylfuran and maleic acid in water is 99.9% stereospecific. Addition of heavy but not light atom salts to the retrodiene reaction reduces the degree of stereospecificity significantly. Taking into account the relatively low concentration (3.5-7 M) of heavy atoms, and the rapid fall off of the heavy atom effect with distance, these results show that a large portion, if not all of the Diels Alder occurs via diradical intermediates.
- Telan, Leila A.,Firestone, Raymond A.
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p. 14269 - 14280
(2007/10/03)
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- Some transformations of adducts of 3,6-dimethoxy-4,5-methylenedioxy-1,2-didehydrobenzene and furans. An approach to the 5,8-dimethoxy-6,7- methylenedioxynaphtho[2,3-c]furan-4,9-dione ring system of ventilone A
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Adducts derived from the aryne 3,6-dimethoxy-4,5-methylenedioxy-1,2-didehydrobenzene (19) with furan and 2-methoxyfuran have been converted into 5,8-dimethoxy-6,7-methylenedioxy-1,2-naphthoquinone (22) and 5,8-dimethoxy-6,7-methylenedioxy-1,4-naphthoquino
- Buttery, Jarrod H.,Wege, Dieter
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p. 409 - 419
(2007/10/03)
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- The effect of the acidifying group on the regioselectivity of the base-induced ring opening of hetero-oxabicyclic [3.2.1] and [3.3.1] systems
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Unsymmetrical 8-oxa-3-thiabicyclo[3.2.1]octane and 9-oxa-3-thiabicyclo[3.3.1]nonane underwent highly regioselective base-induced elimination but low selectivity was observed for the sulfonyl and the aza-oxa systems. A correlation between the regioselectivity of the reaction and the proton undergoing abstraction (i.e. equatorial vs. the axial proton) was made.
- Lautens, Mark,Fillion, Eric,Sampat, Michael
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p. 1501 - 1504
(2007/10/03)
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- Regioselective nucleophilic ring opening of oxabicyclic compounds
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The ring opening of unsymmetrical oxabicyclic compounds was found to be highly regioselective, giving rise to products from the attack of the nucleophile distal to the bridgehead substituent. Ozonolysis furnished acyclic chains with up to five stereocenters and differentiated ends.
- Lautens, Mark,Chiu, Pauline
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p. 773 - 776
(2007/10/02)
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