- Thallium in Organic Synthesis. 56. A Novel Oxidative Intramolecular Cyclization/Rearrangement of 5-Norbornene-trans-2,3-dicarboxylic Acid with Thallium(III) Trifluoracetate (TTFA)
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Treatment of 5-norbornene-trans-2,3-dicarboxylic acid (5) with thallium(III) trifluoracetate (TTFA) and BF3*Et2O results in oxidative intramolecular cyclization, accompanied by rearrangement, to give the previously unknown 5,7-dihydroxy-2,3-norbornanedicarboxylic acid di-γ-lactone (9).
- Taylor, Edward C.,Jagdmann, G.Erik,McKillop, Alexander
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- Synthesis of (1S*,2S*,3S*,4S*,5S*,6S*,7S*,8S*)-1,2,7,8-Tetrachlorotricyclo3,8>octane-4,5-dicarboxylic Acid. Novel Entry into the C2-Bissecocubane System
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Photocaging of the known Diels-Alder dimer of 2,3-dichlorocyclopentadienone, compound 1, followed by alkali-induced double ring-cleavage of the resulting caged diketone rac-2 or its dihydrate rac-3, led to the title tetrachloro dicarboxylic acid rac-5, thus affording a novel entry into the inherently chiral tricyclo3,8>octane (C2-bissecocubane) system.Electrolysis of the disodium salt of rac-5- gave the tetrachloro alkene rac-14, from which other derivatives were obtained by standard methods.
- Baker, Colin J.,Fray, Gordon I.,Geen, Graham R.,Ryan, Keith
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- Synthesis of novel C-2 substituted imidazoline derivatives having the norbornene/dibenzobarrelene skeletons
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Novel imidazoline derivatives were synthesized from the norbornene and dibenzobarrelene skeletons which were obtained by the Diels-Alder reactions of anthracene and cyclopentadiene with the different dienophiles, such as fumaronitrile and fumaric acid. Synthesis of the C-2 substituted imidazolines was performed with high yields from various dinitriles and diacyl dichlorides.
- ?apan, Irfan,Servi, Süleyman
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- Resolution of (±)-Bicyclo[2.2.1]hept-5-ene-trans-2,3-dicarboxylic Acid: Crystal Structure of Its Cinchoninium Salt
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Abstract: Single crystals of (+)-cinchoninium (+)-bicyclo[2.2.1]hept-5-ene-trans-2-carboxyl-3-carboxylate (S,S)-2 were obtained upon resolution of racemic (±)-bicyclo[2.2.1]hept-5-ene-trans-2,3-dicarboxylic acid rac-1 with (+)-cinchonine. An X ray diffraction analysis established the most important secondary interactions between the ions that are deemed responsible for the diastereomeric separation process. From (S,S)-2 enantiomerically pure (+)-bicyclo[2.2.1]hept-5-ene-trans-2,3-dicarboxylic acid (S,S)-1 was isolated in 72 % yield. Graphical Abstract: An X-ray diffraction analysis of (+)-cinchoninium (+)-bicyclo[2.2.1]hept-5-ene-trans-2-carboxyl-3-carboxylate (S,S)-2 established the most important secondary interactions between the ions that are deemed responsible for the diastereomeric separation process.[Figure not available: see fulltext.]
- Jiménez, Lissette,González, Teresa,Brice?o, Alexander,Agrifoglio, Giuseppe,Pastrán, Jesús,Dorta, Romano
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p. 203 - 207
(2016/05/02)
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- Synthesis and evaluation of cationic norbornanes as peptidomimetic antibacterial agents
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A series of structurally amphiphilic biscationic norbornanes have been synthesised as rigidified, low molecular weight peptidomimetics of cationic antimicrobial peptides. A variety of charged hydrophilic functionalities were attached to the norbornane scaffold including aminium, guanidinium, imidazolium and pyridinium moieties. Additionally, a range of hydrophobic groups of differing sizes were incorporated through an acetal linkage. The compounds were evaluated for antibacterial activity against both Gram-negative and Gram-positive bacteria. Activity was observed across the series; the most potent of which exhibited an MIC's ≤ 1 μg mL-1 against Streptococcus pneumoniae, Enterococcus faecalis and several strains of Staphylococcus aureus, including multi-resistant methicillin resistant (mMRSA), glycopeptide-intermediate (GISA) and vancomycin-intermediate (VISA) S. aureus.
- Hickey, Shane M.,Ashton, Trent D.,Khosa, Simren K.,Robson, Ryan N.,White, Jonathan M.,Li, Jian,Nation, Roger L.,Yu, Heidi Y.,Elliott, Alysha G.,Butler, Mark S.,Huang, Johnny X.,Cooper, Matthew A.,Pfeffer, Frederick M.
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p. 6225 - 6241
(2015/06/08)
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- A simple method for resolution of endo-/exo-monoesters of trans-norborn-5-ene-2,3-dicarboxylic acids into their enantiomers
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Separation of optical isomers obtainable from trans-norborn-5-ene-2,3-dicarboxylic acid methyl and tert-butyl monoesters was performed by crystallization of the respective salts prepared with (R)- and (S)-1-phenylethylamine. Starting from racemic endo-monomethyl ester of trans-norborn-5-ene-2,3-dicarboxylic acid, prepared by partial hydrolysis of the cyclopentadiene-dimethyl fumarate adduct, the corresponding (2R, 3R)-endo-monoester was isolated in 97% enantiomeric excess (ee) yield after seven repeated crystallizations from tetrachloromethane. Starting from exo-mono-tert-butyl ester of the same acid, prepared by alcoholysis of the cyclopentadiene-maleic anhydride adduct followed by isomerization, (2R, 3R)-exo-monoester was isolated in >98% ee yield after four repeated crystallizations from ethanol. Crystallization of the acids from the mother liquor yielded products with inverse stereochemical configuration.
- Kovalenko, Vitaly N.,Kozyrkov, Yurii Yu.
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p. 151 - 155
(2015/03/04)
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- High-Load, ROMP-Generated Oligomeric Bis-acid Chlorides: Design of Soluble and Insoluble Nucleophile Scavengers
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(Equation presented) An efficient strategy for scavenging a host of nucleophiles utilizing an oligomeric bis-acid chloride (OBAC), generated from the ROM polymerization of trans-bicyclo[2.2.1]hept-5-ene-2,3-dicarbonyl dichloride, is described. The reactivity and high load of the OBAC reagent is exploited in the scavenging of amines, alcohols, and thiols that are present in excess following a common benzoylation event. Following the scavenging event, these oligomers can be precipitated with EtOAc and filtered (SiO2), leaving benzoylated nucleophiles in excellent yield and purity.
- Moore, Joel D.,Byrne, Robert J.,Vedantham, Punitha,Flynn, Daniel L.,Hanson, Paul R.
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p. 4241 - 4244
(2007/10/03)
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- Optical Resolution of trans-Bicycloheptane-2,3-diamine: Chiral Recognition in the Crystal of its Complex with (2R,3R)-O,O'-Dibenzoyltartaric Acid
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The synthesis of trans-bicycloheptane-2,3-diamine (6c), its optical resolution via formation of its complex with (2R,3R)-O,O'-dibenzoyltartaric acid (-BTA), and the crystal structure determination of this complex by X-ray diffraction techniques are reported.The absolute configuration of 6c in the complex has been determined to be (S,S)-6c from the endowed chirality of -BTA, thus optical resolution of 6c is achieved.Crystal data for the (S,S)-6c*(-BTA) complex is reported: C25H28N2O8*2H2O, M = 520.54, monoclinic P21, a = 9.150(1), b = 8.581(1), c = 17.036(1) Angstroem, β = 103,30(1) deg, V = 1301(2) Angstroem3, Z = 2, R = 0.037.The crystal of the molecular complex is found to have a multilamellar structure partitioned by thin hydrogen bonded sheets containing complex ammonium-carboxylate-water hydrogen bonds.Attached on both sides of the sheet, monolayer templates with benzoyl groups of -BTA and bicycloheptane fragments of 6c stack with the next templates to form hydrophobic bilayers.In the monolayer template, a cavity is formed surrounded by two pairs of two benzoyl groups distinguished from each other by their orientations toward the hydrogen bond sheet.The cavity provides a final site for the chiral recognition of 6c.The (S,S)-enantiomer of 6c is probably distinguished from the (R,R)-enantiomer by the favourable orientation of bicycloheptane skeleton in the cavity.
- Hatano, Keiichiro,Takeda, Tadahiro,Saito, Reiko
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p. 579 - 584
(2007/10/02)
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- A stereoselective biocatalytic Diels-Alder reaction
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Baker's yeast catalyzes the stereoselective Diels-Alder reaction of cyclopentadiene 1 with dienophiles 2, 4 and 6. A predominant formation of exo isomer is observed in some cases.
- Rao,Srinivasan,Bhanumathi
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p. 5959 - 5960
(2007/10/02)
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- Chiral rhodium-diphosphine catalyst capable of catalytic reduction of a tetramisole precursor to give a significant excess of the desired S-(-)isomer, levamisole
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A soluble, chiral, rhodium-containing catalyst which permits the catalytic reduction of prochiral 3-acyl-1-(2-alkoxyethyl)-4-phenyl-2-imidazolinones to chiral 3-acylimidazolidinones with a substantial excess of the desired S optical isomer. The 3-acylimidazolidinones may in turn be substantially converted to levamisole, and S isomer of tetramisole. The resolution of tetramisole to remove the R isomer is thus avoided.
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