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Cyclopropane Ring (cyclopropane + ring)
Selected AbstractsChemInform Abstract: Synthesis and Biological Activity of Permethrin Analogues Containing Various Substituents in Position 2 of the Cyclopropane Ring.CHEMINFORM, Issue 36 2009N. S. Mirzabekova Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Stereocontrolled Synthesis of Carbon,Carbon Double Bond Locked Analogues of Strobilurins Which Are Characterized by a trans-1,2-Disubstituted Cyclopropane Ring.CHEMINFORM, Issue 31 2001Renzo Rossi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Ruthenium-Catalyzed Hydroarylations of Methylenecyclopropanes: Mild C,H Bond Functionalizations with Conservation of Cyclopropane Rings.CHEMINFORM, Issue 50 2008Sergei I. Kozhushkov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis of Methylene- and Alkylidenecyclopropane DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Gérard Audran Abstract Since the methylenecyclopropane moiety is found in many biologically active natural substances, the synthesis of methylene- and alkylidenecyclopropanes remains a considerable challenge. In addition, an attractive feature is their surprising stability, accompanied by a high level of strain, conferring on them an otherwise unattainable chemical reactivity. The growing interest in the chemistry of these compounds has in its turn stimulated the development of alternative approaches to their skeleton, aimed at selectively introducing structural and chemical diversification. The three principal methods to synthesize these important compounds are based on the formation of the cyclopropane ring, the use of preformed cyclopropanes, and the use of preformed methylene- and alkylidenecyclopropanes. , Abbreviations: Ac: acetyl; Ar: aryl; Bn: benzyl; Boc: tert -butoxycarbonyl; Box: bisoxazoline; BTMSA: bis(trimethylsilyl)amide; Bu: butyl; Bz: benzoyl; C: cyclo; Cod: cyclooctadiene; Cp: cyclopentadienyl; Cy: cyclohexyl; Dba: (E,E)-dibenzylideneacetone; DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene; DCE: 1,2-dichloroethane; de: diastereomeric excess; DEAD: diethyl azodicarboxylate; DMAc: N,N -dimethylacetamide; DME: 1,2-dimethoxyethane; DMF: dimethylformamide; DOSP: N - p -dodecylbenzenesulfonylprolinate; Dppb: 1,4-bis(diphenyl)phosphinoborane; Dppe: bis(diphenylphosphino) ethene; E: electrophile; ee: enantiomeric excess; Et: ethyl; Hex: hexyl; L: ligand; LDA: lithium diisopropylamide; LG: leaving group; MCPBA: 3-chloroperoxybenzoic acid; Me: methyl; MEM: methoxyethoxymethyl; MOM: methoxymethyl; Mp: morpholinyl; Ms: mesyl; Naph: naphthyl; NFSI: N -fluorobenzenesulfonimide; Ns: nosyl; Nu: nucleophile; Pent: pentyl; Ph: phenyl; PMB: p -methoxybenzoyl; Pr: propyl; Py: pyridyl; SEM: 2-(trimethylsilyl)ethoxymethyl; TASF: tris(dimethylamino)sulfonium difluorotrimethyl silicate; TBAF: tetra- n -butylammonium fluoride; TBS: tert -butyldimethylsilyl; TEA: triethylamine; Tedicyp: cis,cis,cis -1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane; Tf: trifluoromethanesulfonyl; TFP: tris(2-furyl)phosphine; THF: tetrahydrofuran; THP: tetrahydropyran; TMS: trimethylsilyl; Tol: tolyl; Ts: 4-toluenesulfonyl (tosyl). [source] Acid-catalyzed hydrolysis of bridged bi- and tricyclic compounds.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 9 20023-acetylnortricyclanes, Kinetics, XXXIX, mechanisms of the hydration reactions of 1- Abstract The disappearance of 1- and 3-acetylnortricyclanes (1-Ac and 2-Ac) in aqueous perchloric acid was followed by capillary gas chromatography at different temperatures and acid concentrations. 1-Ac is much less reactive than 2-Ac. The activation parameters, solvent deuterium isotope effects and parameters of excess acidity equations were measured and the products studied. 1-Acetylnortricyclane is hydrated according to the A -2 mechanism, i.e. the carbonyl oxygen is protonated in the fast pre-equilibrium and one water molecule attacks at the rate-limiting stage the partially open cyclopropane ring, producing 6-acetyl-2-norborneols. 3-Acetylnortricyclane is hydrated according to the AdE2 mechanism, i.e. the cyclopropane ring is slowly protonated and opened, with subsequent fast attack of water producing 3-, 5- and 7-acetyl-2-norborneols. Copyright © 2002 John Wiley & Sons, Ltd. [source] Acid-catalyzed hydrolysis of bridged bi- and tricyclic compounds.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 20013-nortricyclanols, Kinetics, XXXVIII, mechanisms of 1- Abstract The disappearance of 1- and 3-nortricyclanols (1-OH and 2-OH) in aqueous perchloric acid was followed by capillary GC at different temperatures and acid concentrations. 1-OH is ca 1000 times more reactive than 2-OH. The activation parameters, solvent deuterium isotope effects and parameters of excess acidity equations were measured and the products were studied. Both isomeric nortricyclanols react according to the AdE2 mechanism, i.e. the cyclopropane ring is protonated at the rate-determining stage of the reaction. The protonation causes, in the case of 1-OH, an isomerization called homoketonization with 2-norbornanone as the only product and, in the case of 2-OH, hydration, i.e. the formation of hydroxyl-substituted norbornyl cations, the fast attack of which by water produces several norbornanediols. Copyright © 2001 John Wiley & Sons, Ltd. [source] Polymerization of Cyclic Monomers, 12,MACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2006Norbert Moszner Abstract Summary: The radical polymerization of different substituted methyl 2-(bicyclo[3.1.0]hex-1-yl) acrylates, 1a,f, was initiated by 2,2,-azoisobutyronitrile (AIBN) at 65,°C in chlorobenzene. The radical homopolymerization of 1a,f occurred through the opening of the cyclopropane ring, and lead to polymers with number-average molecular weights of 13,000 to 434,400 g,·,mol,1 and glass transition temperatures between 77 and 121,°C. The monomers 1a,f showed a similar reactivity to MMA (in the copolymerization with MMA). Selected monomers were determined to be diluent monomers for dental filling composites and enable the preparation of composites that show a significantly reduced polymerization shrinkage, compared to composites based on dimethacrylate diluents. [source] Synthesis and X-ray study of the 6-(N -pyrrolyl)purine and thymine derivatives of 1-aminocyclopropane-1-carboxylic acidCHEMICAL BIOLOGY & DRUG DESIGN, Issue 5 2004M. Cetina Abstract:, The novel purine and pyrimidine derivatives of 1-aminocyclopropane-1-carboxylic acid 1 and 2 were obtained by alkylation of 6-(N -pyrrolyl)purine and thymine with methyl 1-benzamido-2-chloromethylcyclopropanecarboxylate. X-ray crystal structure analysis shows that the cyclopropane rings in 1 and 2 posses Z -configuration. The cyclopropane ring atoms and attached atoms of the benzamido and methoxycarbonyl moiety of both molecules are disposed perpendicularly to each other. The carbonyl oxygen of the methoxycarbonyl moiety adopts in both compounds a synperiplanar conformation with respect to the midpoint of the distal bond of the cyclopropane ring. The torsion angles , and , for the 1-aminocyclopropane-1-carboxylic acid residue in 1 and 2 correspond to a folded conformation, while the torsion angles , define antiperiplanar conformation. Intermolecular hydrogen bonds connect the molecules of 1 into dimers. Each dimer is hydrogen-bonded with four ethanol molecules, thus forming discrete unit. On the contrary, intermolecular hydrogen bonds link the molecules of 2 generating three-dimensional network. [source] ChemInform Abstract: Electrocatalytic Multicomponent Cyclization of Aromatic Aldehydes, Malononitrile, and Malonates into 3-Substituted 2,2-Dicyanocyclopropane-1,1-dicarboxylates.CHEMINFORM, Issue 37 2010A. N. Vereshchagin Abstract The first examples of a direct electrocatalytic multicomponent construction of the cyclopropane ring are given (16 examples). [source] The newly synthesized linoleic acid derivative DCP-LA ameliorates memory deficits in animal models treated with amyloid-, peptide and scopolaminePSYCHOGERIATRICS, Issue 4 2005Tetsu NAGATA Abstract Background:, In our earlier study, 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA), a newly synthesized linoleic acid derivative with cyclopropane rings instead of cis -double bonds, facilitated hippocampal synaptic transmission by stimulating glutamate release from presynaptic terminals as mediated via ,7 acetylcholine (Ach) receptors under the influence of protein kinase C. The present study assessed the possibility of using DCP-LA as a cognitive enhancer in animal models. Methods:, Amyloid-,1,40 peptide (300 pM/day) or saline was continuously injected in the right lateral ventricle of rats for 2 weeks. Then, the water maze test was carried out, once per day for 7 days, 1 h after the intraperitoneal injection with DCP-LA or saline. In a different set of experiments, rats were intraperitoneally injected with scopolamine (1 mg/kg) and the water maze test was performed twice per day, with the first test taking place 1 h after the intraperitoneal injection with DCP-LA, galantamine or saline, and the second test starting 2 min after the end of the first. Results:, Continuous intraventricular injection with amyloid-,1,40 peptide in the rat lateral ventricle prolonged the latency for acquisition in the water maze test. DCP-LA (1 mg/kg, intraperitoneal (i.p.)) significantly improved the impairment, which reached a level similar to the latency for sham. Furthermore, DCP-LA (1 mg/kg, i.p.) significantly ameliorated learning and memory deficits in rats treated with scopolamine and was, if not more, effective than galantamine, a modest inhibitor of acetylcholinesterase with nicotinic ACh receptor modulation. Conclusion:, The results of the present study show that DCP-LA ameliorates learning and memory deficits induced by amyloid-,1,40 peptide or scopolamine. DCP-LA may thus offer new hope for dementia patients. [source] Synthesis and X-ray study of the 6-(N -pyrrolyl)purine and thymine derivatives of 1-aminocyclopropane-1-carboxylic acidCHEMICAL BIOLOGY & DRUG DESIGN, Issue 5 2004M. Cetina Abstract:, The novel purine and pyrimidine derivatives of 1-aminocyclopropane-1-carboxylic acid 1 and 2 were obtained by alkylation of 6-(N -pyrrolyl)purine and thymine with methyl 1-benzamido-2-chloromethylcyclopropanecarboxylate. X-ray crystal structure analysis shows that the cyclopropane rings in 1 and 2 posses Z -configuration. The cyclopropane ring atoms and attached atoms of the benzamido and methoxycarbonyl moiety of both molecules are disposed perpendicularly to each other. The carbonyl oxygen of the methoxycarbonyl moiety adopts in both compounds a synperiplanar conformation with respect to the midpoint of the distal bond of the cyclopropane ring. The torsion angles , and , for the 1-aminocyclopropane-1-carboxylic acid residue in 1 and 2 correspond to a folded conformation, while the torsion angles , define antiperiplanar conformation. Intermolecular hydrogen bonds connect the molecules of 1 into dimers. Each dimer is hydrogen-bonded with four ethanol molecules, thus forming discrete unit. On the contrary, intermolecular hydrogen bonds link the molecules of 2 generating three-dimensional network. [source] | ||||||||||