- PENTACHLOROTROPOLONE AND 3-HYDROXYPENTACHLOROTROPONE
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Pentachlorotropolone(3) was obtained by treatment of octachlorocycloheptatriene(1) with concentrated sulfuric acid.Chlorination of 3 in liquid chlorine afforded a perchlorinated seven-membered reductone(12).Photolysis of 4-hydroxypentachlorobicyclohepta-3,6-dien-2-one(18) gave 3-hydoxypentachlorotropone(19).
- Kusuda, Kousuke,Hara, Nobuya,West, Robert
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- Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
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Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.
- Matic, Mirela,Denegri, Bernard,Kronja, Olga
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supporting information
p. 8986 - 8998,13
(2012/12/12)
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- Electrocarboxylation of chlorinated aromatic compounds
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Chorinated benzenes (1, 4), biphenyls (6, 9), dibenzofurans (10, 15, 17, 18), 2-chlorodibenzo[1,4]dioxine (24) and 1-chloronaphthalene (26) as well as dibenzofuran (12) and naphthalene (27) themselves were transformed into carboxylic acids by galvanostatic electroreduction in the presence of carbon dioxide ("electrocarboxylation"). Dry DMF was used as solvent, zinc or stainless steel as cathode and magnesium as a sacrificial anode in an undivided cell. Hydrogenation of aromatic rings was not observed. However, reductive addition of two molecules of carbon dioxide to form dihydrodicarboxylic acids, e.g. 22 and 29, occurs in the dibenzofuran and naphthalene series.
- Golinske, Dirk,Voss, Juergen,Adiwidjaja, Gunadi
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p. 862 - 880
(2007/10/03)
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- Cross-Conjugated Polychlorinated Derivatives of Cycloheptatriene from Octachlorocycloheptatriene and Hexachlorotropone
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A new convenient synthesis of hexachlorotropone (6) and some condensation reactions of 6 are described, yielding novel polychlorinated cross-conjugated derivatives of cycloheptatriene.Treatment of octachlorocycloheptatriene (5) with benzene/CF3SO3Ag and p
- Drueecke, Stefan,Imming, Peter,Kaempchen, Thomas,Seitz, Gunther
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p. 1595 - 1600
(2007/10/02)
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- Synthesis and Chemical Behavior of Perchlorophenylacetylene
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Perchlorophenylacetylene (6) is synthesized in three steps: (1) vicinal reductive dechlorination of perchlorostyrene (1) to (pentachlorophenyl)acetylene (2), (2) conversion of 2 into its silver acetylide (7), and (3) chlorination of 7 to 6.Some thermal an
- Ballester, Manuel,Castaner, Juan,Riera, Juan,Tabernero, Ignacio
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p. 1413 - 1419
(2007/10/02)
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