- Direct electrochemical reduction of 4,4-(2,2,2-trichloroethane-1,1-diyl)bis(methoxybenzene) (methoxychlor) at carbon and silver cathodes in dimethylformamide
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Cyclic voltammetry and controlled-potential (bulk) electrolysis have been employed to investigate the electrochemical reduction of 4,4-(2,2,2-trichloroethane-1,1-diyl)bis(methoxybenzene), commonly known as the pesticide methoxychlor, at glassy carbon and silver cathodes in dimethylformamide (DMF) containing 0.050 M tetra-n-butylammonium tetrafluoroborate (TBABF4). Reduction of methoxychlor at both glassy carbon and silver shows four voltammetric peaks, the first three of which are associated with cleavage of carbon–chlorine bonds; the fourth peak is assigned to reduction of 4,4-(ethene-1,1-diyl)bis(methoxybenzene). Bulk electrolyses of methoxychlor at reticulated vitreous carbon and silver mesh cathodes at potentials corresponding to each of the first three voltammetric peaks were conducted; coulometric n values and product distributions (determined by means of GC and GC–MS techniques) depend on potential. In particular, two completely dechlorinated products, namely 4,4-(ethane-1,1-diyl)bis(methoxybenzene) and 4,4-(ethene-1,1-diyl)bis(methoxybenzene) have been identified and quantitated. A mechanistic scheme is proposed to account for the formation of the various products.
- McGuire, Caitlyn M.,Peters, Dennis G.
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p. G44 - G49
(2018/06/29)
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- A search for unambiguous vinylic SRN1 reactions
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In a search for unambiguous examples of the vinylic SRN1 route, vinyl bromides Ph(CH3)C=CHBr (10), Ph2C=CHBr (15), An2C=C(Br)An (18) and An2C=CBr2 (20) were treated with Me3CCOCH2- under photostimulation conditions in Me2SO, whereas substrates PhCH=CHBr (2), Ph2C=C(Br)Ph (3), 10 and 15 were similarly allowed to react with PhS- and PhCH2S-. With the strongly basic enolate ion, the prevailing reactions were elimination/addition routes, α-deprotonation followed by 1,2-Ph shift and bromide ion elimination, or halophilic steps. With 18, however, an SRN1 route was obtained. The weakly basic but reducing anion PhS- gave the SRN1 route with 2, 3 and 15. The nucleophilic character of the PhCH2S- anion instead prevailed with 15, whereas with 3 a variety of behaviours was obtained. The mechanistic interpretations were supported by the electrochemically determined redox potentials of the substrates. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Annunziata, Alfonso,Galli, Carlo,Gentili, Patrizia,Guarnieri, Alessandra,Beit-Yannai, Michal,Rappoport, Zvi
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p. 2136 - 2143
(2007/10/03)
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- A facile and high yielding synthesis of symmetrical and unsymmetrical diarylalkynes using diethyl dichloromethylphosphonate as precursor
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The reaction, under internal quench conditions, of diethyl dichloromethylphosphonate and symmetrical or unsymmetrical diaryl ketones in the presence of n-BuLi, leads to the corresponding symmetrical or unsymmetrical diarylalkynes via a Fritsch-Buttenherg-Wiechell rearrangement in a simple, high yielding, one-pot reaction.
- Mouriès, Virginie,Waschbüsch, Rachel,Carran, John,Savignac, Philippe
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p. 271 - 274
(2007/10/03)
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- THE CHEMISTRY OF SOME METHOXYCHLOR DERIVATIVES
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The preparation of 1-chloro-2,2-bis(p-methoxyphenyl)ethylene (3a) and of 1-chloro-2,2-bis(p-hydroxyphenyl)ethylene (3b), required for a study of the microbial degradation of methoxychlor (1a) was reinvestigated.The methoxy compound (3a) was readily obtained by alkaline dehydrohalogenation of 1,1-dichloro-2,2-bis(p-methoxyphenyl)ethane (2a), but similar treatment of 1,1-dichloro-2,2-bis(p-hydroxyphenyl)ethane (2b) gave a chlorine-free compound, characterized as the diethyl acetal of 2,2-bis(p-hydroxyphenylacetaldehyde (5a) on the basis of spectroscopic evidence and comparison with a model compound.Also, 2,2-bis(p-methoxyphenyl)acetic acid (4a) and 2,2-bis(p-hydroxyphenyl)acetic acid (4b) were prepared and the solubility and p-values (ethyl acetate / water) of these acids were determined.
- Baarschers, William H.,Vukmanich, James P.
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p. 932 - 935
(2007/10/02)
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