- Some Transformations of Mono-and Dichloro(diethoxyphosphoryl)acetaldehydes
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Addition of ethanol and diethyl phosphonate to the carbonyl group of 2,2-dichloro-2-(diethoxyphosphoryl)-acetaldehyde has been studied, and the corresponding α-chloro ether, acetal, and phosphorylated metrifonate have been obtained. α,α-Dichloro-α-phospho
- Allakhverdieva, G. E.,Ismailov, V. M.,Mamedov, I. A.,Sadykhova, N. D.,Yusubov, N. N.
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- PREPARATION ELECTROCHIMIQUE DES CHLOROMETHYL ET DICHLOROMETHYL-PHOSPHONATES DE DIETHYLE
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Diethylchloromethyl and dichloromethyl-phosphonates are easily prepared by electrochemical reduction of diethyltrichloromethylphosphonate in alcoholic acetate solutions at a graphite electrode under galvanostatic conditions.
- Tue Bi, Balo,Devaud, Marguerite
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- Synthesis of dichloromethylphosphonates
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Efficient synthesis of O,O-dialkyl, O-alkyl-N,N-dialkylamido and N,N,N',N'-tetraalkyldiamido dichloromethylphosphonates via treatment of O,O-dialkyl, O-alkyl-N,N-dialkylamido, and N,N,N',N'-tetraalkyldiamido trichloromethylphosphonates with diethyl phosph
- Majewski, Piotr,Koszuk, Jacek F.
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experimental part
p. 956 - 962
(2009/12/03)
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- Intramolecular Nucleophilic Reactions of Dialkyl 1,1-Dichloro-2-hydroxyethylphosphonates
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Methods are developed for preparing dialkyl (1,1-dichloro-2-hydroxyethyl)phosphonates. Under the action of sodium hydride these esters enter into intramolecular nucleophilic reactions via two routes yielding α-ketophosphonates and phosphates.
- Guseinov,Klimentova,Kol'tsova,Egereva,Moskva
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p. 441 - 443
(2007/10/03)
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- Carbanions phosphonate prepares par voie electrochimique: formation et reactivite vis-a-vis d'un aldehyde
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Reactivity towards p-methoxybenzaldehyde (ArCHO) of electrochemically generated phosphonate carbanions has been investigated.Electrolyses were carried out at a mercury cathode in DMF and two routes to the desired carbanion have been compared: (i) Deprotonation of phosphonates of general formula (EtO)2P(O)CHYW (Y = W = Cl; Y = H, W = Cl; Y = Cl, W = CO2Et; Y = H, W = CO2Et; Y = CH3, W = CO2Et; Y = Cl, W = CH3), by the bases resulting from the electroreduction of azobenzene; addition of the carbanion formed onto the carbonyl group takes place and leads to the adduct (EtO)2P(O)CYW(Ar)O-. (ii) Two-electron reduction of halophosphonates (EtO)2P(O)CXYW (X = Cl, Y and W as above; X = Br, W = CO2Et, Y = Cl, Br, or CH3); when no H atom is present on the carbon bearing the phosphonate group (Y and W no = H), the same evolution leading to the above adduct is observed, on the contrary, when Y = H, the electrogenerated carbanion deprotonates the substrate and the resulting carbanion (EtO)2P(O)CXW reacts with the aldehyde; giving the adduct (EtO)2P(O)CXW(Ar)O-.Evolution of the intermediate adduct depends on the substituents Y (or X) and W: when W = CO2Et, whatever the nature of Y (or X), diethyl phosphate is eliminated with formation of the ethylenic ArCH=CWY (or X) (Wittig-Horner reaction); the same evolution is observed when Y = W = Cl.When W = Cl and Y = H or CH3, the final product is the phosphonate epoxyde resulting from chloride elimination (Darzens reaction).Chemo- and stereoselectivity depend only on the nature of Y and W but are independent of the mode of generation of the carbanion.Yields are limited by side-protonation reactions, which are related to the basicity of the phosphonate carbanions.Analysis of the results permits selection of the optimal electrolysis conditions for purposes of synthesis.Key words: electrosynthesis, electrogenerated bases, phosphonates, Wittig-Horner.
- Le Menn, Jean-Christophe,Sarrazin, Jean,Tallec, Andre
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p. 1332 - 1343
(2007/10/02)
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- The electrochemical Wittig-Horner reaction; evidence of a stepwise cleavage of a four-membered ring Wittig intermediate
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Electro-reduction of diethyl(trichloromethyl)phosphonate in the presence of aldehydes or ketones relpaces the oxygen atom of the carbonyl group by a dichloromethylene group.The yield of 1,1-dichloroethene product decreases subtantially if the carbonyl com
- Tilborg, W. J. M. van,Smit, C. J.
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p. 202 - 206
(2007/10/02)
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