17577-28-5Relevant articles and documents
New syntheses of substituted pyridazin-6-ones and pyridazin-6-imines
Behbehani,Abdel-Khalik,Elnagdi
, p. 551 - 557 (1999)
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Synthetic method of Wittig reagent
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Paragraph 0022; 0023; 0029; 0030, (2018/03/24)
The invention discloses a synthetic method of a Wittig reagent. The synthetic method comprises the following steps: (1) by taking alpha-halogenated-ester and triarylphosphine as raw materials, carrying out reaction in a two-phase solvent in presence of a halogenated metal salt catalyst, splitting phase after reaction is finished, recycling and reusing an organic phase, crystallizing an aqueous phase to obtain quaternary phosphonium salt, and recycling and reusing mother liquid; and (2) carrying out reaction on the quaternary phosphonium salt obtained in the step (1) in the aqueous phase in presence of an alkali reagent, and cooling and crystallizing after reaction is finished, so that the Wittig reagent product is obtained. The synthetic method disclosed by the invention has the advantagesthat the whole reaction process and conditions are mild, operation is easy, yield is high, cost is low, and amount of three wastes is less, so that the synthetic method disclosed by the invention isapplicable to industrial production.
Thermal decomposition of triphenylphosphonium alkyl ester salts
Castaneda, Fernando,Aliaga, Christian,Acuna, Cristina,Silva, Paul,Bunton, Clifford A.
experimental part, p. 1188 - 1208 (2009/04/16)
In thermolyses of molten triphenylphosphonium alkyl ester bromides and chlorides, alkyl = methyl, ethyl, isopropyl, at 130 and 225°C, initial attack of the halide ion on the methyl group gives the methyl halide and ylid 1, Ph3P = CH2, which can be methylated, or is protonated by the phosphonium salt with transylidation giving Ph3P+-CH3X-, X = Br, Cl. The initial reactions of the ethyl or isopropyl esters are with the halide ion, X-, as a base giving ylid, 1, which can be protonated by HX or by transylidation. The t-butyl ester generates Ph3P+-CH3X-but no products of transylidation. The first-formed ylid1, can be trapped by reactive alkyl and acyl halides, and the transient ylidic esters decompose thermally to triphenyl phosphine oxide, Ph3P = O, react further with unreacted phosphonium ester, or are trapped by added aldehyde in a Wittig reaction. The final product compositions are affected by a decrease in pressure, due to escape of volatile intermediates, and by replacement of the X- halide ion by the less nucleophilic and basic tosylate ion. Reactions under reflux, in solution in chloroform, or in suspension in benzene, are similar to those of the molten salts, but yields are generally lower at the lower temperatures. Copyright Taylor & Francis Group, LLC.
