Microwave-assisted ionic liquid-catalyzed selective monoesterification of alkylphosphonic acids—an experimental and a theoretical study
It is well-known that the P-acids including phosphonic acids resist undergoing direct es-terification. However, it was found that a series of alkylphoshonic acids could be involved in mo-noesterification with C2–C4 alcohols under microwave (MW) irradiation in the presence of [bmim][BF4] as an additive. The selectivity amounted to 80–98%, while the isolated yields fell in the range of 61–79%. The method developed is a green method for P-acid esterification. DFT calculations at the M062X/6–311+G (d,p) level of theory (performed considering the solvent effect of the corresponding alcohol) explored the three-step mechanism, and justified a higher enthalpy of activation (160.6–194.1 kJ·mol–1) that may be overcome only by MW irradiation. The major role of the [bmim][BF4] additive is to increase the absorption of MW energy. The specific chemical role of the [BF4] anion of the ionic liquid in an alternative mechanism was also raised by the computations.
Polymer-supported sulfonated magnetic resin: An efficient reagent for esterification of O-alkyl alkylphosphonic-and carboxylic-acids
A mild and efficient synthetic method has been developed for the esterification of O-alkyl alkylphosphonic-and carboxylic-acids using polymer-supported sulfonated magnetic resins. Polymer-supported resins are recovered using an external magnet and reused several times.
Mild and efficient esterification of alkylphosphonic acids using polymer-bound triphenylphosphine
Mild and efficient esterification of alkylphosphonic acids using primary alcohols, iodine, imidazole and polymer-bound triphenylphosphine is developed.
P-Toluenesulfonic acid-Celite as a reagent for synthesis of esters of alkylphosphonic acids under solvent-free conditions
The coupling reaction of alkylphosphonic acids and alcohols on the surface of p-toluenesulfonic acid-Celite under mild and solvent-free conditions gave the corresponding phosphonates in excellent yields. This method provides a useful rapid synthesis of phosphonates for use in the unambiguous identification of chemical warfare agents.
An efficient method for the esterification of phosphonic and phosphoric acids using silica chloride
Silica chloride is used as an effective heterogeneous catalyst for the rapid esterification of alkyl/aryl phosphonic/phosphoric acids to their corresponding alkyl/aryl phosphonates/phosphates under mild conditions with quantitative yields.
Sathe, Manisha,Gupta, Arvind K.,Kaushik
p. 3107 - 3109
(2007/10/03)
Surface-mediated solid phase reactions: A simple, efficient and base-free synthesis of phosphonates and phosphates on Al2O3
Al2O3-supported solvent free condensation of alkylphosphonic dichlorides with alcohols at room temperature yielded phosphorus esters in excellent yields.
Acharya, Jyotiranjan,Shakya, Purushottam D.,Pardasani, Deepak,Palit, Meehir,Dubey, Devendra K.,Gupta, Arvind K.
p. 194 - 196
(2007/10/03)
CATHODE-CATALYZED TRANSESTERIFICATION OF ALKYLPHOSPHONATES
The cathodic electrolysis of aliphatic alcohols and alkylphophonates in acetonitrile with 0.5 N Et4NClO4 as the base electrolyte leads to mono- and ditransesterified phosphonates.The yield and ratio of these products is a function of the nature of the sta
Niyazymbetov, M. E.,Kostizella, B.,Keitel, I.,Schwartz, K. H.
p. 182 - 186
(2007/10/02)
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