Arylphosphonic acids

The Bart reaction has now been extended to the synthesis of arylphosphonic acids by the interaction of the diazonium fluoroborate and phosphorus trichloride (Doak and Freedman, 1951). 

The chemical shifts, Sp, of substituted arylphosphonic acids (9) have been found to be linearly related to the Hammett a and Taft ojt and cti parameters. The shielding of the phosphorus nucleus increases with the electron-withdrawing properties of the substituents, which is analogous... 

Trimethylsilyl esters of arylphosphonic acids have been... 

The esters of arylphosphonic acids are cleaved to the acids by HC1, HBr, or HI.9b Arylphosphonic dichlorides (ArPOCl2) are easily converted to esters by reaction with the alcohol in pyridine solution.10... 

Other methods for synthesis of arylphosphonic acids or their derivatives fall into four main categories. First, many aromatic compounds react with PC13 under catalysis by A1C13 to form aryldichlorophosphines (ArPCl2).9a n These add chlorine to form... 

Second, arylphosphonic acids may be prepared by the copper-catalyzed reactions of arenediazonium fluoborates with PC13 or PBr3. This method has found wide use.12... 

Third, arylphosphonic acid derivatives have been made by or-ganometallic reactions, such as the reaction of C6H5MgBr with (C2H50)2P0C1 or of phcnyllithium with phosphorodipiperididic chloride.9"11... 

Arylphosphonic acid derivatives, 58, 137 Arylphosphonic dichlorides, 58, 136 Aryltetrachlorophosphoranes, 58, 137 L-Asparagine, carbobenzoxy-, 56, 89 L-Asparagine, NJ-(tnfluoroacetyl)- 56, 125 L ASPARAGINYL-L-LEUCINE, CARBOBENZOXY-,METHYL ESTER, 56, 88 Z-Asp Gly-OEt, 56, 93 (l-Azido-3,3-dimethoxy-l-propenyl)ben-zene, 57, 84... 

Potassium dialkyl phosphite ions react rapidly with aryl iodides in liquid ammonia under irradiation to form diethyl esters of arylphosphonic acid in almost quantitative yields238. The photostimulated reaction of (EtO)2PO ions with 5-chloro-7-iodo-8-isopropoxyquinoline gave 70% of the substitution product with retention of the 5-chloro substituent239. The same nucleophile was formed in THF, and in a mixture of solvents (1 4 THF MeCN) reacts under irradiation with ArX (o-, ra-,/ -iodoanilines, 2-iodo, 3-iodo, 2-bromo and 3-bromopyridines and 3-bromoquinoline) rendering the substitution product in high yields (70-98%) (equation 130)240. 

Arylphosphonic acids (422) have been discovered to react with a variety of alkenes in the presence of Pd(OAc)2 and MesNO providing Heck-type adducts (423). The reaction requires TBAF as the activator (Figure 77). ... 

A one-pot procedure for the synthesis of arylphosphonic acid monoalkyl esters (the hexyl esters were chosen in practice) started... 

Korshak, V.V., Gribova, I.A., and Andreeva, M.A., Organophosphorus polymers. Part 1. Polymerization of cyclic esters of alkyl- and arylphosphonic acids, Izv Akad. Nauk. S.S.SR,. So Khim., 631, 1957 Chem. Abstr, 51, 14621g, 1957. 

Arylphosphonic acid esters from aryldichlorophosphines via aryldichlorophosphine oxides... 

Arylphosphonic acid esters are produced in the reaction of diaryl iodonium salts with trialkyl phosphites in the presence of copper salts, but despite the simplicity of the procedure yields are low owing to side reactions. The cyclic bisarylphosphinic acid (66) is conveniently prepared by fusion of the phosphine oxide (67) with sodium hydroxide. A successful... 

Arylphosphonic acids. Diethyl arylphosphonates can be prepared by reaction of aryl iodides (bromides react more slowly) with this reagent in the presence of sodium in liquid ammonia with irradiation of about 300-350 nm. This arylation is believed to involve radical and radical anion intermediates (SrnI mechanism). ... 

The chlorophosphonium complexes 39, produced (Scheme 8) during the synthesis of cyclic esters of arylphosphonic acids from aryldiazonium tetrafluoroborates and cyclic chlorophosphites, are decomposed by H2S to give the analogous esters of arylthiophos-phonic acids ... 

PH3 was found to be one of the volatile thermolysis products of the arylphosphonous acids RCgH4P(0)(OH)H with R = H or CH3 in chlorobenzene in sealed tubes at 200 to 220 C after 20 h [30]. Pyrolysis studies of /-C4H9PH2 and f-C4HgPH2, intended to investigate the possible use of these compounds as precursors in the OMVPE process, revealed that PH3 is one of the first decomposition products [33, 34]. 

Aryl phosphonic esters are formed by reaction of triaryl phosphites with excess alcohol at 200°C (6.270). The corresponding acids can be obtained from these by hydrolysis. Arylphosphonic acids can be conveniently made from phosphorodipiperidic chloride and a lithium aryl The phosphonic dipiperidic amide so obtained is decomposed by water (6.271). 

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