Thiophen-2-phosphonic acid

In a third procedure, an adhesion promoter of a 3-(ethyl-phosphonic-acid)thiop-hene was applied to the metal surface followed by an electrochemical film preparation [65]. The following procedure was used in this case Mild steel was mechanically polished, then the specimen were treated for 60 minutes in a solution of 3-(ethyl-phosphonic-acid)thiophene. Afterwards, a layer of poly(3-methylthiophene) was formed by electropolymerization in an electrolyte consisting of 0.1 mol 1 3-methylthiophene, 0.1 moll tetrabutyla-mmonium-hexafluorophosphate (N(Bu)4 PFg) in dichloromethane (CH2CI2). 

Another possible source of a phosphorus pendant group was [(2-dihydro grarsinoylphenylamino)methyl]phosphonic acid, which was used to modify the Amberlite XAD-16 polymeric matrix. Subramanian et al. also modified the polystyrene-divinylbenzene copolymer beads (Amberlite XAD-16) by anchoring 6,6,6-trifluoro-2,5-dioxo-4-(thiophene-2-carbonyl)he yl-phosphinic acid in its matrix in order to obtain a new chelating ion-exchange multidentate grafted polymer (Scheme 11.9). ... 

A system with four alkylated thieno[3,2-b]thiophenes, located around a benzene through ethylene linkages, depended for its synthesis on the reaction of aldehyde (82) with [l,2,4,5-tetra(diethoxyphosphorylmethyl)benzyl]phosphonic acid diethyl ester (83) (Scheme 20) [41]. 

More and more, solid catalysts like zeolites, clays or resins are used instead of traditional catalysts. Thus, zeolites are good catalysts for the acylation of non-heterocyclic aromatic compounds, both in the gas phase [2] and in the liquid phase [3]. The acylation of thiophene and of furan can also be carried out in the gas phase with M-5 catalysts [4]. Lasdo and co-woikers have shown that modified clays like montmorillonite doped with ZnCl2 can catalyse the reactioi of arenes with substituted benzoyle chlorides in good yields [5] (70 to 100%). Delmas and co-workers have reported the acylation of furan by carboxylic acids with nafion-H [6] (sulfonic resin) and duolite [7] (ion exchanged phosphonic resin). One of the advantages of these catalysts is the safety of environment. Actually, the use of homogeneous catalysts causes problems of corrosion, waste and troublesome workups [8,9]. 

Benzylic Reactivity. 2,5-Dimethyl-3,4-dinitrothiophen has been condensed with aromatic aldehydes to give 3,4-dinitro-2,5-distyryl-thiophens. " An improved synthesis of 3-nitro-2-styryl-thiophens involves bromination of 3-methyl-2-nitrothiophen with A-bromosuccinimide, followed by a modified Wit-tig reaction. From 2,5-di(chloromethyl)thiophen, the phosphonate was prepared by the Arbusov reaction, which was used for the preparation of 2,5-distyryl-thiophens. Trichloromethyl(thienyl)carbinols have been converted into the corresponding fluoro-derivatives through the reaction with phenyl-tetrafluorophosphorane. The liquid-phase catalytic oxidation of phenyl-(2-thienyl)methane in acetic acid in the presence of cobalt(ll) acetate and sodium bromide has been investigated. ... 

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