Phosphorus carboxylic acids, review

Thioketenes can be prepared in several ways, from carboxylic acid chlorides by thionation with phosphorus pentasulfide [1314-80-3], P2S5, from ketene dithioacetals by p-elimination, from 1,2,3-thiadiazoles with flash pyrolysis, and from alkynyl sulfides (thioacetylenes). The dimerization of thioketenes to 2,4-bis(alkylidene)-l,3-dithietane compounds occurs quickly. They can be cleaved back pyrolytically (63). For a review see Reference 18. 

The pJ a values of phosphine oxides have been measured. Their deviation from Hammett base behaviour, their Ho dependencies, and their sites of protonation have been studied. The acidifying effects of phosphoryl, phosphinyl, and thiophosphinyl groups have been studied. Ionization constants have been used to examine substituent effects in alkanephosphonic acids and phosphinyl-carboxylic acids, structural correlations in various phosphorus acids, and solvent effects on the properties of thiophosphorus acids. The linear free-energy relationships, which are based mainly on p a data, have been analysed and reviewed. ... 

This ring is formed by acid-catalysed reaction of a 2-thiocyanatobenzoyl chloride with hydrogen chloride, or of the corresponding carboxylic acid with phosphorus pentachloride (review of this kind of reaction [2SS7]). The chlorine atom in the product is labile. 

The literature about ligands not containing phosphorus is scarce. Most of the articles report nitrogen-containing ligands, especially substituted bipyridine and ethylene diamine N,N,N, N -tetraacetic acid (EDTA), and were recently reviewed [12], The most commonly used functionalities are sulfonate and carboxylic acid groups. The first functionalization consists of various mono- and disulfonated bipyridines,... 

The chemistry of selenazoles is reviewed in a book <04MI777>. Addition of malonic dinitrile with phosphorus pentaselenide in aqueous ethanol affords selenomalonic diamide 282, which undergoes double cyclization with phenacyl bromide to furnish bis(selenazole) 283 <04S875>. 2-Acyl-l,3-selenazoles 287 are prepared in two steps from bromomethyl ketones 284 and selenoamides 285. A facile preparation of l,3-selenazole-5-carboxylic acids 289 is based on the cyclization of selenazadienes 288 with chloroacetyl chloride <048233>. 

Synthesis of aminophosphonic acids is an active area of research and many methods are now available. Several reviews have been devoted to the synthesis of aminoalkanephos-phonic acids [3-7]. However, most of the described methods for the synthesis of ot-aminophosphonic acids use carbonyl compounds such as aldehydes, ketones, or carboxylic acids as starting compounds. In this chapter, only the synthetic approaches in which the starting phosphorus compounds are H-phosphonate diesters wiU be discussed. 

It is an excellent reagent for the preparation of )V,)V -diarylureas. Reaction of a carboxylic acid, primary amine, and (15) in acetonitrile leads to the disubstituted urea (16) (eq 10). There is an additional competing reaction to the formation of the diarylurea formation of phenyl Al-phenylphosphorodiamidates, involving nucleophilic attack of the carboxylate ion and the aLkylamine on the phosphorus atom of phenyl -phenylphosphoramidoazidate. This work has been fully reviewed. ... 

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