Derivatives of Phosphorus Acids

Organotin esters of the oxy- and thio-acids of phosphorus can be prepared inter alia by azeotropic dehydration of a mixture of the organotin hydroxide or oxide and the acid, or by treating a tin alkoxide or tin amide with the acids, or an organotin halide with a salt of the phosphorus acid. By using different molecular ratios of the reactants, products of different compositions can be obtained. Attempts to prepare phosphites may result in an Arbuzov rearrangement to a phosphorus(V) compound (e.g. equation 13-11).47 

The derivatives of the inorganic phosphorus acids are usually intractable powders which are unsuitable for X-ray diffraction, but those of the organic phosphorus acids are often crystalline and a series of complex solid-state structures which have been described as drums, cubes, oxygen-capped clusters, butterfly formations, crowns, and extended clusters32-51 have been identified. 

Some examples of organotin derivatives of phosphorus acids are given in Table 13-2. 

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There are two main procedures for the derivatization of thesei substances (i) alkaline hydrolysis and derivatization of the products and (ii) derivatization of the intact insecticide. As the products from the hydrolysis are mostly derivatives of phosphorus acid and phenols, the former procedure involves the preparation of esters and ethers of these compounds. In the latter instance derivatives are applied, depending on interfering functional groups present, and further oxidation, reduction and other reactions. 

Notwithstanding controversies on O- against AT-acylation of triazolinones, modern views favour the former. The substantial number of 1,2,4-triazole derivatives of phosphorus acids (8iHC(37)i, p. 241, 247, 316, 357) are acylated on oxygen even when alternative N-acylation would have been possible. 

The most suitable synthetic method for these products is the heterocyc-lization reaction of N-thioacyl derivatives of amino acids (202) with phosphorus tribromide (378, 442-450, 559, 560) or anhydrous trifluoroacetic acid (448, 449, 451, 452) (Scheme 103). Treatment of N-thioacyl amino acids with acetic anhydride leads directly to the thiazolylacetate without isolation of an intermediate thiazolinone (365. 452). 2-Alkoxy-derivatives of A-2-thiazoline-5-one, however, can be obtained without acetylation by this method (453, 454). 

Trifluoromethanesulfonic (triflic) anhydride is commercially available or can be prepared easily by the reaction of triflic acid with phosphorus pentoxide [66] This moderately hygroscopic colorless liquid is a useful reagent for the preparation of various organic derivatives of triflic acid A large variety of organic ionic triflates can be prepared from triflic anhydride A recent example is the preparation of unusual oxo-bridged dicatiomc salts of different types [SS, 89, 90, 91, 92, 93] (equations 38-44) Stabilized dication ether salts of the Huckel aromatic system and some other systems (equations 38 and 39) can be prepared in one step by the... 

Haloacetyl groups have also a synthetic potential. Thus, pesticidal (alkylthio)-vinyl esters of phosphorus acid derivatives have been prepared by the introduction and subsequent displacement of two chlorine atoms in the acetyl moiety attached to the furazan ring (Scheme 69) [73GEP(0)2144393]. 

Nucleophilic attack of amines on fully esterified derivatives of phosphoric acid and its thio-analogues may in general occur at phosphorus or carbon. In an attempt to correlate the rates with structural factors, a study has been reported on a series of compounds of the type (49), ... 

As recently as 1965, Thoma and Stewart predicted that alterations in reaction rates [in the presence of the cycloamyloses] should be anticipated whose magnitude and sign will fluctuate with the reaction type, and added that at the present juncture, it is impossible to sort out confidently. . . which factors may contribute importantly to raising or lowering the activation energy of the reaction. In the short interval between 1965 and the present, a wide variety of cycloamylose-induced rate accelerations and decelerations have, indeed, been revealed. More importantly, rate alterations imposed by the cycloamyloses can now be explained with substantially more confidence. The reactions of derivatives of carboxylic acids and organo-phosphorus compounds with the cycloamyloses, for example, proceed to form covalent intermediates. Other types of reactions appear to be influenced by the dielectric properties of the microscopic cycloamylose cavity. Still other reactions may be affected by the geometrical requirements of the inclusion process. 

In addition to ammonium dioxaborataphosphorinanes, metallic derivatives of phosphorus containing esters of boric acids (162) are also able to participate in ion exchange reactions [Eq. (123)]. 

The H-phosphonate approach entails phosphitylation of a hydroxylic component with an activated unprotected derivative of phosphonic acid to furnish H-phosphonate (a stable tetra-coordinate form of the unprotected monophosphite) followed by oxidation on phosphorus. The H-phosphonate approach is not generally used for the synthesis of monophosphates due to the difficulty of oxidation of the H-phosphonate monoesters and the necessity either to render the phosphorus atom of H-phosphonate into the three-coordinate form by silylation (to form disilylphosphite) or to introduce a protecting group (to form H-phosphonate diester) prior to oxidation. Nevertheless, in rare cases, the H-phosphonate procedure turns out to be a method of choice if, for instance, the simultaneous oxidation of functional groups other than H-phosphonate is required.51... 

Interest in the organotin derivatives of the acids and thioacids of phosphorus arises from their potential biological action and the wide variety of structures that have been identified by X-ray diffraction. These structures are often particularly complex when the compounds are derived from the partially hydrolyzed mono- or diorganotin compounds, and words such as cubes, drums, crowns, butterflies, clusters, oxygen-capped clusters, and extended clusters have been use to describe them. References to the early work are given in Ref 351, and a recent review is available.352... 

It is particularly interesting, that some titanium and tantalum carbene complexes olefinate derivatives of carboxylic acids. These reagents are, moreover, much less basic than phosphorus ylides, and thus enable the olefination of strongly C-H acidic carbonyl compounds. 

By far the most important derivative of sulfuric acid is phosphoric acid. It has been unknowingly used as fertilizer for hundreds of years. The wet process method of manufacture was important until 1920, when furnace acid began increasing in popularity. The wet process, however, has made a comeback because of plant design improvements 60% of phosphoric acid was made by this method in 1954, 88% in 1974, and over 90% currently. The furnace process is used only to make concentrated acid (75-85%) and pure product. It is very expensive because of the 2000 °C temperature required. In the furnace process phosphate rock is heated with sand and coke to give elemental phosphorus, which is then oxidized and hydrated to phosphoric acid. A simplified chemical reaction is ... 

Analogues of (751) react with derivatives of phosphorus-containing acids to form 1-phosphoryl-imidazoles (90CHE599). The same compound also silylates ketones to give enol silyl ethers and/or siloxyalkylimidazoles (Scheme 107) (87JC271). 

Volume 10 is devoted to formation and solvolysis of esters and related reactions, with discussion of the effect of neighbouring groups and biological implications, e.g. enzyme action, where appropriate. The first chapter deals mainly with esters of the inorganic acids of phosphorus and sulphur, Chapter 2 with the formation and solvolysis of esters of organic acids and the final chapter with the solvolysis of related derivatives of carboxylic acids, e.g. halides, amides, anhydrides, cyanides, carbamic acid derivatives. 

Aoids (709) 69. Imidodiphosphoric or Imidopyropbosphoric Aoid (712) 70. Amides and Imides of the Higher Phosphoric Acids (714) 71. The Meta-phosphimic Acids and their Salts (716) 72. Phosphorus Chloronitrides or Phosphonitrilic Chlorides (721) 73. Ammonia Derivatives of Thiophosphoric Acid (725). 

To get a broader concept of the nucleophilic reactivity of phosphorus acid derivatives towards organosilanes we studied mechanism of reactions of triorganosilyl halides with esters of tricoordinate and tetracoordinate phosphorus having the general formulae ... 

Phosphorus containing additives include esters of phosphoric acids, derivatives of thiophosphoric acids, phosphites (Davey, 1950 Sakuri and Sato, 1970), and the metal salts of dithiophosphoric acid diesters, the best known of these compounds being the ZDDPs. The structure of ZDDP films, the composition of the film formed, and the mechanism of action on the molecular level are summarized in Chapter 4. 

In many examples, it is not necessary to prepare the phosphorane. Instead, the dicarbonyl compound is heated with a trialkyl or triaryl ester of phosphorus acid or, less commonly, with a diester of a phosphonous acid (RP(OH)2, where R is an organic group). For example, when the thioester 301 is heated with dipropyl ethylphosphonite the 2-substituted carbapenem 302 is produced in 80% yield (Equation 32) <1997CPB1439>. This general method has been used to prepare 2-sulfide-substituted 1/3-methylcarbapenems <2000CPB126, 2001SC587> and O-protected 2-hydroxymethyl derivatives < 1999JA11261 >. 

The synthesis of bis(alkylphenoxy)derivatives of dithiophosphoric acid is based on the interaction of alkylphenols with phosphorus pentasulfide ... 

The study of organophosphorus chemistry began more than 130 years ago. However, these substances found practical application only after World War II. At present the most widespread application for organophosphorus compounds is pest control in agriculture. Biological activity is characteristic of the following derivatives of phosphorus organic acids ... 

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