Phosphoric Acid and its Derivatives

Phosphoric Acid and its Derivatives.—Triacetyl phosphate18 and diammonium monoacetyl phosphate14 have been obtained by acetylation of phosphoric acid with keten at —10 to —15 °C in diethyl ether and ethyl acetate, respectively the reaction can be controlled to give 90% yields of either product. Long-chain monoalkyl 

Chabrier and Nguyen Thanh Thuong, Comp. rend., 1975, 281, C, 397. 

The phosphoramidic chloride (11) has been employed to phosphorylate phenols and alcohols, including carbohydrates.16 Other activity in phosphorylation chemistry has been mostly concentrated in two main areas. In the first of these, Japanese workers have continued their studies on the use of 2-substituted-4-nitrophenyl-phosphoric acids. The 7V-protonated form of the 2-dimethylamino-compound (12 R = Me) is a better phosphorylating agent than the corresponding 2-diethylamino-compound. The reaction of (12) with hydroxy-amines results in selective O-phos- 

In the second area of interest, the high reactivity of compounds that stems from inherent ring strain in five-membered ring systems has been exploited in the synthesis of mixed diesters of phosphoric acid. These, for example (15), may be obtained by 

Taguchi and Y. Mushika, Chem. andPharm. Bull. Japan), 1975, 23, 1586. 

Phosphoric Acid and its Derivatives.— Di-t-butyl phosphorochloridateandphosphoro-bromidate are unobtainable by standard halogenation procedures, but may be obtained in high yield by phase-transfer halogenation (benzyltriethylammonium chloride in 20 % sodium hydroxide solution-dichloromethane) of di-t-butyl hydrogen phosphonate with carbon tetrachloride or tetrabromide, a procedure in which other dialkyl hydrogen phosphonates yield pyrophosphates.  

Variables in the production of tributyl phosphate have been discussed. In the presence of relatively large amounts (5—15 molar equivalents) ofcaesium fluoride or quaternary ammonium fluorides, 2,2,2-trichloroethyl phosphate esters readily trans-esterify with alcohols the sequential replacement of trichloroethyl groups becomes slower, so allowing the preparation of mixed (including cyclic) trialkyl phosphate esters, with the exception of those from t-butyl alcohol.  

An improved synthesis of 5-acetyl-2-methoxy-5-methyI-2,4-dioxo-l,3,2-dioxa-phospholan (8), starting from the oxyphosphorane (7), has been reported, as has one of the enediol cyclic phosphoryl chloride (9 R==C1) from (9 R=OMe) via the corresponding pyrophosphate by reaction with phosgene-pyridine (see Organophosphorus Chemistry , Vol. 8, p. 106).  

The reaction between alkyl (other than tertiary alkyl) bromides and phosphorus pentasulphide in the presence of aluminium trihalides yields mixtures of phos-phorodi- and phosphorotri-thioic bromides, (RS)P(S)Br2 and (RS)aP(S)Br other alkylating agents have previously been shown to give tetrathioesters. The 2,2-di- 

Ramirez, E. Evangelidou-Tsolis, A. Jankowski, and J. F. Marecek, Synthesis, 1977, 45. 

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Reactions of Phosphoric Acid and its Derivatives.—Theoretical studies on the conformational properties of cyclic and acyclic phosphate esters, including calculations of angle and torsional strain,66 and on the reactivity of monomeric metaphosphates,67 have appeared. 

Scheme 3 contains several of the fundamental structures with penta-valent phosphorus, among them phosphorane itself, PH6 (21), and pentahydroxyphosphorane, P(OH)6 (26). The latter is the hydrate of phosphoric acid H3P04+H20 - P(OH)5. A hydrate of methylphos-phonic acid (CH3)(HO)4P (29), is also included as a model for its esters. Mono- and di-ionized forms, (27), (28), (30), are also given, since their stabilities in various isomeric forms provide important data concerning the role of intermediate oxyphosphoranes in the chemistry of phosphoric acid and its derivatives. A model compound of the 1,2-oxaphospholene ring (31), is provided, since this system, in the form of several derivatives, will be discussed extensively in Section VIII. 

Phosphoric Acid and its Derivatives.— Amongst hydrolysis studies reported during the year are those of di(2,4-dichlorophenyl) phosphate tri(4-iodobenzyl) phosphate in 0.5—4.5M-HC1 in 50% dioxan and l-nitro-2-naphthyl and 4-nitro-l-naphthyl phosphates in 0.01—6M-HC1. The hydrolysis of 2,4-dinitrophenyl dibenzyl phosphate exhibits a 0 kinetic isotope effect that is suggestive of the intermediacy of a monomeric metaphosphate species, whereas an 5 N2-like mechanism is apparent... 

The organization of this Chapter has been changed somewhat from last year. Phosphonous and phosphinous acids and their derivatives, and cyclic esters of phosphorous acid, are not discussed separately from phosphorous acid and its derivatives, because of the similarity of the reactions involved. Two-co-ordinate phosphorus compounds are treated in a separate section like last year phospha-alkenes without phosphorus-heteroatom bonds are not covered. 

Opening of orthoesters with phosphoric acid and its derivatives has been used to prepare glycosyl phosphates.Thus 3,4,6-tri-O-acetyl-a-D-gluco-pyranose 1,2-orthoacetate reacted with decyl, tridecyl, pentadecyl, and hexa-decyl monobenzyl phosphates to give the ]8-l-phosphate derivatives (11). 

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