Thiophosphonic halides

Thio analogs of these compounds, for example, PhP(S)(NHR)2 can also be prepared similarly, from the corresponding thiophosphonic halides and amines or by oxidative addition of sulfur to diaminophosphines, RP(NR92 Phenylphosphonic acid diamides, PhP(Q)(NHBu )2 (Q = S, Se) were prepared from PhP(NHBfr)2 by oxidative addition of sulfur or selenium and the 0x0 derivative PhP(0)(NHBu )2 by oxidation with tert-butyl peroxide. Their lithiation produces unusual cyclic or polycyclic dUithium salts of the phosphonate dianions [PhP(Q)(NBfr)2] (Q = O, S, Se). The dimethylaluminum derivatives PhP(Q)(NBu )2AlMe2 (Q = S, Se) obtained from PhP(Q)(NHBu )2 with AlMes are fom-membered chelate rings. ... 

The (5 p)-phosphinothioate (287) can be separated in pure, crystalline, form from the oily racemic mixture the addition to it of selenium yields the phosphonoselenothioic ester, oxidation of which, by iodine in water, affords the (i p/ p)-diselenide (288). ° Reactions between (carbon tetrahalides CX4 (X = Cl or Br)-Et3N yield the thiophosphonic halides (289), evidently with retention of configuration at phosphorus, since the anilide derived from them has a configuration known to be (S p). ... 

CsFs-PRX (X = Br or Cl). The fluorides CeFs PRF are formed when the last compounds are treated with sodium fluoride in acetonitrile, and the phosphorancs CeFs-PRFs are obtained from the diethylamino-compounds (CeFs-PR-NEta) and arsenic trifluoride the phosphoranes react with hexamethyldisiloxane to give phosphinic acid fluorides, C6F5 P(O)RF.4 0 Preparation of the thiophosphinic halides C6F5-P(S)RX (X = Br, Cl, or F R = Me, Et, Bu. Ph, or CeFs) and of the thiophosphonic halides (C0Fs)2P(S)X has also been described, and their tP and n.m.r. spectra have been discussed.The hydrido(pentafluorophenyl)phosphate (250), obtained from dibromo(pentafluorophenyl)phosphine (Scheme 57), decomposes as shown at 50 °C. ... 

Thiohalides of the type RP(S)X2 and R2P(S)X can be made by heating sulphur with the corresponding phosphonous or phosphinous halides. Phosphonothioic (thiophosphonic) halides can be obtained by the action of hydrogen sulphide on tetrachlorophosphoranes (9.425), or phosphonous halide-aluminium trichloride complex (Chapter 6), or P4SJ0 on the corresponding phosphonic dihalide (9.426), or by reaction (9.427) in which PSCI3 acts as a sulphur donor. Monophenyl phosphine and thionyl chloride produce phenyl phosphonothionic dichloride, which can also be obtained by thermal isomerisation (9.428). 

Michaelis-Becker reaction between dialkyl thiophosphonates, (RO)2P(S)H, and alkyl halides, R X, in the presence of NaOR proceed satisfactorily at 70-80 °C in a few hours to give the diesters, (RO)2P(S)R Under such conditions, or during longer reaction periods or at higher reaction temperatures, the formation of the desired product may be... 

The alkylation, with the more reactive of alkyl halides, of the sodium salts of monoes-terified phosphonothioic acids (equation 22) (see also Scheme 11) or of the disodium salts 107 results in preferential S-alkylation, and the same situation obtains for the salts of phosphinothioic acid " methylation can also be carried out with dimethyl sulphate. Alkylations may also be performed under phase-transfer conditions. From both practical and theoretical perspectives, the subject is more complex, since the course of alkylation reactions depends on the nature of the alkylating agent, on the polarity of solvent and whether this is protic or non-protic and on the concentrations of reactants a study of these features has been the subject of two reports In non-polar or weakly polar aprotic media, or in EtOH, alkylation occurs almost exclusively on sulphur, but in dipolar aprotic solvents, O-alkylation also takes place. The relative yields of sulphur- and oxygen-substituted derivatives, [Qs/Qol depends, for a given solvent, on the nature of substituents on phosphorus, i.e. essentially, whether the substrate is a thiophosphoric, thiophosphonic or thiophosphinic acid. With alkyl tosylates as alkylating agents at 0.02 m in hmpt, the alkylation of sodium 0,0-dialkyl or diphenyl phosphorothioates results in 100% overall conversions with [Qs/Qo] 5 the overall yields for sodium diphenyl- or diisopropyl-phosphinothioates are lower (50-100%) with [Qs/Qo] 1 ... 

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