Phosphorus–nitrogen compounds. Part XLIII. Reactions of NN-dialkylanilines with phosphorus(V) chlorides; examples of ambident nucleophilic behaviour

Abstract

The reactions of hexachlorocyclotriphosphazatriene (N3P3Cl6) with dialkylanilines (PhNR2) yield ‘carbon’-[N3P3Cl5(C6H4·NR2)] and ‘nitrogen-substituted,’[N3P3Cl5(NRPh)] derivatives, whereas the analogous reactions of octachlorocyclotetraphosphazatetraene (N4P4Cl8) yield only ‘nitrogen-substituted’ derivatives [N4P4Cl7(NRPh) and N4P4Cl6(NRPh)2(R = Me)]. The behaviour of phosphoryl chloride with NN-dialkylanilines is much more complex, but ‘carbon-substitution’ predominates. Products include (R2N·C6H4)2P(O)R′, (R2N·C6H4)3P(O), (PhNR)P(O)R′2, and PhNHR (R = Me or Et; R′= Cl, OH, or OEt) and (R2N·C6H4)2P(O)NRPh, (PhNR)3P(O), (PhNR)2P(O)(NHPh), (R2N·C6H4)2CH2, and (R2N·C6H4)3CH (R = Me). From the analogous reactions of thiophosphoryl chloride only (Me2N·C6H4)P(S)(OEt)2 and (Et2N·C6H4)3P(S) were isolated. The behaviour of phosphoryl and thiophosphoryl chlorides with N-methylaniline was briefly investigated. Possible mechanisms for the reactions of phosphorus(V) chlorides with NN-dialkylanilines are briefly discussed. The ambident behaviour of the latter with the former and with cyanuric chloride is compared. S0 Values are deduced from the 1H n.m.r. spectra of the ‘carbon-substituted’ compounds.