Synthesis of Diaminophosphonium Salts [Ph2(ArNH)2P]+Br− (Ar = o-MeC6H4, p-MeC6H4, p-Pr i C6H4, p-EtO2CC6H4, p-MeOC6H4)

Abstract

The behavior of different anilines H2NC6H4R (R = o-Me, p-Me, o-, m- and p− i Pr, p-OMe, p-CO2Et) and 2,6-Me2C6H3NH2 towards trihalophosphoranes was studied. 2,6-Me2C6H3NH2 failed to form the diaminophosphonium salt [Ph2PNH(2,6-Me2C6H3)2]Br, and the aminophosphine oxide Ph2(2,6-Me2C6H3NH)PO was the only isolated product. Both o- and p-toluidine gave the corresponding diaminophosphonium salts; however in the case of o-toluidine, the yield was low and a mixture with the respective aminophosphine oxide was observed. Anilines containing methoxy and ethoxycarbonyl groups in para-position form the diaminophosphonium salts in reasonable yields.