Phosphorus–nitrogen compounds. Part XXXV. Friedel–Crafts reactions of chlorodimethylaminocyclotriphosphazatrienes with benzene

Abstract

Chlorodimethylaminocyclotriphosphazatrienes, N₃P₃Cl_6–n(NMe₂)_n(n= 1,2,2,3,3, and 3) undergo Friedel–Crafts reactions with benzene in the presence of anhydrous aluminium trichloride to give phenyldimethylamino-derivatives, N₃P₃Ph_mCl_6–n–m(NMe₂)_n, whose structures are established by their ¹H n.m.r. spectra. Replacement occurs readily at PCl·NMe₂ groups and more slowly at PCl₂ groups. The hydrocarbons triphenylmethane and diphenylmethane are minor by-products in these reactions but are the major products isolated from attempted Friedel–Crafts reactions of cis-non-geminal-N₃P₃Cl₂(NMe₂)₄. The factors governing the positions of phenylation in the cyclotriphosphazatrienes are discussed.