Formation of triphenylarsinimines (AsAsAs-triphenylarsine imides) by non-nitrene routes: co-oxidation of triphenylarsine and amines or amides with lead tetra-acetate, and related reactions. Preparation of diacetoxytriphenylarsorane

Abstract

Contrary to earlier suggestions, toluene-p-sulphonamide does not react with lead tetra-acetate (LTA) at low temperatures to give p-tolylsulphonylnitrene. Reaction of LTA with triphenylarsine in the presence of toluene-p-sulphonamide gives triphenyl-N-p-tolysulphonylarsinimine (AsAsAs-triphenylarsine p-tolysulphonylimide)(90%)via the intermediacy of the hitherto unknown diacetoxytriphenylarsorane [Ph₃As(OAc)₂]. N-Methylsulphonyl- and N-benzoyltriphenylarsinimines were formed similarly (58–62%). Reaction of triphenylarsine with LTA gave diacetoxytriphenylarsorane as a crystalline reactive solid (87%) which reacted with relevant amides to give the above arsinimines and also the N-p-nitrobenzoyl analogue (51%). These observations led to a simple one-pot reaction of amides with triphenylarsine oxide in acetic anhydride to give the above arsinimines and also N-diphenylphosphinyltriphenylarsinimine [Ph₃AsNP(O)Ph₂] in 65–90% yields. Reaction of LTA with N-aminophthalimide in the presence of triphenylarisine gives triphenyl(phthalimidoamino)arsonium acetate (10). Unlike the case of toluene-p-sulphonamide this reaction may be occurring, at least in part, via a nitrene mechanism to give the corresponding N-phthalimidotriphenylarsinimine ylide (11).