Reduction of nitro- and nitroso-compounds by tervalent phosphorus reagents. Part V. Reduction of alkyl- and methoxy-nitrobenzenes, and nitrobenzene by trialkyl phosphites

Abstract

Reactions of triethyl- and trimethyl-phosphites with o-, m-, and p-nitrotoluene, o- and p-ethylnitrobenzene, o- and p-nitroanisole, and nitrobenzene give the corresponding dialkyl N-arylphosphoramidates, and dialkyl N-alkyl-N-arylphosphoramidates, and, in some cases, trialkyl N-arylphosphorimidates, the probable precursors of the above amidates. In some cases low (⩽18%) yields of dialkyl alkyl-3H-azepin-7-ylphosphonates are formed, indicating the intermediacy of nitrenoid species. Reaction of triethyl phosphite with p-ethyl-, p-methyl-, and p-methoxynitrobenzenes, and of trimethyl phosphite with o-nitroanisole and p-nitrotoluene give low yields of the corresponding dialkyl arylphosphonates, representing the first recorded instances of displacement of a simple aromatic nitrogroup unactivated by either electronic influences or special steric factors.