Heterocyclic N-Acetoxyarylamines, Models for the Putative Ultimate Carcinogens of Aromatic Amines: 2-Acetoxyamino-5-phenylpyridine and 2-Acetoxyaminopyridine

The structures of O-acetyl-N-(5-phenyl-2-pyridyl)hydroxylamine, C₁₃H₁₂N₂O₂, (I) and O-acetyl-N-(2-pyridyl)hydroxylamine, C₇H₈N₂O₂, (II), have been determined to confirm earlier structure assignments based on spectroscopic information. Compound (I) is the probable mutagenic metabolite of the phenylalanine pyrolysis product, 2-amino-5-phenylpyridine. The crystal structures of (I) and (II) are the first reported for heterocyclic N-acetoxyarylamines, the corresponding homocyclic arylamine derivatives being extremely unstable. In the solid state, both (I) and (II) exist as hydrogen-bonded dimers, with the arylamine N atom acting as donor and the pyridine N atom of a neighboring inversion-related molecule as acceptor; the distance between donor and acceptor N atoms is 3.007 (2) Å in (I) and 2.956.(2) Å in (II). This orientation of the N-H bond results in the rotation of the acetoxy group out of the plane of the pyridine ring by 22.5 (2)° in (I) and 27.4 (2)° in (II).

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