Nitroso group-containing compounds
Nitroso compounds contain nitric oxide group attached to an organic moiety. Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines. Many reactions exist which make use of an intermediate nitroso compound such as Barton reaction and Davis–Beirut reaction, as well as in the synthesis of indoles (Baeyer–Emmerling or Bartoli indole synthesis). Nitroso compounds are found in tobacco smoke, chewing tobacco and beer, they are strong carcinogens that produce cancer of the liver and kidney.