Nitroso

Nitroso refers to a functional group in organic chemistry which has the general formula RNO. Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines. A good example is (CH3)3CNO, known formally as 2-methyl-2-nitrosopropane, or t-BuNO, which is prepared by the following sequence:
 * (CH3)3CNH2 → (CH3)3CNO2
 * (CH3)3CNO2 → (CH3)3CNHOH
 * (CH3)3CNHOH → (CH3)3CNO

(CH3)3CNO is blue and exists in solution in equilibrium with its dimer, which is colorless, m.p. 80 − 81 °C.

In the Fischer-Hepp rearrangement aromatic 4-nitroso-anilines are prepared from the corresponding nitrosamines. Another named reaction involving a nitroso compound is the Barton reaction.