nitroryhmät

Nitroryhmät, also known as the nitro functional group, consist of a single nitrogen atom bonded to two oxygen atoms with a double bond to one oxygen and a single bond to the other. In organic chemistry the group is represented as –NO₂ and is typically attached to a carbon skeleton. The nitro group is strongly electron‑withdrawing, making the attached carbon more electrophilic and the compound more acidic than many equivalent hydrocarbons. It is a common motif in both natural products and synthetic intermediates.

The nitro group is introduced primarily through nitration, a substitution reaction where an aromatic ring is reacted with a mixture of nitric acid and sulfuric acid. In aliphatic substrates, electrophilic nitrogen dioxide or trimethylsilylnitrite reagents can be used. Nitro compounds can be reduced to amines through catalytic hydrogenation, metal–acid reductions, or via iron/acetic acid routes, making nitro groups useful functional group transformers.

Because of their high oxidation state and the presence of adjacent oxygen atoms, nitro compounds can be explosive or highly reactive. Many industrial nitro drugs, dyes, explosives, and pesticides contain nitro functionalities. In polymer chemistry nitro groups serve as precursors to nitrile or amide groups after rearrangement or reduction.

Nitroryhmät are studied for their effects on biological activity, particularly in medicinal chemistry where the nitro group can act as a bioisostere or modulate lipophilicity. Their strong electron‑withdrawing character influences both chemical reactivity and pharmacokinetic properties, making the study of nitro derivatives critical for the rational design of new compounds.