3aminophenyl

3-Aminophenyl, commonly called the meta-aminophenyl substituent, refers to a phenyl ring in which an amino group (-NH2) is attached at the third carbon relative to the point of attachment to the rest of the molecule. It is one of three isomeric aminophenyl groups, the others being 2-aminophenyl (ortho) and 4-aminophenyl (para). The meta arrangement influences the electronic and steric properties of the attached molecule and can affect reactivity in subsequent substitutions.

The chemical formula for the 3-aminophenyl substituent is C6H6N, reflecting a phenyl ring (C6H4) bearing an amino group. The amino group on an aryl ring is a basic functional group, but its basicity is reduced compared with aliphatic amines due to conjugation with the aromatic system. The -NH2 group can undergo typical transformations such as acylation, sulfonylation, or diazotization, enabling a range of further functionalizations.

Applications and occurrence: 3-aminophenyl is a common building block in organic synthesis. It appears in the construction of pharmaceuticals, agrochemicals, and dyes, often as part of more complex molecules such as amides, sulfonamides, or heterocyclic frameworks. It also serves in medicinal chemistry as a motif in various candidate compounds, where the meta orientation can influence binding interactions and selectivity.

Synthesis and preparation: Direct nitration of aniline tends to favor ortho and para products; meta selectivity is typically achieved via indirect routes, such as starting from meta-nitrobenzenes followed by reduction, or employing meta-directing protecting groups before later deprotection.