2-Nitroaniline

2-Nitroaniline

2-Nitroaniline

Chemical compound

2-Nitroaniline is an organic compound with the formula H2NC6H4NO2. It is a derivative of aniline, carrying a nitro functional group in position 2.[1] It is mainly used as a precursor to o-phenylenediamine.

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Synthesis

2-Nitroaniline is prepared commercially by the reaction of 2-nitrochlorobenzene with ammonia:[2]

ClC6H4NO2 + 2 NH3 → H2NC6H4NO2 + NH4Cl

Many other methods exist for the synthesis of this compound. Direct nitration of aniline is inefficient since anilinium is produced instead. Nitration of acetanilide gives only traces of 2-nitro isomer is obtained due to the great steric effect of the amide. Sulfonation is usually used to block the 4 position and increases the effectiveness to 56%.[3][4]

Laboratory routes to produce 2-nitroaniline

Uses and reactions

2-Nitroaniline is the main precursor to phenylenediamines, which are converted to benzimidazoles, a family of heterocycles that are key components in pharmaceuticals.[2]

Intramolecular hydrogen-bonding results in a very low basicity for 2-nitroaniline.

Aside from its reduction to phenylenediamine, 2-nitroaniline undergoes other reactions anticipated for aromatic amines. It is protonated to give the anilinium salts. Owing to the influence of the nitro substituent, the amine exhibits a basicity nearly 100,000x lower than aniline itself. Diazotization gives diazonium derivative,[5] which is a precursor to some diazo dyes. Acetylation affords 2-nitroacetanilide.

See also

References

  1. [1]
    "Safety data for o-nitroaniline". Archived from the original on 2009-06-28. Retrieved 2011-01-17.
  2. [2]
    Gerald Booth (2007). "Nitro Compounds, Aromatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_411. ISBN 978-3527306732.
  3. [3]
    T. W. Grahan, Solomons; Craig, B. Fryhle; Scott, A. Snyder (2011). Organic chemistry (11 ed.). John Wiley & Sons. pp. 606–607. ISBN 978-1119077251.
  4. [4]
    Louis Ehrenfeld, Milton Puterbaugh (1929). "o-Nitrianiline". Organic Syntheses. 9: 64. doi:10.15227/orgsyn.009.0064.
  5. [5]
    G. Wittig; R. W. Hoffmann (1967). "1,2,3-Benzothiadiazole 1,1-Dioxide". Org. Synth. 47: 4. doi:10.15227/orgsyn.047.0004.
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