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The Skraup synthesis is a chemical reaction used to synthesize quinolines. It is named after the Czech chemist Zdenko Hans Skraup (1850-1910). In the archetypal Skraup reaction, aniline is heated with sulfuric acid , glycerol , and an oxidizing agent such as nitrobenzene to yield quinoline.
The reaction was first used by Antoine Béchamp to reduce nitronaphthalene and nitrobenzene to naphthylamine and aniline, respectively. [3] The Béchamp reduction is broadly applicable to aromatic nitro compounds. [4] [5] Aliphatic nitro compounds are however more difficult to reduce, often remaining as the hydroxylamine. Tertiary aliphatic ...
A modern synthesis entails reduction of nitrobenzene to phenylhydroxylamine (C 6 H 5 NHOH) which is then oxidized by sodium dichromate (Na 2 Cr 2 O 7). [5] Nitrosobenzene can also be prepared by oxidation of aniline using peroxymonosulfuric acid (Caro's acid) [6] or potassium peroxymonosulfate under biphasic conditions. [7]
Nitrobenzene is an aromatic nitro compound and the simplest of the nitrobenzenes, with the chemical formula C 6 H 5 NO 2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from benzene as a precursor to aniline.
Frederick Sanger. In 1945, Frederick Sanger described its use for determining the N-terminal amino acid in polypeptide chains, in particular insulin. [4] Sanger's initial results suggested that insulin was a smaller molecule than previously estimated (molecular weight 12,000), and that it consisted of four chains (two ending in glycine and two ending in phenylalanine), with the chains cross ...
4-Nitroaniline, p-nitroaniline or 1-amino-4-nitrobenzene is an organic compound with the formula C 6 H 6 N 2 O 2. A yellow solid, it is one of three isomers of nitroaniline. It is an intermediate in the production of dyes, antioxidants, pharmaceuticals, gasoline, gum inhibitors, poultry medicines, and as a corrosion inhibitor. [3]
Nitrobenzene can be obtained by treating benzenediazonium fluoroborate with sodium nitrite in presence of copper. Alternatively, the diazotisation of the aniline can be conducted in presence of cuprous oxide, which generates cuprous nitrite in situ: [C 6 H 5 N 2] + + CuNO 2 → C 6 H 5 NO 2 + N 2 + Cu +
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%.