Nitriles, Imines and Nitro Compounds

Alkyl nitriles show a large dipole moment consistent with polarization in the sense RC sN . Hence many of the properties of the nitrile show a parallel to those of the carbonyl group. Nitriles are at the same oxidation level as a carboxylic acid, whereas an imine corresponds to an aldehyde or a ketone. 

An alternative route involves the nucleophilic substitution of an alkyl or benzyl halide with a cyanide ion. Two reactions are possible, leading to an isocyanide (R N=C) or a cyanide (R -ON). 

Many aryl nitriles are obtained from diazonium salts by treatment with copper(l) cyanide. Hydroxy and amino nitriles are obtained from addition reactions to carbonyl compounds. 

If the nucleophile is the hydroperoxide anion derived from hydrogen peroxide, an imino hydroperoxide is formed. These are useful mild epoxidizing agents and decompose to give amides. Alkaline hydrogen peroxide can be used to hydrolyse nitriles. 

Whereas isolated imines are relatively unstable and readily undergo hydrolysis to form carbonyl compounds, alkylated imines and imino derivatives are found as stable compounds in a variety of situations. Thus a number of nitrogen derivatives of aldehydes and ketones, such as the oxime, semicarbazone and hydrazone, contain an imino fragment. 

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