(- CH CN) group and is called as cyanomethylation reaction. CH CH C H + H - CH - CN i) NaNH -NH ii) H + CH CH CN Ethyl Propionate Ethane nitrile - Ketopentanenitrile XII U13-Organic Nitrogen XII U13-Organic Nitrogen - - - - . . Alkyl Isocyanides (Carbylamines) Nomenclature of isocyanides They are commonly named as Alkyl isocyanides.
The IUPAC system names them as alkylcarbylamines Table : Nomenclature of alkylisocyanides Structural formula Common name IUPAC name NC Methyl isocyanide Methylcarbylamine CH CH NC Ethylisocyanide Ethylcarbylamine CH CH CH NC Propyl isocyanide Propylcarbylamine C H NC Phenyl isocynaide Phenylcarbylamine . . Methods of preparation of isocyanides . From primary amines (carbylamines reaction) Both aromatic as well as aliphatic amines on treatment with CHCl in the presence of KOH give carbylamines NH + CHCl + 3KOH C + 3KCl + 3H O Methylamine Methyl isocyanide NH + CH.Cl + 3KOH C H C + 3KCl + 3H O C H Aniline Phenyl isocyanide .
From alkyl halides Ethyl bromide on heating with ethanolic solution of AgCN give ethyl isocyanide as major product and ethyl cyanide as minor product. CH CH Br + AgCN C H OH heat CH CH - NC + AgBr Ethyl bromide Ethyl isocyanide . From N – alkyl formamide. By reaction with POCl in pyridine.
NH POCl (Pyridine) C + H O h l i id XII U13-Organic Nitrogen XII U13-Organic Nitrogen - - - - . . Properties of isocyanides Physical properties • They are colourless, highly unpleasant smelling volatile liquids and are much more poisonous than the cyanides. • They are only slightly soluble in water but are soluble in organic solvents.
• They are relatively less polar than alkyl cyanides. Thus, their melting point and boiling point are lower than cyanides. . .
Chemical properties ) Hydrolysis : Alkyl isocyanides