The treatment of a nitrile with a mixture of stannous chloride and hydrochloric acid yield the imine salt complex which is subsequently hydrolysed to an aldehyde. This reaction converting of a nitrile to an aldehyde is known as Stephen reduction. It has wide applicability for aromatic aldehydes. The solvents used are ether, ethyl acetate etc. The conversion of an aliphatic and aromatic nitrile into aldehyde proceeds with good yield. Usually lithium triethoxyalumino hydride is used as catalyst.