The Preparation of Dibromoamine and its Reaction with Grignard Reagents

Dibromoamine was prepared by passing dry ammonia into a cold ethereal solution of bromine. The reaction may be represented by the equation: 3 NH3 + 2 Br2 → NHBr2 + 2 NH4Br. A study of the decomposition rates of the dibromoamine solution at 0° and -72° shows that the product decomposes very rapidly at 0°, but it is relatively stable at the lower temperature. Dibromoamine reacts with Grignard reagents to produce primary amines, secondary amines, ammonia, and nitrogen. The percentage yields of these products obtained in two typical reactions were as follows: for n-butyl magnesium chloride; n-butylamine 7.8 per cent, di-n-butylamine 2.2 per cent, ammonia 79.0 per cent, nitrogen 5.9 per cent; for benzyl magnesium chloride; benzylamine 29.6 per cent, dibenzylamine 5.5 per cent, ammonia 42.8 per cent, nitrogen 4.7 per cent