Amines imidoyl halide synthesis

Triphenylphosphine-carbon tetrahalides. 13, 331-332 15, 352 16, 366-368 Acid halides. The relatively mild conditions of converting acids to halides by Ph3P-CX4 can be exploited for a one-flask synthesis of A-methoxy imidoyl bromides, which give rise to nitriles on photolysis. In the presence of EtsN the PhsP-CX4 combination converts amines and CF3COOH to trifluoroacetimidoyl halides. ... 

The classical example of this type of reaction is the v. Braun method of degradation, by which a secondary amine can be transformed into a primary amine, and finally into ammonia, via the imidoyl chloride intermediates. This reaction has been used for the structure elucidation of alkaloids. Although degradative studies are not conducted to any extent today due to the convenience of spectral methods, the v. Braun elimination is still used in organic synthesis to prepare nitriles as well as alkyl halides. 

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