Primary amines are versatile building blocks in synthetic chemistry. If there are numerous methodologies to synthesize primary amine, most of them required the formation of an intermediate. The use of ammonia has already been described for the direct amination of halides; however, because of its poor nucleophilicty, long reaction time was required and the subsequent formation of secondary amines was observed. Herein, we report a simple and efficient continuous flow synthesis of primary ammonium salts from halides and ammonia in water. Continuous flow chemistry enables a reaction time of only 10 minutes, with good to excellent yields and no significiant formation of secondary amine. Volatile amines were produced and easy to isolate due to the formation of the ammonium salt. In addition to a variety of aliphatic halides with various functional groups, other electrophiles such as epoxydes and aromatic halides were also compatible with the reaction conditions. Furthermore, a in-line set-up enables the formation of amides and pyrazoles from the corresponding halide in an automated process which gives the possiblity of a large scale and automated short synthesis.

Synthesis of primary amine HX salts from halides and ammonium hydroxide in continuous flow chemistry

255th National Meeting (2018)

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