Flow Electrochemistry for the N‐Nitrosation of Secondary Amines

A flow electrochemical method towards the synthesis of N‐nitroso compounds from secondary amines using cheap and readily available sodium nitrite has been developed. Sodium nitrite dissolved in aqueous acetonitrile made additional electrolytes unnecessary. This mild and straightforward approach made the use of acids or other harsh and toxic chemicals redundant. This procedure was applied to an assortment of cyclic and acyclic secondary amines (27 examples) resulting in yields of N‐nitrosamines as high as 99 %. To demonstrate the practicality of the process, scaled‐up reactions were performed. Finally, selected products could be purified by using an in‐line acidic extraction. Go with the flow: N‐Nitroso compounds have been synthesised from secondary amines by using sodium nitrite in an electrochemical flow setup. A 1 : 1 mixture of acetonitrile and water was used for this reaction, making this a mild approach avoiding the use of additional supporting electrolytes. N‐Nitrosamines could be obtained in yields up to 99 %, and several compounds could be purified with an in‐line acidic extraction.