Eine einfache Synthese von β‐Chlorzimtsäurenitrilen nach einer modifizierten Vilsmeier‐Haack‐Arnold‐Reaktion

A Simple Synthesis of β‐Chlorocinnamonitriles by a Modified Vilsmeier‐Haack‐Arnold‐Reaction A simple one‐pot synthesis of β‐chloro‐cinnamonitriles 2 can be achieved by treating acetyl arenes 1 first with formamide chlorides and subsequently with hydroxyl amine hydrochloride. The formamide chlorides used are conveniently prepared from an excess of dimethyl formamide and phosphoryl chloride. However it is also possible to employ other N,N‐disubstituted formamides or acid chlorides, respectively. For comparison purposes β‐chloro‐cinnamonitriles 2 have also been synthesized in a two‐step process. Thus 3‐aryl‐3‐chloro‐(2)‐iminium salts 4 are reacted with hydroxyl amine hydrochloride giving rise to 3‐chloro‐cinnamic aldoximes 5. The latter compounds are dehydrated to the corresponding nitriles 2 by refluxing in acetic anhydride following a known procedure.