Oxidation of the easily available 1‐(alkylamino)pyrazolones allows the preparation of the title compounds, which are a new class of heterocycles, in good yields. The structure of these compounds is assigned on the basis of HR mass spectroscopy and sodium borohydride reduction to (Z,E)‐2‐methyl‐3‐phenyl‐N‐(1‐phenylethyl)acrylamide. Ring contraction/rearrangement to 2‐alkyl‐2H‐1,2,3‐triazole is observed under UV irradiation. A possible mechanistic rationalisation of the observed processes is proposed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)