Arylazide, die im Ring elektronenanziehende Gruppen enthalten (wie zum Beispiel 2.4-Dinitro-phenylazid), oder Arylsulfonylazide reagieren gleichfalls auch bei 0" mit den Enaminen energisch nach Schema B : Unter N2-Abspaltung entstehen Umlagerungsprodukte der infolge ihrer Unbestiindigkeit nicht isolierbaren Addukte.Vorliegende Mitteilung befal3t sich mit zwei unerwarteten Umsetzungen zwischen einigen Enaminen und Arylsulfonylaziden.
The reactions of a series of A-methyl-lV-arylhydrazones of ,/3-unsaturated carbonyl compounds 1 with hot polyphosphoric acid are described. Three main courses were observed, depending on the structure of the carbonyl portion of the substrate. Unsaturated -oxo ester hydrazones (la-c) rearranged to give substituted 3-[2-(methylamino)aryl]-2-oxo-3-butenoic acid esters (2a-c); the reaction mechanism strictly resembles the initial steps of the Fischer indole synthesis. Unsaturated aldehyde hydrazones alternatively gave either the di-3-indolylmethane derivatives (3a,b) or the amino nitriles (4a-c). The first process develops through intermediates structurally similar to 2; the latter was demonstrated to be exclusively intramolecular.
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