Zur Synthese von Derivaten des Pyrido[1,2-a]azepins

✍ Scribed by Wolfram Maicr; Wolfgang Eberbach; Hans Fritz

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: German
• Weight: 406 KB
• Volume: 74
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19910740519

✦ Synopsis

On the Synthesis of Derivatives of Pyrido[l,Z-ulazepine

The conjugated pyridinium ylides of type 4 undergo 8n-electrocyclisation affording the heterobicyclic allenes 5 which, in the presence of H 2 0 and H202, are subsequently transformed into the substituted pyrido[l,2-a]azepinones 6, a novel heterocyclic system. The chemical behaviour of 6a, b is dominated by cleavage of the lactam bond and subsequent reaction to pyridine and isoquinoline derivatives, respectively; e.g. reaction of 6a, b with 4,5-dihydro-4-methyl-3H-1,2,4-triazole-3,5-dione affords the cycloadducts 11 and 12 almost quantitatively. The successful transformation of 6b into 15 is described, the latter being the first representative of the presently unknown, potentially antiaromatic pyrido[ 1,2-n]azepine (1). ') Vom 3,4-Benzazepin liegen nur Derivate der Doppelbindungsisomeren mit aromatischem Benzol-Ring vor.