Studies on Diazepines. XXVII. Syntheses of Fully Unsaturated 1H-and 3H-1, 4-Benzodiazepines from 4-Quinolyl Azides

Abstract

Irradiation of the 4-azidoquinolines (7a-d) in a 1 : 1 mixture of methanol and dioxane containing sodium methoxide resulted in ring expansion to form the unstable fully unsaturated 1H-1, 4-benzodiazepines (9a-d), which were tautomerized to the stable 3H-1, 4-benzodiazepines (10a-d) by further treatment with sodium methoxide. Acetylation of the 3H-diazepines (10a and 10d) resulted in tautomerization to afford the 1-acetyl compounds 13a and 13d, which are the first isolated examples of 1H-1, 4-benzodiazepines. From these fully unsaturated diazepines (10 and 13), the 2, 3-dihydro-1H-1, 4-benzodiazepines (14-18) and their 5-oxo derivatives (19 and 20) were prepared.