Acid-promoted behaviour of 1a,7b-dihydro-1H-cyclopropa[c]cinnolines
Abstract
Compounds (1 a–c) undergo in boiling acetic acid a fast reaction to afford 1,4-dihydrocinnolines or 4,5-dihydro1H-1,2-benzodiazepines, which arise from a skeleton rearrangement involving cleavage of the cyclopropane ring. Fragmentation products are also obtained in the case of (1c).