Preparation of 1,10-dimethyl-benzo[c]cinnolines by photochemical cyclodehydrogenation of azobenzenes

摘要

Photocyclodehydrogenation of methylated azobenzene derivatives to the corresponding benzo[c]cinnolines was utilized for the synthesis of a number of compounds featuring sterically hindered methyl groups with different degrees of sterical hindrance including close mutual methyl-methyl interaction. Such compounds are of special theoretical interest in the context of intramolecular dynamics, spectroscopy, and quantum (tunneling) effects. Factors determining synthetic accessibility and product distribution are discussed. [References: 15]