Intramolecular diazo coupling of 2-aminophenylthiophenes. The formation of isomeric thieno[c]cinnolines
Abstract
Thieno[2,3-c]-(4) and thieno[3,2-c]-cinnolines (7) have been obtained by diazotisation and internal coupling of the corresponding 2-(o-aminophenyl)thiophenes. By the same reaction 3-(o-aminophenyl)-2,5-dimethylthiophene gives 1,3-dimethylthieno[3,4-c]cinnoline (9).