Unexpected intramolecular cyclization of 4-(2-halophenyl)-1Hpyrazolo[ 3,4-b]quinolines: Formation of 5- and 7-membered rings from one starter

Abstract

Cyclization of 4-(2-halophenyl)-1H-pyrazolo[3,4-b]quinolines 3a-b and 9a-9b provided two regioisomeric compounds: 6-phenyl-6H-5,6,7-triazadibenzo[f,h] naphtho[3,2,1-cd]azulenes 4,10 and 1,3-diphenyl-3H-indeno[1,2,3-de]pyrazolo[3,4- b]quinolines 2,11. All of them are considered as new building blocks for optoelectronic materials. The two-step synthesis utilized readily available starting materials.