A strategy involving palladium-catalyzed cyclization of halo-phenyl hydrazones and aryl isocyanates provides a convenient approach to the synthesis of 1,3,4-benzotriazepines (4) or 1-arylamide-1H-indazoles (5) in good isolated yields. Microwave irradiation was found to afford high reaction efficiency, while the choice of halophenyl hydrazone had an effect on the pathway of the reaction.

Facile Synthesis of 1,3,4-Benzotriazepines and 1-Arylamide-1H-indazoles via Palladium-Catalyzed Cyclization of Aryl Isocyanates and Aryl Hydrazones under Microwave Irradiation. -The title compounds are prepared from bromo-or iodo-aryl hydrazones, resp., under the same reaction conditions. The nature of substituents on the aryl hydrazones and aryl isocyanates has a significant effect on the reaction selectivity. -(DONG*, C.; XIE, L.; MOU, X.; ZHONG, Y.; SU, W.; Org. Biomol. Chem. 8 (2010) 21, 4827-4830, http://dx.doi.org/10.1039/c0ob00021c ; State