Copper‐Catalyzed C−H Oxygenation of Benzoxepine‐4‐carboxylates: Facile Synthesis and Photophysical Properties of Naphtho[2,1‐d]oxazoles and Benzo[c]phenoxazines

Abstract

An efficient, solvent-free, one-pot protocolw as developed for the preparation of naphtho[2,1-d]oxazoles and benzo[c]phenoxazines by the CÀHo xygenation of benzoxepine-4-carboxylates with benzylamines and anilinesi nt he presence of Cu(OAc) 2 .T he synthesis, UV/vis absorption, fluorescence emission and electrochemical properties have been studied for these heterocyclic compounds. The benzo[c]phenoxazines absorbed in the UV/vis in the range 449-461 nm and fluorescencee mission in the range 562-627 nm. The nitro-andd imethyl-substituted benzo[c]phenoxazines had the most favorablef luorescencee mission in these series of compounds (emission maximaa t6 27 and6 03 nm with quantum yields F f = 0.51 and 0.37, respectively). The optical and electrochemical properties suggest that these compounds can act as electron-transporting materialsf or organic light-emitting diode applications.Scheme1.Previouswork on the synthesis of naphtha[2,1-d]oxazoles, 7 Hbenzo[c]phenoxazines,a nd this work.[a] K.

Stereospecific Synthesis of 3,4-Dihydro-2H-naphtho-1,4-oxazin-2-ones by Unification of Benzoxepine-4-carboxylates with Chiral Amino Acid Ethyl Esters

“…Our research group is interested in the development of novel methods for the preparation of heterocyclic compounds . The research work on benzoxepine-4-carboxylates has produced novel heterocyclic compounds . In continuation of our work on benzoxepine-4-carboxylates, recently, we have prepared useful oxygenated heterocycles .…”