A Tandem Cyclization-Ugi Sequence of Reactions for the Synthesis of 1,4-Benzoxazine-3-carboxamide Derivatives

Benzo[b][1,4]oxazines constitute an important scaffold in synthetic organic chemistry in terms of having special applications in drug discovery and bioactive compounds. Thus, finding new methods for their synthesis is of high importance. In the present study, we have synthesized 2H-benzo[b][1,4]oxazine-3-carboxamide derivatives through a one-pot sequence of SN cyclization-Ugi reaction in ionic liquid, [emim][BF4], as the reaction solvent. Thus, a series of five novel derivatives of the target structure were obtained in 74%–80% yields via a four-component procedure. It was observed that the efficiency of the process under [emim][BF4] conditions is improved in comparison to the conventional Ugi reaction in MeOH medium.