Synthesis of novel pyrazoles incorporating a phenothiazine moiety: unambiguous structural characterization of the regioselectivity in the 1,3-dipolar cycloaddition reaction using 2D HMBC NMR spectroscopy

An efficient and attractive regioselective synthesis of a series of novel pyrazoles containing a phenothiazine moiety was achieved utilizing microwave irradiation. Unambiguous structural assignment of the obtained regioisomers was determined utilizing 2D HMBC NMR techniques as a valuable tool.