Synthesis and spectroscopic properties of a series of novel 2-aryl-3-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones

A series of thirteen novel 2-aryl-3-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-phenyl-C-aryl imines with thiosalicylic acid. The spectroscopic and physical properties are reported and discussed. ¹H-¹⁹F and ¹³C-¹⁹F couplings were observed in the NMR spectra of fluorinated compounds. Through-space interactions were observed in the ¹H and ¹³C NMR spectra of the ortho-nitro compound. Trends were observed in the IR and UV absorptions of the ortho/meta/para-nitro series.