Synthesis of N-(9-oxo-7-phenyl-9H-pyrano[2,3-g]benzothiazol-2-yl)benzamides from 6-aminoflavone

Article abstract of DOI:10.1246/bcsj.67.2326

6-Aminoflavone (1) was treated with aroyl isothiocyanate in acetone at reflux temperature yields N-aroyl-N'-(2-phenyl-4-oxo-4H-[1]benzopyran-6-yl)thioureas. The products obtained on reaction of 2 with PCl₅ in POCl₃ medium leads to N-(9-oxo-7-phenyl-9H-pyrano[2,3-g]-benzothiazol-2-yl)benzamides (4). The structures of the compounds synthesized were established by analytical and spectral data.