A series of substituted 5-, 6-, 7-, and 8-hydroxy-3-phenyl-2H-1,3-benzoxazine-2,4(3H)-diones was synthesized. In a thionation reaction using Lawesson's reagent, only 8-hydroxy derivatives afforded corresponding 4-thioxo analogs and 2,4-dithiones.
All prepared compounds were tested for their in vitro antifungal activity against eight test strains.