4-(4-Oxo-chromen-6-yl)benzoic acid

4-(2,3-Dihydrobenzo[1,4]dioxin-6-yl)benzoic acid

4-(2-Oxo-2,3-dihydrobenzothiazol-6-yl)benzoic acid

4-(3-Oxo-3,4-dihydro-2H-benzothiazin-7-yl)benzoic acid