Tilcotil® Studies [3+2] additions with isothiazol-3(2H)-one 1,1-dioxide

Derivatives of isothiazol-3(2H)-one 1,1-dioxide react regiospecifically with 1,3-dipolar agents. The main regiocontrolling factor is ascertained to be the C?O group of the dipolarophile. The topology of the adducts is also in general agreement with predictions based on perturbation theory. Several adducts can be aromatized to heterocyclic equivalents of saccharin, and may then be elaborated into structural analogs of tenoxicam (Tilcotil® and piroxicam (Feldene®)).