Abstract A new and general synthesis of 2, l-benzisothiazolin-3-ones (2) is described from the corresponding isatoic anhydride (3) and potassium hydrogen sulfide which gives the thioanthranilic acid (4) which is readily oxadized and ring closed to 2 with hydrogen peroxide. Phosphorus oxy-chloride converted 3-hydroxy-2, 1-benzisothiazole to 3-chloro-2, 1-benzisothiazole which gave a number of different 3-substiluted 2, 1-benzisothiazolesby ...