Mechanistic Investigations with the Aid of Isotopic Labeling, IX. Mechanism of the Ring Contraction Reaction of 1,4-Benzthiazin-2,3-4H-dione

Article abstract of DOI:10.1007/BF00799171

By 14C-labeling it is shown that the ring contraction reaction of 1,4-benzothiazin-2,3-4H-dione (1), leading via benzthiazol-2-carbonic acid (2) finally to benzthiazole (3), proceeds via hydrolytic opening of the thiolactone-bond in 1, irrespectively of H(+) or OH(-) catalysis. - (Keywords: 14C-Labeling; Ring contraction reaction; 1,4-Benzothiazin-2,3-4H-dione; Benzthiazole)