Electronic Effects on C-O-C Ether Bonds in 3-Aryloxy Derivatives of Benzisothiazole 1,1-Dioxides: Rapid Ethanolysis of 3-(4-Nitrophenoxy)-1,2-benzisothiazole 1,1-Dioxide, (1), to give 3-Ethoxy-1,2-benzisothiazole 1,1-Dioxide, (2)

The bond lengths in the central C-O-C ether linkage of title compound (1), C₁₃H₈N₂O₅S, are comparable with those found in earlier work on similar compounds. However, (1) was found to undergo very easy solvolysis with ethanol to give (2), C₉H₉NO₃S, for which a structure was also determined, but 3-(4-methoxyphenoxy)-1,2-benzisothiazole 1,1-dioxide, (3), did not hydrolyse under the same conditions. If ground-state structures are important for solvolysis, these results suggest that there should be a difference in the corresponding C-O bond lengths for the ethers (1) and (3). Such differences are not observed. The results can be rationalized by supposing that transition-state energies for ethanolysis are more important factors than those of the ground state.

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