Rearrangement of Indolinesulfonamides to Sulfones Using Polyphosphoric Acid (PPA)

Abstract

Unlike other N-alkylsulfonanilides, indolinesulfonamides hydrolyze in 98% sulfuric acid. Recent work in this laboratory has shown that rearrangement can be achieved by using polyphosphoric acid. A series of substituted indolinesulfonamides has been prepared and rearranged to their corresponding indoline arylsulfones.

Keywords:

• Indoline
• phenylsulfonylindoline
• polyphosphoric acid

Notes

^a Compound 3 is known: Ref. 7 (mp 129.5–131).

^b Compound 4 is known: Ref 8 (mp 100.5–101.5).

^c Compound 5 is known: Ref. 9 (no mp reported).

^d Compound 8 is known: Ref. 10 (mp 75–77).

^e Compound 11 is known: Ref. 11 (mp 135–136).