Triflic Anhydride: A Mild Reagent for Highly Efficient Synthesis of 1,2-Benzisoxazoles, Isoxazolo, and Isothiazolo Quinolines Without Additive or Base

Abstract

The synthetic utility of trifluoromethanesulphonic anhydride (triflic anhydride, TA) without additive or base for the high-yielding synthesis of a wide variety of 1,2-benzisoxazoles from 2-hydroxyaryl aldoximes and ketoximes under mild conditions has been carried out for the first time. As a continuation of our study, syntheses of isoxazolo and isothiazolo quinolones have also been demonstrated using triflic anhydride under similar conditions. This method is simple and has benefits from the easy way to isolate the products in excellent yields.

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GRAPHICAL ABSTRACT

Keywords:

• Aldoximes
• 1,2-benzisoxazoles
• isothiazolo quinolones
• isoxazolo quinolones
• ketoximes
• triflic anhydride

ACKNOWLEDGMENTS

The authors thank the University Sophisticated Instrument Center, KUD, for IR, GC, GC-MS, ¹H NMR, and ¹³C NMR and G. Aridoss for useful discussions.

Notes

^a Isolated yields of pure products.

^b The reaction was carried out in EDC.

^a Isolated yields of pure products.

^b The reaction was carried out in EDC.