A Convenient Synthesis of N-Functionalized Perfluoroalkanesulfonamides

Abstract

This article describes the synthesis of new N-functionalized perfluoroalkanesulfonamides (5) with two sulfonamides functionalities. Perfluoroalkanesulfonyl fluoride underwent a reaction with 2-chloroethylamine hydrochloride or 3-bromopropylamine hydrobromide to give N-(2-chloroethyl or 3-bromopropyl) perfluoroalkanesulfonamides (1). Reaction of (1) with potassium thiocyanate gave N-(2-thiocyanatoethyl or 3-thiocyanatopropyl) perfluoroalkanesulfonamides (3). The sulfonyl chloride derivatives (4) were prepared by reaction of 3 with sulfuryl chloride. In the last step, 4 reacted with ammonia to give the bis sulfonamides derivatives (5). The structures of all new compounds prepared were determined by ¹H, ¹⁹F, and ¹³C NMR spectroscopies and by HR-MS.

Keywords:

• Alkylamine salts
• N-functionalized perfluoroalkanesulfonamides
• perfluoroalkanesulfonyl fluoride

Acknowledgments

We gratefully acknowledge the Ministère de l’Education Nationale et de la Recherche for its financial support (Ph.D. grant to Z. Benfodda).

Notes

^a The conversions were determined by ¹⁹F NMR spectrocopy (d₆-acetone) after treatment of the crude product. They were also determined by the relative integration of the functional CF₂ signal of compounds 1a, 1b, 1c, 1d, 2a, and 2b by the formula (fi/Ni)/(Σfi/Ni) × 100, where fi represents the height integration of the functional CF₂ signal and Ni the number of corresponding atom.

^b All these compounds 1 were crystallized in ethanol/water (V/V, 90:10) media.

^a The conversions were determined by ¹H NMR spectroscopy (d₆-acetone) after treatment of the crude product (the residue was diluted with water and EtOAc and washed with water). They were also determined by the relative integration of the functional CH₂ signal of 3b and 3d compared, respectively, with that of the functional CH₂ signal of 2b and 2d.