Design, characterization, and use of N,N-diethyl-N-sulfoethanaminium hydrogen sulfate {[Et3N-SO3H]HSO4} as a novel and highly efficient catalyst for preparation of α,α′-bis(arylidene)cycloalkanones

Abstract

The aim of this work is to introduce a novel and attractive protic acidic ionic liquid as catalyst for organic synthesis. To achieve this aim, N,N-diethyl-N-sulfoethanaminium hydrogen sulfate {[Et 3 N-SO 3 H]HSO 4 } was prepared by reaction of NEt 3 with ClSO 3 H and then with H 2 SO 4 . The novel acidic ionic liquid was identified by Fourier-transform infrared (FT-IR), 1 H nuclear magnetic resonance (NMR), 13 C NMR, and mass spectroscopies. Its catalytic activity was then examined in the cross-aldol condensation reaction of arylaldehydes with cycloalkanones under solvent-free conditions, obtaining a,a 0 -bis(arylidene)cycloalkanones in high yield after short reaction time. Graphical AbstractKeywords Protic acidic ionic liquid Á N,N-Diethyl-N-sulfoethanaminium hydrogen sulfate {[Et 3 N-SO 3 H]HSO 4 } Á a,a 0 -Bis(arylidene)cycloalkanone Á Crossaldol condensation Á Solvent-free & Abdolkarim Zare

A modified all-in-one DMSO-activating and base releasing reagent for the Parikh-Doering-type benzylic oxidation reaction

“…[37] Within the field of ionic liquids, for a related scaffold (N,N-diethyl-N-sulfoethanaminium hydrogen sulfate) a formal bond between the N and S was proposed based on FT-IR, 1 H and 13 C NMR spectroscopy and mass spectrum data. [38][39][40] Taken, together this gives further confidence on our structural reassignment for triethylsulfoammonium betaine [TESAB] (previously triethylamine-sulfur trioxide complex) with the first single crystal X-ray crystallography reported herein. Furthermore, a search for "any" chemical transformation involving triethylamine-sulfur trioxide complex, returned 43,376 examples but merely two examples for an oxidation reaction.…”