New method of synthesis of tris(2-hydroxyethyl)ammonium salts, 2,8,9-trihydroprotatranes X-[HN(CH₂CH₂OH)₃]⁺, based on the reaction of tris(2-hydroxyethyl)amine (triethanolamine) with ammonium salts NH₄X (X = F, Cl, Br, I, NO₃, ClO₄) was developed. ¹H, ¹³C, ¹⁵N NMR and IR spectra of these protatranes were investigated, as well as those of their analogs with X = RCH₂COO (R = H; 2-MeC₆H₄O; 2-Me-4ClC₆H₃O; 2-MeC₆H₄S; 4-ClC₆H₄S; 4-ClC₆H₄SO₂; 3-IndS; 3-(PhCH₂-IndS) prepared from the corresponding acids RCH₂COOH and triethanolamine. The parameters of IR and NMR spectra of the studied protatranes were governed by the nature of substituent X, which also determined the character of the intra and intermolecular hydrogen bonds NH⋯O and OH⋯O in the protatrane framework.

The review summarizes the data on the synthesis, physicochemical properties, structure, and pharmacological activity elucidation of salts and ionic liquids synthesized based on 2-hydroxyethylamines, aryl chalcogenylacetic acids, and essential metals. The practical application prospects of these novel compounds in medicine and biotechnology are discussed.