Conversion of chiral unsaturated cyanohydrins into chiral carba- and heterocycles via ring-closing metathesis

Aliphatic unsaturated cyanohydrins 1-3 served as starting materials in the synthesis of a set of new chiral unsaturated cyclic 1,2-ethanolamines. Combining a Grignard addition-NaBH₄ reduction sequence with a ring-closing metathesis afforded unsaturated cyclic 1,2-ethanolamines 7-11 and 22-25 in good yields and high ee (96-99%). The conversion of cyanohydrins 1-3 via a DIBAL reduction-transimination-NaBH₄ reduction sequence, using allylamine, followed by ring-closing metathesis yielded tetrahydropyridines 28, tetrahydroazepinols 33 and tetrahydroazocinols 34 in high yields and excellent ee (97-99%).     

Influence of the Buffer Organic Cation on the Chiral Separation of Some Basic Drugs by Capillary Zone Electrophoresis

This paper addresses the influence of small organic cations in the background electrolyte (BGE) on chiral separation by capillary zone electrophoresis (CZE). Seven basic drugs, viz. alprenolol, amphetamine, anisodamine, isoprenaline, pinacidil, synephrine, and verapamil were used as test compounds with hydroxylpropyl-β-cyclodextrin (HP-β-CD) as the chiral selector. Resolution of the chiral test compounds was studied at pH 2.5 in the presence of Tris, ethanolamine, diethanolamine, triethanolamine, diethylamine, and triethylamine, which exist in their cationic forms at this pH value. Among the six cationic additives studied, triethylamine is most effective in enhancing resolution. A tentative mechanism of the effect is proposed.     

Study of Petroleum Resins Modification by Ethanolamins

Possibilities of synthesis and properties of the products of the ozonated petroleum resins modification by ethanolamines was considered. It is founded that ethanolamines interact both with decomposition products of the ozonized groups obtained from ozonated resins, and directly with the ozonized groups themselves. The obtained modified petroleum resins can be used as adhesive and film-forming components in paint materials.     

Viscosities and Excess Properties of Aqueous Solutions of Ethanolamines from 25 to 80°C

Viscosities of aqueous solutions of monoethanolamine and triethanolamine have been measured from 25 to 80°C over the entire range of concentrations. The excess Gibbs energies for viscous flow have been calculated for aqueous solutions of monoethanolamine, triethanolamine, and also for diethanolamine and methyldiethanolamine from our earlier work [J. Chem. Eng. Data 39, 290 (1994)]. The entropy of viscous flow was obtained by using the temperature dependence of the excess Gibbs energy for viscous flow. The structural effects on the viscosity, excess Gibbs energy, and entropy for viscous flow are discussed.     

N,O-ditosylethanolamine as effective reagent for the synthesis of heterocyclic tertiary amine salts

During the synthesis of N-tosylaziridine, two unexpected products were isolated: 1-(2-(p-tolylsulfonamido)ethyl)pyridinium p-tolylsulfonate (3) and N,N,O-tri-(p-tolylsulfonyl)ethanolamine (3a). The structures of 3 and 3a were investigated in solid state by X-ray analysis. A new family of related salts was obtained using an efficient and facile one-pot synthesis consisting in the interaction between various nitrogen heterocycles and N,O-ditosylethanolamine.     

Design, synthesis, and biological evaluation of novel fluorinated ethanolamines

The preparation of novel fluorinated allylamines and their use as key fragments for the stereoselective synthesis of hydroxyethyl secondary amine (HEA)-type peptidomimetics is described. Our strategy employs chiral sulfinyl imines as synthesis intermediates, by treatment of hemiaminal precursors with two equivalents of vinylmagnesium bromide. The subsequent oxidation of the allylic amines to the corresponding epoxides was achieved by treatment with methyl(trifluoromethyl)dioxirane. Finally, epoxide ring opening with a range of nitrogen nucleophiles provided a library of HEA-derived peptidomimetics with a phenyldifluoromethylene moiety. The biological evaluation of these derivatives revealed compounds with remarkable BACE1 inhibitory activity. Docking studies revealed the influence of the fluorine atoms in the binding mode of the synthesized ligands. Furthermore, the biological evaluation of our final products and synthesis intermediates led to the discovery of compounds with antimicrobial activity against Mycobacterium and Nocardia species.