Multicomponent Assembly of Bicyclic Aza-peroxides Catalyzed by Samarium Complexes and Their Cytotoxic Activity.

An original strategy toward bridged tetraoxazaspirobicycloalkanes was developed. The synthesis is based on a three-component condensation-cyclization reaction of primary arylamines with 1,1'-peroxybis (1-hydroperoxycycloalkanes) and pentane-1,5-dial catalyzed by Sm(NO)·6HO. The structures and conformations of the products were determined by X-ray diffraction analysis and H and C NMR spectroscopy.

The mechanism of the replacement of aluminum atoms in 1-ethyl-3-alkylalumolanes by boron atoms with boron halides.

In this study, the mechanism of the replacement reaction of an aluminum atom by a boron atom in the 1-ethyl-3-substituted alumolanes with boron halides is proposed. Theoretical and experimental justifications based on the DFT quantum chemical calculations of the energy parameters of possible reaction routes coupled with monitoring of the reaction between 1-ethyl-3-butylalumolane and BF·EtO, BCl and BBr using H, C, B and Al NMR spectroscopy are provided.

Development of solvent-free protocols for obtaining highly substituted maleates of hyaluronic acid and other glycosaminoglycans.

Solvent-free protocols using microwave-assisted heating (i) or conventional heating without additives (ii) or adding KCO (iii), or triturating at room temperature in the presence of KCO (iv) were first used to esterify glycosaminoglycans (GAG) with maleic anhydride. High and low molecular weight hyaluronic acid (HMW and LMW HA), dermatan sulfate (Ds), heparin (HEP) and C6-oxidized HA (carboxy-HA) were used as substrates for maleation. Protocols (i)-(iii) were most effective for obtaining maleates with high DS (1.

Synthesis and anticancer activity novel dimeric azatriperoxides.

An efficient method was developed for the synthesis of tetra(spirocycloalkane)-substituted α,ω-di(1,2,4,5,7,8-hexaoxa-10-azacycloundecan-10-yl)alkanes by a ring transformation reaction of 3,6-di(spirocycloalkane)-substituted 1,2,4,5,7,8,10-heptaoxacycloundecanes with α,ω-alkanediamines (1,4-butane-, 1,5-pentane-, 1,7-heptane-, 1,8-octane- and 1,10-decanediamines) catalyzed by Sm(NO)/γ-AlO. Using flow cytometry, it was shown for the first time that synthesized dimeric azatriperoxides are efficient apoptosis inducers with Jurkat, K562, U937, and Hek296.

Aluminacyclopentanes in the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes.

An efficient one-pot process for the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes was developed. The method involves the replacement of aluminium in aluminacyclopentanes, prepared in situ by catalytic cycloalumination of α-olefins and α,ω-diolefins, by phosphorus atoms on treatment with dichlorophosphines (R'PCl2). Hydrogen peroxide oxidation and treatment with S8 of the synthesized phospholanes and α,ω-bisphospholanes afforded the corresponding 3-alkyl(aryl)-1-alkyl(phenyl)phospholane 1-oxides, 3-alkyl(aryl)-1-alkyl(phenyl)phospholane 1-sulfides, bisphospholane 1,1'-dioxides, and bisphospholane 1,1'-disulfides in nearly quantitative yields.

Stoichiometric C6-oxidation of hyaluronic acid by oxoammonium salt TEMPO⁺Cl⁻ in an aqueous alkaline medium.

This paper reports the selective oxidation of hyaluronic acid (HA) by stoichiometric quantity of 2,2,6,6-tetramethylpiperidine-1-oxoammonium chloride (TEMPO(+)) in aqueous alkaline medium. High efficiency of the HA oxidation and quantitative yield of carboxy-HA per starting TEMPO(+), as well as unusual behavior of the oxidation system generating an oxygen upon alkali-induced oxoammonium chloride decomposition are demonstrated. The scheme for HA oxidation involving both TEMPO(+) and oxygen produced upon the TEMPO(+)Cl(-) decomposition and/or air oxygen is proposed.