Sergey Z. Vatsadze

In this study, novel tricyclic compounds based on bispidine were prepared via a Michael addition–Henry domino reaction. This reaction sequence proceeds under mild conditions with high diastereoselectivity. Postsynthetic transformation pathways for the resulting nitro alcohols were demonstrated, leading to tricyclic amino alcohols of various structures.

We present a highly efficient strategy for the assembly of bispidine–isoxazolidine-fused multicyclic structures via [3+2] cycloaddition of alkenes to a nitrone-functionalized bispidine framework. The reaction smoothly delivers diverse hybrid heterocycles featuring complex stereochemistry at the isoxazolidine–bispidine junction point in high yields and good selectivity. This approach opens a straightforward pathway to new synthetic analogues of natural compounds (primarily lupine alkaloids) and may prove to be useful for the discovery of new bioactive molecules and ligands for catalysis.

The photophysical processes and photochemical reactions of 1,4-di(azastyryl)benzene (1) derivative {[(E,E)-1](ClO₄)₂} were investigated by absorption, luminescence, and laser kinetic spectroscopy in the water solution. The observed photo processes include dimerization, E-Z isomerization, and intersystem crossing to the triplet state, as well as the complexation [(E,E)-1](ClO₄)₂ with cucurbit[7]uril (CB[7]). The [(E,E)-1](ClO₄)₂ dye dimerization was shown to be energetically more favorable in the excited state than in the ground state. The reversible photoinduced migration of the dye dication in the CB[7] cavity takes place as a result of partial exit of the [(E,E)-1]²⁺ from the cavity and its subsequent conversion to the (E,Z)-isomer in the excited state, which undergoes conversion to the initial complex of {[(E,E)-1]@CB[7]}²⁺ after returning to the ground state. This photoprocess is of interest in relation to the scientific problem of designing photocontrolled supramolecular machines.

The complexation ability of one of the new promising analgesics, thiowurtzine (TW), with a number of cyclodextrin (CD) host molecules was studied using electron and ¹H NMR spectroscopy in methanol and confirmed by quantum-chemical and molecular dynamics calculations. Spectrophotometric and fluorescence titration methods determined the 1 : 1 stoichiometry and stability of the resulting complexes with γ-cyclodextrin derivatives (for TW@HP-γ-CD log K_1:1 = 3.0).

New hybrid bromometallates feature ordered inorganic anions perfectly positioned via Br⋯Br and H-bonding. Sb ⁵⁺ integration creates in-gap states, narrowing the band gap down to 1.27 eV.

Molecular and crystal structures of three 2,2,6,6-tetramethylpiperidine derivatives, including two stable radicals are determined for the first time. The XRD data obtained for two other stable TEMPO radicals are refined. A stable peroxosolvate of the nitroxide radical is reported. The corresponding intermolecular hydrogen bonds are determined for all compounds containing acidic protons.

Впервые установлены молекулярные и кристаллические структуры трех производных 2,2,6,6-тетраметилпиперидина, включая два стабильных радикала; для двух других стабильных радикалов типа ТЕМПО произведено уточнение данных РСА. Найден стабильный пероксосольват нитроксильного радикала, содержащего нитроксильную группу в положении 4. Для всех соединений с кислыми протонами найдены соответствующие межмолекулярные водородные связи.