Publications by authors named "E S Ostapchuk"

Creutzfeldt-Jakob disease (CJD) is a classic representative of the group of prion diseases and is characterized by progressive degeneration of the structures of the nervous system with a variety of neurological symptoms, steady progression and inevitable death. The disease is based on a change in the tertiary structure of the protein, which leads to disruption of the normal functioning of cells. Despite the fact that the etiology and pathogenesis of CJD are now well studied, intravital diagnosis of this serious disease remains difficult due to the peculiarities of the pathological process (unusually long incubation period, variety of clinical symptoms), the lack of pathognomonic markers that make it possible to make a diagnosis with a high degree of confidence, and also insufficient awareness of medical workers.

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A series of novel spirocyclic α-proline building blocks with a spiro conjunction in position 3 of the pyrrolidine ring was prepared to employ two convenient and practical synthetic approaches. Both alternative routes utilize simple and readily available starting materials─cyclic ketones and esters─and comprise 6 and 7 steps, respectively. The methodologies feature distinct advantages, using routine organic chemistry transformations, and are suitable for producing multigram amounts of the target prolines.

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A conceptual strategy for a formal α-alkylation of α-methylene ketones was developed. Diverse 1° and 2° alkyl substituents were generated in the α-position of various ketones via synthesis of enaminone (step 1) and treatment with organomagnesium (step 2) with subsequent catalytic hydrogenation (step 3, 1° alkyl) or organocopper reagents (step 4, 2° alkyl). Tolerance toward ester, Boc-protected amine, and α-fluoro-substituted ketone moieties was demonstrated.

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A series of seven palladium-containing composites, i.e., four Pd/C and three Pd(OH)/C (Pearlman's catalysts), was prepared using modified common approaches to deposition of Pd or hydrated PdO on charcoal.

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In this work, we report on the synthesis, in-depth crystal structure studies as well as optical and magnetic properties of newly synthesized heterometallic quaternary selenides of the EuLnCuSe composition. Crystal structures of the obtained compounds were refined by the derivative difference minimization (DDM) method from the powder X-ray diffraction data. The structures are found to belong to orthorhombic space groups (structure type BaMnS for EuLaCuSe and structure type EuCuS for EuLnCuSe, where Ln = Sm, Gd, Tb, Dy, Ho and Y) and (structure type KZrCuS for EuLnCuSe, where Ln = Tm, Yb and Lu).

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