Novel 5-N,N-disubstituted-5-amino-3-(2-oxopropyl)-1,2,4-thiadiazoles: synthesis and study of neuroprotective and antiproliferative properties

Russian Chemical Bulletin - A series of eight novel 5-N,N-disubstituted-5-amino-3-(2-oxopropyl)-1,2,4-thiadiazoles with diverse lipophilic groups was obtained by reaction of...     

1,2,4-Thiadiazoles as promising multifunctional agents for treatment of neurodegenerative diseases

Detailed studies of properties of new 3-substituted 5-anilino-1,2,4-thiadiazoles containing different substituents at position 3 of the thiadiazole ring were carried out, in particular, their esterase profile and antioxidant properties. It was found that the presence in the molecule of 2-aminopropyl fragment determines an efficient and selective inhibition of butyrylcholinesterase as compared to acetylcholinesterase and carboxylesterase, with radical-scavenging activity being weak. The compounds containing a 2-aminopropenyl fragment possess a high radicalscavenging activity, weakly inhibit cholinesterases, and exhibit anticarboxylesterase activity. A wide spectrum of activity of 3-substituted 5-anilino-1,2,4-thiadiazoles as inhibitors of cholinesterases and highly efficient scavengers of free radicals gives a basis for the optimization of structure and development in this series of original agents for therapy of neurodegenerative diseases.     

New Adamantane Derivatives with NO-Generating Fragment

An approach to the synthesis of adamantane derivatives with NO-generating fragment containing nitroxy group has been developed. 1-Aminoadamantane, memantine, and adamantanecarboxylic acid have been used as initial compounds. The prepared compounds have shown ability to generate nitric oxide in a system mimicking biological reactions of nitro group reduction.     

Boron-chelate assisted synthesis of new bipyrazole derivatives

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Effect of Intrahippocampal Administration of α7 Subtype Nicotinic Receptor Agonist PNU-282987 and Its Solvent Dimethyl Sulfoxide on the Efficiency of Hypoxic Preconditioning in Rats

We have previously suggested a key role of the hippocampus in the preconditioning action of moderate hypobaric hypoxia (HBH). The preconditioning efficiency of HBH is associated with acoustic startle prepulse inhibition (PPI). In rats with PPI > 40%, HBH activates the cholinergic projections of hippocampus, and PNU-282987, a selective agonist of α7 nicotinic receptors (α7nAChRs), reduces the HBH efficiency and potentiating effect on HBH of its solvent dimethyl sulfoxide (DMSO, anticholinesterase agent) when administered intraperitoneally. In order to validate the hippocampus as a key structure in the mechanism of hypoxic preconditioning and research a significance of α7nAChR activation in the hypoxic preconditioning, we performed an in vivo pharmacological study of intrahippocampal injections of PNU-282987 into the CA1 area on HBH efficiency in rats with PPI ≥ 40%. We found that PNU-282987 (30 μM) reduced HBH efficiency as with intraperitoneal administration, while DMSO (0.05%) still potentiated this effect. Thus, direct evidence of the key role of the hippocampus in the preconditioning effect of HBH and some details of this mechanism were obtained in rats with PPI ≥ 40%. The activation of α7nAChRs is not involved in the cholinergic signaling initiated by HBH or DMSO via any route of administration. Possible ways of the potentiating action of DMSO on HBH efficiency and its dependence on α7nAChRs are discussed.     

Proximity effect in the finite and incommensurate ferromagnet/superconductor systems

The original theory of a proximity effect is proposed for the bi- and tri-layered system ferromagnetic metal/superconductor (F/S) in dirty limit. The F₁/S/F₂ trilayer is examined more closely. The distinctions in materials, in thicknesses of F layers (d_f1 and d_f2), in parameters interfaces, and in local environments of layers are considered among the causes of incommensurability of trilayer. The peculiar T_c(d_f1, d_f2) interference pattern is predicted for the F₁/S/F₂ systems. The reentrant superconductivity and possibility of the better observability of the spin-valve regime are discussed.     

Synthesis of diazahomoadamantanones thiosemicarbazones

Thiosemicarbazones of ketones from 3,6-diazahomoadamantane series were prepared by two procedures: by treating 3,6-diazahomoadamantan-9-ones with thiosemicarbazide and by a reaction of substituted (3,6-diazahomoadamantan-9-ylidene)hydrazines with versatile isothiocyanates.     

Critical Temperature of a Superconductor/Ferromagnet Nanostructure near a Magnetic Skyrmion

JETP Letters - Contact between a superconductor and a chiral ferromagnet containing complex magnetic structures (helical or conical texture, skyrmion, and chiral float) has been considered. The...     

Manifestations of the Larkin-Ovchinnikov-Fulde-Ferrell state in bimetal ferromagnet-superconductor structures

Reentrant and periodically reentrant superconductivity in contacts and ferromagnet/superconductor (F/S) superlattices are predicted on the basis of the theory developed in this letter. These effects are consequences of the realization of the Larkin-Ovchinnikov-Fulde-Ferrell state in F layers. An explanation is given for the qualitatively different behavior of the critical temperature observed by different experimental groups on identical F/S structures. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 8, 527–532 (25 October 1997)     

Synthesis of new 2-amino-5-hydroxymethyl-2-thiazolines

A simple and convenient method is proposed for the synthesis of 2-amino-5-hydroxymethylthiazolines with various substituents in the amino group, which is based on hydrolysis of the corresponding 5-halomethyl derivatives of thiazoline in the presence of divalent lead oxide. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 456–463, 2007.