Unusual crystal and molecular structure of the 1-(1-silatranylmethyl)-3,5-dimethylpyrazole complex with zinc dichloride

The crystal and molecular structure of a 1-(1-silatranylmethyl)-3,5-dimethylpyrazole complex with zinc dichloride (I) is determined by XRD. The coordination polyhedron of the zinc atom is a tetrahedron formed by two covalent Zn-Cl bonds and coordination Zn ← N and Zn ← O bonds. Compound I is the first example of how an endocyclic oxygen atom of the silatranyl fragment participates in the coordination of the metal atom with the formation of a six-membered heterocycle.     

Reaction of Norfluorocurarine and 12-Hydroxynorfluorocurarine with Phenylhydrazine

Chemistry of Natural Compounds - The reaction of the indoline alkaloid 12-hydroxynorfluorocurarine with phenylhydrazine produced 1,2-seco-12-hydroxynorfluorocurarine-2,17-phenylhydrazone, the...     

Chemical and radiological toxicity of uranium compounds

Studies into the effects from environmental pollution by uranium compounds have been overviewed. Analysis of the impact of uranium oxides resulted from military operations using armor-piercing shells made of depleted uranium shows a predominance of chemical toxicity caused by the strong oxidizing power of uranyl ions. They induce oxidative stress through the generation of reactive oxygen species. As a result, oxidative damage to biomolecules and disruption of metabolic processes occur. Oxidative DNA damage causes long-term genotoxic effects in the form of mutagenesis, carcinogenesis, and other pathologies. The necessity of prohibiting the use of depleted uranium shells as chemical weapons of mass destruction has been substantiated.     

Synthetic analogs ofPeganum alkaloids VIII. A quantum-mechanical investigation of the reduction of deoxypeganine and its derivatives

The alkaloid deoxypeganine and some of its derivatives have been subjected to reduction with sodium tetrahydroborate and with the complex NaBH₄·BF₃·Et₂O. It has been shown that the structures of the reduction products depend on the presence and positions of substituents in the benzene ring. The quantumchemical calculations performed have confirmed the probable formation of reduced structures of the type ofo-aminobenzylpyrrolidine and the type of a macrocyclic diamine.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 220–225, March–April, 1999.     

A Detonation Afterburner

Doklady Physics - For the first time, a detonation afterburner (DA) for continuous detonation combustion of TS-1 aviation kerosene was developed, manufactured, and tested. Test fires of the DA in...     

Conformational Dynamics and Absolute Configuration of Sawaranin

Chemistry of Natural Compounds - Butyrolactone 1 was isolated from the EtOAc fraction of the EtOH extract of the aerial part of Geranium charlesii (Aitch. & Hemsl.) Vved. The configurations...     

Oxidative cyclocondensation of thio(seleno)-amides and ureas 1. 2-thioxo-4-quinazolone

It has been found for the first time that 2-thioxo-4-quinazolone in the presence of acid catalysts in dimethyl sulfoxide is converted to8H,15H-1, 2, 4-thiadiazolo[3, 2-b:5, 4-b]diquinazoline-8,15-done. The reaction proceeds via oxidative cyclocondensation. The formation of this structure in preference to five other proposed isomers is substantiated using quantum-chemical methods.Institute of Plant Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent 700170. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 845–849, June, 1996. Original article submitted November 27, 1995.