Five-Membered 2,3-Dioxo Heterocycles: LXXI.* Recyclization of 4,5-Diaroyl-1H-pyrrole-2,3-diones by the Action of Substituted Hydrazines. Crystalline and Molecular Structure of 2-(3-Benzoyl- 1-benzyl-5-phenyl-1H-pyrazol-4-yl)-N-(4-methoxyphenyl)- 2-oxoacetamide

2010 ◽  
Vol 46 (10) ◽  
pp. 1546-1549 ◽  
Author(s):  
P. S. Silaichev ◽  
N. V. Kudrevatykh ◽  
Z. G. Aliev ◽  
A. N. Maslivets
Keyword(s):  
Molecular Structure ◽  
Substituted Hydrazines

scholarly journals REACTION OF NITRILIMINES WITH SUBSTITUTED HYDRAZINES: SYNTHESIS OF 1,2,4,5-TETRAAZA-3-PENTENES AND FORMAZANS

2011 ◽  
Vol 19 (19) ◽  
pp. 25-33
Author(s):  
Hany M. M. DALLONI
Keyword(s):  
Molecular Structure ◽  
Spectral Data ◽  
Activated Charcoal ◽  
Lithium Hydride ◽  
Substituted Hydrazines

A series of 1,2, 4, 5-tetraaza-3-pentenes 4a-j were synthesized by the reaction of appropriate nitrilimines 2 with substituted hydrazines (H2NNHCOR, R=Ph, OMe) 3. Heating the compounds 4a-j with activated charcoal in refluxing benzene oxidized to formazans 5a-j and some formazans 5fj (R = OMe) gave s-tetrazinones 6fj in presence of lithium hydride. The microanalysis and spectral data of the synthesized compounds are in fall agreement with their molecular structure.

Novel polyfluoroalkylated pyrazoles from 2-polyfluoroacylcycloalkanones and hydrazines: syntheses and unequivocal molecular structure assignment

2001 ◽  
Vol 79 (2) ◽  
pp. 183-194 ◽  
Author(s):  
D V Sevenard ◽  
O G Khomutov ◽  
M I Kodess ◽  
K I Pashkevich ◽  
I Loop ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Chain Length ◽  
Tautomeric Form ◽  
Ring Size ◽  
Polymethylene Chain ◽  
Structure Assignment ◽  
Substituted Hydrazines

The reaction between 2-trifluoroacetylcycloalkanones and methylhydrazine or phenylhydrazine exclusively yields 3-CF3-pyrazoles. When the chain length of the polyfluorinated substituent in RFC(O) group increases, 5-RF-pyrazoles are isolated. The reaction of 2-trifluoroacetylcyclohexanone with 2-hydrazinopyradine gives 5-hydroxypyrazoline, an intermediate in the formation of 5-CF3-pyrazoles. The regiochemistry of the condensation is probably controlled by the nucleophilicity of the terminal nitrogen in the mono substituted hydrazines and by the steric requirements of the RF group in the 1,3-diketones. Polymethylene chain containing pyrazoles obtained from the 1,3-diketones in question and hydrazine prefer the 3-RF tautomeric form, irrespective of carbocyclic ring size and polyfluoroalkyl group chain length.Key words: polyfluorinated 1,3-diketones, hydrazines, isomeric pyrazoles, molecular structure.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

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