Microdetermination of the keto group by the oxime method

Summary A method was developed for microdetermination of the carbonyl group in ketones, esters of keto acids and also in diketones, capable of giving dioximes, by oximation of them with hydroxylamine hydrochloride in the presence of triethanolamine.     

Mass spectrometry of π-complexes of transition metals : XII. Ferrocenyl and cymantrenyl derivatives of chalcones

The main processes of the electron-impact induced fragmentation of the ferrocenyl and cymantrenyl analogues of chalcones RCOCH=CHR′ (R, R′ = C₅H₄FeC₅H₅, C₅H₄Mn(CO)₃, or aryl) involve a cleavage of the metalligand bond. A “chalcone” mode of fragmentation is weakly pronounced, due to the fact that the positive charge is localized preferably on the metal atom.     

1H NMR and IR Spectroscopic Study of the Structure of the Major Component of the 99mTc HMPAO (Hexamethylpropyleneamino Oxime) Radiopharmaceutical Preparation

d,l-Hexamethylpropyleneamino oxime (HMPAO) was synthesized and isolated from a mixture of d,l - and meso-isomers. The structure of the conformers was studied using ¹H NMR spectroscopy over a broad range of pH. A method for estimating the amount of meso-form present in the mixture of isomers was proposed. It was shown that specific features of the IR spectra depend on the structure of the isomers and on the difference between the packing of molecules in the crystal lattice.     

Reaction of monocyclic ferrocenyl-4,5-dihydropyrazoles with β-dicarbonyl compounds

Monocyclic 3- and 5-ferrocenyl-4,5-dihydropyrazoles with a free NH group in the molecule react with acetylacetone to form the corresponding enaminocarbonyl compounds. The latter were isolated as a single isomer, presumably E. 3-Ferrocenyldihydropyrazoles and 5-ferrocenyl-3-(p-methoxyphenyl)-4,5-dihydropyrazole analogously react with acetoacetic ester. 5-Ferrocenyl-3-phenyl-, 3-(p-bromophenyl)-5-ferrocenyl, and 3,5-diferrocenyl-4,5-dihydropyrazoles react with acetoacetic ester to form acetoacetylpyrazolides.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 12, 2004, pp. 1942–1947.Original Russian Text Copyright © 2004 by E. Klimova, Vazquez Lopez, T. Klimova, Martinez Garcia, Meleshonkova, Ruiz Ramirez.This revised version was published online in April 2005 with a corrected cover date.     

Liquid Entrainment from the Meniscus of a Liquid Wedge by a Moving Horizontal Plate

A hydrodynamic model is proposed for smear formation during the drawing of a film from the meniscus of a limited-volume liquid wedge. It was assumed that the regime of the flow is capillary and the characteristic time of the film formation is small compared to the characteristic time of the change in the meniscus curvature. At small time intervals, the film thickness was determined according to the Landau–Levich–Derjaguin method. At large time intervals, the curvature of the meniscus is described by a linear differential equation for the dynamics of the liquid wedge volume. Under these conditions, the film thickness changes along the plate according to a linear law with the tangent coefficient depending on the capillary number according to a power law, and the profile of the longitudinal section of the smear is close to a right triangle.     

Synthesis of di- and monobromo(ferrocenylvinyl)cyclopropanes

The Wittig olefination of ferrocene-containing chalcones leads to 1,3-dienes and their cyclodimers. The reaction of 1,3-dienes with dibromocarbene yields gem-dibromo(ferrocenylvinyl)cyclopropanes. Upon reductive dehalogenation with ethylmagnesium bromide they afford the corresponding monobromo derivatives. All the obtained compounds were characterized by ¹H and ¹³C NMR, elemental analysis, and mass spectrometry. The structures of compounds 5a,b, 6g, 6h, and 7i were confirmed by X-ray diffraction analysis.     

Asymmetric Induction in the Synthesis of 3,4,5-Trisubstituted Ferrocenyl-4,5-dihydropyrazoles

The asymmetric induction in the synthesis of 3,4,5-trisubstituted 4,5-dihydropyrazoles with ferrocenyl substituents, starting from the E and Z isomers of ,-unsaturated ketones was studied. A high diastereoselectivity was revealed at the 1,2 chiral center chiral center induction, which is independent of the configuration of the starting chalcones.     

Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period

ABSTRACT: BACKGROUND: The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). RESULTS: The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0--20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. CONCLUSIONS: The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages.