Catalytic hydrophosphorylation of alkyl- and acylhydrazones

N-Boc- and N-acylhydrazino phosphonates were obtained for the first time by hydrophosphorylation of the appropriate hydrazones of aliphatic and aromatic aldehydes and heterocyclic and aliphatic ketones in the presence of [tetra(tert-butyl)phthalocyanine]aluminum chloride as a catalyst.     

The chemical composition of the essential oil of the larch

Summary The essential oils of various species of larch have been separated by gas-liquid chromatography under conditions of linear temperature programming.Of the 45 compounds present in each of the essential oils, 32 components have been identified, 16 of which have not previously been found in larch essential oil.The chemical compositions of the oxygen-containing and sesquiterpene hydrocarbons of four species and one variety of larch have been studied. It has been shown that there is no quantitative difference between the compositions of the individual species of larch and only their quantitative compositions differ.Voronezh Institute of Wood Technology. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 456–462, July–August, 1976.     

The chemical composition of the essential oil of the larch

The essential oils of various species of larch have been separated by gas-liquid chromatography under conditions of linear temperature programming. Of the 45 compounds present in each of the essential oils, 32 components have been identified, 16 of which have not previously been found in larch essential oil.     

Study of the interaction of imidazolidine-2-thione with molecular iodine

The crystal and molecular structure of the reaction product of imidazolidine-2-thione and molecular iodine of the composition (C₃H₆N₂S)2?3I₂ was established by X-ray diffraction. The crystal structure is composed of strongly connected five-component associates consisting of three I₂ molecules and two heterocyclic molecules. Quantum chemical calculations followed by the topological analysis of the electron density function provided an estimate of the strongest intermolecular interactions in the crystal structure of the molecular adduct.

     

Selectivity of the optical-absorption method based on an instrumental pick out of Fourier components in the absorption spectrum

The introduction of interference–polarization filters (IPFs) in the structure of an optical–absorption analyzer makes it possible to pick out a harmonic (a Fourier component of the absorption spectrum) providing measurement with the highest sensitivity. The selectivity of such a method of analysis is determined by overlapping the oscillations of the measured and interfering components. By the example of measurement in benzene in the presence of an interfering component (toluene), the possibility is considered for the optimization of selectivity due to the variation of the path-difference dispersion for ordinary and extraordinary interfering rays. The metrological characteristics of the interference–polarization analyzer of C₆H₆ confirming the results of calculations are given.     

Crystal structure of the metastable cubic β<Subscript>ms</Subscript> phase of La<Subscript>2</Subscript>Mo<Subscript>2</Subscript>O<Subscript>9</Subscript> single crystal at <Emphasis Type="Italic">T</Emphasis> = 33 K

The structure of the cubic metastable β_ms phase of La₂Mo₂O₉ single crystal has been precisely investigated by X-ray diffraction at 33 K for the first time. The measurement of the unit-cell parameter of this crystal in the range from room temperature to 33 K showed that the unit-cell parameter and volume change continuously in this range. The crystal has a similar structure at T = 33 K and at room temperature. A local lowering of the symmetry for La and Mo atoms, caused by their displacement, is confirmed, and a similar displacement (which was not observed at room temperature) is revealed for O(1) atoms. The thermal parameters for O(2) and O(3) atoms do not change with a decrease in temperature, in contrast to the thermal parameters of Mo, La, and O(1) atoms. This fact indicates that the O(2) and O3 atoms in this crystal are statically disordered.     

Chemometrics-assisted spectrophotometric method for simultaneous determination of vitamins in complex mixtures

An advanced independent component analysis algorithm (MILCA) is applied for simultaneous chemometric determination of fat- and water-soluble vitamins in complex mixtures. The analysis is based on the decomposition of spectra of multicomponent mixtures in the UV region. The key features of the proposed method are simplicity, accuracy, and reliability. Comparisons between the new algorithm and other established methods (MCR-ALS, SIMPLISMA, other ICA techniques) were made. Our results indicate that in most cases, MILCA is comparable or even outperforms other chemometrics methods taken for comparisons. The influence of different factors (abundance of components, noise, step of spectral scan, and scan speed) on decomposition performance has been investigated. The optimal conditions for spectroscopic registration have been identified. The proposed method was used for analysis of model mixtures and real objects (multivitamin drugs, food additives, and energy drinks). The resolved concentrations match well with the declared amounts and the results of reference methods.