Comparison of ascorbic and citric acid contents inRosa canina L. fruit growing in the Central Asian region

The evaluation ofRosa canina L. fruits and their products is depended in part on their organic acid contents. In this study, ascorbic and citric acid contents inRosa canina L. fruits collected from five different regions in Central Asia were investigated. Amounts of acids determined with the HPLC method were found to be 0.048–0.1143 g/100 g for ascorbic acid and 5.9–7.5 g/100 g for citric acid. Presented at the Third International Symposium on the Chemistry of Natural Products (Bukhara, Uzbekistan, October 19–22, 1998). Deceased. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 768–771, November–December, 1998.     

Radical addition of polychloromethanes toα,α-dichlorovinyl compounds

Conclusions The reaction of CCl₄ and CHCl₃ with CCl₂=CHR, where R=(CH₂)₃H (I) and (CH₂)₃Cl (II), gives compounds of type HCCl₂CH(CCl₃)R, and the adducts HCCl₂CH(CCl)₂CH₂CH₂CH₂Cl (V) from (I) and HCCl₂CH·(CCl₃)CH₂CH₂CHCl₂ (VIII) from (II).From CCl₄ and CC1₂=CHCH₂CH₂CH=CH₂, besides the usual addition product CCl₂=CHCH₂CH₂CHClCH₂· CCl₃, is formed 1,1-dichloro-2-(trichIoromethyl)-5-(chloromethyl)cyclopentane due to stabilization of the CCl₂CH(CCl₃)R radical by intramolecular addition to the CH=CH₂ group and the subsequent cleavage of chlorine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1569–1574, July, 1975.     

Preparation of Titanium Phosphate Sorbents from Products of Processing Sphene Concentrate and Properties of These Sorbents

Procedures for the preparation and granulation of sorbents based on TiO(HPO₄)·nH₂O from the products of processing of sphene concentrate were developed. The sorption and hydrodynamic characteristics of the sorbents were determined.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 66–72.Original Russian Text Copyright © 2005 by Ivanenko, Lokshin, Vladimirova, Avsaragov.     

Alkaloids of far-eastern species ofThalictrum. IV

Summary The alkaloid composition of four far-eastern species ofThalictrum — Th. amurense, Th. contortum, Th. filamentosum, andTh. minus — have been studied, for the first time in the case of the first three species.Th. amurense contains -allocryptopine and thalictrisine, andTh. contortum contains -allocryptopine. Glaucine and thalicsimidine have been found inTh. filamentosum, and argemonine has been isolated fromTh. minus for the first time.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Pacific Ocean Institute of Bioorganic Chemistry, Far-Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 788–791, November–December, 1976.     

Differentiation effect of solvents on the keto-enol equilibrium of heterocyclic β-dicarbonyl compounds

The differentiation effect of a solvent on the equilibrium of five- and six-membered heterocyclic β-keto esters and β-diketones containing =O, =S, =SO, =NR, =NRHC1, and -S-C(R)₂-S-fragments and, for comparison, on the equilibrium of aliphatic and carbocyclic β-keto esters and β-diketones was studied. The differentiating effect of a solvent is explained by different kinds of solvation of the heteroatomic fragments in the ketone and enol forms of heterocyclic β-dicarbonyl compounds.     

Zn(II)-selective membrane electrode based on tetra(2-aminophenyl) porphyrin

A new PVC membrane electrode for Zn²⁺ ions based on tetra(2-aminophenyl) porphyrin (TAPP) as membrane carrier is prepared. The sensor exhibits a linear stable response over a wide concentration range (5.0×10⁻⁵ to 1.0×10⁻¹ M) with a slope of 26.5 mV/decade and a limit of detection 3.0×10⁻⁵ M (1.96 ppm). It has a response time of about l0 s and can be used for at least 8 months without any divergence in potential. The propose membrane sensor revealed good selectivities for Zn²⁺ over a wide variety of other metal ions and can be used in pH range of 3.0–6.0. It was successfully applied to the direct determination of zinc in a pharmaceutical sample and also as an indicator electrode in potentiometric titration of Zn²⁺ ions.     

Flash photolysis studies of the reaction of NH2 radicals with NO

The kinetics of the reaction NH₂ + NO → N₂ + H₂O were studied, using a conventional flash photolysis system. A value of k₁ = (1.1 ± 0.2) × 10¹⁰ & mole^?1 s^?1 was obtained at room temperature and in the pressure range 2–700 torr in the presence of nitrogen. A slight negative temperature coefficient was observed between 300 and 500 K, equivalent to a negative activation energy of 1.05 ± 0.2 kcal mole^?1.