Claisen rearrangement taking place in the mass spectrometer

Conclusions The Claisen rearrangement of bucharaine and of the aldehyde bucharainal takes place under the conditions of mass spectrometry. At low temperatures inversion predominates and at high temperatures the anomalous rearrangement.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 577–583, September–October, 1970.     

Volumetric determination of Pt(IV) in the presence of Ir,Pd, and Rh with ferrous ammonium sulfate in alkaline mannitol medium

A potentiometric reductimetric method for the determination of platinum (Pt(IV)Pt(II)) with a standard Fe(II) solution in an alkaline medium of mannitol is described. The method, the error of which does not exceed 2%, can be used in the presence of palladium, iridium, and rhodium.     

Preparation of arylphosphonates by the reaction of aryl halides with tris(trimethylsilyl) phosphite under homogeneous catalysis conditions

The reaction of tris(trimethylsilyl) phosphite with aryl bromides under homogeneous catalysis conditions gives bis(trimethylsilyl)arylphosphonates. The desilylation of these phosphonate products with methanol leads to arylphosphonic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1461–1462, June, 1991.     

Tricarbocyanines with dihydropyran,dihydrothiapyran, and N-methyltetrahydropyridine rings in the chromophore

Glutaconic dialdehyde dianil salts, the ,-carbon atoms of which are included in dihydropyran, dihydrothiapyran, or N-methyltetrahydropyridine rings, were synthesized. Tricarbocyanine dyes with epoxydimethylene, epithiodimethylene, or N-methylepiminodimethylene groupings were synthesized by condensation of the dianil salts with a 2-methylbenzothiazole quaternary salt. The color of the dyes is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 175–178, February, 1976.     

Spectrophotometric determination of aluminium with chlorophosphonazo I

Aluminium reacts with Chlorophosphonazo I at pH 4-6 to form a water-soluble 1:1 red-violet complex. The absorption maximum is at 610 nm and the apparent molar absorptivity is 1.96 x 10(4) l.mole(-1).cm(-1). The apparent instability constant has been calculated to be 1.8 x 10(-4). The colour of the complex is stable for 24 hr. Beer's law is obeyed over the concentration range up to 0.8 mug ml . Titanium and zirconium interfere seriously.     

Luminescence Quenching between Ce and Eu in LAB3O6

The Ce³⁺ and Eu³⁺ ions in LaB₃O₆ quench each other's luminescence. However, Ce³⁺ quenches Eu³⁺ more effectively than Eu³⁺ quenches Ce³⁺. The critical distances for this quenching are about 15 and 6 Å respectively.     

Common and Specific Features of the Michael Condensation in the Series of 3-R-3H-Furan-2-ones

The Michael condensation in the series of 5-aryl-3H-furan-2-ones with chalcones containing electron-donating substituents was studied. In the case of ,-unsaturated ketones containing an electrondonating substituent, the reaction does not stop at the stage of formation of 1,5-dicarbonyl compounds but is accompanied by intramolecular cyclodehydration yielding a new series of furo[2,3-b]-4H-pyrans. A mechanism of formation of these products was suggested. The structure of reaction products was proved by IR and ¹H NMR spectroscopy.     

Synthesis ofO-methyloximes and nitrones of a series of substituted 4-[2-hydroxy-2-(1H-1,2,4-triazol-1-ylmethyl)cyclohexylidenemethyl]-benzaldehydes and their fungicidal activity

O-Methyloximes and nitrones of a series of substituted 4-[2-hydroxy-2-(1H-1,2,4-triazol-1-ylmethyl)cyclohexylidenemethyl]benzaldehydes have been synthesized, and their fungicidal activity has been assayed. All of them exhibit low fungicidal activity in thein vitro assays and high activity in thein vivo assays; theO-methyl oximes are more active than the corresponding nitrones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2082–2087, December, 1993.     

Lipophilic extracts in phytotherapy and phytocosmetics: Production and biological properties

This review considers methods of obtaining lipophilic extracts from plant raw material, and their composition, biological properties, and use in phytotherapy and phytocosmetics.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 240 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 437–448, July–August, 1998.