A novel transformation of O-methyldalbergin

O-methyldalbergin and related 4-phenylcoumarins are markedly different from ordinary coumarins in their behaviour towards alkali. They are stable in boiling alkali and on addition of mercuric oxide yield coumarilic acids. Phenyl-coumarilic acids undergo decarboxylation readily when boiled with aqueous alcoholic mercuric chloride to yield phenyl substituted coumarones.     

Influence of pore diffusion on the kinetics of catalytic oxidation of ethylene

Internal diffusion influences the kinetics of ethylene oxidation on an industrial silver catalyst at temperatures higher than 240°C. This influence is completely eliminated when the diameter of the catalyst grains is decreased by a factor of 1/2.

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, 240°C. .

     

Catalytic effect of metal ions on photochemical reactions of molecular oxygen, III. Photochemical autoxidation of sulfite catalyzed by manganese(II) ions

The rate of photoinitiated autoxidation of sulfite is influenced by manganese(II) ions even in trace concentrations. An increase in the concentration of manganese(II) ions in the reaction system increases the quantum yield of the photoinitiated reaction.

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(II), - . (II) - .

     

Synthesis of lipophilic derivatives of N-acetylmuramoyl-L-alanyl-D-glutamic acid

The synthesis has been achieved of the hexadecyl -glycosides of N-acetylmur-amoyl-L-alanyl-D-glutamic acid and N-acetyl-nor-muramoyl-L-alanyl-D-glutamic acid and of the -octadecylamide of N-acetylmuramoyl-L-alanyl-D-glutamic acid — lipophilic glycopeptides of differing hydrophilic-lipophilic balance.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 553–557, July–August, 1991.     

Structures of decorine and delcoridine

In order to confirm the structures of the alkaloids delcorine and delcoridine (O-demethyldelcorine) suggested previously, a direct passage has been performed from delcoridine to delcorine and from delcorine to delphatine. It has been shown that the configuration of C₁ - OCH₃ previously suggested for delcorine and delcoridine is incorrect — it should be .Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 621–623, September–October, 1981.     

Reaction of undecyl radicals with aromatic hydrocarbons

A competition method (R^.+O₂RO ₂ ^. , R^.+XHRH+X^.) is proposed to measure the relative rate constants for the interaction of alkyl radicals with different organic compounds. Partial (per C–H bond) rate constants have been determined for the reaction of undecyl radicals with cumene, ethylbenzene and toluene.

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(R^.+O₂RO ₂ ^. , R^.+XHRH+X^.), . ( C–H ) , .

     

Synthesis of derivatives of pentopyranic acid

N⁴-Benzoylcytosine 1-(methyl 2,3,4-tri-O-acetyl--D-glucopyranosiduronate) has been obtained with a yield of 70% by the glycosylation of the trimethylsilyl derivative of N⁴-benzoylcytosine with methyl 1,2,3,4-tetra-O-acetyl--D-glucopyranuronate in the presence of three equivalents of SnCl₄ as condensing agent. Cytosine 1-(-D-glucopyranosiduronamide) (IV) — the amide of pentopyranic acid — has been synthesized in practically quantitative yield by the ammonolysis of the nucleoside (I).Peat Institute, Academy of Sciences of the Belorussian SSR, Minsk. Institute of Bioorganic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 617–619, September–October, 1983.     

Hawaiian plant studies. XIV. Alkaloids of Ochrosia sandwicensis A. Gray

Two quaternary alkaloids were isolated from Ochrosia sandwicensis A. Gray. One was shown to be hunterburnine -methochloride (I), while the other has been named ochrosandwine and its probable structure is 10-hydroxydihydrocorynantheol methochloride (II). The stereochemistry of the related alkaloid huntrabrine methochloride (IV) is elaborated. Two previously isolated yellow Ochrosia bases were shown to be ellipticine hydrochloride and methoxyellipticine for which the structure-8-methoxyellipticine (V) is suggested. A rapid separation of alkaloids from plant material is described, which involves extraction with hot dilute acetic acid, precipitation with Mayer's reagent and conversion of the complex to the chlorides by anion exchange.     

About the microdetermination of thallium with rhodamine B

Summary The spectrophotometric determination of thallium with Rhodamine B as Rhodamine B-thallium(III) tetrabromide using extraction of the complex into benzene was investigated. For the oxidation of thallium(I) ceric sulphate was used. The optimum conditions and interferences of some ions for the determination of microgram amounts of Tl are described. The sensitivity is 0.0028 g of Tl per 1 ml of benzene. 5 g of Tl can be determined with a precision of ±2.4%. The method described may be applied in trace analyses of thallium, where sulphuric-nitric acid is used for the decomposition of the sample.

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Zusammenfassung Ein spektrophotometrisches Verfahren zur Thalliumbestimmung mit Rhodamin B wird beschrieben, bei dem der gebildete Thallium(III)-komplex mit Benzol extrahiert wird. Zur Oxydation von einwertigem Thallium wird Cer(IV)-sulfat verwendet. Die optimalen Bedingungen sowie Störungen durch Fremdionen bei der Bestimmung von g-Mengen Thallium werden beschrieben. Die Empfindlichkeit betrÄgt 0,0028 g Tl/1 ml Benzol. 5 g Tl können mit einer Genauigkeit von±2,4% bestimmt werden. Das beschriebene Verfahren kann bei der Spurenanalyse von Thallium in solchen Proben benutzt werden, die mit Schwefel- und SalpetersÄure aufgeschlossen worden sind.

     

Pregnane glycosides of Cynanchum sibiricum III. The structure of sibiricosides D and E

Summary The structures of two pregnane glycosides fromCynanchum sibiricum Willd. have been established. Sibiricoside D (II) is sibirigenin (cynanchogenin) 3-D-glucosido-D-cymarosido-D-cymarosido-D-cymarosido-D-oleandroside. Sibiricoside E (I) is sibirigenin (or cynanchogenin) 3-D-glucosido-D-glucosido-D-cymarosido-D-cymarosido-D-cymarosido-D-oleandroside.The hypothesis has been put forward that glycosides of isolinoleone are present in the native state which are isomerized into linoleone derivatives in the process of isolation and treatment with acid and alkaline agents.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 171–177, March–April, 1975.