AlPO4 as catalyst in organic reactions. IV. Transesterification of methyl methacrylate

Coke deposition on monometallic Pt, Re, Ir, Ge and Sn catalysts supported on -Al₂O₃, and its influence on activity and selectivity over methylcyclopentene reforming was studied. As a result the effect can be interpreted in terms of metal-support interactions that modify the overall catalytic deactivation rates.

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Pt, Re, Ir, Ge Sn, -Al₂O₃ . , .

     

Steroid alcohols from the ascidianHalocynthia aurantium

The total sterols have been isolated fromHalocynthia aurantium by column chromatography on silica gel. The following steroid alcohols have been identified in it with the aid of GLC, GLC-MS, and¹H NMR: 5-cholestan-3-ol, 24-methylcholestan-3-ol, 24-ethylcholestan-3-ol, 4-methyl-24-ethyl-5-cholestan-3-ol, cholest-5-en-3-ol, 24-methylcholest-5-en-3-ol, 24-ethylcholes-5-en-3-ol, 5-cholest-22-en-3-ol, 24-nor-5-cholest-22-en-3-ol, cholesta-5,22-dien-3-ol, 24-methylcholesta-5,22-dien-3-ol, 24-norcholesta-5,22-dien-3-ol, 24-ethylcholesta-5,24(28)-dien-3-ol, and 24-methylcholesta-5,24(28)-dien-3-ol.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok, and Far-Eastern State University, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 581–585, September–October, 1981.     

Triterpene glycosides ofLeontice eversmannii

Conclusions The structure of leontoside D-a hederagenin pentaoside-has been established. The O-glycosidic moiety of leontoside D is O--D-glucopyranosido-(1 4)-O--L-arabopyranose, and the O-acyl moiety is O--L-rhamnopyranosido-(1 4)-O--D-glucopyranosido-(1 6)-O--D-glucopyranose.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 3, pp. 153–158, 1968     

Fluorine containing β-lactones

Summary Ring opening of -trifluoromethyl- -methyl- -propiolactone is unidirectional and leads to derivatives of -trifluoromethyl- -hydroxybutyric acid.     

Mass spectrometric identification of monoglycosylglycerins in the form of esters of phenylboric acid

Conclusions The mass spectra of phenylboric esters of 3-O--D-glucopyranosyl-, 3-O--D-glucopyranosyl-, 3-O--D-galactopyranosyl-, 3-O--D-galactopyranosyl-, and 3-O--D-mannopyranosyl-L-glycerins were studied. The mass spectra permit a distinguishment of the enumerated compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 821–828, April, 1975.     

Über das 2-Dichlormethyl-oxazolin und seine Kondensation mit 4-Nitrobenzaldehyd

Zusammenfassung N-Dichloracetyläthanolamin (I) wurde über das mit SOCl₂ erhaltene N-Dichloracetyl--chloräthylamin (II) durch Alkali in das 2-Dichlormethyl-oxazolin (III) übergeführt, dessen sehr leicht erfolgende hydrolytische Umwandlungen beschrieben werden. Kondensation von 4-Nitrobenzaldehyd mit (III) erfolgt ohne jedweden Katalysatorzusatz unter den mildesten. Bedingungen an der überaus reaktiven Methingruppe des Dichlormethylrestes von (III) zu 2-[-(4-Nitrophenyl)--oxy-, -dichloräthyl]-oxazolin (VI), dessen Konstitution an Hand eines O-Acetats und durch die saure Hydrolyse zu einer -(4-Nitrophenyl)-, -dichlorhydracrylsäure und Äthanolamin bewiesen wird.Herrn Prof. Dr.L. Ebert zum 60. Geburtstag gewidmet.     

Evaluation of the Compression Behavior of Paracetamol Tablets Produced by Dispersion in β-Cyclodextrin. Part I: Scanning Electron Microscopic Study of Tablets

The compression behaviour of three powder products of Paracetamol–-cyclodextrin solid dispersions (PAR--CD SD) and PAR alone were evaluated using the method of scanning electron microscopy (SEM). The four powder products were: PAR, PAR–-CD physical mixture, kneaded solid dispersion of PAR–-CD and spray dried solid dispersion of PAR–-CD (PAR–-CD ratio of 1 : 1 w/w). By observing the surface, side and broken surface of each tablet sample under different magnifications the compression behaviour, mechanism of consolidation and deformability of particles were evaluated. PAR alone and the PAR–-CD physical mixture were compressed by the brittle fracture mechanism; the PAR–-CD kneaded solid dispersion showed a good plastical deformation. With PAR–-CD spray dried solid dispersion a good plastic deformation and mechanism of cool sintering were postulated. The influence of -CD on the compression behavior of the PAR was proved. The results obtained by the SEM method are well correlated with physicopharmaceutical parameters (crushing strength, disintegration time, friability, elastic recovery and tensile strength) of the tablets.     

Non quasi-stationary state pyrolysis. Induction period of neopentane pyrolysis

The principle of an apparatus using an isothermal continuous flow stirred tank reactor to study homogeneous gas phase reactions at space times of the order of 1 sec is given. With this apparatus, the induction period of neopentane pyrolysis (as an example) has been clearly shown.

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, , 1 . , , .

     

Reforming type Pt/Al2O3 catalyst prepared from [(CH3)3PtX]4 complexes by thermal decomposition

Pt/Al₂O₃ catalysts with good reforming activity were prepared from [(CH₃)₃PtX]₄ (X=Cl, Br, I) complexes and tested in pulse and continuous-flow reactors in n-hexane dehydrocyclization. It has been demonstrated that [(CH₃)₃PtX]₄ complexes are excellent precursors of supported platinum catalysts.

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Pt/Al₂O₃ [(CH₃)₃ PtX]₄ (X=Cl, Br, I) -. , [(CH₃)₃PtX]₄ .

     

<Superscript>1</Superscript>H and <Superscript>13</Superscript>C NMR spectra of some drimanic sesquiterpenoids

One- and two-dimensional homo- and heteronuclear correlation proton, carbon, proton—proton, and proton—carbon NMR spectra of fifteen drimanic sesquiterpenoids: 11,12-dibromodrima-5,8-dien-7-one, drim-8-en-7-one, 11-hydroxydrim-8-en-7-one, 11,12-dihydroxydrim-8-en-7-one, 11-hydroxy-11,12-epoxydrim-8-en-7-one, 11-hydroxy-11,12-epoxydrim-8-en-7-one, 8,9-epoxydriman-7-one, 8,9-epoxydriman-7-ol, 11,12-diacetoxydrim-8-en-7-ol, drimane-7,8,11-triol, 7,8-isopropylidenedioxydriman-11-al, 9, 11-dihydroxydrim-7-en-6-one, drimane-7,8,9-triol, drimane-7,8,11-triol, and drim-8-ene-7,11,12-triol were studied. The proton and carbon chemical shifts were assigned.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2589–2594, December, 2004.     

Triterpene glycosides and their genins from Thalictrum foetidum. III. The structure of cyclofoetoside A

A new glycoside of the cycloartane series — cyclofoetoside A — has been isolated from the epigeal part ofThalictrum foetidum L., and its structure has been established on the basis of chemical transformations and spectral characteristics as 24S-cycloartane-3,16,24,25-tetraol 3-0--L-arabinopyranoside 16-0-[0--L-rhamnopyranosyl-(16)--D-glucopyranoside].Pyatigorsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR; Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 66–71, January–February, 1986.     

Triterpene glycosides of Astragalus and their genins XLII. Cycloartanes of Astragalus tragacantha

Another six components ofAstragalus tragacantha Habl. have been identified on the basis of spectral characteristics and chemical transformations. We have previously described cyclocanthagenin and its 3-0--D-xylopyranoside — cyclocanthoside A — as products of the acid hydrolysis of cyclocanthoside D. Cyclocanthosides B, C, E, and G are here described for the first time and are (24S)-cycloartane-3,6,16,24,25-pentol 3-O-(4-O-acetyl--D-xylopyranoside) 6-O--D-glucopyranoside, (24S)-cycloartane-3,6,16,24,25-pentol 6-O-(6-O-acetyl--D-glucopyranoside) 3-O--D-xylopyranoside, (24S)-cycloartane-3,6, 16,24,25-pentol 6-O--D-glucopyranoside, and (24S)-cycloartane-3, 6, 16, 24, 25-pentol 6-O--D-glucopyranoside 3-O-[O--D-glucopyranosyl-(12)--D-xylopyranoside], respectively.Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Institute of Ecological Genetics, Moldavian Academy of Sciences, Kishenev. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 360–367, May–August, 1992.     

Pulchellin C and inuchinenolide C from Inula caspica

The pseudoguaianolide inuchinenolide C and the eudesmanolide pulchellin C have been isolated for the first time from the flower heads and leaves ofInula caspica Blume, and their spatial structures have been established by an x-ray structural experiment as 2,6-diacetoxy-6-hydroxy-1,7(H),8,10(H)-pseudoguai-11(13)-en-8,12-olide and 2,3-dihydroxy-5,7,8(H)-eudesma-4(15),11(13)-dien-8,12-olide, respectively.Institute of Organic Synthesis and Coal Chemistry, Academy of Sciences of the Kazakh SSR, Karaganda. A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 748–757, November–December, 1990.     

Sulfur-containing carboxylic acids. Communication 3. Synthesis of β-(acetylthio)alkanoic acids amides

Conclusions Amides of -mercapto- or -(acetylthio)alkanoic acids were obtained by the reaction of -thiolactones or -(acetylthio)alkanoic acid chlorides with amines.For Communication 2, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 616–621, March, 1983.     

Comparative study on inclusion complexations of antiinflammatory drug flurbiprofen with β-cyclodextrin and methylated β-cyclodextrins

Abstruct Some physicochemical properties of methylated -cyclodextrins, i.e., heptakis(2,6-di-O-methyl)--cyclodextrin (DM--CyD) and heptakis(2,3,6-tri-O-methyl)--cyclodextrin (TM--CyD) were compared with those of natural -cyclodextrin (-CyD). Inclusion behaviors of -CyD and methylated -CyDs in water and in solid state were studied by solubility analysis, spectroscopies (UV, CD,¹³C-NMR and IR), X-ray diffractometry and thermal analysis, using an antiinflammatory drug flurbiprofen (FP) as a guest molecule. The spectral data suggest that the inclusion mode of FP-TM--CyD is somewhat different from those of FP--CyD and FP-DM--CyD. The solid complexes of FP with - and methylated -CyDs were obtained in molar ratio of 11, and their dissolution behavior and release from suppository base were examined. The data are presented suggesting that DM--CyD is particularly useful for improving the pharmaceutical properties of FP in various dosage forms.     

Polyhydroxysteroids from the Far-Eastern starfishCtenodiscus crispatus

Four new polyhydroxysteroids, 5-cholesta-3,5,6,15,16,25,26-heptaol, 24-ethyl-5-cholesta-3,5,6,15,28,29-heptaol-29-sulfate, (22E)-24-methyl-5-cholest-22-ene-3,5,6,15,25,26-hexaol-26-sulfate, 24-propyl-5-cholesta-3,5,6,8,15,28,29-heptaol, and the known 5-cholesta-3,5,6,15,16,26-hexaol, have been isolated from the starfishCtenodiscus crispatus.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1821–1825, October, 1994.     

Gomphacil — A cardenolide glycoside ofGomphocarpus fruticosus

The leaves ofGomphocarpus fruticosus (L.) R.Br. have yielded the new acetylated glycoside gomphacil, which is (3-O-1,2-O-2)-(3-acetoxy-2-hydroxy-4,6-dideoxyhexulosido)-14-hydroxy-5-card-20(22)-enolide.State Scientific Center for Drugs, Ukraine, 310085, Kharkov, ul. Astronomicheskaya, 33. Ukrainian Pharmaceutical Academy, 310002, Kharkov, ul. Pushkinskaya, 53. Translated from Khimiya Prirodnykh Soedinenii, Vol. 33, No. 1, pp. 71–73, January–February, 1997.     

Thermal analysis of heterocyclic thione donor complexes. Part 1

The thermal decomposition of the Co(II) complexes of 1-methylimidazoline-2(3H)-thione (MImt), general formula Co(MImt)₂X₂ (X=Cl, Br & I), have been studied in air and argon by means of TG and DTG as well as in nitrogen by DTA. Quantitative DTA has been used to derive reaction enthalpies (H _R) from the melting and decomposition endotherms in nitrogen. Decomposition processes have been proposed for the complexes in air and in inert atmospheres. A mean coordinate bond dissociation energy (¯D) has been estimated for the Co-MImt bond in Co(MImt)₂Cl₂.Reaction end products in air have been identified by X-ray powder diffraction.

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Zusammenfassung Die thermische Zersetzung von Kobaltkomplexen des 1-Methylimidazolin-2(3H)-thions (IMmt) der allgemeinen Formel Co(MImt)₂X₂ (X=Cl, Br, J) wurde in Luft und Argon mittels TG und DTG und in Stickstoff mittels DTA untersucht. Reaktionsenthalpien (H_r) wurden durch quantitative DTA aus den in Stickstoffatmosphäre erhaltenen endothermen Schmelz- und Zersetzungspeaks erhalten. Es wurden Mechanismen für die Zersetzungsprozesse der Komplexe in Luft und inerter Atmosphäre vorgeschlagen. Die mittelere Dissoziationsenergie (¯D) der koordinativen Bindung Co—MImt in Co(MImt)₂Cl₂ wurde bestimmt.In Luft erhaltene Reaktionsendprodukte wurden durch Röntgenpulverdiffraktometrie identifiziert.

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1- -2()- () ()₂₂, X=l, I, , . (H _R) . . - ()₂l₂. , , - .

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The author is grateful to Mr. J. R. Creighton, Newcastle upon Tyne Polytechnic, for technical assistance with this work and to Dr. F. Buttler, Teesside Polytechnic for mass spectral data and helpful discussion.     

Simultaneous adsorption of CO and O2 on Ni(100) plane at low temperatures

LEED, AES and TPD studies of CO adsorption at 170 K on the oxygen-covered surface of Ni(100) have revealed its great amount throughout the range of oxygen coverage. With thermal desorption from a mixed layer the appearance of CO₂ due to the reaction CO_ads+O_ads, indicates that a part of oxygen adsorbed on Ni(100) at T=170 K is reactive.

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, () CO 170 Ni(100). . CO₂ Co+ +O, , Ni(100) T=170 .