Identification microcristalloscopique de la Vitamine B1 au moyen d'acide picrolonique

Résumé On propose une réaction microcristalloscopique pour l'identification de la vitamine B₁ au moyen d'acide picrolonique. On observe au microscope, au grossissement de 400×, des cristaux en éventail, dont les deux bouts sont recourbés en forme d'hélice. Les cristaux ayant un faciès spécifique, la réaction est strictement spécifique pour la vitamine B₁ seulement. Les autres vitamines B ne réagissent pas avec l'acide picrolonique. La sensibilité de la réaction est de 0,0062g/l. Limite de dilution 1150000.On a déterminé les relations molaires de la réaction selon la méthode des séries isomolaires et par analyse du composé obtenu. La thiamine et l'acide picrolonique réagissent dans les rapports molaires de l'ordre de 11. On obtient le sel: le picrolonate de thiamine.

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Summary A microcrystalloscopic reaction is proposed for the identification of vitamin B₁ employing picrolonic acid. At a magnification of 400×, the microscope reveals fan-shaped crystals, whose two ends are bent back in a helical form. The crystals have a specific form and consequently the reaction is strictly specific for vitamin B₁ only. The other B vitamins do not react with picrolonic acid. The sensitivity of the reaction is 0.0062g/l. The dilution limit is 1150000.The molar relation of the reaction was determined by the method of isomolar series and by the analysis of the compound obtained. Thiamin and picrolonic acid react in the molar ratios of the order 11. The salt, the picrolonate of thiamin, is obtained.

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Zusammenfassung Eine Kristallfällunggreaktion zur Identifizierung von Vitamin B₁ mit Pikrolonsäure wird vorgeschlagen. Bei 400facher Vergrößerung beobachtet man unter dem Mikroskop fächerförmige Kristalle, die beiderseits schneckenförmig gebogen sind. Sie haben einen charakteristischen Habitus, die Reaktion ist für Vitamin B₁ streng spezifisch. Die anderen Vitamine der B-Gruppe reagieren nicht mit Pikrolonsäure. Die Empfindlichkeit der Reaktion beträgt 6,2 pg/l, die Grenzkonzentration 1150000.Nach der Methode vonJob und durch Analyse des Reaktionsproduktes wurde das Molverhältnis bestimmt. Thiamin und Pikrolonsäure reagieren im Verhältnis 11, wobei Thiaminpikrolonat entsteht.

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Collaborateurs techniques:B. Banev etCh. Droumeva.     

Identification de xanthones et de nouveaux arabinosides de C-glucosides flavoniques dans Swertia perennisL.

Identification of xanthones and new arabinosides of flavone C-glucosides from Swertia perennis L. – Seven tetraoxygenated xanthones [1,3,7,8-tetrahydroxy-xanthone ( 1 ); 1,8-dihydroxy-3,7-dimethoxy-xanthone ( 2 ); 1,7-dihydroxy-3,8-dimethoxy-xanthone ( 3 ); 1-hydroxy-3,7,8-trimethoxy-xanthone ( 4 ); 3,7,8-trihydroxy-xanthone-xanthone-1-0-β-glucoside ( 5 ); 3,7,8-trimethoxy-xanthone-1-0-primeveroside ( 6 ); 8-hydroxy-3,7-dimethoxy-xanthone-1-0-primeveroside ( 7 )] have been isolated chromatographically, using polyamide columns, from roots of Swertia perennis L . From leaves and stems of the same plant, six xanthones [1,5,8-trihydroxy-3-methoxy-xanthone ( 8 ); 1,5-dihydroxy-3-methoxy-xanthone-8-0-β-glucoside ( 9 ); mangiferin ( 10 ); 1 ; 4 ; 5 ] and four flavone C-glycosides [iso-orientin ( 11 ); isovitexin ( 12 ); iso-orientin-6″-arabinoside ( 13 ); isovitexin-6″-arabinoside ( 14 )] have also been isolated. Among these compounds, 7 , 13 and 14 were not encountered before in nature. In the last two compounds, the position of arabinose on the C-glucoside moiety of the flavone was established by ¹³C-NMR. spectroscopy.     

Identification de polymeres par analyse thermique differentielle

Nineteen different polymers having no melting endotherm (foam urea-formol, PVC, vinyl polyacetate, vinyl polybutyral, polymethacrylates, polystyrene and its copolymers) are studied by DTA. The identification is realized due to endothermic decomposition peak and exothermic peaks, according to the general method which has been described previously.

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Zusammenfassung Mittels DTA wurden neunzehn verschiedene Polymere ohne endothermen Peak beim Schmelzen untersucht (Schaum Carbamid-Formol, PVC, Vinylpolyacetat, Vinylpolybutyral, Polymethacrylate, Polystyrol und seine Kopolymere). Die Identifizierung erfolgte in Übereinstimmung mit der unlängst beschriebenen allgemeinen Methode anhand der endothermen Zersetzung speaks und der exothermen Peaks.

     

Etude de L'oxydation de Polyethylenes Par Analyse Thermique Identification des produits de dégradation par infra-rouge

The oxidation of pure and recycled polyethylene samples was studied by thermal analysis (DTA-TG-DSC): presence of two exothermic peaks and mass loss. The thermo-oxidation products, containing C-O and C=O links, were identified by IR spectrometry and GC-MS spectrometry. The oxidation is easier from low to high density polyethylene. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification d'un acide diterpenique du bourgeon de cassis

The acidic fraction of benzenic extract of Blackberry bud (Ribes nigrum L. ) show a diterpene acid identified as hardwickiic acid by IR., UV., RMN. and SM.     

Identification de composes inconnus en spectrometrie de masse par Comparaison a une Bibliotheque sur Cartouches Digitales

An automatic method for interpretation of mass spectra is described. This approach uses the comparison of unknown spectra with those included in a library of standard references. The spectra are stored on digital magnetic tape. Several hundred spectra can be recorded on a cartridge. The tape unit is connected to a minicomputer. This system offers many advantages and is very well suited for medium sized laboratories. The series of compounds studied are the olefins, compounds with very similar spectra, so the method of interpretation has to be powerful. The different parts of the identification algorithm are discussed. The results and experimentation are also presented.     

Identification de la damascénone et de la β-damascone dans le tabac Burley

The successful identification of damascenone (I)

1 DORICENONE (trade mark of Firmenich & Cie, Geneva).

and β-damascone (III)

2 DORINONE (trade mark of Firmenich & Cia, Geneva)

in Burley tobacco oil was achieved through the use of an efficient vapour phase chromatography/mass spectrometry combination. Thus, the occurrence of β-damascone in nature and the presence of damascenone in an essential oil not related to rose oil were demonstrated.     

Contribution à la phytochimie du genre Gentian,XI Identification de nouveaux dérivés de l'iso-orientine extraits des feuilles de Gentiana burseri Lapeyr

Two new derivates of iso-orientin have been isolated and identified from the leaves of Gentiana burseri, LAPEYR. The structure of the new compounds were established as: trans-cafeoyl-2″-iso-orientin (1) and p-β-D-glucosyl-trans-cafeoyl-2″-iso-orientin-4′-O-β-D-glucoside (2).     

Identification et synthèse de nouveaux depsides isolés de la mousse de chêne (Evernia Prunastri (L.) ACH.). 4e Communication

Identification and synthesis of new depsides isolated from oakmoss (Evernia Prunastri (L .) ACH .) Lecanoric acid 5 and 4 new depsides have been isolated from oakmoss (Evernia Prunastri (L .) ACH .) extracts by means of silicagel column chromatography. Various spectral methods including ¹³C-NMR. were used in determining the structure of 4,2″-O-methylgyrophoric acid ( 1 ), lecanoric acid ( 5 ), 2′-O-methylevernic acid ( 2 ), 3′-methylevernic acid ( 3 ) and methyl 3′-methyllecanorate ( 4 ).     

Etude de la fragmentation de derives de L'uracile et de la thymine par Spectrometrie de masse

Original mass spectra of uracil and thymine derivatives are presented with the corresponding fragmentation schemes. In the first series of spectra, the fragmentations of thymine derivatives, including ¹⁴C-2-thymine, dimers, and bromo thymines, confirm the basic retro Diels-Alder mechanism. The second series includes dihydro 5,6-derivatives of uracil (hydroxy and bromo substituents). The behaviour of these molecules is quite different; they are more sensitive to the substituents and a part of the fragmentation is often explained by protonated molecular ions.     

Influence de la Structure de Diverses Fonctions sur l'Evaluation de l'Energie de Correlation

The influence of various correlation functions, multiplying the monoelectronic space function, is studied and applied to the Helium atom and its isoelectronic series. We used Slater-type basis orbitals and the ground and first excited states have been studied, taking into account the virial and cusp conditions. In the ground state, a very good value for the correlation energy is obtained, using a function of the type For the excited states, this type of function overestimates the assumed value of the correlation energy.     

Processus de photopolymerisation du methacrylate de methyle en presence de chlorure de zinc

The photopolymerization of methylmethacrylate in solution or in bulk, initiated by DMPA (2,2-dimethoxy-2-phenylacetophenone) and BP (benzophenone), has been investigated in the presence of ZnCI₂ as a complexing agent. We have studied the steady state polymerization (measurement of R, and OT) and the behaviour of the excited states by laser spectroscopy. We have shown the following points: R_p and DP increase with [ZnCI₂]; the rate constant for propagation increases with [ZnC12]; the rate of initiation remains constant in presence of BP-ZnCl₂ but increases with DMPA-ZnCl₂. The results are accounted for by the results of laser spectroscopy.     

Etude de l'incorporation de l'oxyde de cuivre dans le reseau de l'oxyde de nickel par traitement thermique

NiO prepared at 950° has been impregnated with a solution of copper nitrate and heated at 300°. The incorporation of CuO issued from this treatment in the lattice of NiO during sintering at 450–1100° has been studied by DTA and TG, and chemical analysis. A few experiments by radiocrystallographic analysis and electron diffraction have also been done. The process of incorporation begins at about 600° and is nearly complete at 900°. A sample elaborated at 1100° is homogeneous in the mass but presents in the surface an excess of copper ions which seems to be located at certain points.

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Zusammenfassung Bei 950° erzeugtes NiO wurde mit Kupfer(II)nitratlösung impregniert und auf 300° erhitzt. Der Einbau von CuO (5 %) in das NiO-Netz bei thermischer Behandlung von zwischen 450–1100° wurde durch DTA, TG und chemische Analyse untersucht. Einige Proben wurden auch einer Prüfung durch Radiokristallographie und Elektronendiffraktion unterworfen. Der Einbau beginnt bei 600° und ist bis 900° praktisch vollendet. Eine bei 1100° erzeugte feste Probe, obzwar homogen in der Masse, zeigt an der Oberfläche einen Überschuß von an gewissen Stellen lokalisierten Kupferionen.

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Résumé NiO préparé à 950° a été imprégné par une solution de nitrate cuivrique et chauffé à 300°. L'incorporation de CuO (5 %), ainsi engendré, dans le réseau de NiO, lors de traitements thermiques à 450–1100° a été étudiée par ATD, ATG et analyses chimiques. Quelques essais d'analyses radiocristallographiques et de diffraction électronique ont également été effectués. Le processus d'incorporation se manifeste à partir de 600°. Il est pratiquement complet vers 900°. Un solide élaboré à 1100°, bien qu'homogène dans la masse, présente, en surace, un excédent d'ions Cu^{+ +} qui semble localisé en certains points. , 950°, 300°. , , , 450° 1100°. . 600° 900°. , 1100°, , .

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Nous tenons à exprimer nos remerciements à Messieurs H. Urbain et R. Bacaud, à Mesdames G. Dalmai-Imelik, C. Leclerq et M. A. Gresteau, et à Monsieur A. Renouprez pour leur contribution à cette étude.     

Contribution à la phytochimie du genre Gentiana. XXII. Identification de nouveaux O-glucosides de la mangiférine dans Gentiana asclepiadeaL.

Phytochemistry of genus Gentiana. XXII. Identification of new O-glucosides of mangiferin in Gentiana asclepiadea L. Two new O-glucosides of mangiferin (mangiferin-7-O-β-D -glucoside ( 1 ) and mangiferin-6-O-β-D -glucoside ( 2 )) have been isolated from the leaves of Gentiana asclepiadea L . This is the first full structure elucidation of naturally occurring O-glucosides of C-glucosylxanthones. The known C-glucosylflavone, saponarin ( 5 ) was also identified.     

Etude par microcalorimetrie de la reactivite de deux ammoniacates de chlorure de manganese

The reaction [Mn(NH₃)₂]Cl₂+ 4NH₃ [Mn(NH₃)₆]Cl₂, which is of potential use in chemical heat pumps, was studied by means of differential scanning calorimetry. The thermodynamic conditions, the enthalpy of the reaction, and the heat capacity values for MnCl₂, [Mn(NH₃)₂Ch and [Mn(NH₃)₆Cl₂ were measured. The influence of the reaction kinetics of the experimental procedure and some parameters such as sample temperature, ammonia pressure and scanning rate was examined.

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Zusammenfassung Mittels DSC wurde die Reaktion [Mn(NH₃)₂]Cl₂+4 NH₃ [Mn(NH3_{) 6}]Cl₂ untersucht, die von potentieller Verwendung für chemische WÄrmepumpen ist. Thermodynamische Bedingungen, die Reaktionsenthalpie und WÄrmekapazitÄtswerte für MnCl₂, [Mn(NH₃)₂]Cl₂ und [Mn(NH₃)₆]Cl₂ wurden gemessen. Weiterhin wurde der Einflu\ des Versuchsablaufes und einiger Parameter, wie Probentemperatur, Ammoniakdruck und Scanning-Geschwindigkeit auf die Reaktionskinetik untersucht.