Search results for "Nitrile"
showing 10 items of 1539 documents
ChemInform Abstract: Alkaloid Determination in Crude Extracts from Cortex Quebracho and Opium Applying Capillary Electrophoresis and Capillary Electr…
2010
The applicability of capillary electrophoresis with UV and electrospray ionisation (ESI)-mass spectrometric detection to the determination of alkaloids in crude extracts of Cortex Quebracho and opium has been investigated. The use of a buffer electrolyte consisting of aqueous ammonium acetate (pH 3.1) and acetonitrile resulted in a high performance of peak resolution. Most of the alkaloids have been identified according to the signal of the protonated molecular ion in the ESI mass spectrum
IR-und UV-spektroskopische Eigenschaften einer homologen Reihe von molekulareinheitlichen, 12gliedrige Ringe enthaltenden Leiteroligomeren
1984
The reactions of multiple acrylates of oligo[(hydroxyphenylene)methylene] s (2a–2f), strongly diluted in boiling benzene, with 2,2′-azoisobutyronitrile in a mole ratio of 1:10, were investigated. The elemental analysis and the determination of relative molar masses of the resulting products (3, 4, 5, 6a, 6b, 7a and 7b) demonstrate that their molecules contain two nitrile groups. These data, together with the IR and UV spectra, show that the products are molecularly uniform ladder oligomers with two 1-cyano-1-methylethyl groups on both ends.
Anion interaction with ferrocene-functionalised cyclic and open-chain polyaza and aza-oxa cycloalkanes
2016
A family of ferrocene-functionalised receptors of different topologies have been used as receptors for anions. The compounds have been designed to contain both amine nitrogen and ether oxygen atoms and comprises from monoaza to pentaaza derivatives both open-chain (L1, L2, L3) or cyclic (L4, L5) and having from one to five ferrocenyl groups. Solution studies directed to determine the protonation constants of L1, L2 and L3 have been carried out in water (0.1 mol dm3 KNO3, 25 °C) and those of L4 and L5 in 1,4-dioxane-water (70:30 v/v, 0.1 mol dm -3 KNO 3, 25 °C). The protonation behaviour of the receptors can be explained taking into account electrostatic considerations. Speciation studies in…
Studies in organic mass spectrometry. IV. Electron impact induced fragmentation of 2-substituted 3-(5-isoxazolyl)-4(3H)-quinazolinones of pharmaceuti…
1984
The fragmentation under electron impact of thirteen 2-substituted-3-(5-isoxazolyl)-4(3H)-quinazolinones has been investigated with the aid of metastable ion detection and high resolution measurements. Molecular ions are always abundant and the main primary fragmentation route involves acetonitrile elimination through isoxazole ring opening. The other common processes, particularly those leading to the abundant [R-C8H4N2]+ ion (b or b'), as well as those due to the nature of the 2-substituent are reported and discussed.
Über die polymerisation von acrylnitril mit silbernitrat
1963
Die Polymerisation von Acrylnitril mit AgNO3 in Substanz und in Losung wird untersucht. In orientierenden Kinetischen Versuchen wird gefunden, das die Reaktion nach einem radikalischen Mechanismus ablauft; sie wird durch Licht katalysiert. Auserdem wird die Aktivitat einer Reihe anorganischer Salze und organischer Nitratebei der Initiierung der Polymerisation gepruft. Die Reaktionsmoglichkeiten werden diskutiert. The polymerization of acrylonitrile with AgNO3 in bulk and in solution was investigated. Informative kinetic experiments were carried out and it is suggested that a radical mechanism is operative; light acts as a catalyst. A number of inorganic salts and organic nitrates were check…
Polycondensed nitrogen heterocycles. Part 22. Pyrrolo[3,4-d]-1,2,3-triazines: A new ring system as potential antineoplastic agent
1989
Diazotization of the 3-aminopyrrole-4-carboxamides 6a,b under different conditions directly led to the new ring system pyrrolo[3,4-d]-1,2,3-triazine in excellent yields through an intramolecular coupling reaction. In all the cases it was impossible to isolate the intermediate 3-diazopyrroles.
Better understanding of the ring-cleavage process of cyanocyclopropyl anionic derivatives. A theoretical study based on the electron localization fun…
2005
[reaction: see text] Theoretical calculations at the B3LYP/6-31+G(d), MP2/6-31+G(d), and G3(MP2) levels have been carried out to understand the alternative reaction pathways (the cyclopropyl ring cleavage (RC) and the retrocycloaddition reaction (rCA)) of a constrained tricyanocyclopropyl anionic derivative. The more energetically favorable path is found to be the RC process, a formally "forbidden" rearrangement (Leiviers, M.; Tam, I.; Groves, K.; Leung, D.; Xie, Y.; Breslow, R. Org. Lett. 2003, 5, 19, 3407) yielding an allylic anion system via a concerted transition structure, in agreement with experimental outcomes. rCA is more energetically favorable along a two-stage mechanism, via an i…
Efficient synthesis of 2-bromo-1-[18F]fluoroethane and its application in the automated preparation of 18F-fluoroethylated compounds
2002
An efficient synthesis of 2-bromo-1-[18F]fluoroethane from commercially available 1,2-dibromoethane and its integration into an automated preparation device was developed for the routine synthesis of 18F-fluoroethylated compounds. The 1,2-dibromoethane was reacted with the [18F]fluoride/Kryptofix 2.2.2./carbonate complex in acetonitrile at 70 degrees C for 3 min resulting in 60-70% radiochemical yields. The crude reaction mixture was diluted with water, loaded on a LiChrolute EN-cartridge, eluted with acetonitrile and passed through an AluminaB-cartridge. This method provides 2-bromo-1-[18F]fluoroethane with 98% radiochemical purity and <0.1 micromol of 1,2-dibromoethane within 10 min, thus…
Synthesis and pharmacological activity of silyl isoxazolines 2
2003
Silyl isoxazolines have been synthesized by [2+3] cycloaddition reaction of nitrile oxides to vinyl- and allylsilanes. The addition of 3-pyridylnitrile oxide to 1,3-divinyl-1,1,3,3-tetraphenyldisiloxane affords 1,3-bis{5-[3-(3-pyridyl)isoxazolin-2-yl]}-1,1,3,3-tetraphenyldisiloxane; the latter exists as a mixture of trans- and cis-isomers.The bond angle of the Si–O–Si fragment in thetrans-isomer equals 180(3)° and in the cis-isomer it is 162(3)°.The pharmacological properties of 4-[3-(5-trimethylsilylisoxazolin-2-yl)]pyridinium-chloride have been studied.
Komplexbildung von acrylnitril mit AgNO3 und initiierung der lichtsensibilisierten polymerisation. Zur polymerisation von acrylnitril mit AgNO3, 4. M…
1968
Es wird uber die Komplexbildung von Acrylnitril (AN) mit AgNO3 berichtet, und die experimentellen Ergebnisse werden kinetisch ausgewertet; die Annahme, das im Falle des AN die Initiierung aus einem Komplex des Monomeren mit dem Salz erfolgt, wird enhartet. Daraber hinaus hangt die Polymerisationsgeschwindigkeit von der Wellenlaange des eingestrahlten Lichts ab. fur den Initiierungsmechanismus wird eine Reduktion des Metallions mit gleichzeitiger Bildung eines NO3-Radikals vorgeschlagen, das den eigentlichen Initiator darstellt. The complex formation of acrylonitrile (AN) and AgNO3 is discussed and kinetically evaluated; the assumption that in case of AN the initiation occurs from a complex …