Search results for "Azole"

Synthesis of Naturally Occurring Pyrazine and Imidazole Alkaloids from Botryllus LeachiRID=?a?ID=?a? Dedicated to Prof. G . Märkl on the occasion of …

2004

The synthesis of the naturally occurring and biologically active alkaloids 1 and 2, first isolated from the red ascidian Botryllus leachi by Duran et al. [1], is described and the structure proposed for Botryllazine B (1) is confirmed. The analytical data for 2-(p-hydroxybenzoyl)-4-(p-hydroxyphenyl)imidazole (2) are discussed and compared with the literature. With special emphasis of 1H NMR data the tautomerism of aroylimidazolemethanones is described.

Photoinduced Single Electron Transfer on 5-Aryl-1,2,4-oxadiazoles:  Some Mechanistic Investigations in the Synthesis of Quinazolin-4-ones

1999

The photochemistry of some 5-aryl-3-methoxy- (or 5-aryl-3-phenyl-) 1,2,4-oxadiazoles irradiated in the presence of different sensitizers [such as diphenylacetylene (DAC), 9,10-diphenylanthracene (DAN), or triphenylene (TPH)] or ground-state donors such as triethylamine (TEA) has been investigated. Intermediates arising from breaking of the ring O-N bond develop both into quinazolin-4-ones (by a heterocyclization reaction involving the aryl at the C-5 of the oxadiazole nucleus) and into open-chain products (corresponding to a reduction at the ring O-N bond), in different ratios depending on their structures and photoreaction conditions. A reasonable explanation considers sensitization by pho…

ChemInform Abstract: Photoinduced Single Electron Transfer on 5-Aryl-1,2,4-oxadiazoles: Some Mechanistic Investigations in the Synthesis of Quinazoli…

2010

The photochemistry of some 5-aryl-3-methoxy- (or 5-aryl-3-phenyl-) 1,2,4-oxadiazoles irradiated in the presence of different sensitizers [such as diphenylacetylene (DAC), 9,10-diphenylanthracene (DAN), or triphenylene (TPH)] or ground-state donors such as triethylamine (TEA) has been investigated. Intermediates arising from breaking of the ring O-N bond develop both into quinazolin-4-ones (by a heterocyclization reaction involving the aryl at the C-5 of the oxadiazole nucleus) and into open-chain products (corresponding to a reduction at the ring O-N bond), in different ratios depending on their structures and photoreaction conditions. A reasonable explanation considers sensitization by pho…

Versatile oxidative approach to carbazoles and related compounds using MoCl5.

2013

The unique oxidizing power of molybdenum pentachloride provides an easy to perform, versatile, and high yielding method to construct carbazoles and the corresponding dibenzo analogues of thiophene, furan, and selenophene. The coupling reaction tolerates a variety of functional groups. The synthesis is highly modular. By this approach a precursor for the naturally occurring carbazole koenigicine was prepared.

Thermolysis of 3-(carbazol-3-yl)-2-azidopropenoates

2000

Abstract Thermal cyclisation of 2-azido-3-(carbazol-3-yl)propenoic esters produces the 1,6-dihydropyrrolo[3,2- c ]carbazole and not the 1,9-dihydropyrrolo[2,3- b ]carbazole whereas, in the case of the 4-methylcarbazolyl derivative, the 1,9-dihydropyrrolo[2,3- b ]-carbazole is formed in preference to the alternative pyrido[4,3- c ]carbazole.

ChemInform Abstract: Synthesis of Tetrasubstituted 4,4′-Biimidazoles.

2012

Highly substituted 4,4′-biimidazoles were synthesized, in good to excellent yields, through a multicomponent imidazole ring synthesis by using imidazol-4-yl-ethane-1,2-diones as starting materials. The obtained compounds were preliminarily tested as chromogenic and fluorescent sensors for heavy metals.

Imidazole aus Aldehyden, 1,2-Diketonen und flüssigem Ammoniak. 3. Mitt. über Imidazolsynthesen mit flüssigem Ammoniak

1974

Bei der Darstellung von Imidazolen (3) aus aliphatischen oder aromatischen Aldehyden (1) und 1,2-Diketonen (2) in flussigem Ammoniak unter Druck konnen die verschiedenen Moglichkeiten der C-Substitution des Imidazolkerns realisiert werden. Imidazoles from Aldehydes, 1,2-Diketones and Liquid Ammonia If imidazoles (3) are prepared from aliphatic or aromatic aldehydes (1) and 1,2-diketones (2) in liquid ammonia under pressure, all possibilities of C-substitution of the imidazole nucleus can be realized.

Synthese von 2-(2-Aminoethyl)-4-hydroxymethyl-imidazol+ Synthesis of 2-(2-Aminoethyl)-4-(hydroxymethyl)imidazole

1982

NMR-Spektroskopie an Heterocyclen, 5. Mitt.13C-NMR- und massenspektrometrische Untersuchung N-substituierter Methoxy- und Hydroxy-äthylimidazole

1978

Es wird die 13C-NMR- und massenspektrometrische Untersuchung verschiedener N-substituierter Methoxy- und Hydroxy-athylimidazole beschrieben. Fur den Zerfall von 1,2-Diathyl-4-(2-hydroxyathyl)-imidazol wird ein ausfuhrliches Fragmentierungsschema angegeben. NMR-Spectroscopy of Heterocyclic Compounds, V: 13C-NMR and Mass Spectrometry of N-Substituted (2-Methoxyethyl)- and (2-Hydroxyethyl)-imidazoles The 13C-NMR and mass spectra of various N-substituted (2-methoxyethyl)- and (2-hydroxyethyl)imidazoles are described. A scheme for the fragmentation of 1,2-diethyl-4-(2-hydroxyethyl)imidazole is reported.

Mass spectrometry of 3,4-dihydroquinazolin-4-ones of pharmaceutical interest. Part3. Electron ionization mass spectra of 2-substituted-3-(5′-pyrazoly…

1992

The fragmentation reactions induced by electron impact of eighteen title compounds has been investigated with the aid of low beam energy spectra (14 eV, nom. value), metastable ion detection, high resolution measurements and labelling experiments. The loss of the 4-carbonyl oxygen together with the 3-substituent, which constitutes a characteristic fragmentation route of 3-aryl and 3-heteroaromatic substituted-4(3H)-quinazolinones, is again observed, but the presence of a carboxyethyl group at the 4′-position of the pyrazole ring is responsible of an anomalous loss of 47 daltons from the molecular ion. Lastly, a comparison with the previously described behaviour of 3-(5′-isoxazolyl) derivati…