Results 241 to 250 of about 86,821 (289)

Cyclization of N,N-diethylgeranylamine N-oxide in one-pot operation: preparation of cyclic terpenoid-aroma chemicals

Tetrahedron Letters, 2008
Acid promoted cyclization of the geranylamine N-oxide (E)-4 followed by base-catalyzed intramolecular aldol condensation afforded 1-acetyl-4,4-dimethyl-1-cyclohexene (7) in one-pot operation. Reduction of 7, which possess strong fruity odor, followed by lipase-catalyzed kinetic resolution furnished the acetate (R)-26 (>49.9% yield, >99% ee) and the ...
Kunihiko Takabe, Takashi Yamada, Takenori Miyamoto, Nobuyuki Mase   +3 more
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ChemInform Abstract: STRAINED CYCLIC ACETYLENES, VII. ADDITION OF SULFUR AND PYRIDINE N‐OXIDE TO SEVEN MEMBERED CYCLOALKYNES

Chemischer Informationsdienst, 1980
AbstractDie cyclischen Acetylene (Ia) und (Ib) addieren elementaren Schwefel zu den Dithieten (IIa) und (IIb), mit Pyridin‐N‐oxid (III) und (Ia) IÖO wird das Spiroazepin (IV) erhalten, das thermisch in das Pyridylthiepinon (V) umgelagert werden kann.
A. KREBS, H. COLBERG, U. + HOEPFNER, H. KIMLING, J. ODENTHAL   +4 more
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ChemInform Abstract: An Efficient and Chemoselective Deoxygenation of Hetero Cyclic N‐Oxides Using LiCl/NaBH₄.

ChemInform, 2000
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
S. Raja Ram, K. Purushothama Chary, D. S. Iyengar   +2 more
openaire   +1 more source

Bicyclic 1,2-oxazine N-oxides. Different behaviour in ring fission between systems derived from 5- and 6-membered ring cyclic enamines

Tetrahedron, 1982
Abstract 1,2-Oxazine N-oxides derived from aminocyclohexenes open into the corresponding nitroalkylated trisubstituted enamines, whereas those derived from aminocyclopentenes give stable tetrasubstituted enamines. Both open-chain systems are easily hydrolyzed to the corresponding γ-nitrocycloalkanones.
DANEO S., PITACCO, GIULIANA, RISALITI A., VALENTIN, ENNIO   +3 more
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ChemInform Abstract: Palladium‐Catalyzed Coupling Reactions of Thioimidate N‐Oxides: Access to α‐Alkenyl‐ and α‐Aryl‐Functionalized Cyclic Nitrones.

ChemInform, 2010
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Julie Schleiss, Patrick Rollin, Arnaud Tatibouet   +2 more
openaire   +1 more source

NMR spectra of cyclic nitrones. 4. Synthesis and 13C NMR spectra of 4H-imidazole N-oxides and N,N-dioxides

Chemistry of Heterocyclic Compounds, 1988
4H-Imidazole 1,3-dioxides and 4H-imidazole 3-oxides were obtained by oxidation of 1-hydroxy-3-imidazoline 3-oxides and 1-hydroxy-3-imidazolines with lead and manganese dioxides or the stable nitroxyl radical, while 4H-imidazole 1-oxides were obtained by thermal decomposition of 1-acetoxy-3-imidazoline 3-oxides.
I. A. Grigor'ev, I. A. Kirilyuk, L. B. Volodarskii   +2 more
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A cyclic voltammetric study of some quinoxaline di-n-oxides and quinoxalines in acetonitrile: substituent effect on the cathodic reduction

Electrochimica Acta, 1987
Abstract The cathodic reductions of two series of substituted quinoxaline di- N -oxides and quinoxalines in acetonitrile were measured in the potential range of 0 to −2.0 V and 0 to −2.3 V vs sce , respectively. Two irreversible reductions were observed in the first series, and one reversible reduction for the second.
K.R. Barqawi, M.A. Atfah
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ChemInform Abstract: A Novel and Efficient Deoxygenation of Hetero Cyclic N‐Oxides Using ZrCl₄/NaBH₄.

ChemInform, 2000
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
K. Purushothama Chary, G. Hari Mohan, D. S. Iyengar   +2 more
openaire   +1 more source

ChemInform Abstract: NMR Spectra of Cyclic Nitrones. Part 4. Synthesis and 13C NMR Spectra of 4H‐Imidazole N‐Oxides and N,N‐Dioxides.

ChemInform, 1989
AbstractOxidation of the 1‐hydroxy‐3‐imidazoline 3‐oxides (I) or the 1‐hydroxy‐3‐imidazolines (IIIa) and (IIIc) gives the dioxides (II) or the 4H‐imidazole 3‐monoxides (IVa) and (IVc).
I. A. GRIGOR'EV, L. A. KIRILYUK, L. B. VOLODARSKII   +2 more
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ChemInform Abstract: 2‐CHLORO‐4,5‐DIHYDROIMIDAZOLE; I. REACTIONS WITH SOME HETEROAROMATIC N‐OXIDES, CYCLIC NITRONES, AND ALDOXIMES

Chemischer Informationsdienst, 1984
Abstract2‐Chlorimidazolin ( l) reagiert mit Chinolin‐ N‐oxiden (II) über die Zwischenstufe cyclischer Addukte zu 2‐lmidazolidinon‐Derivaten (III) und (IV).
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