Results 161 to 170 of about 453,943 (222)

Cyclopenta[d]pyridazines and cyclopenta[d][1,2]oxazines

Journal of the Chemical Society C: Organic, 1970
Usually cyclopenta[d]pyridazines and cyclopenta[d][1,2]oxazines are protonated and react with other electrophiles in the five-membered ring at the 5- or the 7-position, although 2-phenyl-1,4-di-t-butylcyclopenta[d]pyridazxine can be brominated at the 6-position. The pyridazines are more reactive than the oxazines.
Douglas Lloyd, N. W. Preston
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ChemInform Abstract: 1,2‐OXAZINE CHEMISTRY PART 4, THE CONFORMATIONAL EQUILIBRIA IN 2,5‐ AND 2,4‐DIMETHYLTETRAHYDRO‐1,2‐OXAZINES

Chemischer Informationsdienst, 1975
AbstractDas Oxazin (IV) wird aus dem Hydrochlorid des Dihydrooxazins (I) über die Stufen (II) und (III) synthetisiert.
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β-Lactams from tetrahydro-1,2-oxazine-3,6-diones

Tetrahedron Letters, 1985
Abstract The photolysis and thermolysis of (4) and the photolysis of (5) result in the formation of the β-lactams (6) and (7); a mechanism which involves 1,4-diradicals is proposed and the possible relationship of this process to the biosynthesis of the β-lactam ring of isopenicillin N is discussed.
James Nally, Nicholas H.R. Ordsmith, Garry Procter   +2 more
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A New Approach to Neuraminic Acid Analogues via 1,2-Oxazines

Organic Letters, 2008
A new stereoselective and potentially very flexible (C(5) + C(3) + C(1)) approach to neuraminic acid derivatives and analogues has been established using enantiopure nitrones and alkoxyallenes as C(3) and C(1) building blocks. Substituent OR(2) in position 4 of neuraminic acid analogues is defined by the alkoxyallene employed for the synthesis of the ...
Bettina, Bressel, Hans-Ulrich, Reissig
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A convenient synthesis of benz-1,2-oxazine derivatives

Chemical Communications, 2000
An expedient synthesis of benz-1,2-oxazine derivatives involving nitrene insertion on a methoxy group is described.
Sukhen Chandra Ghosh, Asish De
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Reductive Transformations of 6H‐1,2‐Oxazines with Hydride Reagents: Formation of Aziridines and 3‐Hydroxyalkylated 1,2‐oxazines

Liebigs Annalen der Chemie, 1993
Abstract6H‐1,2‐Oxazines 1 and 3 are converted into aziridines 2 and 4, respectively, by reduction with LiAlH4. Reduction of 1,2‐oxazine 5 lacking the 6‐alkoxy substituent leads to phenyl ketone 6, 6‐Alkoxy‐substituted 1,2‐oxazine‐3‐carboxylates 7, 9, and 11 are reduced with NaBH4 to give the corresponding 3‐hydroxymethylated compounds 8, 10, and 12 in ...
Reinhold Zimmer, Kai Homann, Hans‐Ulrich Reißig   +2 more
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Synthesis of Some Carbamate Derivatives of 1,2‐Oxazine.

ChemInform, 2001
AbstractFor Abstract see ChemInform Abstract in Full Text.
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Lithiated 3-trifluoromethyl-substituted 1,2-oxazines and their reactions

Journal of Fluorine Chemistry, 1996
Abstract 3-Trifluoromethyl-substituted 1,2-oxazine 1 was smoothly deprotonated with lithiumdiisopropylamine and subsequently treated with various electrophiles. Reactions with alkyl halides furnished the 4-alkylated 1,2-oxazines 4–7 in good yield and with excellent cis -diastereoselectivity, whereas carbonyl compounds could not be employed ...
Reinhold Zimmer, Hans-Ulrich Reissig
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Synthesis of 1,2-Oxazines and Their N-Oxides

HETEROCYCLES, 2002
The available routes to the synthesis of partially saturated 1,2-oxazine isomers or their N-oxides as well as those of their aromatic counterparts are presented.
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1,2-Oxazine chemistry—III

Tetrahedron, 1974
F.G. Riddell, D.A.R. Williams
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