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Reaction of Arylnitroso Derivatives: synthesis of Arylimino 2,5-Dihydrofuranand Arylamino Fulvenes Derivatives
Full text linkHerein we report the reactivity of N-(2,4-dicyano-1,5-dimethyl-3-arylcyclopenta-2,4-dienyl)-2,2,2- trifluoroacetamides and N,N-dimethyl-4-nitrosoaniline which provide compounds derived from Ehrlich-Sachs condensation, dihydrofuran derivatives and fulvene derivatives by adjusting the reaction conditions
Photochemical synthesis of a 4,5-dihydro-furo-azetidinone, a novel beta-lactam system
No full text2,4-Dimethyl-3-phenylisoxazole anhydrobases were easily prepared from the corresponding 5-chloroisoxazolium trifluoromethanesulfonate and carbon anions of 1,3-dioxo compounds in the presence of triethylamine. Photorearrangement of 2-(2,4-dimethyl-3-phenyl-2H-isoxazol-5-ylidene)malonic acid diethyl ester gave a 4,5-dihydrofuroazetidinone in good yield. © 2003 Elsevier Ltd. All rights reserved
Reactivity of a Cyclic alpha-Bromoiminium Bromide towards Nucleophiles
No full textPiperidine‐pyrrolidine ring contraction of 1‐piperideinium bromide (1) was observed by reaction with aqueous bases, sodium methoxide, phenylhydrazine, (S)‐1‐phenylethylamine and sodium borohydride, whereas diazomethane addition mainly gave pyrrolo[3,4‐b]pyridine derivative 8. Some stereochemical features of these reactions have been investigated. 1 gave back bromine under suitable conditions. Copyright © 1987 Journal of Heterocyclic Chemistr
Photochemical Rearrangements of 3-Methylisoxazolopyridines
No full textIrradiation in water-saturated ethyl ether of isoxazolopyridines 1a,e, beside the corresponding oxazolopyridines 2a,e, leads to N-methylcarboxamides 3a,e via 1-2 shift of the methyl group. The isoxazolopyridine 5, bearing a hydrazino group in 4-position, rearranges only to l-aminopyrazolopyridine 6. © 1988
2-Azabicyclo[4.2.0]octane derivatives: Stereoselective photochemical Synthesis and Chemical Reactivity
No full textPhotochemical addition of acrylonitrile to 1,4-dihydropyridines 1 and 2 followed by catalytic hydrogenation of the products gave trans-8- and trans-7-cyano-cis-2-azabicyclo[4.2.0]octane-6-carboxylates 6a, b and 8a, b; the corresponding cis 7b, 9 and trans 6b, 8b stereoisomers were both obtained from 1,4,5,6-tetrahydropyridine 4. Using the chiral 1,4-dihydropyridine 3, azabicyclo[4.2.0]-octanes 6c, 7c and 8c were obtained with an enantiomeric excess in the range 45-15%. Thermal cycloaddition of p-chlorobenzonitrile oxide on the same substrates yielded compounds 10 and 11, with site- and regio-selectivity but without stereoselectivity. Cyclobutane ring opening under basic or acid conditions was observed only for 8-cyano-2-azabicyclo[4.2.0]octane 6b which gave the 1,4,5,6-tetrahydropyridylpropionitrile 15 or the piperidine-2-ol 17
Structure of Ethyl (3aRS,4aSR,5RS,6aSR,7aSR)-7-benzyl-3-(p-chlorophenyl)-6-cyano-3a.4.4a.5.6.6a.7a-octahydrocyclobut[b]isoxazolo[4,5-e]pyridin-4a-carboxylate
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Rearrangement of 3,5-dicyano-1,4-dihydropyridines to densely functionalized cyclopentadienes
No full text3,5-Dicyano-1,4-dihydropyridines underwent ring contraction to give functionalized cyclopentadienes upon treatment with trifluoroacetic anhydride. © 2008 Elsevier Ltd. All rights reserved
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