Zobrazeno 1 - 10
of 307
pro vyhledávání: '"Niceas Schamp"'
Autor:
Niceas Schamp, M. Vandewalle
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 75:539-550
The mass spectra of 18 1, 3-diketones are discussed. Next to the normal α-cleavage of ketones, the most important fragmentations are the McLafferty rearrangement with the second carbonyl function in the ring, the expulsion of carbon monoxide and a s
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1e60b4a29c36f0c8565ebc719b054b8e
https://doi.org/10.1002/bscb.19660750712
https://doi.org/10.1002/bscb.19660750712
Autor:
H. De Pooter, Niceas Schamp
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 77:377-395
By reaction with sodium acetate in hot glacial acetic acid, 2,2-dibromodimedone (VII) is transformed into a mixture of 2-bromo-4,4-dimethyl-2-cyclopentenone (IX), 2,3-dibromo-4,4-dimethyl-2-cyclopentenone (X), 3-acetoxy-2-bromo-5,5-dimethyl-2-cyclohe
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::eff3a70cc30b89a4d2b92ac7c5379a1f
https://doi.org/10.1002/bscb.19680770703
https://doi.org/10.1002/bscb.19680770703
Autor:
Niceas Schamp, Roland Verhé
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 82:283-292
Three syntheses of 4-ethoxycarbonylchroman-3-one, a key intermediate in the synthesis of dehydrorotenoids, were described. The Dieckmann condensation of ethyl (2-ethoxycarbonylmethoxyphenyl) acetate gave only 4-ethoxycarbonylchroman-3-one in high yie
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3c656d848263fa0f413cde95f4a04f64
https://doi.org/10.1002/bscb.19730820311
https://doi.org/10.1002/bscb.19730820311
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 75:230-237
In alkaline medium 5,5-dimethyl-2-cyclohexenone forms a dimer, which is shown to be 2-(3′-keto-5′,5′-dimethyl-cyclohexyl)- 5,5-dimethyl-2-cyclohexenone. The dimerization can be explained as an abnormal Michael addition.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ce4c02a208973f19061c66a79c00badc
https://doi.org/10.1002/bscb.19660750308
https://doi.org/10.1002/bscb.19660750308
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 84:417-433
Treatment of N-1-(2, 2-dichloroalkylidene)t.butylamines 1a-c with excess methanolic sodium methoxide under reflux afforded mainly a mixture of α-methoxy-α,β-unsaturated aldimines 2a-c and the rearrangement products 3, besides small amounts of N-t.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f1a3d4a4cde18f884e29068a90562010
https://doi.org/10.1002/bscb.19750840502
https://doi.org/10.1002/bscb.19750840502
Autor:
M. J. O. Anteunis, Niceas Schamp
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 79:437-440
In reply to the paper of Jefford and Waegell [1] it is shown that non-classical long-range coupling does exist in 3,3,5,5-tetrasubstituted-2-halo-cyclohexanones. Following the reasoning of those authors, an even larger abnormal coupling than original
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ec3f7f839aad2ce0f692061251da7819
https://doi.org/10.1002/bscb.19700790705
https://doi.org/10.1002/bscb.19700790705
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 77:33-42
The mass spectra of 1,3-dioxane and its 2,4,5- and 6-alkyl substituted derivatives are discussed. Two main degradation patterns result respectively from initial elimination of a 2-hydrogen atom or alkyl substituent and from the expulsion of a formald
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ecc4afbfc39156f4274d5ee7ba37befe
https://doi.org/10.1002/bscb.19680770104
https://doi.org/10.1002/bscb.19680770104
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 78:277-284
3,3-Dimethyl-1,2,4-cyclopentanetrione is prepared in high yield by hydrolysis and debromination of the easily accessible 2,3,5,5-tetrabromo-4,4-dimethyl-2-cyclopentenone. Acylation with isovaleric anhydride affords the title compound.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c40a54e7401d437d16f9ea04c7029255
https://doi.org/10.1002/bscb.19690780506
https://doi.org/10.1002/bscb.19690780506
Autor:
W. Coppens, Niceas Schamp
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 81:643-647
A new synthesis of 1, 1-dichloromethylketones is described. Methylketones are converted into cyclohexylketimines, which by N-chlorosuccinimide are chlorinated specifically to 1,1-dichloromethylketimines. Hydrolysis yields 1, 1-dichloromethylketones,
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::50d4f1c0f740090f68ea0b2c9c18574b
https://doi.org/10.1002/bscb.19720810165
https://doi.org/10.1002/bscb.19720810165
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 76:111-122
The mass spectra of 1, 3-cyclohexanedione and its 2, 4 and 5 substituted derivatives are discussed. Most fragmentation patterns can be rationalised starting from the diketo form, through initial 1.2 and 1.6 bond cleavages. Evidence is advanced that i
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1cb4fb956ecf3e5dd41c8ec8c6db96e3
https://doi.org/10.1002/bscb.19670760112
https://doi.org/10.1002/bscb.19670760112