Zobrazeno 1 - 10
of 154
pro vyhledávání: '"Heinz G. Viehe"'
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 98:859-864
A method for trapping of transient carbon centered radicals is proposed. The ESR spectra of radical adducts 4 deriving from α-tert.butylthioacrylonitrile 3a give more information concerning the scavenged radical 2 than the other known radical traps.
Autor:
N. Guillot, F. Evariste, Robert Merényi, Marie-Aimée Decock-Plancquaert, C. Maliverney, Z. Janousek, Heinz G. Viehe
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 101:313-321
New 4-trifluoromethyl-1,3-oxazin-6-ones have been prepared in excellent yields from ethyl 3-amino-4.4.4-trifluorocrotonate (ATFC) by two original procedures: reaction of ATFC with phosgeniminium chlorides to give 2-dialkylamino-4-trifluoromethyl-1,3-
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 102:645-654
We report the chain extension of enamines by two carbon atoms through acid catalyzed nucleophilic substitution of the amine function by ene-1,1-diamines 2. By this vinylogous transamination we have prepared a series of diene-1,1-diamines 10a-h, 12a-e
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 102:129-140
Phosgeniminium salt 1 easily condenses with vinylogues of malononitrile 4 to yield new gamma,gamma-dicyano-alpha-chlorodienamines 13 which can undergo substitutions and heterocyclisation reactions. Vinylogues of malonate do not react with 1 whereas t
Autor:
Heinz G. Viehe, Robert Fuks
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 86:219-235
When ynamines 1 react with electrophiles R⊕; X ⊕, the structure of the products depends strongly on the nature of the electrophilic reagent and of the ynamine. The protonation under various conditions leads only to the cyclobutenylcyanine (D) whe
Autor:
L. Z. Chen, Jean‐Claude Pommelet, Heinz-G. Viehe, André Maquestiau, Robert Flammang, W. Masamba, Robert Merényi
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 98:529-546
Tandem mass spectrometry has been applied to investigate the behaviour of bis-captodative (cd) substituted cyclopropanes NC(SR)CCH2C(SR)CN [1, R=CH3; 2, R=tBu and 3, R=C6H5] upon electron impact (EI) and flash-vacuum pyrolysis (FVP) conditions. Ring-
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 85:892-897
The reaction of 3,4-dihydroisoquinolinium salt 11 with phenyl-N,N-dimethylaminoacetylene 12 affords the (1:2)-adduct, the dihydrobenzo(d)azecinium salt derivative 13. The structure assignment is based on a preliminary X-ray analysis as well as on ana
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 102:663-668
The reaction of β-tert.- aminoacrylonitriles 1 a-1c with dimethyl acetylenedicarboxylate (DMAD) to give pyrrolizidine, indolizidine and pyrroloazepine is described.
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 85:147-149
The alleneamidins 1 has been shown to cyclise to a dihydropyridine derivative 2 by heating for a 2 hours at 220°. This reaction is assumed to proceed via a (1, 5 a)‐sigmatropic hydrogen shift followed by a 6 π‐electrocyclisation. An attempt has
Proceedings of the NATO Advanced Research Workshop, Louvain-la-Neuve, Belgium, January 20-24, 1986