21045-62-5Relevant academic research and scientific papers
Steric effects on the mechanism of reaction of nucleophilic substitution of β-substituted alkoxyvinyl trifluoromethyl ketones with four secondary amines
Vdovenko, Sergey I.,Gerus, Igor I.,Kukhar, Valery P.
, p. 190 - 200 (2008/02/06)
The kinetics of the reaction of β-substituted β-alkoxyvinyl trifluoromethyl ketones R1-CR2= CH-COCF3 (la-e) [(la), R1=C2H5, R2=H; (1b), R 1=R2=CH3; (1c), R1=C 2H5, R2=C6H5; (1d), R1 = C2H5, R2=V-pNO 2C6H4; (1e), R1=C2H 5, R2=C(CH3)3] with four aliphatic amines (2a-d) [(2a), (C2H5)2NH; (2b), (i-C 3H7)2NH; (2c), (CH2)5NH; (2d), O(CH2CH2)2NH] was studied in two aprotic solvents, hexane and acetonitrile. The least reactive stereoisomeric form of (la-d) was the most populated (E-s-Z-o-Z) form, whereas in (1e), the more reactive form (Z-s-Z-o-Z) dominated. The reactions studied proceeded via common transition state formation whose decomposition occurred by 'uncatalyzed' and/or 'catalyzed' route. Shielding of the reaction centre by bulky β-substituents lowered abruptly both k′ ('uncatalyzed' rate constant) and k″ ('catalyzed' rate constant) of this reaction. Bulky amines reduced k″ to a greater extent than k′ as a result of an additional steric retardation to the approach of the bulky amine to its ammonium ion in the transition state. An increase in the electron-withdrawing ability of the β-substituent increased 'uncatalyzed' k′ due to the acceleration of the initial nucleophile attack (k1) and 'uncatalyzed' decomposition of transition state (k2) via promoting electrophilic assistance (through transition state 8). The amine basicity determined the route of the reaction: the higher amine basicity, the higher k3/k2 ratio (a measure of the 'catalyzed' route contribution as compared to the 'uncatalyzed' process) was. 'Uncatalyzed' route predominated for all reactions; however in polar acetonitrile the contribution of the 'catalyzed' route was significant for amines with high pKa and small bulk. Copyright
Increasing the N-H acidity: Introduction of highly electronegative groups into the hydrazine molecule
Bredikhin, Aleksei,T?ubrik, Olga,Sillard, Rannar,M?eorg, Uno
, p. 1939 - 1941 (2007/10/03)
Various hydrazine derivatives containing combinations of trifluoroacetyl, trifluoromethanesulfonyl, and 2,4-dinitrophenyl groups were prepared. Synthetic strategy is studied in terms of using protecting groups and direct acylation. Georg Thieme Verlag Stuttgart.
REACTION OF β-ALKOXYVINYL TRIFLUOROMETHYL KETONES WITH AMINO COMPOUNDS
Gerus, I. I.,Gorbunova, M. G.,Vdovenko, S. I.,Yagupol'skii, Yu. L.,Kukhar', V. P.
, p. 1623 - 1628 (2007/10/02)
The reaction of β-alkoxyvinyl trifluoromethyl ketones with ammonia and primary amines leads to the formation of β-aminovinyl trifluoromethyl ketones RNHCH=CHCOCF3.The data from the IR and NMR spectra of these compounds indicate the presence of a strong in
β-TRIFLUOROMETHYLDICARBOCYANINES AND δ-TRIFLUOROMETHYLMEROCYANINES
Pazenok, S. V.,Gerus, I. I.,Chaika, E. A.,Yagupol'skii, L. M.
, p. 339 - 343 (2007/10/02)
A convenient method was developed for the synthesis of β-trifluoromethylhemicyanines, β-trifluoromethyldicarbocyanines, and δ-trifluoromethylmerocyanines, involving the use of β-alkoxyvinyl trifluoromethyl ketones as the starting compounds.The trifluorome
Oxidation of Vicinal Diols to α-Dicarbonyl Compounds by Trifluoroacetic Anhydride "Activated" Dimethyl Sulfoxide
Amon, Catherine M.,Banwell, Martin G.,Gravatt, G.Lance
, p. 4851 - 4855 (2007/10/02)
Trifluoroacetic anhydride "activated" dimethyl sulfoxide is an effective oxidant for the conversion of vicinal diols into the corresponding α-dicarbonyl compounds or products derived therefrom.Unlike the Swern oxidant, the title reagent system gives good yields of products derived from halogenated substrates.The method has permitted syntheses of previously inaccessible compounds including tropolones, a ?-homo-o-benzoquinone, and a "hyperreactive" α-keto aldehyde.
