10592-26-4Relevant academic research and scientific papers
Hydroamination of 1,3-cyclohexadiene with aryl amines catalyzed with acidic form zeolites
Jimenez, Oriol,Mueller, Thomas E.,Schwieger, Wilhelm,Lercher, Johannes A.
, p. 42 - 50 (2007/10/03)
The intermolecular hydroamination of 1,3-cyclohexadiene with aniline using zeolite catalysts was investigated. The reaction mechanism and the influence of amine basicity on the rate of reaction were studied. Zeolite H-BEA was the most active catalyst, whereas the incorporation of Zn2+ (Zn/H-BEA) led to decreasing catalytic activity, indicating that the reaction is catalyzed by Bronsted acid sites. Subtle shape selective effects determine the reactivity and selectivity of the zeolites.
Comparison of the Tautomerization and Hydrolysis of Some Secondary and Tertiary Enamines
Capon, Brian,Wu, Zhen-Ping
, p. 2317 - 2324 (2007/10/02)
N-Phenylcyclohex-1-en-1-amine, N-(p-chlorophenyl)cyclohex-1-en-1-amine, the N-aryl-2-methylprop-1-en-1-amines, Me2C=CHNLC6H4X, L = H, D, X = H, p-Cl, p-Me, p-MeO, m-NO2, the N-alkyl-2-methylprop-1-en-1-amines, Me2C = CHNDR, R = Me, Et and the (E)-N-alkylprop-1-en-1-amines, MeHC = CHNDR, R = Me, t-Bu, were generated in solution from their N-trimethylsilyl derivatives and characterized by NMR spectroscopy.N-(p-Nitrophenyl)-2-methylprop-1-en-1-amine was isolated from the reaction of isobutyraldehyde and p-nitroaniline, and appreciable amounts (>10percent) of the N-arylcyclohex-1-en-1-amines and N-aryl-2-methylcyclohex-1-en-1-amines were found to be present at equilibrium in DMSO-d6 solution when the aryl group was phenyl, p-chlorophenyl, m-nitrophenyl, or p-nitrophenyl.The kinetics of hydrolysis of all the N-aryl secondary enamines obtained in the above ways were measured in aqueous solution and compared with those of the corresponding N-methyl tertiary enamines.With all enamines there was a region of pH in which kobsd was proportional to 10-pH, and under such conditions it was considered that the rate-determining step was C-protonation.This was supported by the isotope effect kH(1+)/kD(1+) = ca. 3, the observation of general acid catalysis, the much faster rate of hydrolysis of the corresponding imines, and the negative ρ- values.It was found that in the cyclohexenyl series the secondary and tertiary enamines were hydrolyzed at similar rates when the substituents in the aryl group were the same, but in the 2-methylcyclohexenyl and 2-methylpropenyl series the secondary enamines were hydrolyzed much faster than the corresponding tertiary enamines.This was attributed to the tertiary enamines being hindered from attaining the most favorable conformation for p-? conjugation.
Imine-enamine tautomerism in the anils of cyclohexanone and 2-(β-cyanoethyl)cyclohexanone
Kayukova, L. A.,Erzhanov, K. B.,Umarova, Z. N.
, p. 111 - 119 (2007/10/02)
The products from the condensation of cyclohexanone and 2-(β-cyanoethyl)cyclohexanone with para- and ortho-disubstituted anilines in 10percent solutions in carbon tetrachloride exist as mixtures of the imine and enamine tautomers.The tautomeric compositio
Azomethines, 1-Azaallyl Anions, and Metastable Secondary Enamines
Knorr, Rudolf,Weiss, Alfons,Loew, Peter,Raepple, Edith
, p. 2462 - 2489 (2007/10/02)
E/Z equilibrium constants of the ketone anils 6a-s do not depend significantly on the inductive substituent effect. 1H NMR chemical shifts used for configurational classification are also effective for assignments in comparable, isomerically almost pure azomethines 6aa-pp and may be explained by the anisotropic shift model.The 1-azaallyl anions 7 prepared by deprotonation are characterized by 1H NMR spectroscopy.Kinetic and thermodynamic control of this metallation reaction result in different preferential configurations of such anions, the methanolysis of which yields metastable sec. enamines 8 by regio- and stereospecific N-protonation.It is possible to estimate further substituent parameters λd from E/Z equilibria.
