74404-15-2Relevant academic research and scientific papers
Ruthenium-catalyzed transfer hydrogenation of imines by propan-2-ol in benzene
Samec, Joseph S. M.,Baeckvall, Jan-E.
, p. 2955 - 2961 (2007/10/03)
Transfer hydrogenation of a variety of different imines to the corresponding amines by propan-2-ol in benzene catalyzed by [Ru2(CO)4(μ H)(C4Ph4COHOCC4Ph4)] (1) has been studied. The reaction is highly efficient with turnover frequencies of over 800 per hour, and the product amines were obtained in excellent yields. A remarkable concentration dependence of propan-2-ol was observed when the reaction was run in benzene as cosolvent. An optimum was obtained at 24 equivalents of propan-2-ol to imine, and further increase of the propan-2-ol led to a dramatic decrease in rate. Also the use of polar cosolvents with 24 equivalents of propan-2-ol gave a low rate. It was found that ketimines react faster than aldimines and that electron-donating substituents on the imine increase the rate of the catalytic transfer hydrogenation. Electron-withdrawing substituents decreased the rate. An isomerization was observed with imines having an α-hydrogen at the N-alkyl substituent, which is in accordance with a mechanism involving a ruthenium-amine intermediate. It was demonstrated that the ruthenium-amine complex from α-methylbenzylamine, corresponding to the postulated intermediate, can replace 1 as catalyst in the transfer hydrogenation of imines. A primary deuterium isotope effect of kCH/CD = 2.7 ± 0.25 was observed when 2-deuterio-propan-2-ol vas used in place of propan-2-ol in the ransfer hydrogenation of N-phenyl-(1-phenylethylidene)amine.
ADDITION AND LITHIATION REACTIONS OF N-(1-PHENYLALKYLIDENE)ANILINES WITH LITHIUM DIALKYLAMIDES
Strekowski, Lucjan,Patterson, Steven,Cegla, Marek T.,Wydra, Roman L.,Czarny, Agnieska,Harden, Donald B.
, p. 5197 - 5200 (2007/10/02)
Lithium diisopropylamide undergoes an addition reaction to the methyleneamino moiety of the title Schiff's bases substituted with a cyano group at the orto or para position of the aniline, but mediates tautomerization of the unsubstituted and metasubstitu
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.
