38425-96-6Relevant academic research and scientific papers
Sodium borohydride on wet clay: Solvent-free reductive amination of carbonyl compounds using microwaves
Varma, Rajender S.,Dahiya, Rajender
, p. 6293 - 6298 (2007/10/03)
A solvent-flee reductive amination of carbonyl compounds by wet montmorillonite K 10 clay supported sodium borohydride is described; microwave irradiation facilitates the procedure.
Reduction of Schiff Bases with Isopropyl Alcohol and Aluminum Isopropoxide in the Presence of Raney Nickel
Botta, Maurizio,Angelis, Francesco De,Gambacorta, Augusto,Labbiento, Lucia,Nicoletti, Rosario
, p. 1916 - 1919 (2007/10/02)
The reduction of several N-alkyl and N-aryl ketimines to the corresponding secondary amines is described.The reaction, which generally proceeds in high yield, is effected by isopropyl alcohol and aluminium isopropoxide in the presence of Raney nickel.In the absence of the nickel catalyst, that is, under the Meerwein-Ponndorf-Verley conditions, the reaction takes a different route and N-isopropylamines are formed at preference to the direct reduction products.Without the aluminum alkoxide the reduction proceeds only for a small percentage.This reaction, besides offering a new method for the synthesis of secondary amines, represents the first example where the couple aluminum alkoxide/Raney nicel is used in catalytic transfer hydrogenation reactions.
Factors Controlling Regioselectivity in Deprotonations of Unsymmetrical Ketimines
Smith, J. Kirk,Bergbreiter, David E.,Newcomb, Martin
, p. 4396 - 4400 (2007/10/02)
The regioselectivity of deprotonation of equilibrium E-Z mixtures of the benzyl, n-butyl, cyclohexyl, phenyl, and tert-butyl imines of 2-butanone by lithium diisopropylamide (LDA) in tetrahydrofuran has been shown to be a function of both the nitrogen substituent and the temperature of the deprotonation reaction.High regioselectivity at either the methyl or methylene substituent could be obtained for all imines except the benzyl and n-butyl imines.Pure (Z)-2-butanone imines (R = n-C4H9, c-C6H11, t-C4H9), prepared by LDA deprotonation of acetone imines followed by methylation, were deprotonated by LDA at the methyl position at -78 deg C and at 0 deg C.Studies of the rates of deprotonation of the E and Z isomers of n-butyl, cyclohexyl, and tert-butyl imines of 2-butanone and of the rates and mechanisms of isomerizations of these isomeric ketimines were performed.Temperature dependent deprotonation regioselectivity was also observed in lithium diethylamide deprotonations of the benzyl, cyclohexyl, phenyl, and tert-butyl imines of 2-butanone.A general scheme accounting for these results and other accounts of variable regioselectivity in ketimine deprotonation is presented.
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.
