Direct Reductive Amination of Aldehydes and Ketones with 2,4-Ionene-Based Borohydride Exchange Resin as a Novel Polymer-Supported Reducing Agent (original) (raw)
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Organic Letters, 2001
General Methods Reagents were purchased from commercial suppliers and were used without purification unless otherwise noted. Anhydrous tetrahydrofuran was purchased from Fluka Chemika. Dibutyltin dichloride (96%) was purchased from Aldrich Chemical Company. All reactions were performed in borosilicate test tubes with magnetic stirring. Reactors were assembled open to the air, and placed under nitrogen after the addition of all reagents. Chromatography was performed using manual injection on an ISCO SQ16 chromatograph with 10 g prepacked RediSep silica cartridges, and gradients of either ethyl acetate-hexane (anilines) or 2 M methanolic ammonia-dichloromethane (alkylamines). 1 H and 13 C NMR spectra were recorded on a Bruker spectrometer. Chemical shifts are reported in parts per million downfield from an internal Me 4 Si standard. In cases where reactions were monitored by 1 H NMR, samples were prepared by dissolving an aliquot of the crude reaction mixture (approx. 0.04 mL) in CDCl 3 (approx. 1 mL). Melting points are uncorrected and were obtained on a MelTemp apparatus. Combustion analyses were performed by Desert Analytics. Representative Procedure for the Reductive Amination of 4-Methoxybenzaldehyde with Aniline A solution of 4-methoxybenzaldehyde (0.18 mL, 1.5 mmol, 1.0 eq) in THF (0.3 mL) was treated with aniline (0.14 mL, 1.5 mmol, 1.0 eq) and dibutyltin dichloride (9 mg, 3x10-2 mmol, 0.02 eq). The resulting yellow solution was allowed to stir for 2 min, and treated with phenylsilane (0.20 mL, 1.7 mmol, 1.1 eq). After 2 h, thin layer chromatography showed no remaining aniline. The colorless reaction was diluted with
Reductive Amination of Aldehydes with Sodium Borohydride-Silica Gel System†.pdf
Chemical Science Transactions, 2013
A simple and convenient procedure for reductive amination of aldehydes using sodium borohydride in the presence of silica gel as an active and inexpensive catalyst is described. The reactions were carried out with equimolar amounts of amine and aldehyde using silica gel-sodium borohydride in THF at room temperature.
NaBH4/C: A Convenient System for Reductive Amination of Aldehydes
Oriental Journal of Chemistry, 2014
In this context, NaBH 4 in the presence of activated charcoal has been used for thereductive aminationofa varietyof aldehydes withanilines. The reductive amination reactions have been performed within 60-100 min in THFunder reflux conditionsin high to excellent yields of products (85-90%).
One-Pot Reductive Amination of Carbonyl Compounds Using Sodium Borohydride–Amberlyst 15
Synthetic Communications, 2010
A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica chloride as an active, inexpensive, recoverable, and recyclable catalyst is described. The reactions were carried out with equimolar amounts of amine and carbonyl compound using silica chloride-sodium borohydride in THF at room temperature.
NaBH4/PhCO2H: AnEfficient system for Reductive Amination of Aldehydes
Oriental Journal of Chemistry, 2015
Amines can be synthesized from their corresponding of aldehydes. So much methodhas been used for this purpose such as: the reduction of nitro, cyano, azide, carboxamide compounds or the alkylation of amines. These methods have problemssuch as: harsh reaction conditions, overalkylation, low chemical selectivity and generally poor yields. Another method is the reductive amination. Thisreactionhas been carried out by sodium borohydridewith different reducing system 1-2 .Previously, we have reported some systems for this achievement 3-7 .In continuing our efforts for the development of new reducing systems,in this context;we have reported the reductive amination reaction of aldehydes with
Hitchhiker’s Guide to Reductive Amination
Synthesis, 2019
A comparative study of various widely used methods of reductive amination is reported. Specifically, such reducing agents as H2, Pd/C, hydride reagents [NaBH4, NaBH3CN, NaBH(OAc)3], and CO/Rh2(OAc)4 system were considered. For understanding the selectivity and activity of the reducing agents reviewed herein, different classes of starting materials were tested, including aliphatic and aromatic amines, as well as aliphatic and aromatic aldehydes and ketones. Most important advantages and drawbacks of the methods, such as selectivity of the target amine formation and toxicity of the reducing agents were compared. Methods were also considered from the viewpoint of green chemistry.