One-Pot Reductive Amination of Araldehydes by Aniline Using Borohydride with Cecl₃·7H₂O as Catalyst

Abstract

A one-pot, two-step reductive amination of araldehydes or acetophenones with anilines using NaBH 4 as a cheap hydride source and catalysed by CeCl 3 . 7H 2 O has been achieved in EtOH at room temperature in good yields.

Structural derivatization strategies of natural phenols by semi-synthesis and total-synthesis

“…Carbonyl can also be reduced to primary amine in the presence of NH 4 OAc and NaBH 3 CN [ 111 ] (Scheme 12 A-c) or via the intermediate of oxime [ 112 , 113 ] (Scheme 12 A-e). The condensation and hydrogenation can be combined in one-pot by the catalysis of Lewis acid such as CeCl 3 [ 114 ] and titanium isopropoxide [ 115 ] (Scheme 12 A-g). As a common strategy, phenylketone fragments can be translated to hydroxyphenylacetone or α,β-unsaturated ketone by Aldol reaction (Scheme 12 A-h).…”

Formation of 3-Aminophenols from Cyclohexane-1,3-diones

“…N-Benzyl-4-bromoaniline. 51 4-Bromoaniline (1.198 g, 7.00 mmol), PhCHO (0.59 mL, 5.84 mmol), and CeCl 3 •7H 2 O (43.5 g, 0.116 mmol) were added in that order to anhydrous EtOH (12 mL). The reaction flask was stoppered, and stirring was continued for 2.5 h (TLC monitoring, silica, 4:1 EtOAc-hexane).…”

One-pot Reductive Amination of Carbonyl Compounds with NaBH 4 -B(OSO 3 H) 3 /SiO 2 in Acetonitrile and in Solvent-free Condition

“…In these cases, formation and isolation of the imines which followed by reduction can avoid the problem, but the need to isolate imines make its synthetic utility poor. 5 A large number of reducing hydride reagents have been studied for direct reductive amination avoiding the direct reduction of starting carbonyl compound to the corresponding alcohol, including sodium cyanoborohydride (NaBH 3 CN), 6 Pyridine-BH 3 , 7 sodium triacetoxyborohydride (NaBH(OAc) 3 ), 8 hydrosiloxane reagent, 9 titanium(IV) isopropoxide, 10 and Zirconium (IV) isopropoxide. 11 However, many of these methods suffer from diverse disadvantages such as toxic compounds as by-product, hygroscopicity and thermal instability of the reagents, incompatibility with compounds containing * For correspondence a carbon-carbon double or triple bond and other reducible functional groups such as cyano and nitro groups.…”