LaCl3·7H2O as an Efficient Catalyst for One-Pot Synthesis of Highly Functionalized Piperidines via Multi-component Organic Reactions

Abstract

The three-component one-pot synthesis of highly functionalized piperidine derivatives was carried out by condensing 1,3-dicarbonyl compounds with aromatic aldehydes and aniline using a catalytic amount (10 mol%) of LaCl 3 Á7H 2 O in methanol at room temperature. The main features of current protocol include easy work up, mild reaction conditions, good yields and high atom economy.

Y(NO3)3·4H2O-assisted Three-component Synthesis of Polysubstituted Tetrahydropyridines

“…The relative anti-configuration of the product with 2,6-substituents on the six-membered ring of the tetrahydropridine was confirmed by comparing the physical and spectroscopic data of the known compounds with those in the literature. 5,6,10,11,13,19 The possible reaction mechanism for this three-component reaction is shown in Scheme 2. The structure of new compounds 4t and 4u were deduced on the basis of 1 H NMR spectroscopy, mass spectrometry, and elemental analysis.…”

Organocatalyzed Novel Synthetic Methodology for Highly Functionalized Piperidines as Potent α‐Glucosidase Inhibitors

“…According to general procedure, 1h was synthesized starting from ethyl acetoacetate, 4‐methylbenzaldehyde, and 3‐nitroaniline , white solid, m.p. : 119–120°C yield 51%, 1 H NMR (300 MHz, CDCl 3 ) δ H 1.5 (t, 3H, CH 3 ), 2.35–2.5 (m, 2H, CHaHb), 2.45 (s, 6H, CH 3 ) 4.35–4.55 (dq, 2H, CH 2 and 1H, CH), 5.2 (s, 1H, CH), 6.7 (d, 1H, Ar–H), 7–7.1 (m, 8H, Ar–H), 7.2–7.5 (m, 7H, Ar–H), 10.58 (s, 1H, N–H); MS m/z (EI) 592; HRMS calcd.…”

One‐Pot Pseudo Five Component Synthesis of Biologically Relevant 1,2,6‐Triaryl‐4‐arylamino‐piperidine‐3‐ene‐3‐ carboxylates: A Decade Update

“…LaCl 3 .7H 2 O was efficiently catalyzed the reactions of aromatic aldehydes, amines and β‐ketoesters in methanol at room temperature to afford the corresponding functionalized piperidines with excellent yields (Scheme ) . For the synthesis of ethyl 1,2,6‐triphenyl‐4‐(phenylamino)‐1,2,5,6‐tetrahydropyridine‐3‐carboxylate, catalytic activity of a number of other catalysts such as ammonium acetate, AlCl 3 , (NH 4 ) 6 Mo 7 O 24 .4H 2 O, triethyl amine, Al 2 O 3 , ZnCl 2 , FeCl 3 , La 2 O 3 , SiO 2 Cl etc was also examined and among them 10 mol% LaCl 3 .7H 2 O was came out superior in terms of both reaction times as well as product yields.…”

“…LaCl 3 .7H 2 O was efficiently catalyzed the reactions of aromatic aldehydes, amines and β-ketoesters in methanol at room temperature to afford the corresponding functionalized piperidines with excellent yields (Scheme 17). [50] [51] developed a simple, convenient ultrasound-assisted protocol for the synthesis of highly functionalized piperidines via the reaction of substituted benzaldehydes, p-methoxyaniline and methyl acetoacetate in the presence of a catalytic amount of ytterbium (III) trifluoromethanesulfonate (Yb(OTf) 3 ) as an efficient Lewis acidic catalyst in methanol at 60°C.…”