Dy/chitosan: a highly efficient and recyclable heterogeneous nano catalyst for the synthesis of hexahydropyrimidines in aqueous media

Abstract

Dy(III) supported Chitosan nanocatalyst was synthesised by a simple procedure. It was used as catalyst for one pot, three component synthesis of hexahydropyrimidine derivatives. All the reactions were completed in short time period at room temperature and the products were obtained in high to excellent yields. The catalyst was characterized by FT-IR, XRD, SEM-EDX, TEM and ICP-AES analyses. The stability of the catalyst was evaluated by TG analysis. Use of water, ambient conditions, recyclability and high TOF of the catalyst make this protocol a sustainable alternative to existing protocols.

Lanthanum immobilized on chitosan: a highly efficient heterogeneous catalyst for facile synthesis of novel (α,β‐unsaturated) β‐aminoketones

“…The absorption peaks at 1075 and 1378 cm À1 appear due to the stretching vibrations of C-OH and C-N groups, respectively. [11] A similar trend is observed for La/chitosan catalyst in its FT-IR spectrum ( Fig. 1(b)), but with slight changes in the stretching and bending frequencies of OH and NH 2 groups (3432 and 1636 cm…”

Catalytic [2 + 2 + 2] cycloaddition with indium(iii)-activated formaldimines: a practical and selective access to hexahydropyrimidines and 1,3-diamines from alkenes

“… 8 However, this strategy has never been practically utilized because traditional syntheses of HHPs mainly rely on condensation reactions with presynthesized 1,3-diamines. 2 , 9 Development of the aforesaid [2 + 2 + 2] system would provide a direct synthesis of HHPs from alkenes, yet synthetically constitutes a two-step aminoalkyl amination approach for preparing 1,3-diamines from alkenes, a highly applicable but challenging new process that awaits extensive development ( Scheme 1 ). 8 …”

Synthesis of sulfanylidene-diazaspirocycloalkanones in a three-component Mannich-type reaction catalyzed with lactic acid

“…16 The advantages offered by lactic-acid catalysis prompted us to make some preliminary experiments of its use with compounds other than thioamides, and, thus, to find out if it has a more universal applicability to the Mannich-type MCRs. Cyclohexanone was selected as the model reagent since its reactions with aromatic amines and formaldehyde have been studied earlier by numerous authors [9][10][11][12]20 in investigations using both typical and unusual catalysts. The reactions with p-tolylamine, p-bromoaniline, and p-nitroaniline were carried out by us at room temperature in a DMSO solution and, in the case of p-tolylamine, also in ethanol.…”

“…10 Dandia and co-workers obtained several fluorine-containing spirohexahydropyrimidine derivatives using the magnetically separable and easy recyclable heterogeneous CuFe2O4 nanocatalyst, 11 while Zeba and co-workers used a chitosan supported Dy(III) catalyst for the fairly green and energy-sustainable synthesis of hexahydropyrimidine derivatives. 12 An extensive overview of the recent asymmetric domino reactions has been presented by Pellissier. 4 Spirocyclic compounds hold a peculiar and enduring fascination for organic chemists.…”