Cerium Supported Chitosan as an Efficient and Recyclable Heterogeneous Catalyst for Sustainable Synthesis of Spiropiperidine Derivatives

Abstract

A new Ce/chitosan catalyst has been prepared and used for the highly efficient synthesis of diverse range of spiropiperidine derivatives via multicomponent reaction of substituted anilines, formaldehyde and different cyclic active methylene compounds at room temperature in PEG-200. The catalyst could be reused for five consecutive cycles without appreciable loss in catalytic activity. The structure of the catalyst was determined by IR, XRD, EDX, TEM and ICP-AES techniques. The present green protocol has advantages such as novel products, energy sustainability, short reaction times, high yield of products, economic viability and recyclability of the catalyst.

Immobilization of cerium (IV) and erbium (III) in mesoporous MCM‐41: Two novel and highly active heterogeneous catalysts for the synthesis of 5‐substituted tetrazoles, and chemo‐ and homoselective oxidation of sulfides

“…The advent of bands between 3200 and 3400 cm −1 can be due to the stretching vibration of N‐H, indicating that serine was attached to the MCM‐41. After immobilization of cerium and erbium on the surface of MCM‐41@Serine, a decrease in the intensity of the ‐NH band at 1632 cm −1 can be seen, that may be due to the complexation of cerium and erbium with ‐NH 2 groups . The vibration bands at 950–970 cm −1 are attributed to metal being introduced into the channels of MCM‐41.…”

“…After immobilization of cerium and erbium on the surface of MCM-41@Serine, a decrease in the intensity of the -NH band at 1632 cm −1 can be seen, that may be due to the complexation of cerium and erbium with -NH 2 groups. [19] The vibration bands at 950-970 cm −1 are attributed to metal being introduced into the channels of MCM-41. This band corresponds to the vibrations of Si-OH, but the intensity of the band increases and shifts to a lower wavenumber when metals are introduced.…”

“…Among them, erbium has a number of benefits: low cost, low perniciousness of its salts and small radius that contributes to its Lewis acidity . Also, cerium has attracted significant research interest due to its low toxicity, accessibility at middle price and propriety for employment without purification . The most broadly used cerium (IV) reagent in organic chemistry is cerium (IV) ammonium nitrate (CAN).…”

“…[15][16][17] Also, cerium has attracted significant research interest due to its low toxicity, accessibility at middle price and propriety for employment without purification. [18][19][20] The most broadly used cerium (IV) reagent in organic chemistry is cerium (IV) ammonium nitrate (CAN). CAN is the most important one-electron oxidant and has been used broadly for a wide range of oxidative transformations in organic chemistry.…”

Chitosan‐Silica Sulfate Nano Hybrid as a Novel and Highly Proficient Heterogeneous Nano Catalyst for Regioselective Ring Opening of Epoxides via Carboxylic Acids

“…Thus, an increasing industrial and scientific interest has been focused on the application of chitosan in different fields such as pharmaceutical, drug delivery, cosmetics, food packaging, adhesives, waste water treatment, membranes, surface conditioners, hydrogels, and fuel cells . Aside from the extensive utilization of chitosan as a biopolymer support for the synthesis of heterogeneous catalysts, it can be efficiently used as the heterogeneous catalyst in its parental shape without any post‐modification …”