Recyclable Amberlyst-70 as a Catalyst for Biginelli Reaction: An Efficient One-Pot Green Protocol for the Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones

Abstract

An environmentally benign aqueous protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones using Amberlyst-70 as a recyclable catalyst has been developed. The use of resinous, nontoxic, thermally stable and inexpensive Amberlyst-70, as a recyclable heterogeneous catalyst, makes the process simple with negligible chemical waste. Thus renders this method an environmentally acceptable synthetic tool for Biginelli reaction.

An Efficient One-Pot Green Protocol for the Synthesis of 5-Unsubstituted 3,4-Dihydropyrimidin-2(1H)-Ones Using Recyclable Amberlyst 15 DRY as a Heterogeneous Catalyst via Three-Component Biginelli-Like Reaction

“…To evaluate the catalytic effect of various ion exchange resins we started with the model reaction of ethylacetoacetate (1.0 mmol) with benzaldehyde (1.0 mmol) and urea (1.2 mmol) in refluxing ethanol without and with use of Amberlyst-70 and Amberlyst 15 DRY as catalysts to afford dihydropyrimidine 1a and the results obtained were compared with those already reported using other catalysts [30, 31] (Table 1). It can be seen from Table 1 that Amberlyst 15 DRY is the most efficient among the five solid acidic ion exchange resins.…”

Greener and facile aqueous synthesis of pyrazoles using Amberlyst-70 as a recyclable catalyst

“…Moreover, the same group reported the use of nano-organocatalyst for the synthesis of pyrazoles (42). We have recently reported the utility of Amberlyst-70 for aqueous Biginelli reaction (43). In our quest for greener synthetic pathway, we herein report, the use of Amberlyst-70 as a recyclable catalyst for a simple, facile and environmentally benign aqueous synthesis of pyrazoles.…”

Design, ecofriendly synthesis, anticancer and antimicrobial screening of innovative Biginelli dihydropyrimidines using β-aroylpyruvates as synthons

“…Catalysts other than Bronsted acids have been discovered, making it possible to run the reaction under green conditions. Different green catalysts were used, including Nafion-H (21), Amberlyst-70 (22), NaCl (23), garlic (24), caffeine (25), ionic liquids (26), chromium (III) nitrate nonahydrate (27), polyphosphate ester (28), lithium perchlorate (29), perchloric acid doped silica (30) and Dowex (31).…”