ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by poly(ferric 2-acrylamido-2-methylpropanesulfonate)

Zhihao Zhao, Hongguang Dai, and Lan Shi

College of Science, Inner Mongolia Agricultural University, Hohhot, People’s Republic of China

E-mail: imaudm@imau.edu.cn

Received: 28 May 2020  Accepted: 17 August 2020

Abstract:

Poly(ferric 2-acrylamido-2-methylpropanesulfonate) (PFAMPS) was prepared via the reaction of poly(2-acrylamido-2-methylpropanesulfonic acid) and Fe(OH)₃. PFAMPS was used as a heterogeneous catalyst for the Biginelli reaction of aldehyde, ethyl acetoacetate, and urea to synthesize 3,4-dihydropyrimidin-2(1H)-ones with yields of 70–87%. PFAMPS can be recycled six times without significant loss in catalytic activity. For comparison, ferric lignosulfonate (FLSA), ferric cellulose sulfonate (FCSA), ferric starch sulfonate (FSSA), and ferric 732 cation exchange resin (FACER) were used as catalysts of the Biginelli reaction. It was shown that the catalytic activities of recycled FLSA, FCSA, FSSA, and FACER significantly decreased after two reactions. Fe³⁺ in the polymer sulfonates acted as the catalyst for the Biginelli reaction. PFAMPS was the chelate, where the action between Fe³⁺ and the poly(2-acrylamido-2-methylpropanesulfonate) matrix was strong, and Fe³⁺ lost little from the PFAMPS. However, significant Fe³⁺ loss was observed in the FLSA, FCSA, FSSA and FACER polymer matrices after reuse.

Keywords: Biginelli reaction; Catalyst; Poly(ferric 2-acrylamido-2-methylpropanesulfonate); Synthesis

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01327-7

Chemical Papers 75 (2) 583–590 (2021)