Biorenewable Deep Eutectic Solvent for Selective and Scalable Conversion of Furfural into Cyclopentenone Derivatives

Abstract

The development of novel synthetic routes to produce bioactive compounds starting from renewable sources has become an important research area in organic and medicinal chemistry. Here, we present a low-cost procedure for the tunable and selective conversion of biomass-produced furfural to cyclopentenone derivatives using a mixture of choline chloride and urea as a biorenewable deep eutectic solvent (DES). The proposed medium is a nontoxic, biodegradable, and could be reused up to four times without any unfavorable effect on the reaction yield. The process is tunable, clean, cheap, simple and scalable and meets most of the criteria; therefore, it can be considered as an environmental sustainable process in a natural reaction medium.

Montmorillonite K10-Catalyzed Solvent-Free Conversion of Furfural into Cyclopentenones

“…After completion, ethyl acetate was added (3 mL), the catalyst was filtered, and the product was isolated after evaporation of the solvent to afford 2,4-dimorpholinecyclopent-2-enone at 99% yields. Spectral data were in agreement with the literature [61].…”

“…At this point, the experimental procedure was applied to different amines to obtain the desired 4,5-diaminocyclopenten-2-enones, and quantitative yields superior to 90% were obtained in all cases ( Table 2). The reaction gave excellent results after the above reported simple workup with the alicyclic ( Table 2, Entries 2-4), aliphatic ( Table 2, Entries 5-7), and with the aromatic secondary amines ( Table 2, entries 8-9); this reaction takes place especially with secondary amines, by the formation of an enamine intermediate as proposed by a previously reported mechanism of reaction [60,61]. In the case of primary aliphatic amines, the corresponding imine was observed as the only product (Scheme 1).…”

“…The products were isolated after evaporation of the solvent to yield compounds at an efficiency of 90-99%. Spectral data were in accordance with the literature [61].…”

“…Particularly, the chiral 2,4-disubstituted cyclopentenones as prostaglandins have anti-inflammatory [50], anticancer [51], and antiviral activities [52,53], and the presence of an α,β-unsaturated carbonyl group is important for the biological activity of these compounds. The cyclization rearrangement can be realized by different Lewis acids as metallic compounds [54], triflate [55][56][57], and metal chloride [58] in ionic liquids [59], or by using green media as water [60] or deep eutectic solvents [61].…”

Montmorillonite K10-Catalyzed Solvent-Free Conversion of Furfural into Cyclopentenones

“…In this context, furfural is important biomass compound derived and used to synthesize different bio-products [50]. The cyclization rearrangement can be realized by different Lewis acids as metallic compounds [51], triflate [52][53][54], metal chloride [55] in ionic liquids [56] or using green media as water [57] or deep eutectic solvents [58].…”