Preparation of 5-(Acyloxymethyl)furfurals from Carbohydrates Using Zinc Chloride/Acetic Acid Catalyst System and Their Synthetic Value Addition

Abstract

5-(Acyloxymethyl)furfurals (AMFs) have received considerable attention as hydrophobic, stable, and halogen-free congeners of 5-(hydroxymethyl)furfural (HMF) for synthesizing biofuels and biochemicals. In this work, AMFs have been prepared directly from carbohydrates in satisfactory yields using the combination of ZnCl 2 as the Lewis acid catalyst and carboxylic acid as the Brønsted acid catalyst. The process was initially optimized for 5-(acetoxymethyl)furfural (AcMF) and then extended to producing other AMFs. The effects of reaction temperature, duration, loading of the substrate, and dosage of ZnCl 2 on AcMF yield were explored. Fructose and glucose provided AcMF in 80% and 60% isolated yield, respectively, under optimized parameters (5 wt % substrate, AcOH, 4 equiv ZnCl 2 , 100 °C, 6 h). Finally, AcMF was converted into high-value chemicals, such as 5-(hydroxymethyl)furfural, 2,5-bis(hydroxymethyl)furan, 2,5-diformylfuran, levulinic acid, and 2,5-furandicarboxylic acid in satisfactory yields to demonstrate the synthetic versatility of AMFs as carbohydrate-derived renewable chemical platforms.

Efficient Synthesis of Novel Biginelli and Hantzsch Products Sourced from Biorenewable Furfurals Using Gluconic Acid Aqueous Solution as the Green Organocatalyst

“…Ethanol (99.9%) was purchased from CSS China. 5-(Acetoxymethyl)­furfural (AcMF), 5-(hydroxymethyl)­furfural (HMF), 5-(chloromethyl)­furfural (CMF), and 5-(ethoxymethyl)­furfural (EMF) were synthesized and purified using the literature process. ,− …”

“…17 AcMF has recently received significant attention as a hydrophobic congener of HMF with several markets. 18 These five compounds (i.e., 1a− 1e) have been used as representative examples of biorenewable furaldehydes for developing a general synthetic protocol of the Biginelli and Hantzsch reactions. In this regard, 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) and 1,4-dihydropyridines (DHPs) are well-established classes of heterocyclic compounds with pronounced therapeutic properties.…”

“…EMF is a potential fuel oxygenate obtained by acid-catalyzed ethanolysis of sugars and polymeric carbohydrates . AcMF has recently received significant attention as a hydrophobic congener of HMF with several markets . These five compounds (i.e., 1a – 1e ) have been used as representative examples of biorenewable furaldehydes for developing a general synthetic protocol of the Biginelli and Hantzsch reactions.…”

Synthesis of novel Biginelli and Hantzsch products from biorenewable furfurals using 1,4‐diazabicyclo[2.2.2]octanium diacetate as a Brønsted acidic ionic liquid catalyst

“…All the chemicals were used as received without further purification. 5‐(Hydroxymethyl)furfural, 5‐(ethoxymethyl)furfural, and 5‐(acetoxymethyl)furfural were prepared as per the reported literature [40–43] …”

“…5-(Hydroxymethyl)furfural, 5-(ethoxymethyl)furfural, and 5-(acetoxymethyl)furfural were prepared as per the reported literature. [40][41][42][43]…”