1. Sustainable one-pot chemo-enzymatic synthesis of chiral furan amino acid from biomass via magnetic solid acid and threonine aldolase
Lei Gong, Yuansong Xiu, Jinjun Dong, Ruizhi Han, Guochao Xu, Ye Ni Bioresour Technol. 2021 Oct;337:125344. doi: 10.1016/j.biortech.2021.125344. Epub 2021 May 29.
Sustainable synthesis of valuable noncanonical amino acids from renewable feedstocks is of great importance. Here, a feasible chemo-enzymatic procedure was developed for the synthesis of chiral β-(2-furyl)serine from biomass catalyzed by a solid acid catalyst and immobilized E. coli whole-cell harboring l-threonine aldolase. A novel magnetic solid acid catalyst Fe3O4@MCM-41/SO42- was successfully synthesized for conversion of corncob into furfural in an aqueous system. Under the optimum conditions, furfural yield of 63.6% was achieved in 40 min at 180 ℃ with 2.0% catalyst (w/w). Furthermore, biomass-derived furfural was converted into an aldol-addition product β-(2-furyl)serine with 73.6% yield, 99% ee and 20% de by immobilized cells in 6 h. The magnetic solid acid and biocatalyst can be readily recovered and efficiently reused for five consecutive cycles without significant loss on product yields. This chemo-enzymatic route can be attractive for producing noncanonical amino acids from biomass.
2. β-Aryl-α-nitro-α,β-enals as heterodienes and dienophiles
Hugo Lago-Santomé, Patricia Martínez-Bescos, Marta Fernández-González, Lidia Ozores-Viturro, Fernando Cagide-Fagín, Ricardo Alonso J Org Chem. 2014 Sep 19;79(18):8645-51. doi: 10.1021/jo501418u. Epub 2014 Sep 11.
As demonstrated with the β-(2-furyl)-substituted analogue 1b, β-aryl-α-nitro-α,β-enals (1) behave as heterodienes against enamines and enol ethers using their enal unit (e.g., 1b → 12). α-Nitro-α,β-enals can act as well as highly reactive dienophiles to render adducts endowed with nitrogenated quaternary centers (e.g., 1b → 15a). A hetero-Diels-Alder (HDA)/Diels-Alder (DA) sequence from 1b also proved feasible on serial treatment with ethyl vinyl ether and Danishefsky's diene (1b → 14).
3. Antifungal activity of resveratrol against Botrytis cinerea is improved using 2-furyl derivatives
Francesco Caruso, et al. PLoS One. 2011;6(10):e25421. doi: 10.1371/journal.pone.0025421. Epub 2011 Oct 11.
The antifungal effect of three furyl compounds closely related to resveratrol, (E)-3,4,5-trimethoxy-β-(2-furyl)-styrene (1), (E)-4-methoxy-β-(2-furyl)-styrene (2) and (E)-3,5-dimethoxy-β-(2-furyl)-styrene (3) against Botrytis cinerea was analyzed. The inhibitory effect, at 100 µg ml(-1) of compounds 1, 2, 3 and resveratrol on conidia germination, was determined to be about 70%, while at the same concentration pterostilbene (a dimethoxyl derivative of resveratrol) produced complete inhibition. The title compounds were more fungitoxic towards in vitro mycelial growth than resveratrol and pterostilbene. Compound 3 was the most active and a potential explanation of this feature is given using density functional theory (DFT) calculations on the demethoxylation/demethylation process. Compound 3 was further evaluated for its effects on laccase production, oxygen consumption and membrane integrity of B. cinerea. An increase of the laccase activity was observed in the presence of compound 3 and, using Sytox Green nucleic acid stain, it was demonstrated that this compound altered B. cinerea membrane. Finally, compound 3 partially affected conidia respiration.
