Benzenoid Aromatics from Renewable Resources

In this Review, all known chemical methods for the conversion of renewable resources into benzenoid aromatics are summarized. The raw materials that were taken into consideration are CO2; lignocellulose and its constituents cellulose, hemicellulose, and lignin; carbohydrates, mostly glucose, fructose, and xylose; chitin; fats and oils; terpenes; and materials that are easily obtained via fermentation, such as biogas, bioethanol, acetone, and many more. There are roughly two directions. One much used method is catalytic fast pyrolysis carried out at high temperatures (between 300 and 700 °C depending on the raw material), which leads to the formation of biochar; gases, such as CO, CO2, H2, and CH4; and an oil which is a mixture of hydrocarbons, mostly aromatics. The carbon selectivities of this method can be reasonably high when defined small molecules such as methanol or hexane are used but are rather low when highly oxygenated compounds such as lignocellulose are used. The other direction is largely based on the multistep conversion of platform chemicals obtained from lignocellulose, cellulose, or sugars and a limited number of fats and terpenes. Much research has focused on furan compounds such as furfural, 5-hydroxymethylfurfural, and 5-chloromethylfurfural. The conversion of lignocellulose to xylene via 5-chloromethylfurfural and dimethylfuran has led to the construction of two large-scale plants, one of which has been operational since 2023.

Design, synthesis, and physicochemical study of a biomass-derived CO2 sorbent 2,5-furan-bis(iminoguanidine)

In this study, the concept of biomass-based direct air capture is proposed, and the aminoguanidine CO2 chemical sorbent 2,5-furan-bis(iminoguanidine) (FuBIG) was designed, synthesized, and elucidated for the physicochemical properties in the process of CO2 capture and release. Results showed that the aqueous solution of FuBIG could readily capture CO2 from ambient air and provided an insoluble tetrahydrated carbonate salt FuBIGH2(CO3) (H2O)4 with a second order kinetics. Hydrogen binding modes of iminoguanidine cations with carbonate ions and water were identified by single-crystal X-ray diffraction analysis. Equilibrium constant (K) and the enthalpies (ΔH) for CO2 absorption/release were obtained by thermodynamic and kinetic analysis (K7 = 5.97 × 104, ΔH7 = -116.1 kJ/mol, ΔH8 = 209.31 kJ/mol), and the CO2-release process was conformed to the geometrical phase-boundary model (1-(1-α)1/3 = kt). It was found that the FuBIGH2(CO3) (H2O)4 can release CO2 spontaneously in DMSO without heating. Zebrafish models revealed a favorable biocompatibility of FuBIG.

A decade review of triphosgene and its applications in organic reactions

This review article highlights selected advances in triphosgene-enabled organic synthetic reactions that were reported in the decade of 2010-2019. Triphosgene is a versatile reagent in organic synthesis. It serves as a convenient substitute for the toxic phosgene gas. Despite its first known preparation in the late 19th interestingly began only three decades ago. Despite the relatively short history, triphosgene has been proven to be very useful in facilitating the preparation of a vast scope of value-added compounds, such as organohalides, acid chlorides, isocyanates, carbonyl addition adducts, heterocycles, among others. Furthermore, applications of triphosgene in complex molecules synthesis, polymer synthesis, and other techniques, such as flow chemistry and solid phase synthesis, have also emerged in the literature.

Biomass-involved synthesis of N-substituted benzofuro[2,3-d]pyrimidine-4-amines and biological evaluation as novel EGFR tyrosine kinase inhibitors

Shikimic acid (1) is a renewable biomass which could be obtained sustainably through natural product isolation or metabolic engineering. Owing to its great potential in chemical conversion, the value-added utilization of this non-grain biomass has received much attention in recent years. Based on the established transformation route from shikimic acid (1) to methyl 3-dehydroshikimate (3-MDHS, 2) and to the multi-functionalized methyl 2-amino-3-cyanobenzofuran-5-carboxylate (3), we disclose a facile and transition metal-free method to access a series of N-substituted benzofuro[2,3-d]pyrimidine-4-amines in 63%-90% yields. The identification of these compounds as EGFR tyrosine kinase inhibitors has also been described. Among them, compound 5h exhibited the most potent inhibitory effect against EGFR tyrosine kinase with an IC₅₀ of 1.7 nM and excellent antiproliferative activity against A431 and A549 cell lines with a GI₅₀ of 5.1 and 12.3 μM, respectively.

Synthesis of Coumestrol and Aureol

A total synthesis of coumestrol (1) and aureol (2) is described. The Perkin condensation of 2-bromo-4-hydroxylphenylacetic acid (6) and o-hydroxybenzaldehydes (7) gave the corresponding 2'-bromo-3-arylcoumarins (9). A copper-catalyzed consecutive hydroxylation and aerobic oxidative coupling of 9 under microwave conditions facilitated the total synthesis of 1 and 2, respectively, with spectroscopic data highly similar to those of natural products.

A biomass-involved strategy for the synthesis of N-arylated dibenzo[b,e][1,4]oxazepin-11(5H)-ones, acridones, 7,12-dihydrodibenzo[b,e][1,4]oxazocin-6H-ones and dibenzo[b,f]azepin-10(11H)-ones

A chemo- and regio-selective method for the construction of benzo-fused six- to eight-membered N-heterocycles from renewable feedstock shikimic acid is described.

Highly selective synthesis of functionalized polyhydroisoquinoline derivatives via a three-component domino reaction

Two series of novel functionalized polyhydroisoquinoline derivatives have been synthesized via the three-component domino reaction under microwave irradiation conditions.

Selective synthesis of polyfunctionalized hydroisoquinoline derivatives via a three-component domino reaction

Two series of novel polyfunctionalized hydroisoquinoline derivatives have been synthesized via a three-component domino reaction under microwave irradiation conditions.