Biomass and waste exhibit great potential for replacing fossil resources in the production of chemicals. The search for alternative reaction media to replace petroleum-based solvents commonly used in ...chemical processes is an important objective of significant environmental consequence. Recently, bio-based derivatives have been either used entirely as green solvents or utilized as pivotal ingredients for the production of innovative solvents potentially less toxic and more bio-compatible. This review presents the background and classification of these new media and highlights recent advances in their use in various areas including organic synthesis, catalysis, biotransformation and separation. The greenness, advantages and limitations of these solvents are also discussed.
Herein, furfural was synthesized via dehydration of xylose with γ-valerolactone (GVL) in the presence of sulfonated carbon catalysts prepared from eucalyptus activated carbon (EAC) and sulfonating ...agents (H2SO4 and TsOH). Influences of pure and mixed sulfonating agents on physicochemical attributes of the obtained sulfonated carbon catalysts were explored using different characterization techniques (BET, FTIR, NH3-TPD, CHNS, XRD, TGA, SEM and total acid density). The process input variables (temperature, solvent/substrate ratio, time and catalyst loading) influencing the dehydration process were optimized using Taguchi design approach. The best H2SO4 (H)/TsOH (T) molar ratio for the mixed acid sulfonated EAC (EAC-H-T) material to catalyze xylose conversion to furfural was 3:2. The total acid density (0.79 ± 0.08 mmol/g), specific surface area (711.9 m2/g) and sulfur concentration (9.77%) of the EAC-3H-2T catalyst were higher compared to other sulfonated EAC materials. Taguchi optimization approach revealed that highest furfural yield (74.61 ± 0.05 %) was achieved at the optimum conditions of 180 °C dehydration temperature, 1.5 wt% catalyst loading, 3.0 h dehydration time and 3 mL/g GVL/xylose ratio. 1H- and 13C NMR analyses conducted on isolated product obtained under optimum conditions confirmed the formation of furfural. In addition, the EAC-3H-2T catalyst exhibited sustained activity after it was reused for six times.
2,3-Disubstituted benzofurans were synthesized from acrolein dimer and 1,3-dicarbonyl compounds by using N-bromosuccinimide as an oxidizing agent. The method was used to synthesize two commercial ...drug molecules, benzbromarone and amiodarone. The proposed mechanism of the reaction involves a N-bromosuccinimide (NBS)-assisted autotandem catalysis with Lewis acid catalyst. To proof the proposed mechanism, an intermediate was isolated successfully, which can be converted to 4,5,6,7-tetrahydrobenzofurans.
Lignosulfonate (LS) is an organic waste generated as a byproduct of the cooking process in sulfite pulping in the manufacture of paper. In this paper, LS was used as an anionic supporting material ...for immobilizing cationic species, which can then be used as heterogeneous catalysts in some organic transformations. With this strategy, three lignin‐supported catalysts were prepared including 1) lignin‐SO3Sc(OTf)2, 2) lignin‐SO3Cu(OTf), and 3) lignin‐IL@NH2 (IL=ionic liquid). These solid materials were then examined in many organic transformations. It was finally found that, compared with its homogeneous counterpart as well as some other solid catalysts that are prepared by using different supports with the same metal or catalytically active species, the lignin‐supported catalysts showed better performance in these reactions not only in terms of activity but also with regard to recyclability.
Trash, but not as we know it! Lignosulfonate (LS) is a waste biomass generated as a byproduct of a cooking process in sulfite pulping in the manufacture of paper. LS was used as an anionic supporting material for immobilizing cationic species, which can then be used as a heterogeneous catalyst in some organic transformations (see scheme).
Abstract The strategy of designing heterogeneous porous catalysts by a post-modification method is a smart strategy to increase the catalytic power of desired catalysts. Accordingly, in this report, ...metal-organic frameworks based on titanium with acetic acid pending were designed and synthesized via post-modification method. The structure of the target catalyst has been investigated using different techniques such as FT-IR, XRD, SEM, EDX, Mapping, and N 2 adsorption/desorption (BET/the BJH) the correctness of its formation has been proven. The catalytic application of Ti-based MOFs functionalized with acetic acid was evaluated in the preparation of new spiropyrans, and the obtained results show that the catalytic performance is improved by this modification. The strategy of designing heterogeneous porous catalysts through post-modification methods presents a sophisticated approach to enhancing the catalytic efficacy of desired catalysts. In this context, our study focuses on the synthesis and characterization of metal-organic frameworks (MOFs) based on titanium, functionalized with acetic acid pendants, using a post-modification method. Various characterization techniques, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), mapping, and N 2 adsorption/desorption (BET/BJH), were employed to investigate the structure and composition of the synthesized catalyst. These techniques collectively confirmed the successful formation and structural integrity of the target catalyst. The structure of the synthesized products was confirmed by melting point, 1 H-NMR and 13 C-NMR and FT-IR techniques. Examining the general process of catalyst synthesis and its catalytic application shows that the mentioned modification is very useful for catalytic purposes. The presented catalyst was used in synthesis of a wide range of biologically active spiropyrans with good yields. The simultaneous presence of several biologically active cores in the synthesized products will highlight the biological properties of these compounds. The present study offers a promising insight into the rational design, synthesis, and application of task-specific porous catalysts, particularly in the context of synthesizing biologically active candidate molecules.
Whereas the beneficial effect of water on reaction rate is decreased with an increase of the reactant′s hydrophobicity, we report here that the use of glycerol as solvent was able to considerably ...accelerate the reaction rate of an organic reaction even starting from more hydrophobic substrates than those usually used on water. Moreover, the possibility of directly using crude glycerol generated by the biodiesel industry economically and environmentally improves the interest of using glycerol as solvent.
Oxovanadium(V)-5,10,15,20-tetrakis(pyridinium)-porphyrinato-tetra(tricyanomethanide) (VO)TPP(TCM)
was designed, synthesized and characterized by various techniques such as FT-IR, EDX, SEM equipped ...with EDX mappings, CHN elemental analysis, ICP-OES, XRD, SEM, TEM, TGA, DTA, DRS, Kubelka-Munk function (Tauc's plot), and UV-Vis analyses. Then, (VO)TPP(TCM)
was used as a benign and expedient catalyst for the synthesis of numerous heterocyclic compounds such as 5-amino-7-(aryl)-4,7-dihydro-1,2,4triazolo1,5-apyrimidine-6-carbonitriles, 5-amino-7-(aryl)-1,2,4triazolo1,5-apyrimidine-6-carbonitriles, 7-(aryl)-7,12-dihydro-5H-isochromeno4,3-d1,2,4triazolo1,5-apyrimidin-5-ones, and 4-(aryl)-2-(1H-indol-3-yl)-5,6,7,8-tetrahydroquinoline-3-carbonitriles under solvent-free conditions at 100 °C via a cooperative geminal-vinylogous anomeric based oxidation.
A series of N-(4-chlorophenyl) substituted pyrano2,3-cpyrazoles was synthesised and screened for their potential to inhibit kinases and exhibit anticancer activity against primary patient-derived ...glioblastoma 2D cells and 3D neurospheres. A collection of 10 compounds was evaluated against glioma cell lines, with compound 4j exhibiting promising glioma growth inhibitory properties. Compound 4j was screened against 139 purified kinases and exhibited low micromolar activity against kinase AKT2/PKBβ. AKT signalling is one of the main oncogenic pathways in glioma and is often targeted for novel therapeutics. Indeed, AKT2 levels correlated with glioma malignancy and poorer patient survival. Compound 4j inhibited the 3D neurosphere formation in primary patient-derived glioma stem cells and exhibited potent EC
50
against glioblastoma cell lines. Although exhibiting potency against glioma cells, 4j exhibited significantly less cytotoxicity against non-cancerous cells even at fourfold-fivefold the concentration. Herein we establish a novel biochemical kinase inhibitory function for N-(4-chlorophenyl) substituted pyrano2,3-cpyrazoles and further report their anti-glioma activity in vitro for the first time.
KEY MESSAGE
Anti-glioma pyrano2,3-cpyrazole 4j inhibited the 3D neurosphere formation in primary patient-derived glioma stem cells. 4j also displayed PKBβ/AKT2 inhibitory activity. 4j is nontoxic towards non-cancerous cells.
An efficient and simple multicomponent method for the synthesis of new indolyl-pyridines bearing sulfonamide moiety, as multi-functional heterocycles, through a condensation reaction of 3-cyanoacetyl ...indole,
N
-(4-acetylphenyl)-4-methylbenzenesulfonamide, aryl aldehyde, and ammonium acetate in the presence of Fe
3
O
4
@SiO
2
@(CH
2
)
3
-urea-quinolinium trifluoroacetate as a novel and recyclable nanomagnetic catalyst, under solvent-free conditions is developed. The novel catalyst was characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy equipped by energy dispersive spectroscopy, X-ray diffraction, elemental mapping analysis, transmission electron microscopy, thermo gravimetric analysis/derivative thermo gravimetric and vibrating sample magnetometer. We suggested a cooperative vinylogous anomeric-based oxidation as a mechanistic route for the last step of the described synthesis. A simple procedure, high proficiency, and recyclability of the catalyst are the most attractive features of this protocol.
Graphical abstract
Indolyl-pyridines bearing sulfonamide moiety, as a new series of multi-functional heterocycles, were synthesized via a simple and efficient multi-component method.
A straightforward access to tricyclic indoles bearing 3,4-fused seven-membered rings has been established by using 4-aminoindoles as 1,4-bisnucleophiles in three-component reactions. ...1H-Azepino4,3,2-cdindoles, 4,6-dihydro-1H-azepino4,3,2-cdindoles and 1,3,4,6-tetrahydro-5H-azepino4,3,2-cdindol-5-ones could thus be synthesized in one pot in moderate to good yields. Beyond opening access to 3,4-fused tricyclic indoles, the use of easily accessible 4-aminoindoles as C,N-1,4-bisnucleophiles also provides a new platform to be used in a diversity-oriented synthesis strategy, fully displaying its benefits of maximizing molecular complexity and reaction diversity.
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