Tetrahedron Green Chem最新文献

We report a method for the synthesis of symmetrical bibenzyls by the reductive dimerization of benzylic halides using sodium dispersion (SD). SD, a reagent consisting of sodium particles dispersed in mineral oil, has recently attracted attention as a safer but more reactive source of sodium than sodium lump. We have found that the reductive dimerization of benzylic halides proceeds within 1 h at room temperature in tetrahydrofuran (THF) solvent using SD as a reducing agent. This method is highly sustainable for the synthesis of symmetrical bibenzyls since it uses sodium, which is abundant on earth. As the SD-derived mineral oil in the crude product can be readily removed, three natural products were synthesized on a gram scale without the need for column chromatography. The utility of this reaction was also exemplified by a decagram-scale reaction using 2-methyltetrahydrofuran, known as a green alternative solvent to THF.

One of the principles of green and sustainable chemistry is to use green solvents and one-pot synthetic methods which can eliminate the need for drawn-out separation procedures, purification of intermediate compounds, and the production of waste by-products. Considering these concepts of green and sustainable chemistry, an efficient and novel chemoselective one-pot strategy has been developed for the novel synthesis of 2-Aryl-1,3-azoles via Suzuki and Heck cross-coupling reactions via C-2 arylation of azoles under the discriminate temperature using an ionic liquid as green solvent, promoter and ligand. The chemoselective one-pot synthesis, wide substrate scope, moderate to excellent isolated yield of pure products, mild reaction conditions and recycling/reuse of ionic liquid are highlights of this work.

An organobase assisted approach is adopted to synthesize pyranopyrazole derivatives in one pot. Three-component condensation reaction of 3-methylpyrazolin-5-ones, aromatic aldehydes and malononitrile were catalyzed by 5 mol% of 4-dimethylaminopyridine (DMAP) in ethanol at room temperature. Key aspects of this approach are simple filtration without the need of time-consuming column purification; good yields; cost-effectiveness and use of easily available solid organo-base as a catalyst. A broad substrate scope and variety of functional group tolerance permit diversity generation in a one pot operation. In silico, molecular-docking studies of the compounds were performed with anti-inflammatory active drugs i.e. indomethacin and celecoxib and the compounds were also studied for their pharmacokinetic properties absorption, distribution, metabolism, and excretion (ADME). The results obtained for most of the synthesized compounds are promising and all of them comply well satisfying the Lipinski rule of 5 (RO5) with 0 violation.

A metal-free, effective, and sustainable protocol has been developed to carry out C–N and C–C bond-forming reactions leading to the formation of 5-amino-pyrazole-4-carbonitriles and 1H-pyrazolo [1,2-b] phthalazine-5, 10-dione derivatives via a tandem multicomponent reaction using mesoporous MPC@TMG as a basic heterogeneous organocatalyst. The reactions were performed in aqueous medium at room temperature. The synthesized organocatalyst MPC@TMG was characterized by numerous spectroscopic techniques such as Fourier Transform Infrared (FTIR), Powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET), Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX), elemental mapping, and Thermal Gravimetric (TG) analyses. MPC@TMG displayed excellent catalytic potential, high thermochemical stability, and reusability for up to eight catalytic runs and offered the title compounds in excellent yields (>90 %) in a short reaction time (6–15 min). The synthesized compounds were characterized through FTIR, ¹H, and ¹³C Nuclear Magnetic Resonance (NMR) spectroscopy. The use of water as a green solvent, the generality of the method, easy catalyst recovery, a simple work-up procedure, and zero involvement of any metal are the key features of the present protocol making it green and sustainable for the synthesis of the desired heterocycles and is supported by the calculations for green metrics parameters.

Metal oxides are versatile catalysts in organic synthesis, exhibiting diverse properties such as acidity, basicity, redox behaviour, and stability. Among these, tin dioxide (SnO₂) stands out for its resilience and durability, making it a preferred catalyst. The reduced ionic character and high oxidation state (+4) of tin dioxide contribute to its heightened acidity. Tin dioxide based materials have gained significant attention as catalysts in heterocycle synthesis, cross-coupling, decarboxylation, ring-opening and ring-closing reactions, biodiesel synthesis, and glycerol transformations. Additionally, SnO₂-based materials are also employed as photocatalysts and photo-electrocatalysts.

Carbon number upgrading of bio-furans by coupling with other renewable feedstocks is an attractive approach for producing renewable fuel and polymer feedstocks. In this work, used Li-ion battery waste based low cost catalyst was shown as an alternative to expensive noble metal catalysts for coupling furfural with alcohols to give 2-alkyl-3-(2-furyl) acroleins. The catalyst was prepared by pyrolyzing the black electrode coating from 18650 Li-ion cells in a used laptop battery at 600 °C in air. Highest furfural conversions of 72.6, 83.6, 100.0 and 95.4 % were observed for 1-propanol, 1-butanol, 1-pentanol and 1-hexanol respectively, using 0.6 mmol LiOH/mmol of furfural and using 25 mg/mmol of furfural catalyst loading, 0.345 MPa O₂, 110 °C for 4.0 h. However, recycling of LiNi_aMn_bCo_cO_d/graphite catalyst showed significant loss in catalytic activity in four cycles of reuse. A reaction scheme involving oxidation of alcohols to aldehydes followed by base catalyzed aldol condensation was proposed to explain the coupling to give 2-alkyl-3-(2-furyl) acroleins.

The omnipresence of microplastic pollution in the environment has become a main challenge in recent years. One of the primary concerns is the ecotoxicological impact of microplastics on marine ecosystems, as well as the potential risk to humans related to the accumulation of microplastics in the body. Although it has not yet been scientifically proven, their presence in drinking water is a main concern. Studies have shown various strategies and new material development approaches for effectively removing microplastics. Recently, nanocellulose has emerged as a promising bionanomaterial for wastewater treatment. The purpose of this review is to introduce the potential of nanocellulose for microplastic removal. This study consists of three main points: the synthesis method of nanocellulose, the fundamentals of nanocellulose, and the use of these materials for capturing and removing microplastics. In addition, the potential of nanocellulose for antifouling has also been demonstrated. We also provide information regarding the source, fate, and transportation of microplastics in the environment and how to detect them to obtain a better understanding of how microplastics behave and ultimately end up in drinking water systems. Furthermore, we also discuss major challenges and future perspectives concerning the applications of nanocellulose-based materials in microplastic removal. Overall, nanocellulose is a versatile material and further research should be carried out to explore nanocellulose potential to meet the specific requirements for microplastic removal.

Α sustainable access to therapeutics is today imperative. More than ever, synthetic organic chemistry has to embrace all aspects of green chemistry. The utility of multicomponent reactions especially the Ugi reaction is an established approach in drug discovery. Their diversity, speed and effectiveness, combined with their compatibility with the green chemistry principles, render this type of chemistry very often an alternative to the multistep linear synthetic pathways to active pharmaceutical ingredients. This critical review compares green metrics, such as E-factor (environmental factor), AE (atom economy) and PMI (process mass intensity) factors, of the industrial and MCR syntheses of six well-known commercial drugs.

This study unveils a novel approach by efficiently loading earth-abundant cobalt onto a covalent organic framework (COF) for catalyzing the hydrogenation of nitroarenes to aryl amines. The synthesized Co@NC650 nanocomposites exhibit enhanced graphitization and catalytic performance, attributed to synergistic interactions between cobalt and the carbon matrix. The Co@NC650 The resulting material is thoroughly characterized using techniques such as PXRD, XPS, FE-SEM, TEM, and FT-IR. Utilizing this synthesized catalyst, a chemoselective reduction of nitroarenes to corresponding amines is demonstrated under relatively mild conditions, employing molecular hydrogen as sole reductant without any additives or bases. The methodology delivers high yields and exhibits tolerance towards wide range of functional groups. The chemoselective hydrogenation is achieved even in the presence of other potentially reducible functional groups such as ketones, carboxylic acids, amides, sulphonamides, and chalcones. Selected examples showcasing the synthesis of biologically important amines are presented. Furthermore, the proposed catalyst demonstrates reusability without any loss of activity.

An eco-friendly, mild and efficient acylation of various nucleophiles with alkenyl carboxylates via inorganic base catalysis is described. Among five inorganic base species examined, K₂CO₃ was proved to be the most efficient catalyst for the acylation. A broad variety of acylated products were achieved within 15 min at room temperature in high yields. In addition, we found that the 3-position of indoles should have a suitable substituent group under this procedure.