Project description:BackgroundA new, green and environmentally friendly protocol has been developed for the synthesis of tetrahydrodipyrazolopyridine derivatives. The structures of these products were determined in terms of melting point, FTIR, NMR and Mass spectroscopy.ResultsThe tetrahydrodipyrazolopyridine derivatives were synthesized in water through a catalyst-free pseudo-six-component reaction of hydrazine hydrate, ethyl acetoacetate, ammonium acetate and aldehyde at room temperature.ConclusionsThis novel procedure has some advantages such as aqueous media, high yield and simple work-up.
Project description:In this study, we detail the development of a concise and efficient three-component protocol for the regioselective synthesis of highly functionalized bis-indoles through a one-pot, two-step sequential process starting from enaminones 1, indoles 2, and acenaphthylene-1,2-dione 3 that is catalyzed by piperidine and p-methyl benzenesulfonic acid. This protocol has several advantages including simplicity of experimental operation, high efficiency of bond formation, ready availability and low cost of starting materials, environmentally benign conditions, and target molecular diversity.
Project description:The pyrazole scaffold is one of the most prevalent and important tool in medicinal chemistry. Here, we report a method for preparing 3,5-diarylpyrazoles in good to excellent yield by reacting hydrazones of aryl aldehydes with substituted acetophenones in ethanol in the presence of dimethyl sulfoxide/cat. I2/cat. HCl. The reverse process, reacting hydrazones of substituted acetophenones with aryl aldehydes under the same conditions, also provides 3,5-diarylpyrazoles in good to excellent yields. Reaction of hydrazones of aldehydes with 2'-aryloxy ketones in the presence of cat. HCl in ethanol and the catalyst-free reaction of phenacyl bromides with hydrazones of aldehydes in ethanol also gave good to excellent yields of 3,5-diarylpyrazoles.
Project description:It is a long-standing challenge to combine mixed monomers into multiblock copolymer (MBC) in a one-pot/one-step polymerization manner. We report the first example of MBC with biodegradable polycarbonate and polyester blocks that were synthesized from highly efficient one-pot/one-step polymerization of cyclohexene oxide (CHO), CO2 and ε-caprolactone (ε-CL) in the presence of zinc-cobalt double metal cyanide complex and stannous octoate. In this protocol, two cross-chain exchange reactions (CCER) occurred at dual catalysts respectively and connected two independent chain propagation procedures (i.e., polycarbonate formation and polyester formation) simultaneously in a block-by-block manner, affording MBC without tapering structure. The multiblock structure of MBC was determined by the rate ratio of CCER to the two chain propagations and could be simply tuned by various kinetic factors. This protocol is also of significance due to partial utilization of renewable CO2 and improved mechanical properties of the resultant MBC.
Project description:A simple and convenient protocol has been developed for the synthesis of N-amino-3-cyano-2-pyridone derivatives by a one-pot reaction of cyanoacetohydrazide, activated nitrile substrates (malononitrile, ethyl cyanoacetate, cyanoacetamide) and aromatic aldehydes in the presence of piperidine in water or a mixture of water and ethanol. The sequence of cascade reactions includes Knoevenagel condensation, Michael addition, intramolecular cyclization, imine-enamine tautomerization and oxidative aromatization. The main advantages of this procedure are availability of starting compounds, simple procedure, mild conditions, easy purification of products and the use of water or water/ethanol as green solvents.
Project description:In this study, magnetic polyborate nanoparticles (MPBNPs) were prepared via a simple procedure from boric acid by using ball-milling and then characterized by various spectroscopic, microscopic and analytical methods including FT-IR, EDX, XRD, FESEM, VSM and TGA analysis. The obtained MPBNPs were further explored, as a green and highly efficient catalyst, in the multi-component synthesis of a wide range of tetra-substituted imidazoles from cascade cyclocondensation as well as in situ air oxidation of benzil or benzoin, aromatic aldehydes, primary amine and ammonium acetate in EtOH, as a green solvent, under reflux conditions. Additionally, environmentally friendly conditions for the preparation of the catalyst by the use of non-toxic reactants, facile procedure and high to excellent yields of the desired products as well as the use of a green solvent are some advantages of this new protocol.
Project description:A simple, efficient and highly diastereoselective one-pot three-component synthesis of functionalized 2,6-disubstituted-4-tosyloxytetrahydropyrans was performed. The synthesis features an optimized Prins cyclization in which an aromatic homoallylic alcohol, an aromatic/aliphatic aldehyde, and p-toluenesulfonic acid (catalyst and reagent) are reacted in the presence of molecular sieves (MS) 4 Å at reflux in dichloromethane to afford excellent yields (72-96%) within short reaction times (20-90 min). The MS 4 Å-promoted synthesis proved to be versatile enough to provide an array of symmetrical and unsymmetrical tetrahydropyran derivatives in economical manner. Furthermore, cleavage of the 4-tosyl group under mild conditions afforded 4-hydroxytetrahydropyran in excellent yields (95-96%).
Project description:Based upon a consecutive one-pot Sonogashira-Glaser coupling-cyclization sequence a variety of 2,5-di(hetero)arylthiophenes were synthesized in moderate to good yields. A single Pd/Cu-catalyst system, without further catalyst addition, and easily available, stable starting materials were used, resulting in a concise and highly efficient route for the synthesis of the title compounds. This novel pseudo five-component synthesis starting from iodo(hetero)arenes is particularly suitable as a direct access to well-defined thiophene oligomers, which are of peculiar interest in materials science.
Project description:A one-pot three-component protocol for the preparation of arylsulfonyl alkynes through the reaction of ethynyl-benziodoxolone (EBX) reagents, DABSO (DABCO·SO2), and either organomagnesium reagents or aryl iodides with a palladium catalyst is reported. A broad range of aryl and heteroarylalkynyl sulfones were obtained in 46-85% overall yield.
Project description:An efficient one-pot synthesis of pyrazolo[3,4-d]pyrimidine derivatives by the four-component condensation of hydrazines, methylenemalononitriles, aldehydes and alcohols has been developed via two different reaction pathways. The structures of target products were characterized by IR spectroscopy, NMR ((1)H and (13)C) spectroscopy and HRMS (ESI) spectrometry. The crystal structure of 4-ethoxy-6-(2-nitrophenyl)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine was determined by single crystal X-ray diffraction.