o-Feng Xia

Metal-Free Three-Component Oxyazidation of Alkenes with Trimethylsilyl Azide and N-Hydroxyphthalimide

A novel and facile oxyazidation of alkenes under metal-free and mild conditions has been reported. A remarkable feature of the developed procedure is consecutive construction of C-O and C-N bonds in one step. The process allows quick and selective assembly of alkyl azide from readily available starting materials, where N-hydroxyphthalimide was used as an oxygen-radical precursor and TMSN3 as the N3 source. A range of aromatic alkenes bearing synthetically useful functional groups was tolerated.

Copper-catalyzed C–H alkylation of 8-aminoquinolines via 8-amide chelation assistance

A copper-catalyzed 8-amide chelation-assisted C–H alkylation of 8-aminoquinolines is described. The secondary and tertiary alkyl carboxylic acids can be used as alkylating agents. This reaction allows for the highly regioselective preparation of C2-adamantyl 8-aminoquinoline scaffolds by the decarboxylative alkylation catalytic system.

Synthesis of Mo-doped TiO2 nanowires/reduced graphene oxide composites with enhanced photodegradation performance under visible light irradiation

In this research, anatase type Mo-doped TiO2 nanowires/reduced graphene oxide (Mo-TiO2NWs/RGO) composites were successfully synthesized using a one-step alkali hydrothermal method followed by a calcination treatment at 500 °C, in which commercial TiO2 nanoparticles (Degussa P25) and graphene oxide (GO) were used as the precursors. GO was reduced to RGO during the alkali hydrothermal progress, and Mo was incorporated into the lattice of TiO2 nanowires (TiO2NWs) simultaneously. The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-visible diffuse reflectance spectroscopy (DRS). The photocatalytic properties of the prepared catalysts were evaluated for the photodegradation of methylene blue (MB) under visible light irradiation. The results showed that Mo-TiO2NWs/RGO composites exhibited much higher photocatalytic activity in comparison to the mono-modified or non-modified TiO2NWs, the photodegradation efficiency of Mo-TiO2NWs/RGO composites could reach up to 94.1% in 120 min, and no obvious deactivation was observed in the durability experiments. The mechanism of the enhanced photocatalytic activity, which arose from the synergistic effect of the morphology modification, Mo doping and graphene incorporation, was put forward.

Conversion of glucose into 5-hydroxymethylfurfural catalyzed by chromium(III) Schiff base complexes and acidic ionic liquids immobilized on mesoporous silica

A series of novel catalysts were prepared by immobilizing chromium(III) Schiff base complexes and acidic ionic liquids onto the surface of MCM-41, and characterized by FT-IR, TG, XRD, SEM, TEM, NH3-TPD, ICP-OES and N2 sorption studies. The catalytic activity of the prepared solid catalysts was investigated for the conversion of biomass (mainly including glucose, fructose and inulin) in the presence of DMSO. The dependencies of catalytic activity on reaction parameters such as temperature, reaction time and solvent were investigated and the reaction conditions were optimized. A HMF yield of 43.5% was achieved from glucose using Cr(salen)-IM-HSO4-MCM-41 as the catalyst in DMSO at 140 °C for 4 h. Furthermore, the catalyst also demonstrated good activity, and as high as 83.5% HMF was directly obtained from fructose, and the HMF yield reached 80.2% when inulin was selected as the substrate. The immobilized catalysts developed in this study present improved performance over other solid catalysts, and they have been efficiently and easily recycled at least five times without significant loss of activity in glucose conversion and HMF yield.

Catalytic dehydration of fructose to 5-hydroxymethylfurfural over a mesoscopically assembled sulfated zirconia nanoparticle catalyst in organic solvent

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in DMSO was performed over a sequence of mesoscopically assembled sulfated zirconium nanostructures (MASZN) derived from zirconyl chloride with a template as a fastening agent. The materials were characterized by X-ray diffraction, FTIR spectroscopy, NH3 temperature-programmed desorption, pyridine FTIR spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and N2 sorption. The heterogeneous catalyst MASZN with Lewis–Bronsted acid sites had a superior performance in the dehydration of fructose to HMF. With MASZN-3 as catalyst, a HMF yield of 91.9% with a 98.5% fructose conversion was obtained at 110 °C for 120 min in DMSO. Finally, the catalyst MASZN-3 was recycled in four consecutive cycles with scarcely any loss of activity. The excellent catalytic properties together with its easy synthesis, low cost, and nontoxic nature make this MASZN a promising catalyst for the development of new and efficient processes for biomass-based chemicals.

Metal-free oxidative functionalization of C(sp3)–H of ketones and alcohols for the synthesis of isoquinolinonediones

A metal-free alkyl radical induced addition/cyclization reaction of acrylamide has been developed. The process involved C(sp3)–H bond cleavage, alkylation of the double bond, and intramolecular cyclization, which provides a new method for the synthesis of 4-substituted isoquinoline-1,3(2H,4H)-dione derivatives. In addition, the product can be easily transformed into tetrahydrofuro[2,3-c]isoquinolin-5(2H)-one derivatives in moderate yield.

Entangled Cu Complex Over Fe3O4@SiO2 as Supported Catalyst for Synthesis of Alkenyl Nitriles with Aromatic Aldehydes and Acetonitrile

An efficient, green and practical approach to synthesize alkenyl nitriles using new supported Cu(II) catalyst via aromatic aldehydes and acetonitrile was developed. The novel catalyst was characterized by FT-IR, XRD, SEM/EDX, TEM, TGA and VSM. Interestingly, the catalyst was found to be active for synthesis of alkenyl nitriles, which were readily obtained in good yields under mild conditions. But most importantly, the original catalyst could be conveniently recovered and recycled from the reaction system by applying an external magnet and reused in four cycles without significant loss in catalytic activity.Graphical Abstract