A catalyst and solvent-free room temperature synthesis of pyrroles is described.

Synthetic organic transformations, which utilize large amount of hazardous raw materials, solvents, catalysts and energy as well as producing large amount of chemical waste, are vital for the production of...

We report herein a facile in situ synthesis of Pd nanoparticles (NPs) supported on mesoporous graphitic carbon nitride (mpg-C 3 N 4 /Pd) during the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of nitroarenes at room temperature. In the presented protocol, a three-component cascade reaction is realized in a pressure tube at room temperature, encompassing (i) in situ generation of Pd NPs supported on mpg-C 3 N 4 via reduction of mpg-C 3 N 4 /Pd(II) nanocomposites by AB, (ii) the mpg-C 3 N 4 /Pd catalyzed dehydrogenation of AB and (iii) the transfer hydrogenation of nitro groups through the mpg-C 3 N 4 /Pd catalyst. The scope of the mpg-C 3 N 4 /Pd catalyzed tandem dehydrogenation of AB and hydrogenation reactions were studied over a wide range of nitroarenes (10 examples), which are all selectively converted to the corresponding anilines within only 1-2 min with the yields up to 99 % under ambient conditions. It was also shown that the mpg-C 3 N 4 /Pd catalysts could be scaled up to large scale production of anilines and reused up to ten times without any significant loss in the yields. Additionally, the mpg-C 3 N 4 /Pd catalysts were isolated after the hydrogenation reactions and tested as catalysts in the hydrolysis of AB by studying the detailed reaction kinetics. The isolated mpg-C 3 N 4 /Pd nanocatalysts showed a very high performance in hydrogen generation from the hydrolysis of AB by providing an initial turnover frequency (TOF) of 66.3 min À1 .[a] Assist.

Addressed herein is a facile one-pot synthesis of graphene hydrogel (GHJ) supported Pd nanoparticles (NPs), namely Pd-GHJ nanocomposites, via a novel method that comprises the combination of hydrothermal treatment and polyol reduction protocols in water. The structure Pd-GHJ nanocomposites were characterized by TEM, HR-TEM, XRD, XPS, Raman spectroscopy and BET surface area analysis. Then, Pd-GHJ nanocomposites were used as a heterogeneous catalysts in the tandem dehydrogenation of ammonia borane and hydrogenation of nitroarenes (Ar–NO2) to anilines (Ar–NH2) in the water/methanol mixture at room temperature. A variety of Ar–NO2 derivatives (total 9 examples) were successfully converted to the corresponding Ar–NH2 by the help of Pd-GHJ nanocomposites catalyzed tandem reactions with the conversion yields reaching up to 99% in only 20 min reaction time. Moreover, Pd-GHJ nanocomposites were demonstrated to be the reusable catalysts in the tandem reactions by preserving their initial catalytic performance after five consecutive catalytic cycles. It is believed that the presented synthesis protocol for the Pd-GHJ nanocomposites and the catalytic tandem hydrogenation reactions will make a significant contribution to the catalysis and synthetic organic chemistry fields.