Highly Chemo‐ and Regioselective Reduction of Aromatic Nitro Compounds Catalyzed by Recyclable Copper(II) as well as Cobalt(II) Phthalocyanines

Abstract

Copper/cobalt phthalocyanines were established for the first time as catalysts for the very efficient chemo-and regioselective reduction of aromatic nitro compounds to generate the corresponding amines. The selective reduction of nitro compounds was observed in the presence of a large range of functional groups such as aldehyde, keto, acid, amide, ester, halogen, lactone, nitrile and heterocyclic functional groups. Furthermore, the present method was found to be highly regioselective towards the reduction of aromatic dinitro compounds in a short time with high yields. In most of the cases the conversion and selectivity were > 99% as monitored by GC-MS. The reduction mechanism was elucidated by UV-vis and electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

Reduction of Sulfoxides to Sulfides in the Presence of Copper Catalysts

“…Besides molybdenum-, iron-, and zinc-based systems the application of copper can be beneficial. Indeed, the potential of copper catalyst in reduction techniques has been explored in the reduction of various functionalities [46][47][48][49][50][51][52][53][54][55][56][57][58]. However, the catalytic reduction of sulfoxides in the presence of copper has been so far unreported, while the converse process has been studied [59].…”

Chemoselective Transfer Hydrogenation to Nitroarenes Mediated by Cubane‐Type Mo3S4 Cluster Catalysts

“…[4] A crucial issue for the general application of catalysts for nitro reduction is selectivity. [7,8] Hence, a wide variety of organometallic catalysts based on Pd, [7] Ru, [7][8][9] Rh, [7] Co, [10] Cu, [10] and even Fe [11] have been described. Recently, Corma and co-workers demonstrated that Au-based catalysts show high selectivity for the reduction of the nitro arenes.…”

Highly efficient water-mediated approach to access benzazoles: metal catalyst and base-free synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles

“…In continuation of our work on the development of synthetic methodologies for various important organic transformations [9,[55][56][57][58][59][60], herein we report an effective watercatalyzed method for the synthesis of 2-substituted benzazoles including benzimidazoles, benzoxazoles, and benzothiazoles in water as reaction medium.…”