Reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles over AlN supported redox cobalt catalysts

Metal-Organic Skeleton-Derived W-Doped Ga2O3-NC Catalysts for Aerobic Oxidative Dehydrogenation of N-Heterocycles

N-heterocycles with quinoline structures hold significant importance within the chemical and pharmaceutical industries. However, achieving their efficient transformations remains a vital yet challenging endeavor. Herein, a series of W-doped Ga2O3-NC catalysts were synthesized using a Ga-MOF-derived strategy through a simple solvothermal method, with a remarkably high activity and selectivity towards the oxidative dehydrogenation of N-heterocycles. Furthermore, the MOF-derived W-doped Ga2O3-NC catalysts exhibit remarkable substrate tolerance and recyclability. The outstanding catalytic activity was attributed to the robust synergistic interaction between the W species and the Ga2O3-NC carrier, which facilitates the activation of hydrogen atoms in the C-H and C=N bonds on both the oxygen molecule and the substrate to produce H2O2. Additionally, the solvent effect of methanol can significantly enhance dehydrogenation due to its strong ability to donate and accept protons of hydrogen bonding. The present work provides a new approach to MOF-derived non-precious metal catalysts for achieving the efficient oxidation dehydrogenation of N-heterocycles.

Recent advances in the synthesis of N-heteroarenes via catalytic dehydrogenation of N-heterocycles

Bio-active molecules having N-heteroarene core are widely used for numerous medicinal applications and as lifesaving drugs. In this direction, dehydrogenation of partially saturated aromatic N-heterocycles shows utmost importance for the synthesis of heterocycles. This feature article highlights the recent advances, from 2009 to April 2021, on the dehydrogenation of N-heteroaromatics. Notable features considering the development of newer catalysis for dehydrogenations are: (i) approaches based on precious metal catalysis, (ii) newer strategies and catalyst development technology using non-precious metal-catalysts for N-heterocycles having one or more heteroatoms, (iii) Synthesis of five or six-membered N-heterocycles using photocatalysis, electrocatalytic, and organo-catalytic approaches using different homogeneous and heterogeneous conditions' (iv) metal free (base and acid-promoted) dehydrogenation along with I₂, N-hydroxyphthalimide (NHPI) and bio catalyzed miscellaneous examples have also been discussed, (v) mechanistic studies for various dehydrogenation reactions and (vi) synthetic applications of various bio-active molecules including post-drug derivatization are discussed.