Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal‐Free Catalyst under Air

Abstract

Graphene oxide (GO) has been developed as an inexpensive,e nvironmental friendly, metal-free carbocatalyst for the dehydrogenation of nitrogen heterocycles.V aluable compounds,s uch as quinoline, 3,4-dihydroisoquinoline,q uinazoline,a nd indole derivatives,h aveb een successfully used as substrates.T he investigation of various oxygen-containing molecules with different conjugateds ystems indicated that botht he oxygen-containing groups and large p-conjugated system in GO sheets are essential for this reaction.

Synthesis of a molecularly defined single-active site heterogeneous catalyst for selective oxidation of N-heterocycles

“…The oxidative dehydrogenation of N -heterocycles is used to synthesize high-value products, such as quinoline, isoquinoline, quinazoline, and indole derivatives, most of which can behave as bioactive compounds, pharmaceutical molecules and functional materials, and this remains an interesting topic in organic synthesis. Various catalysts, including transitional metal-based 38 – 59 and carbon-based catalysts 36 , 37 , have been studied extensively. Due to the importance of this transformation, it was chosen as the model reaction to test the catalytic performance of these carbonyl group-containing molecules.…”

Iodine-catalyzed convergent aerobic dehydro-aromatization toward benzazoles and benzazines

“…10-12 However, due to the involvement of transition metals and other specialized catalysts or amounts of oxidants, these dehydrogenation protocols are oen expensive or not environmentally friendly. In recent years, Lewis acids, 13 photoredox catalysis, 14 electrocatalysis 15 and graphene oxide (GO) 16 were used for the same goal (Scheme 1b). In addition, potassium tert-butoxide 17 and elemental sulfur 18 also could promote the dehydrogenation process.…”

A Deoximation Method for Deprotection of Ketones and Aldhydes Using a Graphene‐Oxide‐Based Co‐catalysts System

“…Graphene is a single atomic plane of graphite, constructed with sp 2 -hybridized carbon atoms in a perfect hexagonal lattice. [18] Recently, graphene oxides (GOs) have been developed as catalysts in the Friedel-Crafts acylation of active aromatic compounds, [19] Friedel-Crafts addition reaction of indoles to α,βunsaturated ketones and nitrostyrenes, [20] aza-Michael addition of amines and electrondeficient olefins, [21] Michael addition reactions, [22] direct alkylation reaction between styrenes and alcohols, [23] direct alkylation reaction between iodobenzene and benzene, [24] oxidization reaction of benzene to phenol, [25] oxidation of tetralin to tetralol and tetralone, [26] oxidation of cyclohexane to cyclohexanol, cyclohexanone, and adipic acid, [27] ring-opening reactions, [28] dehydrogen-ation of nitrogen heterocycles, [29] direct iodination of arenes and ketones, [30] trifluoromethylation of arenes, [31] and other reaciotns. [32][33][34] In this work, we report a highly efficient, easily recyclable and simple method for deoximation with good yields under mild conditions using a co-catalysts system composed of graphene oxide (GO) prepared by Hummers' method, [35] sodium nitrite (NaNO 2 ) and air.…”