Direct Access to Acylated Azobenzenes via Pd-Catalyzed C–H Functionalization and Further Transformation into an Indazole Backbone

Azobenzenes were readily acylated at the 2-position through a Pd-catalyzed C–H functionalization from simple aromatic azo compounds and aldehydes in good yields. The obtained acylated azobenzenes could be efficiently converted into the corresponding indazole derivatives in nearly quantitative yields

A Unique Alkylation of Azobenzenes with Allyl Acetates by Rh^III-Catalyzed C–H Functionalization

A novel Rh^III-catalyzed direct alkylation of azobenzenes with allyl acetates through C–H activation and functionalization is demonstrated in which the allyl acetates serve as unique alkylation agents. The rhodium-catalyzed alkylation provides a highly efficient and atom-economic approach to a series of azo compounds

<i>ortho</i>-Heteroarylation of Azobenzenes by Rh-Catalyzed Cross-Dehydrogenative Coupling: An Approach to Conjugated Biaryls

A direct cross-dehydrogenative coupling strategy for <i>ortho</i>-C–H activation and functionalization of azobenzenes with heteroarenes in the presence of a Rh catalyst was developed. Excellent regioselectivity was achieved by azo-coordinated Rh to realize oxidative C–H/C–H cross-coupling, providing a series of π-conjugated biaryls in good yields

Direct Carbo-Acylation Reactions of 2‑Arylpyridines with α‑Diketones via Pd-Catalyzed C–H Activation and Selective C(sp2)–C(sp2) Cleavage

An efficient carbo-acylation reaction of 2-arylpyridines with α-diketones via Pd-catalyzed C–H bond activation and C–C bond cleavage in the presence of TBHP was developed that generated aryl ketones in good yields. The highly selective formation of aryl ketones was observed when 2-arylpyridines reacted with aromatic/aliphatic α-diketones

Heterogeneous Photocatalytic Oxidative Cleavage of Polystyrene to Aromatics at Room Temperature

Heterogeneous photocatalytic aerobic oxidation systems have been developed for selective degradation of polystyrene (PS) to aromatic monomers at room temperature and ambient pressure. The TiO2 particles modified with potassium stearate or N,N-diethyl-3-(trimethoxysilyl)­propan-1-amine photocatalyzed the oxidative cleavage of commercial PS to benzoic acid with up to 43.5 mol % yield. Mechanistic studies revealed that the initial alkyl C–H oxidation and C–C cleavage were greatly improved by these alkaline modifiers. The superoxide anion radical and singlet oxygen acted as the key oxidative species during the degradation process. Common PS waste from daily life also underwent efficient degradation with 18–44.2 mol % yields of benzoic acid on the developed catalysts

Iron-Catalyzed C(sp³)–H Acyloxylation of Aryl‑2<i>H</i> Azirines with Hypervalent Iodine(III) Reagents

This letter describes an iron-catalyzed C­(sp³)–H acyloxylation of aryl-2<i>H</i> azirines with hypervalent iodine­(III) reagents (HIRs) serving as both an oxidant and a reagent. This methodology provides a rapid access to a wide range of monoacyloxylated 3-aryl-2<i>H</i>-azirines in moderate to good yields

Visible-Light Photoredox Catalyzed Three-Component Cyclization of 2<i>H</i>‑Azirines, Alkynyl Bromides, and Molecular Oxygen to Oxazole Skeleton

A novel three-component cyclization of 2<i>H</i>-azirines, alkynyl bromides, and molecular oxygen under visible-light photoredox catalysis at room temperature has been developed, which provides a direct approach to a wide range of substituted oxazoles in moderate to good yields

Effects of MEL-A on cell cycle distributions of B16 cells.

<p>Cells were treated with different concentrations of MEL-A for 24 h. (a) ~ (e) refer to the cell cycle distributions of B16 cells treated by 0, 9.0, 15.0, 20.0, 25.0 μg/mL MEL-A, respectively. G1/G0, S, G2/M and Sub-G1 indicate the different cell phases. Mean ± SD, n = 3. The results in (f) summarized the relative ratios of each cell cycle, indicating that MEL-A caused cell cycle arrest at the S phase. The cell population of Sub-G1 phase was slightly increased with exposure to above 15.0 μg/mL of MEL-A.</p

Cyclization of Azobenzenes Via Electrochemical Oxidation Induced Benzylic Radical Generation

An electrochemical oxidation-induced cyclization of ortho-alkyl-substituted azobenzenes has been developed. The direct electrochemical benzylic C–H functionalization with respect to azobenzenes could proceed in the absence of any catalyst or external chemical oxidant to afford a number of 2H-indazole derivatives in moderate to good yields. This protocol enables the reuse of the byproduct to the same 2H-indazoles, thus significantly reducing pollution discharge in synthetic chemistry