Reported is a new green protocol for the efficient in situ generation of nitrile oxides through NaCl/ Oxone oxidation of aldoximes and their dipolar cycloaddition.The key feature is the use of a green chemistry approach to address the substrate scope of aldoximes: broad scope (aliphatic, aromatic, and alkenyl aldoximes) without production of organic byproducts derived from oxidant and/or catalyst. Importantly, NaCl/Oxone-promoted three-component cycloaddition of aldehyde, hydroxylamine hydrochloride, and alkene was demonstrated to be competent (63−81%).

By targeting a new binding region at the interface between αβ-tubulin heterodimers at the colchicine binding site, we designed a series of 7-substituted 1-methyl-1,4-dihydroindeno[1,2-c]pyrazoles as potential tubulin polymerization inhibitors. Among the compounds synthesized, 2-(6-ethoxy-3-(3-ethoxyphenylamino)-1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy)acetamide 6a and 2-(6-ethoxy-3-(3-ethoxyphenylamino)-1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy)-N-hydroxyacetamide 6n showed noteworthy low nanomolar potency against HepG2, Hela, PC3, and MCF-7 cancer cell lines. In mechanism studies, 6a inhibited tubulin polymerization and disorganized microtubule in A549 cells by binding to tubulin colchicine binding site. 6a arrested A549 cells in G2/M phase that was related to the alterations in the expression of cyclin B1 and p-cdc2. 6a induced A549 cells apoptosis through the activation of caspase-3 and PARP. In addition, 6a inhibited capillary tube formation in a concentration-dependent manner. In nonsmall cell lung cancer xenografts mouse model, 6a suppressed tumor growth by 59.1% at a dose of 50 mg/kg (ip) without obvious toxicity, indicating its in vivo potential as anticancer agent.

The discovery of iron(ii) bromide and cerium(iii) bromide as a bifunctional catalyst enables the oxidative rearrangement of indoles with hydrogen peroxide as the terminal oxidant.

Achmatowicz rearrangement (AchR) is a very important transformation for the synthesis of various heterocyclic building blocks and natural products. Here, the discovery of Fenton chemistry for AchR using a bifunctional catalyst (FeBr2 or CeBr3), which has environmental friendliness and a broad substrate scope at the same time has been reported. This method addresses the major limitation of conventional chemical (hazardous) and enzymatic (limited scope) methods. Mechanistic studies suggested that reactive brominating species (RBS) is the true catalyst for AchR and that Fenton chemistry [Fe/Ce (cat.) + H2O2 → HO•/HOO• + H2O] is responsible for the oxidation of bromide into RBS. Importantly, this in situ RBS generation from M-Br x –H2O2 under neutral conditions addresses the long-lasting problem of many haloperoxidase mimics that require a strong acidic additive/medium for bromide oxidation with H2O2, which creates opportunities for many other brominium-mediated organic reactions.

Fenton chemistry (FeII + H2O2 → HO•/HOO• + H2O) generates reactive oxygen species (ROS) that are used for treatment of wastewater and oxidation of organic molecules and play a key role in biological oxidation systems. This study shows that Fenton chemistry can be used for generation of reactive brominating species (RBS) under neutral conditions at room temperature. The in situ RBS are successfully used for three types of oxidative bromination reactions. This green and nonacidic new method addresses the safety and environmental challenges of existing oxidative bromination methods. Additionally, this neutral Fenton–bromide system addresses the long-lasting problem of many functional haloperoxidase mimics that required strong acids for oxidation of bromide ion with hydrogen peroxide. This new green and mild method for generating RBS will significantly benefit the wide applications of brominated organic compounds in organic synthesis and the fine chemical and pharmaceutical industries.

(di-)Thioacetals and (di-)thioketals serve commonly as protecting groups of carbonyls and alcohols in organic synthesis, and therefore require highly efficient and chemoselective methods for desulfurization into carbonyls or alcohols. Although...

A solvent-free catalytic protocol for the Achmatowicz rearrangement was developed and enabled one-pot sequential reactions.

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