NaOAc-Promoted [3+1+2] Annulation of -Pivaloyl Oximes, Aldehydes, and 2-Methylbenzothiazole Salts: Synthesis of 1-Azaphenothiazines.

This paper presents an efficient strategy for constructing 1-azaphenothiazines through the NaOAc-promoted [3+1+2] annulation of -pivaloyl oximes, aldehydes, and 2-methylbenzothiazole salts. The reaction is conducted in ethanol and employs oxygen as the oxidant under catalyst-free conditions. The process is amenable to various -pivaloyl oximes, 2-methylbenzothiazole salts, and aldehydes, affording the target products in satisfactory yields.

Bifunctionalization of styrene through ring-opening-recombination strategy of phenylpropathiazole salt.

By opening the ring of a benzothiazole salt, we provide a sulfur source for the bifunctional reaction of styrene. The ring-opening-recombination reaction of the benzothiazole salt simultaneously constructs new C-S, C-O, and CO bonds after C-S bond breaking. The reaction proceeds in green solvents, requires no transition metal catalyst, and is compatible with many functional groups.

Facile Synthesis of 2-Methylenebenzothiazoles from Benzothiazole Salts and 4-Hydroxycoumarins by Ball Milling.

A simple and practical method for the synthesis of 2-methylenebenzothiazoles via the coupling of a benzothiazole salts and 4-hydroxycoumarins have been described herein. The reaction showed a good substrate range and functional compatibility under mechanochemical conditions, and proceeded without catalysts or solvents. The 2-methylenebenzothiazoles products were achieved via the formation of a C=C double bond and exhibited strong luminescence and typical aggregation-induced emission (AIE) properties, indicating their potential for use as fluorescent materials.

Copper-Promoted -Alkylation and Bromination of Arylamines/Indazoles Using Alkyl Bromides as Reagents for Difunctionalization.

Practical copper-promoted -alkylation and bromination of arylamines/indazoles with alkyl bromides are described; the -alkylation-C-4-bromination and -dialkylation-C-4-bromination of arylamines, and -alkylation-C-3-bromination of indazoles, with alkyl bromides have been analyzed. The full use of alkyl bromides as alkylating and brominating building blocks without atom wastage, indicating excellent atom and step economy, has been highlighted. Eco-friendly oxygen and water are the reaction oxidant and byproduct, respectively.

Nitrogen-Doped Carbon Supported Nanocobalt Catalyst for Hydrogen-Transfer Dearomative Coupling of Quinolinium Salts and Tetrahydroquinolines.

A nitrogen-doped carbon supported nanocobalt catalyst was developed and successfully applied for the hydrogen-transfer coupling of quinolinium salts and tetrahydroquinoline compounds. The selective coupling of the C6 sites of tetrahydroquinolines (THQs) with the α sites of quinoline salts generated a series of 2-substituted -alkyl-tetrahydroquinolines. This catalytic conversion method, which can be employed to synthesize various functionalized tetrahydroquinolines, has several advantages that include excellent hydrogen transfer selectivity, a reusable and inexpensive catalyst, and environmental friendliness.

Nucleophilic Dearomatization Strategy to Synthesize Disubstituted 3-Isoquinolinones under Transition Metal-Free Conditions.

Herein, a one-pot protocol for constructing the disubstituted isoquinolinone derivatives via the three-component reactions of 3-haloisoquinolines, alkyl halides, and indoles under transition-metal-free conditions is described. The reaction realized the trifunctionalization of isoquinoline via a dearomatization strategy, which displayed high chemical selectivity, excellent functional group tolerance, and a wide range of substrates, and is environmentally friendly. The three-component coupling involves the construction of new C-N, C═O, and C-C bonds in one step.