Synthesis of Benzo[b]fluoranthenes and Spiroacridines from Fluorene-Derived Alkenes and N-Arylimines via a Tandem Reaction with Benzynes

Arynes Promoted Dehydrosulfurization of Thioamides: Access to Nitriles and Diaryl Sulfides

An aryne-promoted dehydrosulfurization reaction of thioamides to give nitriles and diaryl sulfides in a one-pot manner is presented. Aromatic, heteroaromatic, and aliphatic natural products and drug-derived nitriles and diaryl sulfides were obtained in good to excellent yields. Especially, selenoamide was also a suitable substrate and produced diaryl selenide and nitrile in high yields. The D-labeled experiments indicated that the protons of thioamides transfer to diaryl sulfides.

Trideuteromethylthiolation through Reaction of Arynes, S-Methyl-d3 Sulfonothioate with Sulfonamides or Amides: Access to Trideuteromethylated Sulfilimines

A direct and practical three-component tandem reaction of arynes, S-methyl-d3 sulfonothioate with sulfonamides or amides is developed. The reaction is highly efficient and chemoselective, which allows mild synthesis of trideuteromethylated sulfilimines with broad substrate scope and good functional group compatibility, giving the products in good to excellent yields with 92%-99% deuterium incorporation. Mechanism studies disclosed sulfenamide that generated in situ is the key intermediate for the reaction. This protocol provides potential method for introduction of -SCD3 moiety for deuteration of marked drugs and drug candidates containing sulfilimine skeleton.

Synthesis, Structures and Photophysical Properties of Asymmetric Fulvene-[b]-fused BODIPYs

Herein, we developed a one-pot procedure to synthesize novel fulvene-[b]-fused BODIPYs from α-(2-alkynylphenyl)-pyrrole and acylpyrrole, using 5-exo cyclization as the key transformation. Compared to benzene-[b]-fused BODIPYs, although they have similar chemical compositions, their structures and properties significantly differ from each other, which can be attributed to the less aromaticity of the fulvene linker than benzene. Notably, fulvene-[b]-fused BODIPY 1 b exhibits helical-twisted core skeleton, intensified red-shifted absorption, and peak fluorescence. In addition, the pathway of this one-pot reaction and the mechanism of POCl3 mediated 5-exo cyclization have been proposed by a combining experimental and computational study.

Synthesis of Sulfilimines via Multicomponent Reaction of Arynes, Sulfamides, and Thiosulfonates

In this work, a facile and efficient method for the synthesis of sulfilimines through multicomponent reaction of arynes, sulfamides, and thiosulfonates was developed. A variety of structurally diverse substrates and functional groups were very compatible in the reaction, giving the corresponding sulfilimines in good to high yields. This protocol could be conducted on a gram scale, and the product was easily converted to sulfide and sulfoximine. Mechanism studies revealed that sulfenamide generated in situ is the key intermediate for the reaction.

Construction of Alkylidene Fluorene Scaffolds Using Pd-Catalyzed Direct Arene/Alkene Coupling Strategy

A versatile synthetic method for the construction of alkylidene fluorenes and their heteroarene derivatives has been developed successfully by means of a Pd(II)-catalyzed direct C-H/C-H coupling of o-alkenyl biaryls. Use of the Pd(OAc)₂ catalyst under aerobic oxidation conditions gives rise to the corresponding alkylidene fluorenes having various functional groups and diversely fused polycyclic systems. The resulting products can serve as versatile synthetic building blocks for the construction of structurally diverse polycyclic arenes and heteroarenes.

Assembly of unsymmetrical 1,3,5-triarylbenzenes via tandem reaction of β-arylethenesulfonyl fluorides and α-cyano-β-methylenones

A transition-metal-free tandem reaction of β-arylethenesulfonyl fluorides and α-cyano-β-methylenones has been revealed. In the presence of cesium carbonate, 2-arylethenesulfonyl fluorides react with α-cyano-β-methylenones through a tandem Diels-Alder cycloaddition/sulfur (VI) fluoride...

Transition-Metal-Free Synthesis of 4-Amino Isoquinolin-1(2H)-ones via Tandem Reaction of Arynes and Oxazoles

A facile and transition-metal-free method for the synthesis of 4-amino isoquinolin-1(2H)-ones has been developed. Arynes react with 4, 5-disubstituted oxazoles through a tandem Diels-Alder reaction/dehydrogenation-aromatization/tautamerization process to produce 4-amino isoquinolin-1(2H)-ones...

Construction of 6H-benzo[c]thiochromenes via a tandem reaction of arynes with thionoesters

A mild and transition-metal free method has been proposed for the synthesis of 6H-benzo[c]thiochromenes via the tandem reactions of arynes with thionoesters.

The catalytic influence of phosphotungstic acid-functionalized Fe3O4 MNPs blended with TiO2 on the synthesis of novel spiro-acridines and the evaluation of their medicinal potential through molecular docking studies

This manuscript describes an effective and rapid three-component synthesis of a novel series of spiro-acridine derivatives by integrating the pharmacologically dynamic hydantoin-phenytoin as the prime synthetic equivalent. The process was accelerated by Fe3O4@TiO2-PTA magnetic nanoparticles (MNPs), which acted as the heterogeneous catalytic system, under ultrasonic conditions. The reaction was performed in the green PEG-200 solvent under aerophilic conditions to obtain products with excellent yields. The characteristics of the synthesized magnetic nano-catalysts were corroborated through powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), FT-IR, and VSM techniques. In addition, the structures of the synthesized compounds were ascertained on the basis of elemental analyses and spectro-analytical data (1H NMR, 13C NMR, and mass spectrometry). High yields, smaller E-factor, considerable atom economy, easy recovery, and recyclability of the catalyst and solvent are the captivating features of the developed protocol. Moreover, in view of the ongoing global research on COVID-19, herein, we tried to identify the potential sites of the synthesized moiety that can suitably fit the receptor sites of the main protease of SARS-CoV-2 (SARS-CoV-2 Mpro).

Copper-Catalyzed Tandem Radical Cyclization of 8-Ethynyl-1-naphthyl-amines for the Synthesis of 2H-Benzo[e][1,2]thiazine 1,1-Dioxides and its Fluorescence Properties

A copper-catalyzed radical cascade dehydrogenative cyclization of N-tosyl-8-ethynyl-1-naphthylamines under air is described herein for the synthesis of thioazafluoranthenes. The reaction proceeds smoothly with high efficiency and a broad reaction scope. The product is indeed a new fluorophore and its photophysical properties are also investigated. Based on the results, we are pleased to find that the Stokes shift of amino-linked thioazafluoranthenes in dilute tetrahydrofuran is determined to be 143 nm (4830 cm^-1).

Controllable construction of isoquinolinedione and isocoumarin scaffolds via RhIII-catalyzed C–H annulation of N-tosylbenzamides with diazo compounds

An efficient protocol for the synthesis of isoquinolinediones by Rh^III-catalyzed C–H activation/annulation/decarboxylation of N-tosylbenzamides with diazo compounds is reported.