A new application of rhodanine as a green sulfur transferring agent for a clean functional group interconversion of amide to thioamide using reusable MCM-41 mesoporous silica

Lawesson's Reagent: Providing a New Approach to the Forgotten 6-Thioverdazyl Radical

A new method for the preparation of the underrepresented 1,5-dimethyl-6-thioverdazyl radicals has been developed employing Lawesson's reagent (LR). The synthetic route involves the direct thionation of the carbonyl group of the corresponding dialkylbishydrazone followed by cyclization to give the tetrazinanthione verdazyl precursor on a gram scale. Subsequent oxidation yields the 6-thioverdazyl radical. It was determined that thionation of substrates containing electron-withdrawing groups in the ortho- or para-positions was high yielding. In contrast, for the parent phenyl group or substrates bearing weakly electron-donating substituents, thionation efficiency was significantly reduced. This could be overcome by utilizing partial in situ cyclization, which occurs during work up, to generate the tetrazinanthione directly via a one-pot synthesis. Density functional theory suggests that the LR fragment interacts with the carbonyl prior to cycloaddition and subsequent to cycloreversion, leading to the thiocarbonyl. The electronic nature of the radical is characterized with electron paramagnetic resonance as well as the first report of 6-thioverdazyl redox properties.

Thioisomünchnones versus Acrylamides via Copper-Catalyzed Reaction of Thioamides with Diazocarbonyl Compounds

A novel carbenoid-mediated approach to thioisomünchnones was developed by intermolecular copper-catalyzed reactions of diazoacetamides with aromatic and heteroaromatic thioamides bearing a pyrrolidine moiety. The direction of the reaction can be switched toward 2-amino-2-heteroarylacrylamides by replacing the pyrrolidine with an aniline group or by the use of 2-cyano-2-diazoacetamides. The proposed mechanism and DFT calculations allowed us to rationalize the effect of substituents on the reaction direction. Effective methods were found for the synthesis of previously unknown both 2-heteroarylthioisomünchones and 2-heteroarylacrylamides, based on a wide scope of available reagents with a similar structure. Some of the synthesized thioisomünchnones exhibited multicolor fluorescence in the solid state and solutions.

Water Mediated Direct Thioamidation of Aldehydes at Room Temperature

A mild, greener approach toward thioamide synthesis has been developed. Its unique features include water-mediated reaction with no input energy, additives, or catalysts as well. The presented protocol is attractive with readily available starting materials and the use of different array amines, along with a scaled-up method. Biologically active molecules such as thionicotinamide and thioisonicotinamide can be synthesized from this procedure.

Cellulose-reinforced poly(ethylene-co-vinyl acetate)-supported Ag nanoparticles with excellent catalytic properties: synthesis of thioamides using the Willgerodt–Kindler reaction

Cellulose, a bio-derived polymer, is widely used in food packaging, dye removal, coatings, and solid-supported catalysis. Heterogeneous catalysts play a critical role in environmental remediation. In this context, the demand for green and cost-effective catalysts has rapidly increased. In this study, cellulose was extracted from rice straw, and a highly active solid-supported catalytic model was developed. First, cellulose was conjugated with poly(ethylene-co-vinyl acetate) (PEVA), and then Ag nanoparticles (AgNPs) were inserted into the cellulose–PEVA composite. The process involved the reduction of AgNPs in the presence of sodium borohydride. The fabricated hybrid catalyst was characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray, and powder X-ray diffraction. Thereafter, the obtained hybrid was used as a catalyst for the Willgerodt–Kindler reaction of aromatic aldehydes, amines, and S₈ to synthesize thioamides with excellent yields. The developed catalytic system exhibited high stability and recyclability. Moreover, the mechanical properties of the hybrid catalyst were evaluated using tensile strength and impact tests. RGB analysis of digital images was also performed to investigate the primary components of the catalyst.

The AgNPs@cellulose–PEVA hybrid catalyst presented excellent catalytic efficacy for the Willgerodt–Kindler reaction, facilitating the selective formation of C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> S bonds.

Crystal structure of a new phen-yl(morpholino)methane-thione derivative: 4-[(morpholin-4-yl)carbothioyl]benzoic acid

4-[(Morpholin-4-yl)carbothioyl]benzoic acid, C12H13NO3S, a novel phen-yl(morpholino)methane-thione derivative, crystallizes in the monoclinic space group P21/n. The morpholine ring adopts a chair conformation and the carb-oxy-lic acid group is bent out slightly from the benzene ring mean plane. The mol-ecular geometry of the carb-oxy-lic group is characterized by similar C-O bond lengths [1.266 (2) and 1.268 (2) Å] as the carboxyl-ate H atom is disordered over two positions. This mol-ecular arrangement leads to the formation of dimers through strong and centrosymmetric low barrier O-H⋯O hydrogen bonds between the carb-oxy-lic groups. In addition to these inter-molecular inter-actions, the crystal packing consists of two different mol-ecular sheets with an angle between their mean planes of 64.4 (2)°. The cohesion between the different layers is ensured by C-H⋯S and C-H⋯O inter-actions.

Synthesis of α-Keto Thioamides by Metal-Free C═C Bond Cleavage in Enaminones Using Elemental Sulfur

An unprecedented method for cleaving the C═C bond in N, N-disubstituted enaminones in the presence of elemental sulfur and N, N-dimethyl-4-aminopyridine is disclosed. Without using any metal catalyst or additive, the cascade functionalization of both C═C and C-H bonds takes place to enable the formation of new C═S and C-N bonds, thus providing a facile and practical method for the synthesis of N, N-disubstituted α-keto thioamides.

A efficient protocol for the synthesis of thioamides in [DBUH][OAc] at room temperature

A novel, simple and eco-friendly method to synthesize thioamides from aryl nitriles and sodium sulfide (Na₂S·9H₂O) catalyzed by 1,8-diazabicyclo[5,4,0]undec-7-enium acetate ([DBUH][OAc]) ionic liquid (IL) at room temperature was developed in this paper.

Piperazinylpyrimidine modified MCM-41 for the ecofriendly synthesis of benzothiazoles by the simple cleavage of disulfide in the presence of molecular O2

Synthesis of benzothiazoles by metal free cleavage of disulfide bond.

Cubic Ag2O nanoparticle incorporated mesoporous silica with large bottle-neck like mesopores for the aerobic oxidative synthesis of disulfide

Ag₂O nanoparticle supported on silica with large bottle-neck like mesopores for the aerobic oxidative synthesis of disulphides in water.