In this review, we spotlight the methods for the direct synthesis of synthetically and biologically important 1-sulfonyl-1, 2, 3-triazoles via [3+2] cycloaddition between easily available terminal alkynes and sulfonyl azides. The review is divided into two major sections. The first section focuses exclusively on the synthesis of 1-(N-sulfonyl)-4-substituted 1,2,3-triazoles, while the second section will discuss preparation of 1-(N-sulfonyl)-5-substituted 1,2,3-triazole derivatives.
A series of new nickel(II) dithiocarbamate complexes of general formula [M L2], (where L=benzyl(4-fluorobenzyl)carbamodithioate (L1), benzyl(4-cyanobenzyl)carbamodithioate (L2), ethyl(4-methylbenzyl)carbamodithioate (L3), (4-methoxybenzyl) (naphthalen-1-ylmethyl)carbamodithioate (L4) and ethyl(4-methoxybenzyl)carbamodithioate (L5)) have been synthesized, and characterized via elemental analysis, FT-IR, electronic spectra, 1H NMR, 13C NMR, Mass spectrometry and Thermogravimetric analysis (TGA). The continuous variation method (Job's method) was used to determine the stoichiometry of the complexes. TGA was used to analyze the thermal decomposition behavior of metal complexes in nitrogen atmosphere. As a result of the thermal decomposition process, all of the complexes produced NiS as the final product. X-ray Diffraction (XRD), Energy dispersive X-ray analysis (EDAX), and Transmission electron microscopy (TEM) studies confirm the formation of NiS nanomaterial. Crystalline size of NiS was obtained between 19.97 to 21.35nm range by applying the Scherrer equation using XRD. Solid-state electrical conductivities reveal that all the complexes behave as a semiconductor at room temperature. All the synthesized dithiocarbamate ligands and complexes were screened against five human bacterial pathogens (Escherichia coli, Staphylococcus aureus, Salmonella typhi, Aeromonas hydrophila, and Shigella boydii) by disc diffusion method. Solvent extraction studies show that the ligand has strong extractability towards metal ions in a basic medium (pH=10).
α-Ketothioesters are safely and efficiently synthesized from arylacetylenic sulfones and dimethyl sulfoxide (DMSO) in the presence of equivalent of water and catalytic amount of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) under microwave irradiation. Arylacetylenic sulfones and dimethyl sulfoxide first form arenecarbonyl sulfonyl dimethylsulfonium methylides via nucleophilic addition, ring closure, and 4e ring opening. The methylides undergo a radical process to generate α-methylthio-α-sulfonylacetophenones, which further convert to α-ketothioesters through the Pummerer oxidation. Compared to the previous methods, the current method is safer and more efficient.
Reaction of thiopyrano[4,3-b]indole-3(5H)-thiones and dimethyl acetylenedicarboxylate (DMAD) proceeds via two competing cascade pathways. Initially, both the pathways begin from thiocarbonyl sulfur and acetylene carbon atoms interaction. Then two parallel processes take place: an alkyne–thiocarbonyl metathesis and a (3 + 2) cycloaddition. In the next stages, in both cases, thiophene ring formation and thiopyran ring opening proceed. Finally, (4 + 2) cycloaddition reactions of intermediate thioketones and a second equivalent of DMAD leads to the resulting thiopyrano[4,3-b]indole derivatives bearing thienyl substituent. The kinetic and thermodynamic characteristics of both pathways were compared on the basis of DFT and ab initio 6-311++G(d,p) quantum chemical calculations.
Cu (OAc)2 was immobilized on the surface of magnetic nanoparticles modified by Imine-Thiazole acting as a ligand. This immobilization is done to fabricate a new and green magnetically recoverable copper catalyst [Fe3O4@SiO2-(Imine-Thiazole)-Cu (OAc)2]. Techniques such as ICP-OES, TEM, FT-IR, EDX, SEM, TGA, VSM, and XRD were used to characterize the structure of Fe3O4@SiO2-(Imine-Thiazole)-Cu (OAc)2 nanocomposite. To Synthesize 2-substituted benzothiazoles, the nanocomposite of Fe3O4@SiO2-(Imine-Thiazole)-Cu (OAc)2 was used as a catalyst via a one-pot three-component reaction of 2-iodoanilines, benzyl chlorides and S8. Recycling experiments revealed that a simple magnetic separation could be used to recover the copper nanocatalyst, and this nanocatalyst can be recycled eight times without any deterioration in catalytic activity.
Herein, Tin-impregnated graphene oxide (Sn/GO) composite was designed and tested for the catalytic removal of sulfides from the simulated and real commercial oils in the hydrogen peroxide and formic acid (HCOOH/H2O2) oxidation system. The prepared GO and Sn/GO were characterized in terms of surface morphology and other catalytic properties, which confirmed that the Sn/GO catalyst has a large surface area and more surface functional groups than GO. The desulfurization activity of the Sn/GO-HCOOH/H2O2 system was analyzed for the model dibenzothiophene (DBT) and real commercial oil at different substrate concentrations, time, temperature, pH, and oxidant and catalyst doses. The results showed that the Sn/GO-HCOOH/H2O2 system removed 97% DBT from the model oil and accumulative sulfur of 90%, 69%, and 61%, respectively, from gasoline, diesel, and kerosene oil employing 0.03 g/10 mL catalyst, 2 mL of H2O2/HCOOH in 50 min at 50°C, and pH 3. Sn/GO could be recycled up to five consecutive runs retaining more than 57% efficiency. Due to its environmental greenness, ease of preparation, and cost-effectiveness, this unique catalyst-oxidant system can be envisioned for the oxidation of sulfides from real oils.
Research Highlights
Pristine and Sn-loaded GO composite were synthesized and characterized.
The Sn/GO-HCOOH/H2O2 system oxidized 97 and 90 % DBT from the model and real oil.
O2− radicals generated due to synergism between Sn/GO and HCOOH/H2O2 species.
The Sn/GO-HCOOH/H2O2 system remained active for five successive reuses.
A straightforward and convenient synthesis of symmetrical and unsymmetrical thiourea derivatives by the reaction of primary amines and carbon disulfide in the presence of a Zn catalyst is presented. Under modest reaction conditions, a range of biologically relevant thiourea derivatives can be produced in good to outstanding yields without a lengthy work-up. A variety of primary aliphatic and aromatic amines with various substituted functional groups were transformed into thiourea derivatives. Zn-mediated symmetric thiourea creation occurs at room temperature for aliphatic amines, whereas for aromatic amines it occurs at 60°C. However, unsymmetrical thiourea for aliphatic amines occurs at 0°C. Benefits of this method include environment-friendly reaction conditions, sustainability, and enumerating tolerance of functional groups such as hydroxyl and halides. Experimental observations were rationalized by DFT calculations based on transition structures and zwitterionic intermediate stabilities.
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