10.1002/ejoc.201601364
The research presents a novel organocatalytic asymmetric sulfa-Michael addition reaction of 2-aminothiophenols to trans-chalcones, leading to the first enantioselective synthesis of 2,3,4,5-tetrahydro-1,5-benzothiazepines. These heterocyclic compounds are significant in medicinal chemistry and possess a variety of pharmacological properties. The study involved a meticulous optimization process to overcome challenges such as the instability of 2-aminothiophenols and the stereochemical instability of the intermediates during reductive amination. The reaction conditions were optimized using various bifunctional organocatalysts, with catalyst 3d showing the best performance. The solvent was also found to significantly influence the reaction, with 1,4-dioxane being optimal. The optimized protocol involved the use of degassed 1,4-dioxane and the addition of 2-aminothiophenol in solution to prevent dimerization and ensure reproducibility. The second step, reductive amination, was carefully investigated to prevent racemization, with conditions involving NaBH3CN and AcOH in methanol at 0°C proving effective. The scope of the reaction was tested with variously substituted trans-chalcones and 2-aminothiophenols, yielding the desired benzothiazepines in moderate to good yields and enantioselectivities. Analyses included 1H NMR, CSP-HPLC, and single-crystal X-Ray analysis to determine product purity, enantiomeric excess, and absolute configuration, respectively.
10.1002/jhet.139
The research explores the synthesis and biological evaluation of fluorinated dibenzofuran derivatives. The study aims to investigate the impact of incorporating fluorine into organic molecules on their pharmacological properties, specifically focusing on their potential antimicrobial, antiviral, and antioxidant activities. Key chemicals used in the research include 4-difluoromethoxy-dibenzofuran-1-carboxaldehyde, various 2-hydroxy acetophenones, copper chloride, and 2-aminothiophenol. The synthesized compounds were subjected to biological screening, which revealed that none of the tested compounds exhibited significant antioxidant, antimicrobial, or antiviral activities. The study concludes that while fluorine incorporation is known to enhance pharmacological properties in many compounds, the specific derivatives synthesized in this study did not demonstrate the expected biological activities. This suggests that further modifications or different synthetic approaches may be necessary to achieve the desired biological effects.
10.1016/S0040-4039(01)81249-1
The research focuses on the synthesis, structure, and chemistry of 1-thia-4-azanaphthalene. The study was prompted by the hypothesis that 1-thia-4-azabenzenes could be synthesized by alkylation of 4H-[1,4]-thiazines at sulfur followed by deprotonation at nitrogen. Key chemicals involved in the research include 2-aminothiophenol, ethyl 2-chlorobenzoylacetate, methyl triflate, and Na2CO3. The synthesis process involved condensing 2-aminothiophenol with ethyl 2-chlorobenzoylacetate to form 2-carbethoxy-3-phenyl-4H-[1,4]-benzothiazine, which was then methylated with methyl triflate to produce the sulfonium salt. This salt was subsequently treated with Na2CO3 to yield the desired thiazanaphthalene. The study also investigated the thermal decomposition of the synthesized compound, revealing two rearrangement products and providing insights into the zwitterionic character and potential reaction mechanisms.
10.1080/10426500701852661
The research focuses on an efficient and convenient method for synthesizing 1,5-benzothiazepines and benzodiazepines without the use of solvents. The study employs chalcones as starting materials, reacting them with o-amino thiophenol and o-phenylenediamine in the presence of inorganic supports such as silica gel and alumina. These reactions are carried out at 80°C under solvent-free conditions, resulting in the formation of the desired heterocyclic compounds. The synthesized compounds are characterized using elemental analysis, IR, 1H NMR, and 13C NMR spectroscopy. The research also evaluates the antibacterial activity of the synthesized compounds against pathogens like B. subtilis, E. coli, and S. typhi, revealing that some of the compounds exhibit weak to moderate antibacterial activity. The study highlights the advantages of solvent-free conditions over traditional methods, emphasizing the efficiency and environmental benefits of this approach in the synthesis of these important heterocyclic compounds.
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