874148-02-4Relevant academic research and scientific papers
Complementary performance of organoselenides and organotellurides as antimicrobials agents
Borges, Felipe G.,Zugman, Tay,Bandeira, Pamela T.,Dalmolin, Mara C.,Scariot, Débora B.,Garcia, Francielle P.,de Oliveira, Alfredo R.M.,Nakamura, Celso V.,Piovan, Leandro
, p. 462 - 475 (2021/02/12)
Fungi and bacteria are well-known pathogens for plants, fruits, and animals, including humans. In this context, the prospection of antimicrobial agents is crucial to provide new alternatives for the treatment of microbial diseases. Hence, selenium- and tellurium-containing compounds are underexploited and herein, antimicrobial activity of several organochalcogenated compounds was evaluated against Gram-negative and Gram-positive bacteria and fungi. A direct comparison between Se- and Te-containing compounds was performed, as well as structure-activity relationship studies. Among assayed compounds, secondary Se-amines LQ16 and LQ20 and secondary Te-amine LQ28 showed excellent results against a variety of fungi, while primary Te-amine LQ10 demonstrated promising results against bacteria. These results suggest organoselenides and organotellurides may be used for the development of new antimicrobial agents.
Stereoselective Bioreduction of Telluro-Acetophenones to Optically Active Hydroxy Tellurides
Bandeira, Pamela Taisline,Gotor-Fernández, Vicente,Piovan, Leandro
, (2020/02/27)
Organotellurium compounds exhibit a broad range of useful applications in organic synthesis, materials science and medicinal chemistry fields. Despite their increasing applicability, the synthesis of enantiomerically pure organotellurium compounds remains nowadays scarcely reported in the literature. Herein, the chemical synthesis and biocatalyzed reductions of a set of telluro-acetophenones using both (R) and (S)-selective alcohol dehydrogenases (ADHs) is described for the first time, obtaining enantiomerically enriched hydroxy tellurides with excellent selectivities under very mild reaction conditions. On the one hand, enantiopure para-substituted (S)-hydroxy tellurides were obtained using the Ras-ADH (77–95 % conversion) and ADH-A (52–75 %), the ADH-A leading to the enantiopure (S)-hydroxy tellurides substituted at the meta-position (69–75 %). On the other hand, the evo-1.1.200 displayed high selectivity towards the preparation of optically alcohols with substitutions at the para-position of the aromatic ring (60–68 % conversion and 92–97 % ee), while the Lb-ADH led to the best results when reducing bulky ketones at the meta-position (79–82% conversion and 88–99 % ee).
Synthesis, Antioxidant Activity and Cytotoxicity of N-Functionalized Organotellurides
Bandeira, Pamela T.,Dalmolin, Mara C.,de Oliveira, Mariana M.,Nunes, Karine C.,Garcia, Francielle P.,Nakamura, Celso V.,de Oliveira, Alfredo R.M.,Piovan, Leandro
supporting information, p. 410 - 415 (2019/01/04)
The use of antioxidants is the most effective means to protect the organism against cellular damage caused by oxidative stress. In this context, organotellurides have been described as promising antioxidant agents for decades. Herein, a series of N-functionalized organotellurium compounds has been tested as antioxidant and presented remarkable activities by three different in vitro chemical assays. They were able to reduce DPPH[rad] radical with IC50 values ranging from 5.08 to 19.20 μg mL?1, and some of them also reduced ABTS[rad]+ radical and TPTZ-Fe3+ complex in ABTS[rad]+ and FRAP assays, respectively. Initial structure-activity relationship discloses that the nature of N-substituent strongly influenced both activity and cytotoxicity of the studied compounds. Furthermore, radical scavenging activities of N-functionalized organotellurides have been compared with those of their selenilated congeners, demonstrating that the presence of tellurium atom has an essential role in antioxidant activity.
Straightforward microwave-assisted synthesis of organochalcogen amines by reductive amination
Dalmolin, Mara C.,Bandeira, Pamela T.,Ferri, Matheus S.,de Oliveira, Alfredo R.M.,Piovan, Leandro
, p. 32 - 39 (2018/08/28)
Organoselenium and organotellurium amines have been shown to present a broad range of interesting properties for both synthetic and biological applications. Despite the current interest in this class of compounds, only few methods to access organochalcogen amines are described in literature, most which involve restrictive conditions associated with displacement reaction, metal-assisted reactions or enzymatic approach. In general, these methods produce organochalcogen amines in poor yields, by long reactions that require protective groups. In this regard, a set of aryl chalcogen (Se, Te) amines were prepared by reductive amination employing a microwave-assisted one-pot protocol. This approach offered a convenient and versatile method to synthesize primary and secondary organochalcogen amines with significantly short time reactions (5–10 min) and satisfactory yields (40–89%).
Synthesis of unsymmetrical diorganyl chalcogenides under greener conditions: Use of an iodine/DMSO system, solvent- and metal-free approach
Saba, Sumbal,Rafique, Jamal,Braga, Antonio L.
supporting information, p. 1446 - 1452 (2015/05/27)
Herein, we report a greener iodine-catalyzed protocol to access different types of unsymmetrical diorganyl chalcogenides. This new approach works in the absence of solvent and metal. The desired products were obtained in good to excellent yields using one equivalent of arylboronic acids, half an equivalent of various diorganyl dichalcogenides, iodine (10 mol%) as a catalyst and 2 equivalents of dimethyl sulfoxide (DMSO; as oxidant), with a reaction time of 10 min under microwave irradiation.
An alternative approach for the synthesis of aryl-alkyl tellurides: Reaction of aryl iodides with metal alkyltellurolates promoted by CuI
Silva, Márcio S.,Comasseto, Jo?o V.
supporting information; experimental part, p. 8763 - 8768 (2011/12/02)
Aryl iodides react with metal organotellurolates in tetrahydrofuran/ dimethylformamide in the presence of CuI (5 mol %) or CuI (5 mol %) and 1,10-phenanthroline (10 mol %) to afford the corresponding aryl-alkyl tellurides in good yields.
Suzuki-Miyaura cross-coupling reactions of aryl tellurides with potassium aryltrifluoroborate salts
Cella, Rodrigo,Cunha, Rodrigo L. O. R.,Reis, Ana E. S.,Pimenta, Daniel C.,Klitzke, Clecio F.,Stefani, Helio A.
, p. 244 - 250 (2007/10/03)
Palladium(0)-catalyzed cross-coupling between potassium aryltrifluoroborate salts and aryl tellurides proceeds readily to afford the desired biaryls in good to excellent yield. The reaction seems to be unaffected by the presence of electron-withdrawing or electron-donating substituents in both the potassium aryltrifluoroborate salts and aryl tellurides partners. Biaryls containing a variety of functional groups can be prepared. A chemoselectivity study was also carried out using aryl tellurides bearing halogen atoms in the same compound. In addition, this new version of the Suzuki-Miyaura cross-coupling reaction was monitored by electrospray ionization mass spectrometry where some reaction intermediates were detected and analyzed.
