84280-95-5Relevant academic research and scientific papers
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
, p. 410 - 415 (2019)
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.
Synthesis, Mechanism Elucidation and Biological Insights of Tellurium(IV)-Containing Heterocycles
Souza, Jo?o Pedro A.,Menezes, Leociley R. A.,Garcia, Francielle P.,Scariot, Débora B.,Bandeira, Pamela T.,Bespalhok, Mateus B.,Giese, Siddhartha O. K.,Hughes, David L.,Nakamura, Celso V.,Barison, Andersson,Oliveira, Alfredo R. M.,Campos, Renan B.,Piovan, Leandro
supporting information, p. 14427 - 14437 (2021/09/25)
Inspired by the synthetic and biological potential of organotellurium substances, a series of five- and six-membered ring organotelluranes containing a Te?O bond were synthesized and characterized. Theoretical calculations elucidated the mechanism for the oxidation-cyclization processes involved in the formation of the heterocycles, consistent with chlorine transfer to hydroxy telluride, followed by a cyclization step with simultaneous formation of the new Te?O bond and deprotonation of the OH group. Moreover, theoretical calculations also indicated anti-diastereoisomers to be major products for two chirality center–containing compounds. Antileishmanial assays against Leishmania amazonensis promastigotes disclosed 1,2λ4-oxatellurane LQ50 (IC50=4.1±1.0; SI=12), 1,2λ4-oxatellurolane LQ04 (IC50=7.0±1.3; SI=7) and 1,2λ4-benzoxatellurole LQ56 (IC50=5.7±0.3; SI=6) as more powerful and more selective compounds than the reference, being up to four times more active. A stability study supported by 125Te NMR analyses showed that these heterocycles do not suffer structural modifications in aqueous-organic media or at temperatures up to 65 °C.
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).
Pentafluoro(aryl)-λ6-tellanes and Tetrafluoro(aryl)(trifluoromethyl)-λ6-tellanes: From SF5 to the TeF5 and TeF4CF3 Groups
Bornemann, Dustin,Pitts, Cody Ross,Ziegler, Carmen J.,Pietrasiak, Ewa,Trapp, Nils,Kueng, Sebastian,Santschi, Nico,Togni, Antonio
supporting information, p. 12604 - 12608 (2019/08/16)
The TeF5 group is significantly underexplored as a highly fluorinated substituent on an organic framework, despite it being a larger congener of the acclaimed SF5 group. In fact, only one aryl-TeF5 compound (phenyl-TeFsub
Diacetal Ditellurides as Highly Active and Selective Antiparasitic Agents toward Leishmania amazonensis
Bandeira, Pamela T.,Souza, Jo?o Pedro A.,Scariot, Débora B.,Garcia, Francielle P.,Nakamura, Celso V.,De Oliveira, Alfredo R. M.,Piovan, Leandro
supporting information, p. 806 - 810 (2019/05/06)
Leishmaniasis is a neglected tropical disease and a public health concern in at least 98 countries, affecting mainly the poorest populations. Pharmaceuticals and chemotherapies available for leishmaniasis treatment have several limitations, which clearly justify the efforts to find new potential antileishmanial drugs. In this context, antiprotozoal activities toward different Leishmania species have been reported for hypervalent tellurium compounds, which motivated us to investigate, for the first time, the leishmanicidal properties of some nonhypervalent diaryl ditellurides. Thus, this work describes in vitro activity against Leishmania amazonensis and the cytotoxicities of diaryl ditellurides. Ditelluride LQ7 revealed a strong leishmanicidal activity on promastigotes and amastigotes at submicromolar levels (IC50 = 0.9 ± 0.1 and 0.5 ± 0.1 μmol L-1, respectively) and presented selectivity indexes greater than those of reference drug miltefosine. This preliminary study suggests that diaryl ditellurides may be promising scaffolds for the development of new agents for leishmaniasis treatment.
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%).
