63 research outputs found
Chemo- and enantioselective sulfoxidation of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) into chiral BEDT-TTF-sulfoxide
Selective sulfoxidation of BEDT-TTF (bis(ethylenedithio)-tetrathiafulvalene) with enantiopure (camphoryl-sulfonyl)oxaziridine derivatives provided the inner monosulfoxide, as demonstrated using single crystal X-ray analysis, with an enantiomeric excess of 44% (up to 74% after recrystallization)
Aerobic Copper-Mediated Domino Three-Component Approach to 2-Aminobenzothiazole Derivatives
An unprecedented three-component reaction involving a 2,2′-diaminodiaryl disulfide, copper cyanide, and an electrophile is described. This transformation is based on an oxidative copper-mediated S-cyanation as a key step and involves a cyanation/cyclization/acylation domino sequence enabling a rapid and efficient synthesis of diversely substituted 2-aminobenzothiazole derivatives. Notably, this reaction proceeds via an original mechanism involving an intermolecular migration of the acyl group
Supplementary data for the article: Ristić, P.; Todorović, T. R.; Blagojević, V.; Klisurić, O. R.; Marjanović, I.; Holló, B. B.; Vulić, P.; Gulea, M.; Donnard, M.; Monge, M.; Rodríguez-Castillo, M.; López-de-Luzuriaga, J. M.; Filipović, N. R. 1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-Carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study. Crystal Growth & Design 2020, 20 (7), 4461–4478. https://doi.org/10.1021/acs.cgd.0c00287
Supplementary material for: [https://pubs.acs.org/doi/10.1021/acs.cgd.0c00287#]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4200]Related to accepted version: [https://cherry.chem.bg.ac.rs/handle/123456789/4203
1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study
Four silver-based coordination polymers, {[Ag(L)2](BF4)}∞ (1), {[Ag(H2BTC)(L)]·(H3BTC)}∞ (2), {[Ag2(H2BTEC)(L)2]·3.33H2O}∞ (3), and [Ag(H25SSA)(L)]∞ (4), were synthesized using thiomorpholine-4-carbonitrile (L) as the primary ligand and three aromatic polyoxoacids as coligands: trimesic (H3BTC), pyromellitic (H4BTEC), and 5-sulfosalicylic acid (H35SSA). Compounds 1 and 3 are two-dimensional, while 2 and 4 are one-dimensional. L acts as a bis-monodentate ligand, while the Ag(I) ion is three-coordinated in 2 and four-coordinated in all of the other compounds. The tetrahedral coordination of Ag(I) in 3 leads to an almost complete absence of intermolecular interactions with the metal center. All compounds show reasonable photocatalytic activity for photocatalytic degradation of mordant blue 9 dye, with reaction rates in the 0.036–0.056 min–1 range. Changes in the reaction rates can be correlated with the type and coordination of the coligand. Complex 3 exhibits photoluminescence at 77 K, while 4 exhibits photoluminescence at both room temperature and 77 K. Luminescence lifetimes indicate electronic transitions of singlet parentage, where transitions are allowed. A TD-DFT study determined the contributions of individual singlet–singlet electronic excitations to the fluorescence, indicating that metal– intraligand transitions are responsible for luminescence in both complexes.This is the peer-reviewed version of the article: Ristić, P., Todorović, T.R., Blagojević, V., Klisurić, O.R., Marjanović, I., Holló, B.B., Vulić, P., Gulea, M., Donnard, M., Monge, M., Rodríguez-Castillo, M., López-de-Luzuriaga, J.M., Filipović, N.R., 2020. 1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study. Crystal Growth & Design 20, 4461–4478. [https://doi.org/10.1021/acs.cgd.0c00287]Supplementary material: [https://hdl.handle.net/21.15107/rcub_dais_9452
Synthesis of Sulfur-Containing Exo -Bicyclic Dienes and Their Diels-Alder Reactions to Access Thiacycle-Fused Polycyclic Systems
International audienceThe stereocontrolled synthesis of unprecedented sulfur-containing exo-bicyclic 1,3-dienes is reported through a palladium-catalyzed reductive cyclization of sulfur-linked 2-bromoenynes. The fused bicyclic structure provides a better stability to the thiacyclic diene compared to the simple 3,4-dimethylenetetrahydrothiophene. Their reactivity toward several dienophiles has been investigated, and various original thiacycle-fused polycyclic systems have been obtained with high or total diastereoselectivity. Moreover, they are the first exo-bicyclic dienes used in Diels–Alder reactions. The relative configurations of four cycloadducts have been unambiguously assigned by X-ray crystallographic analysis. Mechanistic details of the cycloadditions have been examined by computational means
Regulation of branched-chain amino acid biosynthesis by alpha-acetolactate decarboxylase in Streptococcus thermophilus
Aims: To demonstrate the presence of an active alpha-acetolactate decarboxylase in Streptococcus thermophilus and to investigate its physiological function.
Methods and Results: Streptococcus thermophilus CNRZ385 contains a gene encoding an alpha-acetolactate decarboxylase. Comparison of the production of alpha-acetolactate and its decarboxylation products, by the parent strain and an alpha-acetolactate decarboxylase-deficient mutant, demonstrated the presence of a control of the pool of alpha-acetolactate by valine, leucine and isoleucine. This control occurs via an allosteric activation of the alpha-acetolactate decarboxylase. Cell-free extracts of S. thermophilus were not able to decarboxylate the isoleucine precursor alpha-acetohydroxybutyrate.
Conclusions: These results strongly suggest that one of the physiological functions of the alpha-acetolactate decarboxylase in S. thermophilus is to regulate leucine and valine biosynthesis by diverting the flux of alpha-acetolactate towards acetoin when the branched-chain amino acids are present at a high concentration.
Significance and Impact of the Study: Regulation of branched-chain amino acid biosynthesis by alpha-acetolactate decarboxylase may occur in several other micro-organisms and explain some of their growth properties
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