ISSN / EISSN : 0040-4039 / 0040-4039
Published by: Elsevier BV (10.1016)
Total articles ≅ 103,303
Latest articles in this journal
Tetrahedron Letters, Volume 76; doi:10.1016/j.tetlet.2021.153266
Tetrahedron Letters, Volume 76; doi:10.1016/s0040-4039(21)00505-0
Tetrahedron Letters, Volume 76; doi:10.1016/s0040-4039(21)00508-6
Tetrahedron Letters, Volume 76; doi:10.1016/s0040-4039(21)00509-8
Tetrahedron Letters, Volume 75; doi:10.1016/j.tetlet.2021.153202
We report the metal-free chalcogenation of cycloketone oxime esters with dichalcogenides via a radical process. Because of the metal-free condition and use of readily accessible dichalcogenides, this method is an effective and green strategy for the synthesis of chalcogen-substituted butyronitrile.
Tetrahedron Letters, Volume 75; doi:10.1016/j.tetlet.2021.153205
Three pairs of isocoumarin enantiomers, (±)-prunomarin A (1), (±)-pestalactone B (2), and (±)-3, including three new compounds, (+)-/(−)-1 and (+)-2, were isolated from the endophytic fungus Phomopsis prunorum (F4-3). These enantiomeric pairs were existed as partial racemates and were achieved by chiral-HPLC separation. Their structures were elucidated by comprehensive spectroscopic data, X-ray diffraction, and ECD analysis. Compounds (±)-1 represented the first examples of naturally occurring sulfoxide-containing isocoumarin derivatives. Compound 1 showed anti-inflammatory activity for NO production with an IC50 value of 84.2 µM. Compounds (+)-/(−)-3 exhibited strong phytotoxicity against Amaranthus retroflexus.
Tetrahedron Letters, Volume 75; doi:10.1016/j.tetlet.2021.153204
Iron is an essential nutrient to nearly all living beings. However, its acquisition poses a significant challenge to many organisms, including most bacteria. One of the main iron uptake strategies employed by bacteria is the uptake of siderophores, small molecules that chelate extracellular iron. The pathogenic species Pseudomonas aeruginosa produces two different siderophores, pyochelin and pyoverdine. P. aeruginosa senses the amount of bioavailable extracellular iron in order to regulate the production levels of each of these two siderophores. In previous work, we found that a series of pyochelin biosynthetic shunt products enhanced the growth of P. aeruginosa in iron- depleted conditions when prechelated with iron. Thus, on the basis of these results, we investigated the physiochemical and biological properties of a series of non-native oxygen counterparts to these metabolites in the current study.
Tetrahedron Letters; doi:10.1016/j.tetlet.2021.153248
Small molecules that selectively bind to the pseudokinase JH2 domain over the JH1 kinase domain of JAK2 kinase are sought. Virtual screening led to the purchase of 17 compounds among which 9 were found to bind to V617F JAK2 JH2 with affinities of 40 – 300 μM in a fluorogenic assay. Ten analogues were then purchased yielding 9 additional active compounds. Aminoanilinyltriazine 22 was particularly notable as it shows no detectable binding to JAK2 JH1, and it has a 65-μM dissociation constant Kd with V617F JAK2 JH2. A crystal structure for 22 in complex with wild-type JAK2 JH2 was obtained to elucidate the binding mode. Additional de novo design led to the synthesis of 19 analogues of 22 with the most potent being 33n with Kd values of 2–3 μM for WT and V617F JAK2 JH2, and with 16-fold selectivity relative to binding with WT JAK2 JH1.
Tetrahedron Letters; doi:10.1016/j.tetlet.2021.153246
Synthesis of a novel compound, which possibly carries N → N coordination interaction has been achieved. In this species, the lone pair of electrons from a nitrogen atom of 1,3,5-trimethyl-1,2,4-triazole moiety has been found to be donated to an N+ centre. Electronic structure analysis including EDA (Energy Decomposition Analysis) of the compound supports the presence of coordination interactions between ligands and central nitrogen atom.
Tetrahedron Letters; doi:10.1016/j.tetlet.2021.153250
Fluspidine is a high affinity ligand of the σ1 receptor. To further improve the ligand affinity, fluspidine analogs were systematically synthesized and screened herein. To design the modified ligand analogs, a docking simulation of the protein–ligand complex structure was examined. By using the developed synthetic strategy involving asymmetric catalytic 1,4-reduction of α,β -unsaturated carboxylic esters catalyzed by a chiral cobalt complex, 20 candidates of modified fluspidines were synthesized. The structure–activity relationships showed the development of a hybridized modified fluspidine. In addition, the inhibitory rate could be improved from 45% to 71%. This result demonstrates the importance of the development of a new synthetic method towards improving the ligand performance by providing a series of analogs.