Nucleophilic addition of water and of methanol to 3,6-diamino-2,4,5,7-tetrabromo-9-[2-(methoxycarbonyl) phenyl]-9H-xanthen-9-ylium, 4BrR123, yields respectively 2-(3,6-diamino-2,4,5,7-tetrabromo-9-hydroxy-9H-xanthen-9-yl)xanthyl benzoate, HO4BrR123 and 2-(3,6-diamino-2,4,5,7-tetrabromo-9-methoxy-9H-xanthen-9-yl)xanthyl benzoate, MeO4BrR123. The novel experimental results are addressed theoretically. The linear free energy relationship, LFER, second-order perturbation theory analysis of the natural bond orbital, NBO, and quantum theory of atoms in molecules, QTAIM, lead to the same conclusion: the electron-withdrawing effect of bonded Br atoms in 4BrR123 extremely enhances the molecular electrophilicity, as compared to 3,6-diamino-9-[2-(methoxycarbonyl) phenyl]-9H-xanthen-9-ylium, R123. The reactivity of these diaminoxanthylium cations is discussed in the context of local and global softness in extended conjugated systems.
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http://dx.doi.org/10.1021/jp307461m | DOI Listing |
J Am Chem Soc
December 2024
Department of Chemistry and Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei 106319, Taiwan (R.O.C.).
Reactive carbonyl species (RCS) are important biomarkers of oxidative stress-related diseases because of their highly reactive electrophilic nature. Despite their potential as triggers for prodrug activation, selective labeling approaches for RCS remain limited. Here, we utilized triphenylphosphonium groups to chemoselectively capture RCS via an aqueous Wittig reaction, forming α,β-unsaturated carbonyls that enable further functionalization.
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December 2024
Organic Chemistry Division, CSIR-National Chemical Laboratory (CSIR-NCL) Pune 411 008 India
The isoquinoline core is present in one of the largest subsets of bioactive natural products. The multifunctional isoquinoline core exerts diverse bioactivity, resulting in the development of numerous isoquinoline-based drugs and molecules that are currently under clinical trials. We developed a new approach for phosphite-mediated [1,2] alkyl migration for an overall -C-H alkylation -alkylation of isoquinoline.
View Article and Find Full Text PDFChem Sci
December 2024
Department of Chemistry, School of Science, Westlake University 310030 Hangzhou Zhejiang Province China.
Sulfonium is an electrophilic and biocompatible group that is widely applied in synthetic chemistry on small molecules. However, there have been few developments of peptide or protein-based sulfonium tools. We recently reported sulfonium-mediated tryptophan crosslinking and developed NleSme2 (norleucine-dimethylsulfonium) peptides as dimethyllysine mimics that crosslink site-specific methyllysine readers.
View Article and Find Full Text PDFBeilstein J Org Chem
December 2024
LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, NOVA FCT , 2829-516 Caparica, Portugal.
The reactivity of our recently disclosed hypervalent iodine reagents (HIRs) bearing a benzylamine with in situ-generated sulfenate salts was investigated. Under the studied conditions sulfonamides have been obtained in up to 52% yield. This reaction has been extended to a variety of HIRs and sulfenate salts to explore the different reactivity of these new reagents.
View Article and Find Full Text PDFChem Asian J
December 2024
Ashoka University, Chemistry, Rajiv Gandhi Educational Hub, India, 131029, Sonipat, INDIA.
The catalytic efficiency of M-H2tpda pincer complexes (M = Mn(I), Fe(II), Co(III)) in CO2 hydrogenation, emphasizing the role of transition metal center variability have been discussed. The DFT analysis demonstrates that complexes with low αR values form weaker M-H bonds, enhancing catalyst reactivity with the elongation of M-H bond. The analysis further displays excellent catalytic performance for Mn-H2tpda (ΔE = 20.
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