Chinese Journal of Chemistry最新文献

Legionaminic acid (Leg) is a bacteria-specific nonulosonic acid that has emerged as a promising target for the development of pathogen diagnostics and vaccines, especially against critical-priority Acinetobacter baumannii. However, immunological studies of Leg-containing glycoconjugates remain largely unexplored due to the limited availability of structurally well-defined Leg glycosides. Herein, we developed an additive-controlled glycosylation strategy using a 5-N,4-O-carbonyl-protected Leg thioglycoside donor, which enabled the stereoselective synthesis of both α- and β-linked Leg glycosides. To assess their immunological properties, these Leg glycosides were further elaborated into two Leg5,7NAc2-CRM197 glycoconjugates. Immunological evaluation revealed that Leg functions as an antigenic epitope whose antibody specificity is governed by its anomeric configuration.

Perovskite solar cells (PSCs) have reached power conversion efficiencies (PCEs) over 27%, yet further improvements in stability remain critical. Surface passivation is an effective strategy to reduce defects and enhance device durability. Inorganic passivation, in particular, offers stronger chemical bonding and denser protection against moisture and oxygen compared to organic small molecules. Recent studies have employed mild organic ligands to introduce inorganic anions, creating an inorganic passivation layer on the perovskite surface. Here, we report a solution-based passivation approach using sulfate salts coordinated with butylamine, hexylamine, and octylamine, spin-coated onto perovskite surfaces. By tuning the alkylamine chain length, we modulate the passivation effect. With hexylamine sulfate treatment, we achieve a champion PCE of 26.3% for small-area devices and 23.4% for mini solar modules with an active area of 20.8 cm². Moreover, under continuous illumination at 60 °C during maximum power point (MPP) tracking, the devices retain 97.2% of their initial efficiency after 600 h. Our results demonstrate that ligand-optimized inorganic passivation using alkylammonium sulfates enables both high efficiency and excellent operational stability.

The development of sustainable methods for the oxidation of alcohols to aldehydes or ketones remains an important goal in synthesis. In this work, we synthesized a series of nitrate-bearing oxoammonium salts and demonstrated their efficiency as metal-free catalysts for the aerobic oxidation of alcohols. These catalysts operate under mild conditions and exhibit a broad substrate scope, efficiently oxidizing both primary and secondary alcohols. The catalytic system performs effectively on a gram scale with industrially relevant substrates, providing a valuable alternative to current protocols. The system operates via a hydride-transfer mechanism and a self-sustained NOₓ-mediated redox cycle, with molecular oxygen as the terminal oxidant.

Benzo[d]isothiazole motif has emerged as a privileged structure in medicinal chemistry and agricultural science. However, conventional synthetic methods are plagued by tedious multistep procedures, low atom economy and harsh reaction conditions, rendering the development of a facile and convenient approach for the synthesis of compounds containing a benzo[d]isothiazole moiety highly desirable. We herein present a one-pot enantioselective protocol that integrates a dearomative (3+2) cycloaddition of 2-nitrobenzofurans with 2-(N-2,2,2-trifluoroethyl)benzothiophene-derived ketimines and a subsequent DPPH-mediated rearrangement. This methodology affords an efficient route to enantiomerically pure benzo[d]isothiazole-containing polyheterocyclic derivatives in excellent outcomes (up to 95% yield, > 20 : 1 dr and 99% ee). The synthetic utility of this protocol is further substantiated by scale-up synthesis, downstream transformations, as well as late-stage modification of biologically active molecules.

To advance organic solar cells (OSCs) commercialization, high efficiency and stable devices processed in air and eco-friendly conditions are essential. Herein, two siloxane-based additives, Th-SiO incorporating an electron-donating thiophene unit and Qx-SiO incorporating an electron-deficient quinoxaline unit, were developed. The two retained additives exhibited excellent multifunctionality. In the PM6:L8-BO system, they could effectively regulate intermolecular interactions and active layer morphology, optimize charge transport, and suppress charge recombination. The two additives significantly enhanced the photovoltaic performance of devices fabricated under N₂ and high-humidity air conditions, while also enabling high-performance air processing with a non-halogenated green solvent. Both additives showed good universality. When using 2PACz as the hole transporting layer material, Th-SiO-processed D18:L8-BO devices achieved an efficiency of 20.39%. In the PM6:L8-BO system, the additives Th-SiO and Qx-SiO improved the light and thermal stabilities of the devices simultaneously, yet exhibited different characteristics: Qx-SiO-processed devices showed superior light stability, whereas Th-SiO-processed devices exhibited better thermal stability. The research provides valuable insights for the chemical structure design of novel multifunctional additives.

Irradiation of a mixture of vinyldiazo esters and azides with blue light, in the absence of any photocatalyst or additive, generates unconventional β-diazoimines. Mechanistically, the reaction involves the selective decomposition of vinyldiazo compounds under blue light to form singlet free vinylcarbenes, which undergo intramolecular [2+1] cyclization to produce unstable cyclopropene-1-carboxylates. These intermediates subsequently participate in a 1,3-dipolar cycloaddition with azides, followed by ring-opening via retro-1,3-dipolar cycloaddition to generate β-diazoimines. One-pot, diazo-preserving diversifications of β-diazoimines provide access to α-diazoesters bearing distal functional groups that are otherwise difficult to introduce. These transformations include nucleophilic addition and reduction to give γ-amino-α-diazoacetates, as well as oxidation to afford β-carboxamido-α-diazoesters. The synthetic potential of these unusual diazo compounds was demonstrated. For example, Rh(II)-catalyzed N–H insertion of γ-amino-α-diazoester afforded azetidine, while reduction of its diazo group with PⁿBu₃ promoted an intramolecular aminolysis to yield a γ-lactam product. Interestingly, controllable intramolecular 1,3-C–H and 1,4-N–H insertion reactions of β-carboxamido-α-diazoester were achieved using different catalyst systems, providing cyclopropane and β-lactam derivatives, respectively.