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A visible-light-induced directed decarboxylative disulfuration of α-keto acids and oxamic acids was developed. As a result, a series of versatile mono acyl disulfide derivatives was synthesized under mild and sustainable reaction conditions. This protocol has a broad substrate scope, good functional-group tolerance, and excellent synthetic applications. [ABSTRACT FROM AUTHOR]

The development of efficient heterostructures combining covalent organic frameworks (COFs) and ideal semiconductors can significantly improve photocatalytic performance for pollutant degradation. Herein, we present the design, synthesis, and characterization of a core‐shell‐structured nanocomposite comprising covalent triazine framework‐encased Fe3O4 magnetic particles employed as a heterojunction photocatalyst for activating peroxymonosulfate (PMS) in phenol degradation. The distinctive internal structure between the TpMa shell (Tp=2,4,6‐trihydroxy‐1,3,5‐benzenetricarboxaldehyde, Ma=melamine) and the Fe3O4 core (Fe3O4@TpMa) facilitated charge transfer and accelerated charge separation. Furthermore, PMS served as an electron acceptor, enhancing photogenerated charge separation and maximizing the production of reactive oxygen species. The Fe3O4@TpMa/PMS system demonstrated remarkable photocatalytic performance and stability, achieving complete phenol degradation (10 mg L−1) in 40 min. The exceptional photocatalytic activity resulted from the synergistic effect of ⋅OH, SO4⋅−, O2⋅−, 1O2, and h+ generated in the Fe3O4@TpMa/PMS system during the degradation process. Overall, this material offers excellent potential for solar‐driven pollutant degradation and enables the development of COF‐based materials for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted extensive attention as promising photocatalysts for CO2 reduction. However, there are few reports on the relationship between keto‐enol tautomerism and COFs photocatalyst activity. Three different β‐ketoenamine‐based COFs were prepared by varying the proportion of hydroxyl units in the aldehyde precursor, in which only the HCOF‐2 shows the structural features of the reversible keto‐enol tautomerism. Through density functional theory (DFT) calculations and experiments, the effects of keto‐enol tautomerism on the light absorption intensity, band position, band gap, and carrier separation of these COFs were investigated. The reversible keto‐enol tautomerism contributes to narrowing the band gap and promoting the light absorption capacity. In addition, the reversible keto‐enol tautomerism leads to molecular polarization, which promotes the separation and transmission of carriers within the material. As a result, HCOF‐2 exhibits optimal photocatalytic activity, yielding 309 and 96 μmol g−1 of CO and CH4 respectively within 10 h. This work provides an explanation of the relationship between keto‐enol tautomerism and photocatalytic activity. [ABSTRACT FROM AUTHOR]

α-Phenylglyoxylic acid is a novel cyclization reagent. In this study, three cyclization products were synthesized by the reaction of α-phenylglyoxylic acids with ortho -functionalized anilines in deep eutectic solvents (DES). The five-membered-ring-formation products, the 2-arylbenzothiazoles, with a highest yield of 88%, were obtained by the reaction between 0.30 mmol of an o -aminothiophenol and 0.30 mmol of an α-phenylglyoxylic acid in choline chloride (ChCl)/ d -(–)-tartaric acid DES at 60 °C for 0.5 h. The six-membered-ring-formation products, 3-aryl-2 H -benzo[ b ][1,4]oxazin-2-one derivatives, were obtained in yields up to 99% by the reaction between 0.30 mmol of an o -aminophenol and 0.60 mmol of an α-phenylglyoxylic acid in ChCl/urea DES at 80 °C for 2.0 h. In the reaction between 0.30 mmol of o -phenylenediamine and 0.45 mmol of an α-phenylglyoxylic acid in ChCl/anhydrous tin(II) chloride DES at 70 °C for 1.5 h, the six-membered-ring-formation products, 3-arylquinoxalin-2(1 H)-one derivatives, were synthesized, with a highest yield of 96%. This cyclization reaction occurred without the addition of other catalysts, and the title compounds were obtained with good yields under mild conditions. [ABSTRACT FROM AUTHOR]

This is the first report of a simple and general method for acetalization- of aldehydes via an α-chymotrypsin-induced reaction under mild conditions. A broad range of aromatic and heteroaromatic aldehydes have been acetalized under neutral conditions in good yields using a catalytic amount of chymotrypsin. [ABSTRACT FROM AUTHOR]