The validity of chemical reaction mechanistic domains defined by skin sensitisation in the Quantitative Structure-Activity Relationship (QSAR) ecotoxicity system, KAshinhou Tools for Ecotoxicity (KATE), March 2009 version, has been assessed and an external validation of the current KATE system carried out. In the case of the fish end-point, the group of chemicals with substructures reactive to skin sensitisation always exhibited higher root mean square errors (RMSEs) than chemicals without reactive substructures under identical C- or log P-judgements in KATE. However, in the case of the Daphnia end-point this was not so, and the group of chemicals with reactive substructures did not always have higher RMSEs: the Schiff base mechanism did not function as a high error detector. In addition to the RMSE findings, the presence of outliers suggested that the KATE classification rules needs to be reconsidered, particularly for the amine group. Examination of the dependency of the organism on the toxic action of chemicals in fish and Daphnia revealed that some of the reactive substructures could be applied to the improvement of the KATE system. It was concluded that the reaction mechanistic domains of toxic action for skin sensitisation could provide useful complementary information in predicting acute aquatic ecotoxicity, especially at the fish end-point.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1080/1062936X.2011.569944 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Chiral medium-sized rings, albeit displaying attractive properties for drug development, suffer from numerous synthetic challenges due to difficult cyclization steps that must take place to form these unusually strained, atropisomeric rings from sterically crowded precursors. In fact, catalytic enantioselective cyclization methods for the formation of chiral seven-membered rings are unknown, and the corresponding eight-membered variants are also sparse. In this work, we present a substrate preorganization-based, enantioselective, organocatalytic strategy to construct seven- and eight-membered rings featuring chirality that is intrinsic to the ring in the absence of singular stereogenic atoms or single bond axes of chirality.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry and Materials Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
The Nozaki-Hiyama-Kishi reaction offers effective and reliable strategies for the preparation of alcohols via carbon-carbon bond formation. Typical methods usually require stoichiometric amounts of chromium salts, co-transition metals, and auxiliary reagents, which limits their practical application in industrial chemistry. To mitigate these limitations, substantial efforts have been made to develop chromium-catalytic approaches.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
A 1,1-hydroboration of alkynylgermanes with unique -Ge/B stereochemistry under transition-metal-free conditions is reported. Mechanistic studies suggest that a pathway involving α-boration followed by a stepwise 1,2-Ge/H shift on the intermediate structurally lies between an alkyne-Ge π complex and a typical vinyl cation. The resulting Ge/B bimetallic modules, along with a /Ge/B trimetallic variant, can be conveniently transformed into trisubstituted olefins through iterative divergent cross-coupling.
View Article and Find Full Text PDFJ Org Chem
January 2025
College of Chemistry and Chemical Engineering, Green Catalysis & Synthesis Key Laboratory of Xinyang City, Xinyang Normal University, Xinyang 464000, China.
A novel and efficient method for the intermolecular hydroxysulfonylation of vinylarenes using sodium sulfinates has been achieved through aerobic copper catalysis. This transformation proceeded smoothly with green air as the terminal oxidant in the presence of Cu (I)/1,10-phenanthroline as an efficient catalytic system, leading to an array of β-hydroxysulfones in moderate to high yields. The significant advantages of this protocol are the mild reaction conditions, readily available starting materials, good functional-group compatibility, synthetic convenience, and practicability.
View Article and Find Full Text PDFInorg Chem
January 2025
Institute of Chemistry, Université de Strasbourg, CNRS, Strasbourg 67000, France.
The present study details the synthesis and characterization of a robust, monomeric Al-H aluminate supported by a tridentate -phenolate ligand, isolated as [][Li(THF)] and [][N(Bu)] salts, which were then exploited as CO hydroboration catalysts. As initial reactivity studies, it was observed that the nucleophilic Al-H anion in [][C] (C = countercation [Li(THF)] or [N(Bu)]) reacts fast with CO, to afford the corresponding Al-formate complexes [][C], which were isolated and structurally characterized. Such anions were then exploited as potential CO reduction catalysts.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!