89076-25-5Relevant academic research and scientific papers
Fundamental studies and development of nickel-catalyzed trifluoromethylthiolation of aryl chlorides: Active catalytic species and key roles of ligand and traceless MeCN additive revealed
Yin, Guoyin,Kalvet, Indrek,Englert, Ulli,Schoenebeck, Franziska
supporting information, p. 4164 - 4172 (2015/04/14)
A catalytic protocol to convert aryl and heteroaryl chlorides to the corresponding trifluoromethyl sulfides is reported herein. It relies on a relatively inexpensive Ni(cod)2/dppf (cod = 1,5-cyclooctadiene; dppf = 1,1′-bis(diphenylphosphino)ferrocene) catalyst system and the readily accessible coupling reagent (Me4N)SCF3. Our computational and experimental mechanistic data are consistent with a Ni(0)/Ni(II) cycle and inconsistent with Ni(I) as the reactive species. The relevant intermediates were prepared, characterized by X-ray crystallography, and tested for their catalytic competence. This revealed that a monomeric tricoordinate Ni(I) complex is favored for dppf and Cl whose role was unambiguously assigned as being an off-cycle catalyst deactivation product. Only bidentate ligands with wide bite angles (e.g., dppf) are effective. These bulky ligands render the catalyst resting state as [(P-P)Ni(cod)]. The latter is more reactive than Ni(P-P)2, which was found to be the resting state for ligands with smaller bite angles and suffers from an initial high-energy dissociation of one ligand prior to oxidative addition, rendering the system unreactive. The key to effective catalysis is hence the presence of a labile auxiliary ligand in the catalyst resting state. For more challenging substrates, high conversions were achieved via the employment of MeCN as a traceless additive. Mechanistic data suggest that its beneficial role lies in decreasing the energetic span, therefore accelerating product formation. Finally, the methodology has been applied to synthetic targets of pharmaceutical relevance.
Synthesis and structure-activity relationships of benzophenone hydrazone derivatives with insecticidal activity
Boeger, Manfred,Duerr, Dieter,Gsell, Laurenz,Hall, Roger G.,Karrer, Friedrich,Kristiansen, Odd,Maienfisch, Peter,Pascual, Alfons,Rindlisbacher, Alfred
, p. 191 - 202 (2007/10/03)
A broad range of benzophenone hydrazone derivatives was prepared and tested against selected chewing insect pests, allowing the analysis of structure-activity relationships. Good activity was found only when the aromatic rings were substituted at the 4-positions with an halogen atom and a triflate or perhaloalkoxy group. In contrast, a number of substituents on the hydrazone part led to active compounds, the best results being achieved with acyl-type substituents. The excellent laboratory and greenhouse activity of the best representatives was confirmed in semi-field trials against Spodoptera littoralis. ° 2001 Society of Chemical Industry.
Synthesis and insecticidal activity of 4-perhaloalkoxy (or thioalkyl) benzophenonehydrazone derivatives
Duerr, Dieter,Gsell, Laurenz,Hall, Roger G.,Karrer, Friedrich,Pascual, Alfons,Rindlisbacher, Alfred
, p. 584 - 587 (2007/10/03)
Benzophenonehydrazone derivatives containing a mesylate or triflate substituent are known to exhibit insecticidal activity. In the present study, such substituents have been replaced by perhaloalkoxy groups. High levels of activity against lepidopteran pests were observed in greenhouse trials. For optimum activity, the substituents should be relatively small. In semi-field trials, however, none of the compounds tested showed sufficient persistence to warrant further development.
