- Ruthenium(II) complexes bearing bidentate acylthiourea ligands for direct oxidation of amine α-carbon to amide
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In this study, the synthesis and structural characterization of ruthenium complexes supported by S,O-acylthiourea ligands (L1-L6) with different substituent groups as well as auxiliary ligands PPH3, CO, and Cl and their evaluation as catalysts for direct oxidation of the α-methylene group in amines were reported. Ru(II) complexes, Ru1-Ru6, were prepared from the reaction of the RuH(CO)Cl(PPh3)3 precursor and ligands L1-L6 having different electronic and steric properties. The ligands and complexes prepared were characterized by FT-IR, 1H–13C- and/or 31P NMR spectroscopic techniques. The molecular structures of Ru1 and Ru3 complexes with appropriate crystal quality were also confirmed by X-ray single crystal analysis. Solid-state structures of Ru1 and Ru3 revealed that the ruthenium center is surrounded by one carbonyl, one chloride, two PPh3 ligands, and the S,O-donor atoms from the acylthiourea ligand in bidentate monoanionic form. The catalytic activity of all complexes for the α-oxygenation reactions of primary benzylic amines to amides was investigated. Overall, all catalysts exhibited excellent activity and selectivity towards the formation of amide production under the present reaction conditions. In addition, both catalyst activation and product selectivity/formation were particularly dependent on the amount/type of base and oxygen.
- Aslan, Muhammed,Gumus, Ilkay
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- Thiosemicarbazones and thiadiazines derived from fluorinated benzoylthioureas: Synthesis, crystal structure and anti-Trypanosoma cruzi activity
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A series of thiosemicarbazones was obtained by condensation of halogenated N-(diethylaminothiocarbonyl)benzimidoyl chlorides (3b–3h) with 4,4-dimethyl-3-thiosemicarbazide. The activity of the halogenated compounds against the parasite Trypanosoma cruzi was evaluated and compared to the previously reported activity of the corresponding non-substituted thiosemicarbazone. It was found that the halogen-substitution enhances in most cases the anti-parasitic activity. The meta-fluorinated compound (4g) was identified as the most potent one (IC50= 9.0 μM, CC50 > 200 μM), having a selectivity index (SI = IC50/CC50), which is 4-times higher than that of the non-substituted compound. Slight modification of the reaction conditions employed for the synthesis of some of the benzoylthioureas 3a–3g led to the unexpected formation of novel halogenated 6-amino-1,3,5-thiadiazine-2-thiones.
- Salsi, Federico,Bulh?es Portapilla, Gisele,Schutjajew, Konstantin,Carneiro, Zumira Aparecida,Hagenbach, Adelheid,de Albuquerque, Sérgio,da Silva Maia, Pedro Ivo,Abram, Ulrich
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- Fluorine hydrogen short contacts and hydrogen bonds in substituted benzamides
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A series of fluorine substituted benzamides 1-10 was synthesised and investigated by spectroscopic methods (NMR, IR, MS) and X-ray structure analysis. The configuration of these compounds strongly depends on solvent, temperature and substitution pattern.
- Hennig, Lothar,Ayala-Leon, Ketty,Angulo-Cornejo, Jorge,Richter, Rainer,Beyer, Lothar
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experimental part
p. 453 - 460
(2009/12/04)
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