36440-58-1Relevant academic research and scientific papers
Nickel-Catalyzed Asymmetric Hydrogenation of γ-Keto Acids, Esters, and Amides to Chiral γ-Lactones and γ-Hydroxy Acid Derivatives
Guo, Qianling,Hou, Guohua,Huang, Yuping,Xiao, Guiying,Xie, Chaochao,Zi, Guofu
supporting information, p. 2722 - 2727 (2022/04/19)
A highly efficient asymmetric hydrogenation of a series of γ-keto acid derivatives, including γ-keto acids, esters, and amides, using a Ni-(R,R)-QuinoxP? complex as the catalyst has been developed to afford chiral γ-hydroxy acid derivatives with excellent enantioselectivities, up to 99.9% ee. This method provides not only an economical one-pot approach for the synthesis of chiral γ-lactones but also access to (S)-norfluoxetine, an inhibitor of neural serotonin reuptake and an essential intermediate for pharmaceutical synthesis.
Enantioselective C-H Amination Catalyzed by Nickel Iminyl Complexes Supported by Anionic Bisoxazoline (BOX) Ligands
Dong, Yuyang,Lund, Colton J.,Porter, Gerard J.,Clarke, Ryan M.,Zheng, Shao-Liang,Cundari, Thomas R.,Betley, Theodore A.
supporting information, p. 817 - 829 (2021/02/03)
The trityl-substituted bisoxazoline (TrHBOX) was prepared as a chiral analogue to a previously reported nickel dipyrrin system capable of ring-closing amination catalysis. Ligand metalation with divalent NiI2(py)4 followed by potassium graphite reduction afforded the monovalent (TrHBOX)Ni(py) (4). Slow addition of 1.4 equiv of a benzene solution of 1-adamantylazide to 4 generated the tetrazido (TrHBOX)Ni(κ2-N4Ad2) (5) and terminal iminyl adduct (TrHBOX)Ni(NAd) (6). Investigation of 6 via single-crystal X-ray crystallography, NMR and EPR spectroscopies, and computations revealed a Ni(II)-iminyl radical formulation, similar to its dipyrrinato congener. Complex 4 exhibits enantioselective intramolecular C-H bond amination to afford N-heterocyclic products from 4-aryl-2-methyl-2-azidopentanes. Catalytic C-H amination occurs under mild conditions (5 mol % catalyst, 60 °C) and provides pyrrolidine products in decent yield (29%-87%) with moderate ee (up to 73%). Substrates with a 3,5-dialkyl substitution on the 4-aryl position maximized the observed enantioselectivity. Kinetic studies to probe the reaction mechanism were conducted using 1H and 19F NMR spectroscopies. A small, intermolecular kinetic isotope effect (1.35 ± 0.03) suggests an H-atom abstraction step with an asymmetric transition state while the reaction rate is measured to be first order in catalyst and zeroth order in substrate concentrations. Enantiospecific deuterium labeling studies show that the enantioselectivity is dictated by both the H-atom abstraction and radical recombination steps due to the comparable rate between radical rotation and C-N bond formation. Furthermore, the competing elements of the two-step reaction where H-removal from the pro-R configuration is preferred while the preferential radical capture occurs with the Si face of the carboradical likely lead to the diminished ee observed, as corroborated by theoretical calculations. Based on these enantio-determining steps, catalytic enantioselective synthesis of 2,5-bis-tertiary pyrrolidines is demonstrated with good yield (50-78%) and moderate ee (up to 79%).
Synthesis of Enantiopure γ-Lactones via a RuPHOX-Ru Catalyzed Asymmetric Hydrogenation of γ-Keto Acids
Li, Jing,Ma, Yujie,Lu, Yufei,Liu, Yangang,Liu, Delong,Zhang, Wanbin
supporting information, p. 1146 - 1153 (2019/01/30)
A RuPHOX?Ru catalyzed asymmetric hydrogenation of γ-keto acids has been developed, affording the corresponding enantiopure γ-lactones in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 10000 S/C) under the indicated reaction conditions and the resulting products can be transformed to several enantiopure building blocks, biologically active compounds and enantiopure drugs. (Figure presented.).
Synthesis and antimicrobial activity of some novel oxadiazole derivatives
Islam, Mojahidul,Siddiqui, Anees A.,Rajesh, Ramadoss,Bakht, Afroz,Goyal, Sunil
experimental part, p. 441 - 447 (2009/04/07)
A series of 5-{3′-oxo-6′-(substituted aryl)-2′,3′, 4′,5′-tetrahydropyridazin-2′-ylmethyl}-2-substituted 1,3,4-oxadiazole has been synthesized. Appropriate aromatic hydrocarbon reacts with succinic anhydride in the presence of AlCl3 to yield β-aroyl propionic acid (1a). The corresponding acid is cyclized with hydrazine hydrate to give 6-(substituted aryl)-2,3,4,5-tetrahydro-3-pyridazinone (1b).This ntermediate after reaction with ethyl bromoacetate, was hydrazinolyzed into 3-oxo-6-(substituted aryl)-2, 3, 4, 5-tetrahydropyridazinyl acetohydrazide (1c).The resulting product was converted into 5-{3′-oxo-6′-(substituted aryl)-2′,3′,4′,5′- tetrahydropyridazin-2′-ylmethyl]-2-substituted 1,3,4-oxadiazole (Scheme 1). All the final compounds were structurally elucidated on the basis of IR, 1H-NMR, MS data and elemental analysis and screened for antibacterial, antifungal and antitubercular activity. All the compounds are evaluated for their antibacterial activity against E. coli, S. aureus, Miavcoccus luteus and Klebsiella pneumoniae by using cup plate technique in the nutrient agar at 100 μg/mL concentration. Antitubercular activity was determined using the BACTEC 460 system. Stock solutions of test compounds were prepared in DMSO. MIC of rifampin was calculated by established procedures.All the synthesized compounds were screened at 6.25 μg/mL against M. tuberculosis H37 Rv comparable with that of standard rifampicin and isoniazid. All the final compounds were evaluated for antifungal activity against C. albicans and C. neoformans by using cup-plate method in the Sabouraud agar media The zone of inhibition (mm) of each compound was determined and compared with standard drug fluconazole.
Synthesis, antitubercular, antifungal and antibacterial activities of 6-substituted phenyl-2-(3′-substituted phenyl pyridazin-6′-yl)-2,3, 4,5-tetrahydropyridazin-3-one
Islam, Mojahidul,Siddiqui, Anees A.,Rajesh, Ramadoss
experimental part, p. 353 - 362 (2009/04/11)
A series of 6-substituted phenyl-2-(3′-substituted phenyl pyridazin-6′-yl)-2,3,4,5-tetrahydropyridazin-3-ones has been synthesized. An appropriate aromatic hydrocarbon reacts with succinic anhydride in presence of AlCl3 to yield β-aroyl propionic acid. The corresponding acid was cyclized with hydrazine hydrate to give 6-(substituted aryl)-2,3,4,5- tetrahydro-3-pyridazinone, which was heated on steam bath with phosphorus( V) oxychloride to yield 3-chloro 6-substituted phenyl pyridazine. This intermediate after reaction with hydrazine hydrate was converted into 3-hydrazino-6- substituted phenyl pyridazine. The resulting product was converted into 6-substituted phenyl-2-(3′-substituted phenyl pyridazin-6′-yl)-2,3, 4,5-tetrahydropyridazin-3-one by reacting with substituted aroyl propionic acid. Spectral data (IR, NMR, mass spectra) confirmed the structures of the synthesized compounds. The synthesized compounds were investigated for their in vitro antitubercular, antifungal and antibacterial activities. The results indicated that the synthesized compounds have mild to potent activities with reference to their appropriate reference standards.
