22065-57-2Relevant articles and documents
White-light emission from a structurally simple hydrazone
Shao, Baihao,Stankewitz, Nell,Morris, Jacob A.,Liptak, Matthew D.,Aprahamian, Ivan
, p. 9551 - 9554 (2019)
Two hydrazones featuring a unique excitation wavelength-dependent dual fluorescence emission have been developed. The mixing extent of the two emission bands can be modulated by tuning the excitation wavelength, resulting in multicolor and even white light emission from structurally simple hydrazones.
Semi-Synthesis of C-Ring Cyclopropyl Analogues of Fraxinellone and Their Insecticidal Activity against Mythimna separata Walker
Dong, Qing-Miao,Tang, Jiang-Jiang,Wang, Min-Ran,Yang, Xiao-Jun
, (2020)
Fraxinellone (1) is a naturally occurring degraded limonoid isolated from Meliaceae and Rutaceae plants. As a potential natural-product-based insecticidal agent, fraxinellone has been structurally modified to improve its activity. Furan ring of fraxinellone is critical in exhibiting its insecticidal activity, but with few modifications. Herein, C-ring-modified cyclopropyl analogues were semi-synthesized by Rh(II)-catalyzed cyclopropanation. The structures of the target compounds were well characterized by NMR and HRMS. The precise three-dimensional structural information of 3a was established by X-ray crystallography. Their insecticidal activity was evaluated against Mythimna separata Walker by a leaf-dipping method. Compound 3c exhibited stronger insecticidal activity than 1 and toosendanin against M. separata with teratogenic symptoms during the different periods, implying that cyclopropanation of the furan ring could strengthen the insecticidal activity of fraxinellone.
Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium-Catalyzed Carbene Insertion into Si?H Bonds
Franz, Annaliese K.,Jagannathan, Jake R.,Targos, Karina
supporting information, (2021/11/27)
We report carbene insertion into Si?H bonds of polyhedral oligomeric silsesquioxanes (POSS) for the synthesis of highly functionalized siloxane nanomaterials. Dirhodium(II) carboxylates catalyze insertion of aryl-diazoacetates as carbene precursors to afford POSS structures containing both ester and aryl groups as orthogonal functional handles for further derivatization of POSS materials. Four diverse and structurally varied silsesquioxane core scaffolds with one, three, or eight Si?H bonds were evaluated with diazo reactants to produce a total of 20 new POSS compounds. Novel diazo compounds containing a fluorinated octyl group and boron-dipyrromethene (BODIPY) chromophore demonstrate the use of highly functionalized substrates. Transformations of aryl(ester)-functionalized POSS compounds derived from this method are demonstrated, including ester hydrolysis and Suzuki–Miyaura cross-coupling.
Visible Light-Promoted Sulfoxonium Ylides Synthesis from Aryl Diazoacetates and Sulfoxides
Lu, Juan,Li, Lei,He, Xiang-Kui,Xu, Guo-Yong,Xuan, Jun
supporting information, p. 1646 - 1650 (2021/05/28)
A visible light-promoted reaction of donor/acceptor diazoalkanes with sulfoxides towards the synthesis of synthetically useful sulfoxonium ylides was reported. The reaction occurred under sole visible light irradiation without the need of any transition-metals or additives, affording the corresponding sulfoxonium ylides in moderate to good yields. The success of late-stage modification of natural isolates or drug candidates, scale-up reaction and transformation of sulfoxonium ylides to other useful molecules further rendered the approach valuable.
Copper-Catalyzed Oxidation of Hydrazones to Diazo Compounds Using Oxygen as the Terminal Oxidant
Liu, Wenbin,Twilton, Jack,Wei, Bo,Lee, Maizie,Hopkins, Melissa N.,Bacsa, John,Stahl, Shannon S.,Davies, Huw M. L.
, p. 2676 - 2683 (2021/03/03)
A mild method for accessing diazo compounds via aerobic oxidation of hydrazones is described. This catalytic transformation employs a Cu(OAc)2/pyridine catalyst and molecular oxygen from ambient air as the terminal oxidant, generating water as the sole byproduct and affording the desired diazo compounds within minutes at room temperature. A broad array of electronically diverse aryldiazo esters, ketones, and amides can be accessed. Pyridine dramatically enhances the rate of the reaction by solubilizing the copper catalyst and serving as the Br?nsted base in the turnover-limiting proton-coupled oxidation of hydrazone by copper(II). Insights gained from mechanistic studies led to expansion of the scope of this method to include diaryl hydrazones, delivering diaryl diazomethane derivatives, which cannot be accessed via established diazo transfer methods. The products of this method may be employed in rhodium carbene catalysis without isolation of the diazo intermediate to afford cyclopropane products in good yield with high enantioselectivity.
