60018-13-5Relevant articles and documents
Sulfonium ion-promoted traceless Schmidt reaction of alkyl azides
Ardiansah, Bayu,Kakiuchi, Kiyomi,Morimoto, Tsumoru,Tanimoto, Hiroki,Tomohiro, Takenori
, p. 8738 - 8741 (2021/09/08)
Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction through 1,2-migration of C-H and C-C bonds was accessible to the one-pot substitution reaction.
Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
supporting information, p. 18591 - 18598 (2021/06/28)
A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
Efficient preparation and application of monodisperse palladium loaded graphene oxide as a reusable and effective heterogeneous catalyst for suzuki cross-coupling reaction
Diler, Fatma,Burhan, Hakan,Genc, Hayriye,Kuyuldar, Esra,Zengin, Mustafa,Cellat, Kemal,Sen, Fatih
, (2019/11/29)
A homogeneously dispersed graphene oxide supported palladium nanomaterial (Pd?GO) has been successfully synthesized and used as a catalyst in cross-coupling reactions at room temperature. Various analytical techniques such as X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) were used to characterize the monodisperse Pd?GO. Monodisperse Pd?GO nanomaterials were used for the cross-coupling reactions which brought together organic molecules with functional significance. This catalyst showed superior catalytic activity and stability for these coupling reactions. High product yields, short reaction times and mild reaction conditions, obtained by the using of developed catalysts. Importantly, the catalyst can be used at least five experiments successfully without losing its efficiency.
Fine-Bubble-Slug-Flow Hydrogenation of Multiple Bonds and Phenols
Iio, Takuya,Nagai, Kohei,Kozuka, Tomoki,Sammi, Akhtar Mst,Sato, Kohei,Narumi, Tetsuo,Mase, Nobuyuki
supporting information, p. 1919 - 1924 (2020/11/09)
We describe a promising method for the continuous hydrogenation of alkenes or alkynes by using a newly developed fine-bubble generator. The fine-bubble-containing slug-flow system was up to 1.4 times more efficient than a conventional slug-flow method. When applied in the hydrogenation of phenols to the corresponding cyclohexanones, the fine bubble-slug-flow method suppressed over-reduction. As this method does not require the use of excess gas, it is expected to be widely applicable in improving the efficiency of gas-mediated flow reactions.
Catalytic Access to Functionalized Allylic gem-Difluorides via Fluorinative Meyer–Schuster-Like Rearrangement
An, Rui,Li, Huimin,Liao, Lihao,Wu, Jin-Ji,Xu, Yang,Zhao, Xiaodan
supporting information, p. 11010 - 11019 (2020/05/18)
An unprecedented approach for efficient synthesis of functionalized allylic gem-difluorides via catalytic fluorinative Meyer–Schuster-like rearrangement is disclosed. This transformation proceeded with readily accessible propargylic fluorides, and low-cost B–F reagents and electrophilic reagents by sulfide catalysis. A series of iodinated, brominated, and trifluoromethylthiolated allylic gem-difluorides that were difficult to access by other methods were facilely produced with a wide range of functional groups. Importantly, the obtained iodinated products could be incorporated into different drugs and natural products, and could be expediently converted into many other valuable gem-difluoroalkyl molecules as well. Mechanistic studies revealed that this reaction went through a regioselective fluorination of alkynes followed by a formal 1,3-fluorine migration under the assistance of the B–F reagents to give the desired products.
Hydrogenation of hydrophobic substrates catalyzed by gold nanoparticles embedded in Tetronic/cyclodextrin-based hydrogels
Chevry,Menuel,Léger,No?l,Monflier,Hapiot
, p. 9865 - 9872 (2019/07/04)
Hydrogenation of alkenes, alkynes and aldehydes was investigated under biphasic conditions using Au nanoparticles (AuNP) embedded into combinations of α-cyclodextrin (α-CD) and a poloxamine (Tetronic90R4). Thermo-responsive AuNP-containing α-CD/Tetronic90R4 hydrogels are formed under well-defined conditions of concentration. The AuNP displayed an average size of ca. 7 nm and a narrow distribution, as determined by TEM. The AuNP/α-CD/Tetronic90R4 system proved to be stable over time. Upon heating above the gel-to-sol transition temperature, the studied catalytic system allowed hydrogenation of a wide range of substrates such as alkenes, alkynes and aldehydes under biphasic conditions. Upon repeated heating/cooling cycles, the Au NP/α-CD/Tetronic90R4 catalytic system could be recycled several times without a significant decline in catalytic activity.
Discovery of Lipophilic Bisphosphonates That Target Bacterial Cell Wall and Quinone Biosynthesis
Malwal, Satish R.,Chen, Lu,Hicks, Hunter,Qu, Fiona,Liu, Weidong,Shillo, Alli,Law, Wen Xuan,Zhang, Jianan,Chandnani, Neal,Han, Xu,Zheng, Yingying,Chen, Chun-Chi,Guo, Rey-Ting,Abdelkhalek, Ahmed,Seleem, Mohamed N.,Oldfield, Eric
supporting information, p. 2564 - 2581 (2019/03/07)
We report that alkyl-substituted bisphosphonates have activity against Bacillus anthracis Sterne (0.40 μg/mL), Mycobacterium smegmatis (1.4 μg/mL), Bacillus subtilis (1.0 μg/mL), and Staphylococcus aureus (13 μg/mL). In many cases, there is no effect of serum binding, as well as low activity against a human embryonic kidney cell line. Targeting of isoprenoid biosynthesis is involved with 74 having IC50 values of ～100 nM against heptaprenyl diphosphate synthase and 200 nM against farnesyl diphosphate synthase. B. subtilis growth inhibition was rescued by addition of farnesyl diphosphate, menaquinone-4 (MK-4), or undecaprenyl phosphate (UP), and the combination of MK-4 and UP resulted in a 25× increase in ED50, indicating targeting of both quinone and cell wall biosynthesis. Clostridioides difficile was inhibited by 74, and since this organism does not synthesize quinones, cell wall biosynthesis is the likely target. We also solved three X-ray structures of inhibitors bound to octaprenyl diphosphate and/or undecaprenyl diphosphate synthases.
Method for preparing dihydrocitronellal
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Paragraph 0053-0112, (2019/12/08)
The invention provides a method for preparing dihydrocitronellal. The method comprises the following steps of: taking raw material citral as a hydrogen acceptor, taking an alcohol compound as a hydrogen donor, and carrying out intermolecular hydrogen transfer reaction under the action of a catalyst system to obtain the dihydrocitronellal; the citral acid value is required to be less than 0.1 mg KOH/g; the catalyst system comprises heterogeneous nickel catalyst components including nickel, a carrier and bimetallic alkoxide. The method has the advantages of normal reaction pressure, low reactiontemperature, easy control, cheap and easily available catalyst, high product selectivity and raw material conversion rate, high byproduct selectivity, easy separation of the dihydrocitronellal by rectification, simple and feasible method, and suitability for industrial production.
An Atom-Economic and Stereospecific Access to Trisubstituted Olefins through Enyne Cross Metathesis Followed by 1,4-Hydrogenation
Ratsch, Friederike,Schmalz, Hans-Günther
supporting information, p. 785 - 792 (2018/01/27)
The combination of intermolecular enyne cross metathesis and subsequent 1,4-hydrogenation opens a stereocontrolled and atom-economic access to trisubstituted olefins. By investigating different combinations of functionalized alkyne and alkene substrates, we found that the outcome (yield, E / Z ratio) of the Grubbs II-catalyzed enyne cross-metathesis step depends on the substrate's structure, the amount of the alkene (used in excess), and the (optional) presence of ethylene. In any case, the 1,4-hydrogenation, catalyzed by 1,2-dimethoxybenzene-Cr(CO) 3, proceeds stereospecifically to yield exclusively the E -products from both the E- and Z- 1,3-diene intermediates obtained by metathesis. A rather broad scope and functional group compatibility of the method is demonstrated by means of 15 examples.
On the Use of Polyelectrolytes and Polymediators in Organic Electrosynthesis
Schille, Benjamin,Giltzau, Niels Ole,Francke, Robert
supporting information, p. 422 - 426 (2018/02/21)
Although organic electrosynthesis is generally considered to be a green method, the necessity for excess amounts of supporting electrolyte constitutes a severe drawback. Furthermore, the employment of redox mediators results in an additional separation problem. In this context, we have explored the applicability of soluble polyelectrolytes and polymediators with the TEMPO-mediated transformation of alcohols into carbonyl compounds as a test reaction. Catalyst benchmarking based on cyclic voltammetry studies indicated that the redox-active polymer can compete with molecularly defined TEMPO species. Alcohol oxidation was also highly efficient on a preparative scale, and our polymer-based approach allowed for the separation of both mediator and supporting electrolyte in a single membrane filtration step. Moreover, we have shown that both components can be reused multiple times.
