6091-44-7Relevant academic research and scientific papers
Photochemical synthesis, structure and spectroscopic properties of [W(CO)4(C5H10N)2CH2]
Koci?cka, Paulina,Kochel, Andrzej,Szymańska-Buzar, Teresa
, p. 105 - 107 (2014)
Dipiperidylmethane (CH2dipip) coordinates to photochemically created W(CO)4 species to give a tungsten(0) complex [W(CO) 4(CH2dipip)]. The structure of the new bidentate amine complex of tungsten(0) was established by spectroscopic methods (NMR, IR, UVVis) in solution and by single-crystal X-ray diffraction studies. A preliminary experiment indicates that the tungsten complex emits light at λmax. 556 nm, when it is excited by λmax. 523 nm in the solid state at room temperature.
Metal-Free Synthesis of Heteroaryl Amines or Their Hydrochlorides via an External-Base-Free and Solvent-Free C-N Coupling Protocol
Fan, Guang-Gao,Jiang, Bo-Wen,Sang, Wei,Cheng, Hua,Zhang, Rui,Yu, Bao-Yi,Yuan, Ye,Chen, Cheng,Verpoort, Francis
, p. 14627 - 14639 (2021/11/01)
Herein, a metal-free and solvent-free protocol was developed for the C-N coupling of heteroaryl halides and amines, which afforded numerous heteroaryl amines or their hydrochlorides without any external base. Further investigations elucidated that the basicity of amines and specific interactions derived from the X-ray crystallography analysis of 3j′·HCl played pivotal roles in the reactions. Moreover, this protocol was scalable to gram scales and applicable to drug molecules, which demonstrated its practical value for further applications.
PRODUCTION METHOD OF CYCLIC COMPOUND
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Paragraph 0057; 0059; 0061; 0063, (2021/05/05)
PROBLEM TO BE SOLVED: To provide an industrially simple production method of a cyclic compound. SOLUTION: A production method of a cyclic compound includes a step to obtain a reduced form (B) by reducing an unsaturated bond in a ring structure of an aromatic compound (A) by means of catalytic hydrogenation of the aromatic compound (A) or its salt using palladium carbon as a catalyst under a normal pressure, in which the aromatic compound (A) has one or more ring structures selected from a group consisting of a five membered-ring, a six membered-ring, and a condensed ring of the five membered-ring or the six membered-ring with another six membered-ring, a hetero atom can be included in the ring structure, and the aromatic compound (A) can have one or two side chains bonded to the ring structure and does not have any carbon-carbon triple bond in the side chain. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
Ceria supported Ru0-Ruδ+ clusters as efficient catalyst for arenes hydrogenation
Cao, Yanwei,Zheng, Huan,Zhu, Gangli,Wu, Haihong,He, Lin
supporting information, p. 770 - 774 (2020/08/24)
Selective hydrogenation of aromatic amines, especially chemicals such as aniline and bis(4-aminocyclohexyl)methane for non-yellowing polyurethane, is of particular interests due to the extensive applications. To conquer the existing difficulties in selective hydrogenation, the Ru0-Ruδ+/CeO2 catalyst with solid frustrated Lewis pairs was developed for aromatic amines hydrogenation with excellent activity and selectivity under relative milder conditions. The morphology, electronic and chemical properties, especially the Ru0-Ruδ+ clusters and reducible ceria were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), CO2 temperature programmed desorption (CO2-TPD), H2 temperature programmed reduction (H2-TPR), H2 diffuse reflectance Fourier transform infrared spectroscopy (H2-DRIFT), Raman, etc. The 2% Ru/CeO2 catalyst exhibited good conversion of 95% and selectivity greater than 99% toward cyclohexylamine. The volcano curve describing the activity and Ru state was found. Owning to the “acidic site isolation” by surrounding alkaline sites, condensation between the neighboring amine molecules could be effectively suppressed. The catalyst also showed good stability and applicability for other aromatic amines and heteroarenes containing different functional groups.
Solvent-freeN-Boc deprotection byex situgeneration of hydrogen chloride gas
De Borggraeve, Wim M.,Gilles, Philippe,Van Mileghem, Seger,Verschueren, Rik H.
supporting information, p. 5782 - 5787 (2021/07/12)
An efficient, scalable and sustainable method for the quantitative deprotection of thetert-butyl carbamate (N-Boc) protecting group is described, using down to near-stoichiometric amounts of hydrogen chloride gas in solvent-free conditions. We demonstrate theex situgeneration of hydrogen chloride gas from sodium chloride and sulfuric acid in a two-chamber reactor, introducing a straightforward method for controlled and stoichiometric release of HCl gas. The solvent-free conditions allow deprotection of a wide variety ofN-Boc derivatives to obtain the hydrochloride salts in quantitative yields. The procedure obviates the need for any work-up or purification steps providing an uncomplicated green alternative to standard methods. Due to the solvent-free, anhydrous conditions, this method shows high tolerance towards acid sensitive functional groups and furnishes expanded functional group orthogonality.
Direct Amidation of Esters by Ball Milling**
Barreteau, Fabien,Battilocchio, Claudio,Browne, Duncan L.,Godineau, Edouard,Leitch, Jamie A.,Nicholson, William I.,Payne, Riley,Priestley, Ian
supporting information, p. 21868 - 21874 (2021/09/02)
The direct mechanochemical amidation of esters by ball milling is described. The operationally simple procedure requires an ester, an amine, and substoichiometric KOtBu and was used to prepare a large and diverse library of 78 amide structures with modest to excellent efficiency. Heteroaromatic and heterocyclic components are specifically shown to be amenable to this mechanochemical protocol. This direct synthesis platform has been applied to the synthesis of active pharmaceutical ingredients (APIs) and agrochemicals as well as the gram-scale synthesis of an active pharmaceutical, all in the absence of a reaction solvent.
Can Heteroarenes/Arenes Be Hydrogenated Over Catalytic Pd/C Under Ambient Conditions?
Tanaka, Nao,Usuki, Toyonobu
, p. 5514 - 5522 (2020/07/24)
Hydrogenation of over a dozen aromatic compounds, including both heteroarenes and arenes, over palladium on carbon (Pd/C, 1–100 molpercent) with H2-balloon pressure at room temperature is reported. Analyses using pyridine as a model substrate revealed that acetic acid was the best solvent, as using only 1 molpercent Pd/C provided piperidine quantitatively. Substrate scope analysis and density functional theory calculations indicated that reaction rates are highly dependent on frontier molecular orbital characteristics and the steric bulkiness of substituents. Moreover, the established method was used for the concise synthesis of the anti-Alzheimer drug donepezil (Aricept?).
Photoredox-Catalyzed Addition of Carbamoyl Radicals to Olefins: A 1,4-Dihydropyridine Approach
Cardinale, Luana,Konev, Mikhail O.,Jacobi von Wangelin, Axel
supporting information, p. 8239 - 8243 (2020/06/20)
Functionalization with C1-building blocks are key synthetic methods in organic synthesis. The low reactivity of the most abundant C1-molecule, carbon dioxide, makes alternative carboxylation reactions with CO2-surrogates especially important. We report a photoredox-catalyzed protocol for alkene carbamoylations. Readily accessible 4-carboxamido-Hantzsch esters serve as convenient starting materials that generate carbamoyl radicals upon visible light-mediated single-electron transfer. Addition to various alkenes proceeded with high levels of regio- and chemoselectivity.
Reduction of Amides to Amines under Mild Conditions via Catalytic Hydrogenation of Amide Acetals and Imidates
Kadyrov, Renat
, p. 185 - 191 (2018/11/23)
A simple and general protocol was developed for selective conversion of amides into amines. Amides were converted into amide acetals and imido esters by O-alkylation and then hydrogenated without isolation into amines under very mild reaction conditions over standard hydrogenation catalysts. Triethyloxonium tertafluoroborate, methyl trifluoromethanesulfonate, dimethyl sulfate and ethyl chloroformate were validated as alkylating agent. The synthetic utility of this approach was demonstrated by the selective carbonyl reduction of peptide groups. Carbonyl reduction of peptide group proceeds chemoselective without racemization of the neighboring chiral center. (Figure presented.).
Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates for the efficient synthesis of substituted 4,5,6,7-tetrahydro-1H-indole derivatives
Mamedov, Vakhid A.,Hafizova, Elena A.,Zamaletdinova, Anastasiya I.,Rizvanov, Il'dar Kh.,Mirgorodskaya, Alla B.,Zakharova, Lucia Ya.,Latypov, Shamil K.,Sinyashin, Oleg G.
, p. 9143 - 9153 (2015/11/09)
Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates has been accomplished for the synthesis of various polysubstituted 4,5,6,7-tetrahydroindoles. This one-pot, general and highly regioselective method avoids harsh conditions and expensive catalysts. It proceeds with high atom-efficiency and shows a broad substrate scope and functional group tolerance, making it a highly practical approach for the preparation of various tetrahydroindole derivatives. A family of 17 tetrahydroindoles was synthesized in good yields, which is indicative of the general character of this reaction. 10 of the tetrahydroindole derivatives with various substituents were successfully transformed into the corresponding indoles. This methodology allows access to indoles bearing ω-halo- (mostly chloro-)butyl and pentyl substituents at the nitrogen atom (by variation of enamines) and at the C2, C3 positions (by variation of pyruvates, including bromoaryl and chloroalkyl derivatives). The reaction can be used in conjunction with enamine synthesis offering a practical three-component heteroannulation methodology to produce 4,5,6,7-tetrahydroindoles from cyclohexanone, pyrrolidine and arylchloropyruvates.
