- Simplified preparation of a graphene-co-shelled Ni/NiO@C nano-catalyst and its application in theN-dimethylation synthesis of amines under mild conditions
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The development of Earth-abundant, reusable and non-toxic heterogeneous catalysts to be applied in the pharmaceutical industry for bio-active relevant compound synthesis remains an important goal of general chemical research.N-methylated compounds, as one of the most essential bioactive compounds, have been widely used in the fine and bulk chemical industries for the production of high-value chemicals. Herein, an environmentally friendly and simplified method for the preparation of graphene encapsulated Ni/NiO nanoalloy catalysts (Ni/NiO@C) was developed for the first time, for the highly selective synthesis ofN-methylated compounds using various functional amines and aldehydes under easy to handle, and industrially applicable conditions. A large number of primary and secondary amines (more than 70 examples) could be converted to the correspondingN,N-dimethylamines with the participation of different functional aldehydes, with an average yield of over 95%. A gram-scale synthesis also demonstrated a similar yield when compared with the benchmark test. In addition, it was further proved that the catalyst could easily be recycled because of its intrinsic magnetism and reused up to 10 times without losing its activity and selectivity. Also, for the first time, the tandem synthesis ofN,N-dimethylamine products in a one-pot process, using only a single earth-abundant metal catalyst, whose activity and selectivity were more than 99% and 94%, respectively, for all tested substrates, was developed. Overall, the advantages of this newly developed method include operational simplicity, high stability, easy recyclability, cost-effectiveness of the catalyst, and good functional group compatibility for the synthesis ofN-methylation products as well as the industrially applicable tandem synthesis process.
- Liu, Jianguo,Ma, Longlong,Song, Yanpei,Zhang, Mingyue,Zhuang, Xiuzheng
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supporting information
p. 4604 - 4617
(2021/06/30)
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- Multimodal Anion Exchange Matrices
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The invention discloses a separation matrix which comprises a plurality of separation ligands, defined by the formula R1-L1-N(R3)-L2-R, immobilized on a support, wherein R1 is a five- or six-membered, substituted or non-substituted ring structure or a hydroxyethyl or hydroxypropyl group; L1 is either a methylene group or a covalent bond; R2 is a five- or six-membered, substituted or non-substituted ring structure; L2 is either a methylene group or a covalent bond; R3 is a methyl group; and wherein if R1 is a hydroxyethyl group and L1 is a covalent bond, R2 is a substituted aromatic ring structure or a substituted or non-substituted aliphatic ring structure.
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Paragraph 0081; 0083; 0084; 0089
(2015/11/23)
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- Palladium meditated CPhenyl-H bond activation of 2-furylimines versus tert-2-furylbenzylamines
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The reactions of 2-furylimines 2a-f and Na2PdCl4 in the presence of NaOAc at 8-10°C result in nitrogen-palladium coordinated complexes 3a-f. Reduction of 2d-f with NaBH4 followed by N-methylation leads to the corresponding tert-2-furylbenzylamines 5a-c. Treatment of 5a-c with Na2PdCl4 at the same reaction condition as mentioned above affords palladacycles 6a-c where the Pd atoms connect to the phenyl ring rather than the furyl ring. The fact that 5a-c are more active than 2d-f in CPhenyl-H bond activation implies that the electron density of C10 or C8 atom in former is higher than those in latter. Compounds 3a-f, 5a-c, 6a-c were identified by elemental analysis, IR and NMR. In addition, the structures of 3b, 3f and 6c were also confirmed by their single crystal X-ray diffractions.
- Hu, Zhao-Xia,Ma, Nan,Zhang, Jin-Hua,Hu, Wen-Ping,Wang, Hong-Xing
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- Reusable supported ruthenium catalysts for the alkylation of amines by using primary alcohols
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Efficient and recyclable ruthenium catalysts were synthesized from readily available polystyrene-or silica-supported phosphine ligands. Catalysts bound to the polymer support through an ether linkage showed good to excellent activity towards the N-alkylation of primary and secondary amines to afford the alkylated products in 62-99 % yield at 120-140°C. The supported phosphine ligand/ruthenium ratio was found to be crucial for higher catalytic activity and lower ruthenium leaching. The continuous flow N-alkylation of amines was demonstrated by using the supported catalyst in a column reactor. By adopting the hydrogen-borrowing strategy, the synthesis of the anti-Parkinson agent Piribedil was established in 98 % yield at 140°C. Support group steals the show: An efficient Ru-based heterogeneous catalyst from readily available supported phosphine ligands is developed. The nature of the linkage and the extent of ruthenium incorporation are crucial in determining the catalytic activity. The catalyst can be recycled and used under continuous flow in a packed-bed reactor. The alkylation of cyclic amines is achieved in excellent yield at moderate temperatures in the absence of any external base.
- Peishan, Siah,Dang, Tuan Thanh,Seayad, Abdul Majeed,Ramalingam, Balamurugan
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p. 808 - 814
(2014/03/21)
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- SYNTHETIC BIOREGULATORS OF POLY-CIS CAROTENOID BIOSYNTHESIS
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Seventeen new bioregulators were synthesized and tested for their ability to induce the biosynthesis of poly-cis carotenes in the flavedo of Marsh white seedless grapefruit.The effects of these new bioregulators are the same as that of the previously reported dibenzylamines, but several of the new compounds are more effective and cause the accumulation of up to 162 μg/g dry wt of poly-cis carotenes in the flavedo as compared to the maximum of 74 μg/g dry wt observed previously.The compounds tested were substituted N-benzyl furfurylamines, N-benzyl, N-methyl furfurylamines and N-alkyl , N-methyl benzylamines.They demonstrate the ability of tertiary as well as secondary amines to stimulate the formation of poly-cis carotenes.The interaction of N-(4-bromobenzyl) furfurylamine, one of the more effctive of the new compounds, with lycopene and β-carotene inducers is also reported.Key Word Index - Citrus paradisi; Rutaceae; Marsh white seedles grapefruit; carotenoid biosynthesis; bioregulators; secondary amines; poly-cis carotenoids; prolycopene.
- Poling, Stephen M.,Hsu, Wan-Jean,Yokoyama, Henry
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p. 601 - 604
(2007/10/02)
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