- An Improved Synthesis of 3,6-Dihydro- as -indacene
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This contribution describes an updated synthetic route to 3,6-dihydro- as -indacene along with full characterization of all inter mediates. The title compound is prepared by Mannich condensation of 2-methylfuran with formaldehyde and dimethylamine hydrochloride, quaternization of the resulting amine with methyl iodide, and conversion into the ammonium hydroxide salt by treatment with silver oxide in water. Subsequent Hoffmann elimination and [6,6]-cycloaddition through pyrolysis produces a furanocyclophane, which after photooxidation, intramolecular cycloaddition, and dehydration with sodium carbonate affords 2,3,6,7-tetrahydro-1,8-dione- as -indacene. Reduction of this diketone gives a mixture of alcohols, which after dehydration under slightly basic or acidic conditions produces 3,6-dihydro- as -indacene. The structure is confirmed by X-ray diffraction, and all intermediates are characterized by means of 1H and 13C NMR spectroscopy.
- Dibdalli, Yuvaraja,Faúndez, Rodrigo,Preite, Marcelo,Molins, Elies,Chávez, Ivonne,Amshumali, Mungalimane K.,Morales-Verdejo, Cesar,Manriquez, Juan M.
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- 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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- Base-Mediated Borylsilylation/Silylation of Ammonium Salts with Silylborane
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This work describes a base-mediated borylsilylation of benzylic ammonium salts to synthesize geminal silylboronates bearing benzylic proton under mild reaction conditions. Deaminative silylation of aryl ammonium salts was also achieved in the presence of
- Du, Xian,Guan, Yun-Shi,Li, Yi-Hui,Liang, Guohai,Luo, Yong,Qi, Wan-Ying,Wang, Zi-Ying,Wei, Xun,Xu, Xiao-Hong,Yuan, Han,Zhen, Jing-Song
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supporting information
p. 5988 - 5992
(2021/08/31)
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- A Novel Route to Synthesize N,N-Dimethyl Arylmethylamines from Aryl Aldehydes, Hexamethylenetetramine and Hydrogen?
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Developing simple and green routes to access valuable chemicals is of significance. Herein, we present a green and novel route to synthesize N,N-dimethyl arylmethylamines (DAMAs) from hexamethylenetetramine (HMTA) and aryl aldehydes in the presence of hydrogen, and a series of DAMAs can be obtained in good yields. This approach opens the precedent for HMTA as N,N-dimethylamine source to synthesize chemicals with N,N-dimethylamine group, which has promising applications for N-containing chemicals synthesis.
- Ke, Zhengang,Yu, Bo,Wu, Yunyan,Zhao, Yanfei,Yang, Peng,Guo, Shien,Liu, Zhimin
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supporting information
p. 842 - 846
(2020/05/14)
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- Synthetic method of methyl cyclopentenolone
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The invention relates to a preparation method of methyl cyclopentenolone, which comprises the following steps: (1) controlling the pH value and temperature of a reaction system, and reacting a dimethylamine hydrochloride, a formaldehyde aqueous solution and 2-methyl furan to generate N, N-dimethyl-5-methyl furfuryl amine; (2) when it is monitored that the content of the 2-methyl furan is not reduced any more, adjusting the pH value of the reaction solution to be less than 1 by using an acid solution, and reacting to obtain a product 1-dimethyl amino-2, 5-hexanedione; and (3) adjusting the pH value of the reaction solution to 12-13 by using an alkali, reacting, extracting the reaction solution, concentrating to recover the solvent, and rectifying to obtain a product 2-(dimethylamino)-3-methyl-2-cyclopentene-1-one; and (4) mixing 2-(dimethylamino)-3-methyl-2-cyclopentene-1-one with hydrochloric acid, reacting, hydrolyzing, crystallizing and purifying to obtain methyl cyclopentenolone, and concentrating and recycling a reaction mother liquor Compared with the prior art, the method has the advantages that remote and automatic operation is facilitated, wastewater treatment is reduced, and the raw material dimethylamine hydrochloride can be reused.
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Paragraph 0015; 0035-0038; 0041-0044; 0047-0050; 0053-0056
(2021/01/15)
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- Synthesis method of N,N-dimethyl-5-methylfurfurylamine
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The invention discloses a synthesis method of N,N-dimethyl-5-methylfurfurylamine. The method comprises the steps of adding paraformaldehyde, dimethylamine hydrochloride, a solvent, namely, water, and hydrochloric acid of which the catalyst concentration is 37% into a flask, and enabling the materials to react for 2 hours under the conditions that the temperature is 50 DEG C to 70 DEG C and the pH value is 3 to 4; after reaction, cooling the materials to 20 DEG C to 40 DEG C, and after dropwire adding 2-methylfuran of which the concentration is 98% while stirring, heating the materials to 60 DEG C to enable the materials to perform reflux reaction for 4 to 7 hours; and after reaction, adding a saturated sodium hydroxide solution to regulate the pH value to be 12 to 14, and carrying out alkaline water phase separation and decompression distillation purification, so as to obtain an N,N-dimethyl-5-methylfurfurylamine product. The synthesis method has the advantages that toxicity of reactants is greatly reduced, pungent smells are greatly decreased, operation is greatly simplified, and sewage is avoided.
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Paragraph 0027-0031
(2018/02/03)
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- Cholinergic agents structurally related to furtrethonium. 1
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A series of 5-substituted-2-(dimethylaminomethyl)-furyl derivatives 4 was prepared, with the aim of discovering novel antimuscarinic agents which are selective for smooth muscle as opposed to cardiac tissue.Both non-quaternary and quaternary ammonium compounds were synthesised.The agonist starting point, furtrethonium 3, was gradually transformed into antagonist by introduction of lipophilic and bulky groups in position 5 of this molecule.In particular, the introduction of α-hydroxy-α-cyclohexylbenzyl moiety (compound 9b), a lipophilic group characteristic ofantimuscarinic agents, caused an appreciable increase of the antagonist's potency, and the lengthening of the distance between this lipophilic group and the furan ring, obtained by introduction of an ester, ether or amide group, led to some selectivity towards smooth muscle (compounds 19, 21, 25).Interestingly, compound 19, with an ester moiety as a spacer group, proved to be at least 20 times more potent in rat ileum (pKB = 7.3) and rat bladder (pKB = 7.2) than guinea-pig atria (pKB = 5.9). furtrethonium derivatives / cholinergic agents / antimuscarinic activity
- Manfredini, S.,Guarneri, M.,Simoni, D.,Grana, E.,Boselli, C.,et al.
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p. 153 - 162
(2007/10/02)
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- NMR studies of bond order in distorted aromatic systems
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The 4JH-C=C-Me coupling constant has been previously established1,2 as a probe of bond order. This has now been used to examine the bond orders of compounds containing severely distorted benzene nuclei. In the case of 3,4-di-tert-butyltoluene, no electronic distortions in the aromatic ring can be detected by this method. A series of moderately to severely distorted paracyclophanes show no perturbation of electronic structure, with the possible exception of 8-methyl[6]paracyclophane, which exhibits a barely significant deviation from unstrained values. These conclusions are supported by the results of SCF-MO calculations.
- Gready, Jill E.,Hambley, Trevor W.,Kakiuchi, Kiyomi,Kobiro, Kazuya,Sternhell, Sever,Tansey, Charles W.,Tobe, Yoshito
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p. 7537 - 7540
(2007/10/02)
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- MANNICH REACTIONS OF FURAN AND 2-METHYLFURAN USING PRE-FORMED IMONIUM SALTS
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Good yields of 2-dialkylaminomethylfurans are obtained when N,N-dialkylmethylene-imonium chlorides are allowed to interact with furan in acetonitrile at room temperature; similar results are obtained using 2-methylfuran.
- Heaney, Harry,Papageorgiou, George,Wilkins, Robert F.
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p. 2377 - 2380
(2007/10/02)
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