- Preparation method of betahistine
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The invention discloses a preparation method of betahistine. The preparation method comprises the following steps: in the continuous flow reactor, 2 - vinylpyridine and methylamine salt solution are reacted to obtain the betahistine, and the preparation method is sufficient. Therein, 2 - vinylpyridine is not diluted or diluted with solvent and fed. The residence time of the reaction is not less 0.6 min. The reaction temperature is 100 - 250 °C. prepared by the method of the invention, the conversion rate of the raw material is high, the selectivity and yield of the product are high, the solvent residue is low, and the reaction time is short.
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Paragraph 0046-0052; 0067-0176;
(2021/09/29)
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- Continuous Flow Process for the Synthesis of Betahistine via Aza-Michael-Type Reaction in Water
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A continuous flow process for the preparation of betahistine with a 90% isolated yield has been reported. 2-Vinylpyridine and saturated methylamine hydrochloride aqueous solution were used as starting materials to achieve excellent results in the silicon carbide flow reactor, which can tolerate the corrosion of chloride ions at high temperature (170 °C) and pressure (25 bar). In the continuous flow process, the product can be obtained in 2.4 min with excellent conversion (>99%) and product selectivity (94%). The throughput can reach 1.06 kg h-1, and the purity of the final product was greater than 99.9% by distillation, which were in accordance with the needs of production. This new process using environmentally friendly water as the solvent is energy-efficient, time- and cost-economic, and offers a 50% reduction in process mass intensity compared to the batch process.
- Sun, Maolin,Yang, Jingxin,Fu, Youtian,Liang, Chaoming,Li, Hong,Yan, Guoming,Yin, Chao,Yu, Wei,Ma, Yueyue,Cheng, Ruihua,Ye, Jinxing
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supporting information
p. 1160 - 1166
(2021/05/06)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- Preparation method of orthographic optimizing betahistine hydrochloride
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The invention discloses a preparation method of orthographic optimizing betahistine hydrochloride, and relates to the field of drug preparation. The preparation method includes the steps: adding raw materials into a reaction bottle according to the feeding ratio (molar ratio) of 2-methylpyridine to paraformaldehyde of 1:0.57, leading in nitrogen, stirring mixture for 20 hours at the temperature of125 DEG C and at 4 barometric pressure, performing reduced pressure distillation, and collecting distillation cut at the temperature of 130-145 DEG C and under the pressure of 16mm mercury columns toobtain light-yellow oily 2-hydroxyethyl pyridine; adding the 2-hydroxyethyl pyridine into a three-opening bottle, adding sodium hydroxide according to the feeding ratio of 2-(2-Hydroxyethyl)pyridineto sodium hydroxide of 1:0.05, heating the mixture to reach 95-100 DEG C, stirring the mixture for 2 hours, removing a water layer, performing reduced pressure distillation on an oil layer, and collecting the distillation cut at the temperature of 65-70 DEG C and under the pressure of 17mm mercury columns to obtain 2-vinylpyridine. The preparation method is simple in technological process, safe tooperate and mild in reaction, production efficiency and product quality can be greatly improved, and production cost is reduced.
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- The catalytic effect of anion-exchanged supported ionic liquid on aza-Michael-type addition
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Abstract: An effective synthesis of anion-exchanged supported ionic liquids using diatomaceous earth as solid support and its catalytic effect on the aza-Michael-type addition is described. Anionic polytungstophosphate and bisulfate ion are used in the anion-exchange step in catalyst design. In addition, the aza-Michael-type addition of various amines to 2- and 4-vinyl pyridine was examined in this article. The catalytic system can be separated from the reaction mixture and recycled in subsequent reactions. The structure of anion-exchanged supported ionic liquid on diatomaceous earth was studied by XRD, FT-IR, SEM, TGA and BET techniques. The structure of organic products was determined by 1HNMR, 13CNMR, FTIR, CHN and MASS spectroscopy. Graphical Abstract: [Figure not available: see fulltext.].
- Ghasemi, Mohammad Hadi,Kowsari, Elaheh
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p. 3691 - 3709
(2017/06/20)
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- Aza-Michael-type addition reaction catalysed by a supported ionic liquid phase incorporating an anionic heteropoly acid
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In this work, we have obtained substituted amines under mild conditions in good yields using the Aza-Michael-type addition of various amines to vinyl compounds catalysed by a supported ionic liquid incorporating an anionic heteropoly acid. Different catalysts, including Lewis acids, Br?nsted acids and heteropoly acids were investigated in which heteropoly acids having dual Br?nsted and Lewis acid characteristics were excellent catalysts. The ionic liquid incorporating a polytungstate anion supported on magnetic diatomaceous earth as a magnetically separable heterogeneous catalyst offered the best results in terms of yield. The solid nanocatalyst was easily removed with a magnet.
- Ghasemi, Mohammad Hadi,Kowsari, Elaheh,Shafiee, Abbas
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supporting information
p. 1150 - 1153
(2016/03/09)
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- Development of a general non-noble metal catalyst for the benign amination of alcohols with amines and ammonia
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The N-alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N-alkyl amines. However, as a potentially clean and economic choice for N-alkyl amine synthesis, non-noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N-alkylation of ammonia or amines with alcohol or primary amines. N-alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N-heterocyclic compounds, and secondary amines could be N-alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one-pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation. Copyright
- Cui, Xinjiang,Dai, Xingchao,Deng, Youquan,Shi, Feng
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supporting information
p. 3665 - 3675
(2013/03/29)
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- Pharmaceutical combination of betahistine and trimetazidine
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This invention is related to pharmaceutical combination of betahistine or pharmaceutically acceptable salts thereof and trimetazidine or pharmaceutically acceptable salts thereof.
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- Tetracyclic benzimidazole derivatives and combinatorial libraries thereof
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The present invention relates to novel tetracyclic benzimidazole derivative compounds of the following formula: wherein R1to R10have the meanings described in here. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing tetracyclic benzimidazole derivative compounds.
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- METHOD FOR TREATING CHRONIC PAIN USING MEK INHIBITORS
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The invention features a method for treating chronic pain using a compound selected from formulae (I), (II)A, (I)B and (I)C.
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- Benzenesulfonamide derivatives and their use as MEK inhibitors
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Benzenesulfonamides of formula (I), in which W is OR1, NR2OR1, NRARB, NR2NRARB, or NR2(CH2)2-4NRARBand the other variables as defined in the claims, are inhibitors of MEK and are effective in the treatment of proliferative diseases, cancer, stroke, heart failure, xenograft rejection, arthritis, cystic fibrosis, hepatomegaly, cardiomegaly, Alzheimer's disease, complications of diabetes, septic shock, and viral infection.
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- 2-aminopyridine derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminopyridine derivative compounds of the following formula: wherein R1to R5have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminopyridine derivative compounds.
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- Symmetry-Based Inhibitors of HIV Protease. Structure-Activity Studies of Acylated 2,4-Diamino-1,5-diphenyl-3-hydroxypentane and 2,5-Diamino-1,6-diphenylhexane-3,4-diol
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The structure-activity relationships in two series of novel, symmetry-based inhibitors of HIV protease, the enzyme responsible for maturation of the human immunodeficiency virus, are described.Beginning with lead compounds 3-6, the effect of adding polar, heterocyclic end groups to one or both ends of the symmetric or pseudosymmetric inhibitors was probed.Aqueous solubility was enhanced >1000-fold while maintaining potent inhibition of purified HIV-1 protease and anti-HIV activity in vitro.Pharmacokinetic studies in rats indicated a substantial difference in the absorption properties of mono-ol-based and diol-based inhibitors.The oral bioavailability of inhibitor 19 in rats was 19percent; however, the Cmax obtained failed to exceed the anti-HIV EC50 in vitro.Substantial plasma levels of potent inhibitors of the diol class were not obtained after oral administration in rats; however, the optimal combination of aqueous solubility and in vitro antiviral activity of several inhibitors support their potential use in intravenous therapy.
- Kempf, Dale J.,Codacovi, Lynnmarie,Wang, Xiu Chun,Kohlbrenner, William E.,Wideburg, Norman E.,et al.
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p. 320 - 330
(2007/10/02)
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- Catalytic N-Dealkylation of Tertiary Amines--A Biomimetic Oxygenation Reaction
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A heterogeneous catalyst system is described for N-dealkylation of tertiary amines.A large number of tertiary amines including some important synthetic drugs were N-dealkylated to give the corresponding secondary amines in 50-65percent yields.The reaction was carried out at room temperature by stirring a solution of a tertiary amine in methanol containing 10percent palladium-on-charcoal catalyst.The reaction had absolute requirement for molecular oxygen like the enzymatic dealkylation reaction.It also needed methanol to act as the reductant of molecular oxygen like the NADPH in the enzymatic reaction.A catalytic cycle similar to cytochrome P-450-catalysed oxygenation cycle is proposed for activation and transfer of oxygen to the α-carbon of tertiary amines to give unstable carbinolamines which on dissociation yield secondary amines.
- Chaudhuri, Naba K.,Servando, Ofelia,Markus, Bohdan,Galynker, Igor,Sung, Ming-Sang
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p. 899 - 903
(2007/10/02)
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- 9-Xanthylamin oalkylpyridine derivatives
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9-Xanthylaminoalkylpyridine derivatives are prepared. These compounds are inhibitors of gastric acid secretion.
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