15430-48-5Relevant articles and documents
Synthesis method of betahistine hydrochloride
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Paragraph 0031; 0032; 0035; 0036; 0041-0046; 0053; 0054, (2021/11/19)
The invention discloses a synthesis method of betahistine hydrochloride, which is a transition metal catalyst at room temperature. The basic reagent was added to a round-bottomed flask and methylamine, 2 - hydroxypyridine and an organic solvent were added under nitrogen protection. After the addition, the reaction was completed 40 - 150 °C. The reaction solution is cooled to room temperature, water is added, the transition metal catalyst is recovered by suction filtration, the filtrate is separated off, and the aqueous phase is extracted 3 times with ethyl acetate. The organic phase was washed with saturated brine and dried over anhydrous sodium sulfate, and the organic solvent was distilled off under reduced pressure. The residue was dissolved in ethanol, passed through dry hydrogen chloride and suction filtered, the filter cake was washed with a proper amount of ethanol, and dried in vacuo to yield a product. The transition metal catalyst used in the invention is a commercial reagent, has high activity, does not need to be separately prepared, and can be used repeatedly. The method has the advantages of cheap and easily available reaction raw materials, short reaction route, simple and convenient operation, environmental friendliness, good safety, high product yield and purity, easiness in industrial production and the like.
Convenient Continuous Flow Synthesis of N-Methyl Secondary Amines from Alkyl Mesylates and Epoxides
Lebel, Hélène,Mathieu, Gary,Patel, Heena
, p. 2157 - 2168 (2020/11/23)
The first continuous flow process was developed to synthesize N-methyl secondary amines from alkyl mesylates and epoxides via a nucleophilic substitution using aqueous methylamine. A variety of N-methyl secondary amines were produced in good to excellent yields, including a number of bioactive compounds or their precursors. Up to 10.6 g (88% yield) of an N-methyl secondary amine was produced in 140 min process time. The amination procedure included an in-line workup, and the starting mesylate material was also produced in continuous flow from the corresponding alcohol. Finally, an in-line process combining the mesylate synthesis and nucleophilic substitution was developed.
Aza-Michael-type addition reaction catalysed by a supported ionic liquid phase incorporating an anionic heteropoly acid
Ghasemi, Mohammad Hadi,Kowsari, Elaheh,Shafiee, Abbas
supporting information, p. 1150 - 1153 (2016/03/09)
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.
