- Synthesis method of 13-methyl berberine alkaloid
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The invention belongs to the field of organic synthesis, and particularly relates to a synthesis method of 13-methyl berberine alkaloid. The method comprises the following steps: reaction a: taking arylethylamine and aryl formaldehyde as main starting raw materials, and reacting in the presence of other auxiliary materials to obtain secondary amine hydrochloride; and reaction b: taking secondary amine hydrochloride and pyruvic aldehyde as main raw materials, and reacting in the presence of other auxiliary materials to obtain the 13-methyl berberine alkaloid. According to the invention, aryl ethylamine and aryl formaldehyde are used as raw materials to synthesize secondary amine hydrochloride, and then the secondary amine hydrochloride and pyruvic aldehyde are subjected to Pickering-Schengger reaction/Friedel-Crafts hydroxyalkylation reaction/dehydration reaction/oxidation reaction in an anhydrous formic acid solution under the assistance of a dewatering agent and an oxidizing agent, so that the 13-methylberberine alkaloid is prepared at the yield of more than 80%, and the synthesis steps are simplified and easy to operate; and various expensive metal catalysts and excessive acid catalysis are not needed, the productivity is high, and the cost is low.
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Paragraph 0044-0050; 0054-0057
(2022/03/17)
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- Total Synthesis of (-)-Canadine, (-)-Rotundine, (-)-Sinactine, and (-)-Xylopinine Using a Last-Step Enantioselective Ir-Catalyzed Hydrogenation
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A concise asymmetric total synthesis of a group of tetrahydroprotoberberine alkaloids, (-)-canadine, (-)-rotundine, (-)-sinactine, and (-)-xylopinine, has been accomplished in three steps from the commercially available corresponding disubstituted phenylethylamine and disubstituted benzaldehyde. Our synthesis toward these four alkaloids took advantage of the following strategy: In the first step, we achieved an efficient and sustainable synthesis of secondary amine hydrochlorides via a fully continuous flow; in the second step, we developed a Pictet-Spengler reaction/Friedel-Crafts hydroxyalkylation/dehydration cascade for the construction of the dihydroprotoberberine core structure (ABCD-ring); and in the last step, Ir-catalyzed enantioselective hydrogenation was employed for the introduction of the desired stereochemistry at the C-14 position in the tetrahydroprotoberberine alkaloids. This work significantly expedites the asymmetric synthesis of the entire tetrahydroprotoberberine alkaloid family as well as a more diverse set of structurally related non-natural analogues.
- Chen, Fener,Chen, Wenchang,Chen, Yu,Jiang, Meifen,Li, Weijian,Tang, Pei,Yang, Zhi
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p. 8143 - 8153
(2021/06/28)
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