Practical Processes for Producing Fluorinated alpha-Ketocarboxylic Esters and Analogues Thereof
申请人:Central Glass Company, Limited
公开号:US20180050976A1
公开(公告)日:2018-02-22
It is possible to produce a fluorine-containing α-ketocarboxylic ester hydrate by reacting a fluorine-containing α-hydroxycarboxylic ester with sodium hypochlorite or calcium hypochlorite of 21 mass % or greater in mass percentage of composition. Furthermore, it is possible to produce a fluorine-containing α-ketocarboxylic ester by reacting the hydrate with a dehydrating agent. Furthermore, it is possible to produce a fluorine-containing α-ketocarboxylic ester hemiketal by reacting the fluorine-containing α-ketocarboxylic ester hydrate with a lower alcohol or a trialkyl orthocarboxylate. Moreover, it is possible to produce a fluorine-containing α-ketocarboxylic ester by reacting the hemiketal with a dealcoholization agent.
A New Strategy for the Synthesis of α-Difluoromethyl-Substituted α-Hydroxy and α-Amino Acids
作者:Sergey N. Osipov、Alexander S. Golubev、Norbert Sewald、Thomas Michel、Alexey F. Kolomiets、Alexander V. Fokin、Klaus Burger
DOI:10.1021/jo9608331
日期:1996.1.1
A newmethod for the preparation of alpha-chlorodifluoromethyl-, alpha-bromodifluoromethyl-, and alpha-difluoromethyl-substituted alpha-hydroxy and alpha-amino acid esters 11, 19-21 is described. The key step of the synthesis is the regioselective alkylation of ketones 5, 7-9 and imines 16-18 with C-nucleophiles. The ketones 7-9 are readily available from 3,3,3-trifluorolactate 1 by a five-step procedure
Difluoropyruvate was prepared fromtrifluoroaceticanhydride via 3 steps (Friedel–Crafts type addition, reductive defluorination, and ozonolysis) in 30% yield.