- For the synthesis of montelukast intermediate compound and its preparation method
-
The invention relates to a pharmaceutical intermediate and a preparation method thereof, and especially relates to an intermediate compound represented by the formula (1) for synthesizing montelukast; wherein in the formula the X' represents a halogen ele
- -
-
-
- The palladium-catalyzed aerobic kinetic resolution of secondary alcohols: Reaction development, scope, and applications
-
The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbonate and tert-butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23°C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kinetic resolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good-toexcellent selectivity factors. This catalyst system has also been applied to the desymmetrization of meso-diols, providing high yields of enantioenriched hydroxyketones.
- Ebner, David C.,Bagdanoff, Jeffrey T.,Ferreira, Eric M.,McFadden, Ryan M.,Caspi, Daniel D.,Trend, Raissa M.,Stoltz, Brian M.
-
supporting information; experimental part
p. 12978 - 12992
(2010/06/19)
-
- The resolution of important pharmaceutical building blocks by palladium-catalyzed aerobic oxidation of secondary alcohols
-
The palladium-catalyzed aerobic oxidative kinetic resolution of key pharmaceutical building blocks is described. Substrates investigated are relevant to the enantioselective preparation of Prozac, Singulair, and the promising hNK-1 receptor antagonist from Merck. The latter provides the most selective aerobic oxidative kinetic resolution yet described.
- Caspi, Daniel D.,Ebner, David C.,Bagdanoff, Jeffrey T.,Stoltz, Brian M.
-
p. 185 - 189
(2007/10/03)
-