US 7,538,234 B2
Preparation of Optically active 2-(1-hydroxyethyl)-5-hydroxynaphtho[2,3-b]furan-4, 9-diones having anticancer activities
Akira Iida, Kyoto (Japan); Harukuni Tokuda, Kyoto (Japan); and Mitsuaki Yamashita, Takasaki (Japan)
Assigned to Taheebo Japan Co., Ltd., Osaka (Japan)
Filed on Jan. 29, 2008, as Appl. No. 12/11,759.
Claims priority of application No. 2007-145680 (JP), filed on May 31, 2007.
Prior Publication US 2008/0300415 A1, Dec. 04, 2008
Int. Cl. C07D 307/92 (2006.01)
U.S. Cl. 549—458 6 Claims
 
1. A method for preparing an optically active 2-(1-hydroxyalkyl)-5-hydroxynaphtho[2,3-b]furan-4,9-dione compound of the formula (II):

OG Complex Work Unit Drawing
wherein R is C1-C6 alkyl, comprising asymmetrically reducing a compound of the formula (I):

OG Complex Work Unit Drawing
wherein R is the same as defined above, in the presence of an asymmetric ruthenium complex and a hydrogen donor, wherein the asymmetric ruthenium complex is selected from the group consisting of Ru[(S,S)-Tsdpen](p-cymene) (chemical name: [(1S,2S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine]-(p-cymene) ruthenium (II)), RuCl[(S,S)-Tsdpen](p-cymene) (chemical name: chloro [(1S,2S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine]-(p-cymene) ruthenium (II)), RuCl[(S,S)-Tsdpen](mesitylene) (chemical name: chloro [(1S,2S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine]-(mesitylene) ruthenium (II)) and RuCl[(S,S)-Msdpen](p-cymene) (chemical name: chloro[(1S,2S)-N-(methanesulfonyl)-1,2-diphenylethanediamine]-(p-cymene) ruthenium (II)).