T. Kometani, Y. Sakai, H. Matsumae
1997
Citations
0
Influential Citations
13
Citations
Journal
Journal of Fermentation and Bioengineering
Abstract
Abstract Bakers' yeast-mediated reduction of ( RS )-2-(4-methoxyphenyl)-1,5-benzothiazepin-3,4(2 H ,5 H )-dione [( RS )-1] to (2 S ,3 S )-2,3-dihydro-3-hydroxy-2-(4-methoxyphenyl)-1,5-benzo-thiazepin-4(5 H )-one, a key intermediate in the synthesis of diltiazem hydrochloride, was investigated for industrial application. We found that an aggregate of ( RS )-1, formed by the addition of its DMF solution to water, was soluble in an aqueous medium at about 20 mg/ l . Thus, the asymmetric reduction using the ( RS )-1 aggregate successively proceeded in the presence of ethanol under aerobic conditions. In this procedure, 100 g of the substrate was reduced in 1 l of the aqueous medium to produce the desired chiral intermediate with over 99% enantiomeric excess in 80% yield.