ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary A key chiral intermediate lactol(3)[3aS (3aα,4α,7α,7aα)]-hexahydro-4,7-epoxy-isobenzofuran-1 (3H)-one was prepared for the total synthesis of a new thromboxane antagonist. The stereoselective hydrolysis of (exo,exo)-7-oxabicyclo[2.2.1]heptane-2,3-dimethanol, diacetate ester (1) to the corresponding chiral monoacetate ester (2) was carried out with lipases, among which Amano P-30 lipase from Pseudomonas sp. was most effective since it gave the desired enantiomer of monoacetate ester. A yield of 75 mol% and optical purity of 〉99% was obtained when the reaction was conducted in a biphasic system with 10% toluene at 5 g/l of the substrate. Lipase P-30 was immobilized on Accurel polypropylene (PP) and the immobilized enzyme was reused (five cycles) without loss of enzyme activity, productivity or optical purity. The reaction process was scaled-up to 80 1 (400 g substrate) and monoacetate (2) was isolated in 80 mol% yield with 99.3% optical purity as determined by chiral HPLC and nuclear magnetic resonance (NMR) analysis. A gas chromatography of 99.5% and specific rotation, [α]D of -7.6° was obtained. The chiral monoacetate ester (2) was oxidized to its corresponding aldehyde and subsequently hydrolyzed to give lactol (3).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00178167
Permalink
