| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject new carboxylic acid ester useful as an intermediate for producing cyclobytane nucleotides useful as antiviral agents by allowing an enzyme for hydrolyzing ester group to act on a specific carboxylic acid ester. SOLUTION: A carboxylic acid ester of formula II (R and R1 are each a 1-5C alkyl or the like). The ester of formula II is obtained by allowing an enzyme (especially a protease derived from Bacillus licheniformis) for enantio- selectively hydrolyzing ester groups usually in a concentration of 1-100,000 units/liter to act on a (±)-trans-3,3-dialkoxy-1,2-cyclobutanedicarboxylic ester of formula I in a concentration of 0.001-2 moles/liter in the reaction system at 0-40 deg.C for 1 min to 200 hr. |
