| 摘要 |
2110572 9221675 PCTABS00017 Optically active lactones are described, such as an intermediate lactone having formula (VIa) where R and R2 are each independently alkyl with 1 to 6 carbon atoms, cycloalkyl with 6 to 10 carbon atoms, aryl with 6 to 10 carbon atoms, or arylalkyl with 7 to 19 carbon atoms, R4 is H or C1-6 alkyl, and Ar is a homo- or heteroaromatic ring with 5 or 6 ring atoms being optionally substituted by C1-6 alkyl or alkoxy groups, halogen atoms, cyano or nitro groups. Such optically active, intermediate lactones are prepared from L-aspartic acid, and can be readily converted to (+)-pilocarpine and its analogues by hydrolysis, reduction, and hydrogenation, such as to an optically active lactone having formula (VIII) which is (+)-pilocarpine when R is ethyl, R4 is H, and Ar is 1-methylimidazol-5-yl.
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