| 摘要 |
The present invention is directed to a nitrogen-containing fused heterocyclic carboxylic acid having an absolute configuration of "R" of the formula [XIX]: <IMG> wherein Y is a member selected from the group consisting of a phenylsulfonyl , naphthylsulfonyl and biphenylylsulfonyl group which may be unsubstituted or substituted by a member selected from a nitro group, a C1-6 alkyl group, a C1-6 alkoxy group, a C3-6 cycloalkyl group, a halogen atom, and a thienyl group or C1-6 alkylsulfonyl group, and n is 0 or 1, or a salt thereof. The compounds of the present invention are used as intermediates in processes for the preparation of camptothecin derivatives having antitumor activities.
|
