| abstract |
A process for preparing an S type 4-substitutednhydroxypyrano-indolidine compound of the formulan(VII):n nwherein R° is a residue of a nitrogen-containing fusednheterocyclic carboxylic acid having an absolutenconfiguration of "R" which is obtained by removingnhydroxy group from the carboxyl group of saidncarboxylic acid (in which the nitrogen atom containednin the residue is protected), is described. n The process involves reduction, alkanoylation,nnitrosation, rearrangement and intramolecularncyclization reactions. |