S-type 2-substituted hydroxy-2-indolinylbutyric ester compounds and process for preparation thereof

摘要

A process for preparing an S type 4-substituted hydroxypyrano-indolidine compound of the formula (VII): <CHEM> wherein R DEG is a residue of a nitrogen-containing fused heterocyclic carboxylic acid having an absolute configuration of "R" which is obtained by removing hydroxy group from the carboxyl group of said carboxylic acid (in which the nitrogen atom contained in the residue is protected), is described. The process involves reduction, alkanoylation, nitrosation, rearrangement and intramolecular cyclization reactions.