Process for the preparation of substituted thiazolidinedione

A process, for preparing a compound of formula (IA):

• or a tautomeric form thereof or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, wherein:
• A1 represents a substituted or unsubstituted aromatic heterocyclyl group;
• R1 represents a hydrogen atom, an alkyl group, an acyl group, an aralkyl group, wherein the aryl moiety may be substituted or unsubstituted, or a substituted or unsubstituted aryl group;
• A2 represents a benzene ring having in total up to five substituents;
• and
• n represents an integer in the range of from 2 to 6;
• which process comprises treating a compound of formula (IIB):
• or a tautomeric form thereof or a salt thereof, or a solvate thereof, wherein A1, A2, R1 and n are as defined in relation to formula (IA) with a complex hydride reducing agent or a source of a complex hydride reducing agent.