Process development and scale-up of PPAR α/γ Dual agonist lobeglitazone sulfate (CKD-501)

A scaleable synthetic route to the potent PPARα/γ dual agonistic agent, lobeglitazone (1), used for the treatment of type-2 diabetes was developed. The synthetic pathway comprises an effective five-step synthesis. This process involves a consecutive synthesis of the intermediate, pyrimidinyl aminoalcohol (6), from the commercially available 4,6-dichloropyrimidine (3) without the isolation of pyrimidinyl phenoxy ether (4). Significant improvements were also made in the regioselective 1,4-reduction of the intermediate, benzylidene-2,4-thiazolidinedione (10), using Hantzsch dihydropyridine ester (HEH) with silica gel as an acid catalyst. The sulfate salt form of lobeglitazone was selected as a candidate compound for further preclinical and clinical study. More than 2 kg of lobeglitazone sulfate (CKD-S01, 2) was prepared in 98.5% purity after the GMP batch. Overall yield of 2 was improved to 52% from 17% of the original medicinal chemistry route.