Lobeglitazone Sulfate

Description

Lobeglitazone sulfate, an oral peroxisome proliferator-activated receptor (PPARa/c) dual agonist with IC50 = 20 and 18 nM respectively, was developed by Chong Kun Dang Pharmaceutical in Korea for the treatment of diabetes. This drug is differentiated from two other PPAR agonists available—pioglitazone and rosiglitazone —which lack PPARa activity. The most likely processscale preparation of lobeglitazone sulfate follows the route described in a process communication from Chong Kun Dang Pharmaceutical.

Synthesis

Commercially available 4,6-dichloropyrimidine (152) was treated with a stoichiometric equivalent of p-methoxyphenol (153) in the presence of KF in warm DMF . Upon completion of this reaction, 2-methylaminoethanol was added to the mixture to provide pyrimidine 154 in high yield. Next, alcohol 154 underwent a substitution reaction with p-fluorobenzaldehyde (155) under basic conditions to provide alkoxy benzaldehyde 156 which was converted to the benzylidene thiazolidindione 158 upon subjection to Knoevenagel conditions with 2,4-thiazolidinedione (157) in 90% yield. Finally, reduction of olefin 158 was facilitated by treatment with the Hantzsch ester (159) in the presence of silica gel followed by treatment with methanolic sulfuric acid (96%) at low temperature to ultimately furnish lobeglitazone sulfate in 90% yield.