Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Sequential, position-selective, Pd-catalyzed cross-coupling reactions of 2,4-dibromo-5-hydroxymethylthiazole provided the scaffold for the synthesis of GW501516, the most potent PPARβ/δ agonist yet described, and equally selective analogs at the thiazole-C4 position.