3-Bromo-4-pyridinecarboxaldehyde acts as a reagent in the synthesis of 3,4,5-trisubstituted 4,5-dihydro-1,2,4-oxadiazoles agonists which interact with the G-protein-coupled bile acid receptor 1 (TGR5) inducing insulin secretion which may be used as a potential treatment for diabetus mellitus.