Synthesis and in vitro biological evaluation of new pyrimidines as glucagon-like peptide-1 receptor agonists

The therapeutic success of peptide glucagon-like peptide-1 (GLP-1) receptor agonists for the treatment of type 2 diabetes mellitus has inspired discovery efforts aimed at developing orally available small-molecule GLP-1 receptor agonists. In this study, two series of new pyrimidine derivatives were designed and synthesized using an efficient route, and were evaluated in terms of GLP-1 receptor agonist activity. In the first series, novel pyrimidines substituted at positions 2 and 4 with groups varying in size and electronic properties were synthesized in a good yield (78–90%). In the second series, the designed pyrimidine templates included both urea and Schiff base linkers, and these compounds were successfully produced with yields of 77–84%. In vitro experiments with cultured cells showed that compounds 3a and 10a (10⁻¹⁵–10⁻⁹ M) significantly increased insulin secretion compared to that of the control cells in both the absence and presence of 2.8 mM glucose; compound 8b only demonstrated significance in the absence of glucose. These findings represent a valuable starting point for the design and discovery of small-molecule GLP-1 receptor agonists that can be administered orally.