Bridgehead-methyl analog of SC-53116 as a 5-HT4 agonist.

Abstract Pyrrolizidine benzamide (±)- 2 , the bridgehead-methyl analog of SC - 53116 , was prepared and evaluated for 5-HT 4 agonism activity in the rat tunica muscularis (TMM) mucosae assay. Compound (±)- 2 has an EC 50 of 449 nM in the TMM assay, as compared to 23 nM for SC - 53116 , and 66 nM for the racemate of SC - 53116 .