The identification of substituted benzothiophene derivatives as PGE2 subtype 4 receptor antagonists: From acid to non-acid

We disclose herein our preliminary SAR study on the identification of substituted benzothiophene derivatives as PGE2 subtype 4 receptor antagonists. A potent EP4 antagonist 6a (Ki = 1.4 nM with 10% HSA) was identified. Furthermore, we found that an acidic group was not essential for the EP4 antagonizing activity in the series and neutral replacements were identified. This opens a new direction for future EP4 antagonist design.