Exploration of pyrrole derivatives to find an effective potassium-competitive acid blocker with moderately long-lasting suppression of gastric acid secretion

Publication date: Available online 27 April 2017
Source:Bioorganic & Medicinal Chemistry
Author(s): Haruyuki Nishida, Ikuo Fujimori, Yasuyoshi Arikawa, Keizo Hirase, Koji Ono, Kazuo Nakai, Nobuhiro Inatomi, Yasunobu Hori, Jun Matsukawa, Yasushi Fujioka, Akio Imanishi, Hideo Fukui, Fumio Itoh
With the aim to discover a novel excellent potassium-competitive acid blocker (P-CAB) that could perfectly overcome the limitations of proton pump inhibitors (PPIs), we tested various approaches based on pyrrole derivative 1 as a lead compound. As part of a comprehensive approach to identify a new effective drug, we tried to optimize the duration of action of the pyrrole derivative. Among the compounds synthesized, fluoropyrrole derivative 20j, which has a 2-F-3-Py group at position 5, fluorine atom at position 4, and a 4-Me-2-Py sulfonyl group at the first position of the pyrrole ring, showed potent gastric acid-suppressive action and moderate duration of action in animal models. On the basis of structural properties including a slightly larger Clog P value (1.95), larger log D value (0.48) at pH 7.4, and fairly similar pKa value (8.73) compared to those of the previously optimized compound 2a, compound 20j was assumed to undergo rapid transfer to the stomach and have a moderate retention time there after single administration. Therefore, compound 20j was selected as a new promising P-CAB with moderately long duration of action.

Graphical abstract

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