Effect of removal of the 14-hydroxy group on the affinity of the 4, 5-epoxymorphinan derivatives for orexin and opioid receptors. (1st March 2022)

• Record Type: Journal Article
• Authors: Katoh, Koki; Yamamoto, Naoshi; Ishikawa, Yukiko; Irukayama-Tomobe, Yoko; Tanimura, Ryuji; Saitoh, Tsuyoshi; Nagumo, Yasuyuki; Kutsumura, Noriki; Yanagisawa, Masashi; Nagase, Hiroshi
• Is Part Of: Bioorganic & medicinal chemistry letters. Volume 59(2022)
• Publication Date: 2022-03-01
• Subjects: Structure-activity relationship -- D-nor-nalfurafine -- 14-H nalfurafine -- 14-dehydration nalfurafine -- KOR; Bioorganic chemistry -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1016/j.bmcl.2022.128527
• Languages: English
• ISSNs: 0960-894X

Abstract

Graphical abstract: Abstract: To investigate the contribution of hydrogen bonding between the 14-hydroxy group and the 6-amide chain on the binding affinity of nalfurafine toward KOR and OX1 R, we prepared the 14-H and 14-dehydrated nalfurafine and their five-membered D-ring nalfurafine (D-nor-nalfurafine) derivatives. The 14-H and 14-dehydrated nalfurafine derivatives showed almost the same affinity for KOR as nalfurafine and more potent affinity for OX1 R. On the other hand, 14-H and 14-dehydrated D-nor-nalfurafine derivatives showed weak affinity for KOR and almost no affinity for OX1 R. The conformational analyses suggested that the 6-amide chains of the nalfurafine derivatives are mainly oriented just at or downward from the C-ring, while those of the D-nor-nalfurafine derivatives were mainly oriented toward the upper side of the C-ring even in the absence of the 14-hydroxy group. We postulated that the ion–dipole interaction between the 6-amide and the 16-nitrogen might stabilize the upwardly oriented 6-amide group. These results suggested that the 14-hydroxy group and the ion–dipole interaction would play important roles in the orientation of the 6-amide group, which might control the affinity between KOR and OX1 R.