1. The first original report of this study for structurally novel NOP receptor agonist as analgesic was including in the following poster and oral presentation: Hayashi, S.; Hirao, A.; Imai, A.; Sugie, Y.; Nakata, E.; Ohashi, K.; Kato, A.; Yamada, Y.; Toide, K. Novel Potent ORL1 Receptor Agonists as Anti-Anxiety Drug and Analgesic Drug. In The 25th Medicinal Chemistry Symposium Abstracts, The Pharmaceutical Society of Japan, Division of Medicinal Chemistry: Nagoya, Japan, November 29–December 1, 2006; The 25th Medicinal Chemistry Symposium Executive Committee, The Pharmaceutical Society of Japan, Division of Medicinal Chemistry: Tokyo, Japan, 2006, 2P-49, pp 262–263. See also Ref. 2.
2. The present article is also the first publication of the original synthetic study of HPCOM and its analogues herein, and the synthetic method is different from that of MCOPPB as new-class antianxiety drug and its analogues. The details of design, synthesis, SAR, and pharmacological evaluation study of novel NOP receptor agonist MCOPPB and the different series of analogues also including in Ref. 1 have been precedently published as the series of articles, that is, Refs. 2b–d
3. Novel Non-Peptide Nociceptin/Orphanin FQ Receptor Agonist, 1-[1-(1-Methylcyclooctyl)-4-piperidinyl]-2-[(3R)-3-piperidinyl]-1H-benzimidazole: Design, Synthesis, and Structure−Activity Relationship of Oral Receptor Occupancy in the Brain for Orally Potent Antianxiety Drug
4. Discovery of 1-[1-(1-Methylcyclooctyl)-4-piperidinyl]-2-[(3R)-3-piperidinyl]-1H-benzimidazole: Integrated Drug-Design and Structure-Activity Relationships for Orally Potent, Metabolically Stable and Potential-Risk Reduced Novel Non-Peptide Nociceptin/Orphanin FQ Receptor Agonist as Antianxiety Drug
5. Pharmacological Characterization of the Newly Synthesized Nociceptin/Orphanin FQ–Receptor Agonist 1-[1-(1-Methylcyclooctyl)-4-piperidinyl]-2-[(3R)-3-piperidinyl]-1H-benzimidazole as an Anxiolytic Agent