Design, Synthesis, and Biological Evaluation of Retinoic Acid-Related Orphan Receptor γt (RORγt) Agonist Structure-Based Functionality Switching Approach from In House RORγt Inverse Agonist to RORγt Agonist.

Retinoic acid receptor-related orphan receptor γt (RORγt) agonists are expected to provide a novel class of immune-activating anticancer drugs via activation of Th17 cells and Tc17 cells. Herein, we describe a novel structure-based functionality switching approach from in house well-optimized RORγt inverse agonists to potent RORγt agonists. We succeeded in the identification of potent RORγt agonist 5 without major chemical structure change. The biochemical response was validated by molecular dynamics simulation studies that showed a helix 12 stabilization effect of RORγt agonists. These results indicate that targeting helix 12 is an attractive and novel medicinal chemistry strategy for switching existing RORγt inverse agonists to agonists.

Discovery of [ cis-3-({(5 R)-5-[(7-Fluoro-1,1-dimethyl-2,3-dihydro-1 H-inden-5-yl)carbamoyl]-2-methoxy-7,8-dihydro-1,6-naphthyridin-6(5 H)-yl}carbonyl)cyclobutyl]acetic Acid (TAK-828F) as a Potent, Selective, and Orally Available Novel Retinoic Acid Receptor-Related Orphan Receptor γt Inverse Agonist.

A series of tetrahydronaphthyridine derivatives as novel RORγt inverse agonists were designed and synthesized. We reduced the lipophilicity of tetrahydroisoquinoline compound 1 by replacement of the trimethylsilyl group and SBDD-guided scaffold exchange, which successfully afforded compound 7 with a lower log  D value and tolerable in vitro activity. Consideration of LLE values in the subsequent optimization of the carboxylate tether led to the discovery of [ cis-3-({(5 R)-5-[(7-fluoro-1,1-dimethyl-2,3-dihydro-1 H-inden-5-yl)carbamoyl]-2-methoxy-7,8-dihydro-1,6-naphthyridin-6(5 H)-yl}carbonyl)cyclobutyl]acetic acid, TAK-828F (10), which showed potent RORγt inverse agonistic activity, excellent selectivity against other ROR isoforms and nuclear receptors, and a good pharmacokinetic profile. In animal studies, oral administration of compound 10 exhibited robust and dose-dependent inhibition of IL-17A cytokine expression in a mouse IL23-induced gene expression assay. Furthermore, development of clinical symptoms in a mouse experimental autoimmune encephalomyelitis model was significantly reduced. Compound 10 was selected as a clinical compound for the treatment of Th17-driven autoimmune diseases.

CCR5 antagonists as anti-HIV-1 agents. Part 2: Synthesis and biological evaluation of N-[3-(4-benzylpiperidin-1-yl)propyl]-N,N'-diphenylureas.

We have previously reported the novel lead compound 1a as a CCR5 antagonist for treatment of HIV-1 infection. SAR studies on incorporating various acyl groups as a replacement for the 5-oxopyrrolidine-3-carbonyl group of the lead structure resulted in the discovery of N-[3-(4-benzylpiperidin-1-yl)propyl]-N,N'-diphenylurea (4a) with significantly improved CCR5 binding affinity. Substitutions (4-Cl, 4e,f; 4-Me, 4i) on the N'-phenyl ring further increased the binding affinity. Introduction of polar substituents on the phenyl ring of the 4-benzylpiperidine moiety enhanced the inhibitory activity of the HIV-1 envelope-mediated membrane fusion (4v,w), suggesting that polar substituents at this position can interfere effectively with HIV-1 cell entry.

Discovery of a thieno[2,3-d]pyrimidine-2,4-dione bearing a p-methoxyureidophenyl moiety at the 6-position: a highly potent and orally bioavailable non-peptide antagonist for the human luteinizing hormone-releasing hormone receptor.

We have previously disclosed the first potent and orally effective non-peptide antagonist for the human luteinizing hormone-releasing hormone (LHRH) receptor, a thieno[2,3-b]pyridin-4-one derivative, T-98475 (1). Extensive research on developing non-peptide LHRH antagonists has been carried out by employing a strategy of replacing the thienopyridin-4-one nucleus with other heterocyclic surrogates. We describe herein the design and synthesis of a series of thieno[2,3-d]pyrimidine-2,4-dione derivatives containing a biaryl moiety, which led to the discovery of a highly potent and orally active non-peptide LHRH antagonist, 5-(N-benzyl-N-methylaminomethyl)-1-(2,6-difluorobenzyl)-6-[4-(3-methoxyureido)phenyl]-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (9k: TAK-013). Compound 9k showed high binding affinity and potent in vitro antagonistic activity for the human receptor with half-maximal inhibition concentration (IC(50)) values of 0.1 and 0.06 nM, respectively. Oral administration of 9k caused almost complete suppression of the plasma LH levels in castrated male cynomolgus monkeys at a 30 mg/kg dose with sufficient duration of action (more than 24 h). The results demonstrated that the thienopyrimidine-2,4-dione core is an excellent surrogate for the thienopyridin-4-one and that thienopyrimidine-2,4-diones and thienopyridin-4-ones constitute a new class of potent and orally bioavailable LHRH receptor antagonists. Furthermore, molecular modeling studies indicate that the unique methoxyurea side chain of 9k preferentially forms an intramolecular hydrogen bond between the aniline NH and the methoxy oxygen atom. The hydrogen bond will shield the hydrogen bonding moieties from the solvent and reduce the desolvation energy cost. It is therefore speculated that the intramolecular hydrogen bond resulting from judicious incorporation of an oxygen atom into the terminal alkyl group of the urea may increase the apparent lipophilicity to allow increased membrane permeability and consequently to improve the oral absorption of 9k in monkeys. On the basis of its profile, compound 9k has been selected as a candidate for clinical trials and it is expected that it will provide a new class of potential therapeutic agents for the clinical treatment of a variety of sex-hormone-dependent diseases.