Synthesis and SAR of sulfoxide substituted carboxyquinolines as NK3 receptor antagonists.

The neurokinin-3 (NK3) receptor is regarded as a potential novel target for treating patients with schizophrenia. Herein we report the synthesis and SAR of a series of C3-alkylsulfoxide substituted quinolines as potent NK3 receptor antagonists. These compounds have excellent NK3 functional activity, good selectivity and drug-like properties. Several key compounds have good in vitro/in vivo DMPK characteristics, and are active in a gerbil locomotor activity model.

4-aryl piperazine and piperidine amides as novel mGluR5 positive allosteric modulators.

Positive allosteric modulation of metabotropic glutamate receptor 5 (mGluR5) is regarded as a potential novel treatment for schizophrenic patients. Herein we report the synthesis and SAR of 4-aryl piperazine and piperidine amides as potent mGluR5 positive allosteric modulators (PAMs). Several analogs have excellent activity and desired drug-like properties. Compound 2b was further characterized as a PAM using several in vitro experiments, and produced robust activity in several preclinical animal models.

SAR development of a series of 8-azabicyclo[3.2.1]octan-3-yloxy-benzamides as kappa opioid receptor antagonists. Part 2.

Further structure activity relationship studies on a previously reported 8-azabicyclo[3.2.1]octan-3-yloxy-benzamide series of potent and selective kappa opioid receptor antagonists is discussed. Modification of the pendant N-substitution to include a cyclohexylurea moiety produced analogs with greater in vitro opioid and hERG selectivity such as 12 (kappa IC50=172 nM, mu:kappa ratio=93, delta:kappa ratio=>174, hERG IC50=>33 microM). Changes to the linker conformation and identity as well as to the benzamide ring moiety were also investigated.

Discovery of 8-azabicyclo[3.2.1]octan-3-yloxy-benzamides as selective antagonists of the kappa opioid receptor. Part 1.

Initial high throughput screening efforts identified highly potent and selective kappa opioid receptor antagonist 3 (κ IC(50)=77 nM; µ:κ and δ:κ IC(50) ratios>400) which lacked CNS exposure in vivo. Modification of this scaffold resulted in development of a series of 8-azabicyclo[3.2.1]octan-3-yloxy-benzamides showing potent and selectivity κ antagonism as well as good brain exposure. Analog 6c (κ IC(50)=20 nM; µ:κ=36, δ:κ=415) was also shown to reverse κ-agonist induced rat diuresis in vivo.

Naphtho[2,1-b][1,5] and [1,2-f][1,4]oxazocines as selective NK1 antagonists.

Previously we reported on the synthesis and properties of a series of highly potent piperidinyl 2-subsituted-3-cyano-1-naphthamide NK1 antagonists that includes 3 and 4. Here we report our efforts to alleviate a troublesome atropisomeric property of those derivatives by introduction of a tethering bridge that, in addition, could be used to lock the resulting cyclic derivatives in a purported NK1 pharmacophore conformation. Using 3 as a starting point, the naphtho[2,1-b][1,5]oxazocine, 17, was found to contain the optimal ring tether size (8) for retaining NK1 activity, was more NK1 versus NK2 selective, and reduced the number of atropisomers from four to two. Cyclic derivatives 29 and 32, which exist as essentially single atropisomers in the purported pharmacophore conformation, were prepared in the closely related naphtho[1,2-f][1,4]oxazocine series as part of an effort to use mono methyl substitution of the tethering bridge as a conformation stabilizing factor. Both 29 and 32 were found to be less active as NK1 antagonists than the non-methylated parent 28 possibly due to methyl group destabilization of receptor interaction. We discuss the above findings in the context of a previously proposed NK1 pharmacophore model and present a further refinement of that model.

Design, synthesis, and SAR of tachykinin antagonists: modulation of balance in NK(1)/NK(2) receptor antagonist activity.

Through optimization of compounds based on the dual NK(1)/NK(2) antagonist ZD6021, it was found that alteration of two key regions could modulate the balance of NK(1) and NK(2) potency. Substitution of the 2-naphthalene position in analogues of ZD6021 resulted in increased NK(1) potency and thus afforded NK(1) preferential antagonists. Alterations of the piperidine region could then increase NK(2) potency to restore dual NK(1)/NK(2) selectivity. Through these efforts, three novel receptor antagonists from a single chemically related series were identified; two are dual NK(1)/NK(2) antagonists, and the third is an NK(1) preferential antagonist. In this paper, the factors affecting the balance of NK(1) and NK(2) selectivity in this series are discussed and the in vitro and in vivo properties of the novel antagonists are described.