Discovery of clinical candidate 1-(4-(3-(4-(1H-benzo[d]imidazole-2-carbonyl)phenoxy)pyrazin-2-yl)piperidin-1-yl)ethanone (AMG 579), a potent, selective, and efficacious inhibitor of phosphodiesterase 10A (PDE10A) (original) (raw)

Triazoloquinazolines as a novel class of phosphodiesterase 10A (PDE10A) inhibitors

Bioorganic & Medicinal Chemistry Letters, 2011

Novel triazoloquinazolines have been found as phosphodiesterase 10A (PDE10A) inhibitors. Structureactivity studies improved the initial micromolar potency which was found in the lead compound by a 100-fold identifying 5-(1H-benzoimidazol-2-ylmethylsulfanyl)-2-methyl-[1,2,4]triazolo[1,5-c]quinazoline, 42 (PDE10A IC 50 = 12 nM) as the most potent compound from the series. Two X-ray structures revealed novel binding modes to the catalytic site of the PDE10A enzyme.

Synthesis and in vitro evaluation of new analogues as inhibitors for phosphodiesterase 10A

European Journal of Medicinal Chemistry, 2011

A series of analogues were synthesized by optimizing the structure of papaverine. The in vitro PDE10A binding affinity ( IC 50 ) values for these new analogues were measured; for compounds that have IC 50 value less than 60 nM for PDE10A, the binding affinities (IC 50 value) for PDE3A and PDE3B were tested. Of these analogues, compounds 6a, 6b, 6n, 8b, 8c and 11 displayed relatively higher PDE10A potency with IC 50 value in the range of 28-60 nM. The most potent compound 1-(4-(2-(2-fluoroethoxy)ethoxy)-3-methoxybenzyl)-6,7-dimethoxyisoquinoline (8c) has the IC 50 value of 28 ± 1.2 nM for PDE10A, 2200 ± 437 nM for PDE3A and 2520 ± 210 nM for PDE3B. Compared to papavarine, compound 8c displayed similar PDE10A potency but improved selectivity to PDE10A versus PDE3A and PDE3B. To identify high potent PDE10A inhibitor, further optimization of the structures of these analogues is necessary.

Discovery of benzo[d]imidazo[5,1-b]thiazole as a new class of phosphodiesterase 10A inhibitors

Bioorganic & Medicinal Chemistry Letters, 2013

The design, synthesis and structure activity relationship studies of a series of compounds from benzo[d]imidazo[5,1-b]thiazole scaffold as phosphodiesterase 10A (PDE10A) inhibitors are discussed. Several potent analogs with heteroaromatic substitutions (9a-d) were identified. The anticipated binding mode of these analogs was confirmed by performing the insilico docking experiments. Later, the heteroaromatics were substituted with saturated heteroalkyl groups which provided a tool compound 9e with excellent PDE10A activity, PDE selectivity, CNS penetrability and with favorable pharmacokinetic profile in rats. Furthermore, the compound 9e was shown to be efficacious in the MK-801 induced psychosis model and in the CAR model of psychosis.

Identification of a Novel Orally Bioavailable Phosphodiesterase 10A (PDE10A) Inhibitor with Efficacy in Animal Models of Schizophrenia

Journal of Medicinal Chemistry, 2015

We report the continuation of a focused medicinal chemistry program aimed to further optimize a series of imidazo[1,2-a]pyrazines as a novel class of potent and selective phosphodiesterase 10A (PDE10A) inhibitors. In vitro and in vivo pharmacokinetic and pharmacodynamic evaluation allowed the selection of compound 25a for its assessment in preclinical models of psychosis. The evolution of our medicinal chemistry program, structure− activity relationship (SAR) analysis, as well as a detailed pharmacological profile for optimized lead 25a are described.

Pyrido[4,3- e ][1,2,4]triazolo[4,3- a ]pyrazines as Selective, Brain Penetrant Phosphodiesterase 2 (PDE2) Inhibitors

ACS Medicinal Chemistry Letters, 2015

A novel series of pyrido[4,3-e][1,2,4]triazolo-[4,3-a]pyrazines is reported as potent PDE2/PDE10 inhibitors with drug-like properties. Selectivity for PDE2 was obtained by introducing a linear, lipophilic moiety on the meta-position of the phenyl ring pending from the triazole. The SAR and protein flexibility were explored with free energy perturbation calculations. Rat pharmacokinetic data and in vivo receptor occupancy data are given for two representative compounds 6 and 12.

Synthesis and In Vitro Evaluation of 8-Pyridinyl-Substituted Benzo[e]imidazo[2,1-c][1,2,4]triazines as Phosphodiesterase 2A Inhibitors

Molecules

Phosphodiesterase 2A (PDE2A) is highly expressed in distinct areas of the brain, which are known to be related to neuropsychiatric diseases. The development of suitable PDE2A tracers for Positron Emission Tomography (PET) would permit the in vivo imaging of the PDE2A and evaluation of disease-mediated alterations of its expression. A series of novel fluorinated PDE2A inhibitors on the basis of a Benzoimidazotriazine (BIT) scaffold was prepared leading to a prospective inhibitor for further development of a PDE2A PET imaging agent. BIT derivatives (BIT1–9) were obtained by a seven-step synthesis route, and their inhibitory potency towards PDE2A and selectivity over other PDEs were evaluated. BIT1 demonstrated much higher inhibition than other BIT derivatives (82.9% inhibition of PDE2A at 10 nM). BIT1 displayed an IC50 for PDE2A of 3.33 nM with 16-fold selectivity over PDE10A. This finding revealed that a derivative bearing both a 2-fluoro-pyridin-4-yl and 2-chloro-5-methoxy-phenyl un...

Discovery of novel pyrazolopyrimidinone analogs as potent inhibitors of phosphodiesterase type-5

Bioorganic & Medicinal Chemistry, 2015

Cyclic guanosine monophosphate (cGMP) specific phosphodiesterase type-5 (PDE5), a clinically proven target to treat erectile dysfunction and diseases associated with lower cGMP levels in humans, is present in corpus cavernosum, heart, lung, platelets, prostate, urethra, bladder, liver, brain, and stomach. Sildenafil, vardenafil, tadalafil and avanafil are FDA approved drugs in market as PDE5 inhibitors for treating erectile dysfunction. In the present study a lead molecule 4-ethoxy-N-(6-hydroxyhexyl)-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)benzenesulfonamide, that is, compound-4a, an analog of pyrazolopyrimidinone scaffold has been identified as selective PDE5 inhibitor. A series of compounds was synthesized by replacing N-methylpiperazine moiety (ring-C) of sildenafil structure with different N-substitutions towards sulfonamide end. Compound-4a showed lower IC 50 value (1.5 nM) against PDE5 than parent sildenafil (5.6 nM) in in vitro enzyme assay. The isoform selectivity of the compound-4a against other PDE isoforms was similar to that of the Sildenafil. In corroboration with the in vitro data, this molecule showed better efficacy in in vivo studies using the conscious rabbit model. Also compound-4a exhibited good physicochemical properties like solubility, caco-2 permeability, c Log P along with optimal PK profile having no significant CYP enzyme inhibitory liabilities. Discovery of these novel bioactive compounds may open a new alternative for developing novel preclinical candidates based on this drugable scaffold.

Discovery of a new series of [1,2,4]triazolo[4,3-a]quinoxalines as dual phosphodiesterase 2/phosphodiesterase 10 (PDE2/PDE10) inhibitors

Bioorganic & Medicinal Chemistry Letters, 2013

Abbreviations: CNS, central nervous system; cAMP, 3 0 ,5 0 -cyclic adenosine monophosphate; cGMP, 3 0 ,5 0 -cyclic guanosine monophosphate; PDE2, phosphodiesterase 2; PDE10, phosphodiesterase 10; SAR, structure-activity relationship.