ABSTRACT
A practical synthesis of capromorelin (1), a growth hormone secretagogue, is described that utilizes as a key step a crystallization-induced dynamic resolution (CIDR) of (±)-3a-benzyl-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo[4,3-c]pyridin-3(3aH)-one [(±)-2] by L-tartaric acid salt formation, yielding (R)-2.L-tartaric acid in high chemical yield (>85%) and with diastereomeric excess (de) of â¼98%. Treatment of (R)-2.L-tartaric acid with ammonium hydroxide provided (R)-2 without loss of chiral purity. In situ generated (R)-2 was coupled with (R)-3-(benzyloxy)-2-(2-(tert-butoxycarbonyl)-2-methylpropanamido)propanoic acid [(R)-3] to give predominantly a single diastereomer of N-Boc-protected capromorelin [(1R,3aR)-4]. This process was used to prepare bulk quantities of capromorelin from (±)-2 to support preclinical toxicology studies.
Subject(s)
Piperidines/chemical synthesis , Pyrazoles/chemical synthesis , Thermodynamics , Crystallography, X-Ray , Models, Molecular , Molecular Structure , Piperidines/chemistry , Pyrazoles/chemistryABSTRACT
Previous drug discovery efforts identified classical PYK2 kinase inhibitors such as 2 and 3 that possess selectivity for PYK2 over its intra-family isoform FAK. Efforts to identify more kinome-selective chemical matter that stabilize a DFG-out conformation of the enzyme are described herein. Two sub-series of PYK2 inhibitors, an indole carboxamide-urea and a pyrazole-urea have been identified and found to have different binding interactions with the hinge region of PYK2. These leads proved to be more selective than the original classical inhibitors.
Subject(s)
Focal Adhesion Kinase 2/antagonists & inhibitors , Indoles/pharmacology , Protein Kinase Inhibitors/pharmacology , Pyrazoles/pharmacology , Urea/pharmacology , Animals , Crystallography, X-Ray , Dose-Response Relationship, Drug , Focal Adhesion Kinase 2/metabolism , HEK293 Cells , Humans , Indoles/chemical synthesis , Indoles/chemistry , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Rats , Structure-Activity Relationship , Urea/analogs & derivatives , Urea/chemistryABSTRACT
Synthesis and structure-activity relationship (SAR) studies on 5-trifluoromethylpyrido[4,3-d]pyrimidin-4(3H)-ones, a novel class of calcium receptor antagonists is described with particular emphasis on optimization of the pharmacokinetic/pharmacodynamic parameters required for a short duration of action compound. Orally-active compounds were identified which displayed the desired animal pharmacology (rapid and transient stimulation of parathyroid hormone) essential for bone anabolic effects.
Subject(s)
Anabolic Agents/chemistry , Pyrimidinones/chemistry , Receptors, Calcium-Sensing/antagonists & inhibitors , Administration, Oral , Anabolic Agents/administration & dosage , Anabolic Agents/pharmacokinetics , Animals , Male , Parathyroid Hormone/metabolism , Pyrimidinones/administration & dosage , Pyrimidinones/pharmacokinetics , Rats , Rats, Sprague-Dawley , Receptors, Calcium-Sensing/metabolism , Structure-Activity RelationshipABSTRACT
The synthesis, in vitro properties, and in vivo pharmacokinetics for a series of sulfoximine-substituted trifluoromethylpyrimidines as inhibitors of proline-rich tyrosine kinase, a target for the possible treatment of osteoporosis, are described. These compounds were prepared as surrogates of the corresponding sulfone compound 1. Sulfone 1 was an attractive PYK2 lead compound; however, subsequent studies determined this compound possessed high dofetilide binding, which is an early indicator of cardiovascular safety. Surprisingly, the corresponding sulfoximine analogs displayed significantly lower dofetilide binding, which, for N-methylsulfoximine (S)-14a, translated to lower activity in a patch clamp hERG K(+) ion channel screen. In addition, compound (S)-14a shows good oral exposure in a rat pharmacokinetic model.
Subject(s)
Ether-A-Go-Go Potassium Channels/metabolism , Focal Adhesion Kinase 2/antagonists & inhibitors , Pyrimidines/chemistry , Pyrimidines/pharmacology , Administration, Oral , Animals , Drug Evaluation, Preclinical , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Humans , Imines/chemistry , Osteoporosis/drug therapy , Patch-Clamp Techniques , Phenethylamines , Pyrimidines/pharmacokinetics , Rats , Structure-Activity Relationship , Sulfonamides , Sulfones/chemistryABSTRACT
Previous studies have demonstrated the CYP3A4 mediated oxidation of the 5-aminooxindole motif, present in the trifluoromethylpyrimidine class of PYK-2 inhibitors, to a reactive bis-imine species, which can be trapped with glutathione (GSH) in human liver microsomal incubations. The corresponding 5-aminobenzsultam derivatives, which should possess a similar oxidative liability, do not form GSH conjugates in microsomal incubations. In the current study, we conducted a retrospective analysis on representative 5-aminooxindole and 5-aminobenzsultam PYK-2 inhibitors utilizing CYP3A4 molecular docking and quantum chemical calculations to rationalize the bioactivation differences. Our analysis revealed key differences in (a) active site binding and (b) two-electron oxidation rates, which correlate with GSH adduct formation with the two moieties. The value of linear ion/orbitrap mass spectrometry to detect GSH conjugates with greater sensitivity, compared with conventional triple quadrupole mass spectrometry approaches, was also demonstrated in the course of these studies.
Subject(s)
Benzene Derivatives/pharmacology , Cytochrome P-450 CYP3A/metabolism , Focal Adhesion Kinase 2/antagonists & inhibitors , Glutathione/metabolism , Indoles/pharmacology , Amines/pharmacology , Catalysis , Computer Simulation , Humans , Mass Spectrometry , Microsomes , Models, Molecular , Oxidation-Reduction , Oxindoles , Protein Binding , Protein Kinase InhibitorsABSTRACT
Sulfonamides, exemplified by 3a, were identified as highly selective EP(2) agonists. Lead optimization led to the identification of CP-533536, 7f, a potent and selective EP(2) agonist. CP-533536 demonstrated the ability to heal fractures when administered locally as a single dose in rat models of fracture healing.
Subject(s)
Osteogenesis/drug effects , Pyridines/chemistry , Receptors, Prostaglandin E/agonists , Animals , Male , Pyridines/administration & dosage , Pyridines/pharmacokinetics , Rats , Rats, Sprague-Dawley , Receptors, Prostaglandin E/metabolism , Receptors, Prostaglandin E, EP2 Subtype , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Sulfonamides/chemistry , Sulfonamides/pharmacologyABSTRACT
The synthesis and SAR for a series of diaminopyrimidines as PYK2 inhibitors are described. Using a combination of library and traditional medicinal chemistry techniques, a FAK-selective chemical series was transformed into compounds possessing good PYK2 potency and 10- to 20-fold selectivity against FAK. Subsequent studies found that the majority of the compounds were positive in a reactive metabolite assay, an indicator for potential toxicological liabilities. Based on the proposed mechanism for bioactivation, as well as a combination of structure-based drug design and traditional medicinal chemistry techniques, a follow-up series of PYK2 inhibitors was identified that maintained PYK2 potency, FAK selectivity and HLM stability, yet were negative in the RM assay.
Subject(s)
Focal Adhesion Kinase 2/antagonists & inhibitors , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Animals , Combinatorial Chemistry Techniques , Crystallography, X-Ray , Disease Models, Animal , Drug Design , Focal Adhesion Protein-Tyrosine Kinases/antagonists & inhibitors , Humans , Molecular Conformation , Molecular Structure , Osteoporosis/drug therapy , Pyrimidines/chemistry , Rats , Structure-Activity RelationshipABSTRACT
Heptanoic acid lactams, exemplified by 2, were identified as highly selective EP4 agonists via high throughput screening. Lead optimization led to the identification of lactams with a 30-fold increase in EP4 potency in vitro. Compounds demonstrated robust bone anabolic effects when administered in vivo in rat models of osteoporosis.
Subject(s)
Bone Density/drug effects , Bone Development , Bone and Bones/drug effects , Organ Size/drug effects , Ovariectomy , Receptors, Prostaglandin E/agonists , Animals , Female , Osteoporosis , Rats , Rats, Sprague-Dawley , Receptors, Prostaglandin E, EP4 SubtypeABSTRACT
Two series of 6-hydroxy and 7-hydroxy tetrahydroisoquinolines were prepared. Evaluating a range of C-1, C-4, and N-substituents led to the discovery of ER alpha and ER beta selective analogs.
Subject(s)
Selective Estrogen Receptor Modulators/chemical synthesis , Tetrahydroisoquinolines/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Estrogen Receptor alpha/chemistry , Estrogen Receptor beta/chemistry , Female , Humans , Inhibitory Concentration 50 , Ligands , Protein Binding , Selective Estrogen Receptor Modulators/pharmacology , Structure-Activity Relationship , Tetrahydroisoquinolines/chemical synthesisABSTRACT
Novel pyrazolinone-piperidine dipeptide derivatives were synthesized and evaluated as growth hormone secretagogues (GHSs). Two analogues, capromorelin (5, CP-424391-18, hGHS-R1a K(i)=7 nM, rat pituicyte EC(50)=3 nM) and the des-methyl analogue 5c (hGHS-R1a K(i)=17 nM, rat pituicyte EC(50)=3 nM), increased plasma GH levels in an anesthesized rat model, with ED(50) values less than 0.05 mg/kg iv. Capromorelin showed enhanced intestinal absorption in rodent models and exhibited superior pharmacokinetic properties, including high bioavailabilities in two animal species [F(rat)=65%, F(dog)=44%]. This short-duration GHS was orally active in canine models and was selected as a development candidate for the treatment of musculoskeletal frailty in elderly adults.
Subject(s)
Dipeptides/chemical synthesis , Dipeptides/pharmacology , Growth Hormone/metabolism , Piperidines/chemical synthesis , Piperidines/pharmacology , Pyrazoles/chemical synthesis , Pyrazoles/pharmacology , Animals , Cells, Cultured , Chemical Phenomena , Chemistry, Physical , DNA, Complementary/metabolism , Dipeptides/pharmacokinetics , Dogs , Drug Design , Female , Half-Life , Humans , Indicators and Reagents , Indoles/pharmacology , Magnetic Resonance Spectroscopy , Piperidines/pharmacokinetics , Pituitary Gland/cytology , Pituitary Gland/drug effects , Pituitary Gland/metabolism , Pyrazoles/pharmacokinetics , Rats , Rats, Sprague-Dawley , Rats, Wistar , Solubility , Spiro Compounds/pharmacologyABSTRACT
New tert-butyl, picolyl and fluorinated analogues of capromorelin (3), a short-acting growth hormone secretagogue (GHS), were prepared as part of a program to identify long-acting GHSs that increase 24-h plasma IGF-1 levels. Compounds 4c and 4d (ACD LogD values >or=2.9) displayed extended plasma elimination half-lives in dogs, primarily due to high volumes of distribution, but showed weak GH secretagogue activities in rats (ED(50)s>10 mg/kg). A less lipophilic derivative 4 (ACD LogD=1.6) exhibited a shorter canine half-life, but stimulated GH secretion in two animal species. Repeat oral dosing of 4 in dogs for 29 days (6 mg/kg) resulted in a significant down-regulation of the post dose GH response and a 60 and 40% increase in IGF-1 levels relative to pre-dose levels at the 8- and 24-h post dose time points. Compound 4 (CP-464709-18) has been selected as a development candidate for the treatment of frailty.