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A series of inhibitors of mammalian 15-lipoxygenase (15-LO) based on a 3,4,5-tri-substituted pyrazole scaffold is described. Replacement of a sulfonamide functionality in the lead series with a sulfamide group resulted in improved physicochemical properties generating analogs with enhanced inhibition in cell-based and whole blood assays., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A series of 2,4,5-tri-substituted imidazoles has proven to be highly potent in inhibiting mammalian 15-lipoxygenase (15-LO) with excellent selectivity over human isozymes 5- and P-12-LO. Non-symmetrical sulfamides (e.g., 21a-n) were found to be suitable replacements for the earlier arylsulfonamide-containing members of this series (e.g., 2, 14a-p). Several members of these series also demonstrated potent inhibition of human 15-LO in a cell-based assay.

A series of inhibitors of mammalian 15-lipoxygenase based on tryptamine and homotryptamine scaffolds is described. Compounds with aryl substituents at C-2 of the indole core of tryptamine and homotryptamine sulfonamides (e.g., 37a-p) proved to be potent inhibitors of the isolated enzyme. Selected compounds also demonstrated desirable inhibition selectivities over isozymes 5- and P-12-LO.

A series of substituted spirobenzazepines was prepared and evaluated as V(1a) and V(2) dual vasopressin receptor antagonists. Compounds 7p and 7q have been shown to be not only potent inhibitors of vasopressin receptors, but also have exhibited an excellent overall pharmaceutical suitability profile.

A novel series of spirobenzazepines was synthesized and evaluated for V1a and V2 receptor antagonist activity. Compounds 8b, 8i, and 8k have shown selective V1a receptor antagonist activity. Compounds 8p and 8q were shown to be dual V1a/V2 receptor antagonists.

Inhibition of the sodium hydrogen exchanger isoform-1 (NHE-1) has been shown to limit damage to the myocardium under ischemic conditions in animals. While most known NHE-1 inhibitors are acylguanidines, this report describes the design and synthesis of a series of heterocyclic inhibitors of NHE-1 including aminoimidazoles with undiminished in vitro activity and oral bioavailability.

A series of benzoxazinones has been synthesized and tested for PPARgamma agonist activity. Synthetic approaches were developed to provide either racemic or chiral compounds. In vitro functional potency could be measured through induction of the aP2 gene, a target of PPARgamma. These studies revealed that compounds with large aliphatic chains at the nitrogen of the benzoxazinone were the most potent. Substitution of the chain was tolerated and in many cases enhanced the in vitro potency of the compound. Select compounds were further tested for metabolic stability, oral bioavailability in rats, and efficacy in db/db mice after 11 days of dosing. In vivo analysis with 13 and 57 demonstrated that the series has potential for the treatment of type 2 diabetes.

A series of benzoxazinones was synthesized as PPARgamma agonists. The compounds were obtained in seven steps, and SAR was developed by variations to the core shown below. The compounds were tested as functional agonists in the induction of the aP2 gene in preadipocytes, and the most potent compound in the series has an EC(50)=0.51 microM. The potency was further confirmed through a PPAR-Gal4 construct. Efficacy has been demonstrated in the db/db mouse model of hyperglycemia.

A first-in-class non-peptide antagonist of the motilin receptor was identified through electronic screening of our corporate database against a 3D pharmacophore. The pharmacophore was developed from the motilin 22 residue endogenous peptide using NMR structural data, principles of peptide folding, and peptide structure activity relationships. The NMR data supported helical content within the peptide, and both the hydrophobic staple and N-capping box motifs were identified in the motilin sequence. The conformational features of these motifs were imposed on the peptide structure, providing a constrained conformer as a starting point for database searching. A trisubstituted cyclopentene lead was identified directly from the electronic search. Compounds in this series inhibit the binding of 125I-motilin to human antral smooth muscle membrane and antagonize motilin-induced intracellular calcium mobilization in cells expressing the human motilin receptor. A potent compound developed through optimization, RWJ 68023, is active in binding and cell-based functional assays and is also effective in inhibiting motilin-induced contractility in segments of rabbit duodenum. This orally active compound is currently undergoing clinical evaluation for the treatment of gastrointestinal disorders associated with altered motility.

We have characterized a series of nonsteroidal progesterone receptor ligands, the tetrahydropyridazines. Compounds in this series, exemplified by RWJ 26819, demonstrate high affinity and unprecedented specificity for the progesterone receptor relative to other steroid hormone receptors. Like steroidal progestins, RWJ 26819 induces binding of the receptor to a progesterone response element in vitro, and stimulates gene expression in and proliferation of T47D human breast cancer cells. When administered to rabbits orally or subcutaneously, the compound induces histological changes in the uterine lining comparable to those induced by levonorgestrel. It also inhibits ovulation in monkeys. Though less potent in cells and in animal models than would be predicted from binding affinity alone, their enhanced selectivity suggests that they could be effectively used in a clinical setting. Most of the tetrahydropyridazines synthesized are progestin agonists or mixed agonists and antagonists in vitro; however, one compound with antagonist activity in the rabbit uterine transformation assay has been identified.

A series of 3-aryl-1-(arylsulfonyl)-1,4,5,6-tetrahydropyridazine allosteric modulators of the GABAA receptor was synthesized, and biological activity was examined in vitro and in vivo. Beginning with 1a, stepwise modification of the substituents and conservation of the scaffold yielded a chemical series in which the modulatory activity was enhanced by the presence of GABA. The SAR suggests, but does not establish, that the compounds bind to the steroid binding site on the GABAA receptor. The GABA shift for each compound indicates that all compounds in this series are either agonists or partial agonists.

Progesterone receptor antagonists are a promising class of therapeutic drugs indicated for the treatment of a variety of reproductive conditions. Understanding their mechanism of action at the molecular level is an important prerequisite for the development of future generations of these drugs. Using limited proteolytic analysis to monitor conformational changes in the progesterone receptor, we can detect three distinct classes of progestin antagonist. The effect of the first, RU486, on the conformation of the carboxyl terminus of the receptor has been previously described. The second, exemplified by RWJ 47626, a nonsteroidal compound with in vitro antiprogestin activity, induces a proteolytic fragment pattern indistinguishable from that induced by the agonist R5020. Finally, ZK299 induces a fragment pattern intermediate between that induced by R5020 and RU486. Site-directed mutagenesis of the carboxyl-terminal tail of the progesterone receptor indicates that the region containing the putative activation function AF-2 is differentially exposed to proteolytic attack depending on the nature of the antagonist bound. The differentially exposed region is most accessible when the antagonist RU486 is bound, less accessible when the antagonist ZK299 is bound, and least accessible when the antagonist RWJ47626 or agonist R5020 is bound. The results suggest that multiple types of antiprogestin can be defined in terms of their effects on the conformation of the carboxyl-terminal activation function of the progesterone receptor.

A novel series of nonsteroidal heterocycles was discovered which display cell-type selective, high-affinity (nanomolar) binding to the progesterone receptors from TE85 osteosarcoma cells but > 1 microM binding affinity to the progesterone receptors from T47D and ZR75 human breast carcinoma cells. Structure-activity relationships were developed for a set of these compounds, and a representative analog 1-(3,4-dichlorobenzoyl)-3-phenyl-1,4,5,6-tetrahydropyridazine++ + (1i, RWJ 25333) was chosen for further evaluation. RWJ 25333 stimulated the in vitro proliferation of human osteoblast-like cells but not human breast cells.

A series of close analogues of the potent, long-acting cardiotonic bemoradan (2a) was synthesized and examined in both in vitro and in vivo test systems. Changing the oxygen heteroatom at the 1-position of the benzoxazine ring of bemoradan to sulfur gave 4a, a more potent enzyme inhibitor and in vivo cardiotonic compound by the iv route. Intraduodenal administration of bemoradan, however, showed a superior response compared to its sulfur analogue, possibly due to oxidation of sulfur followed by a facile Pummerer rearrangement. Model studies were performed to examine the effect of the oxidation state of sulfur. Lack of a heteroatom at the 1-position, 3a (Y-590), afforded a compound with activity and potency very similar to those of bemoradan while the 1-selena compound gave a much less potent analogue 5. Analogues having a methyl group on the 4-nitrogen (2b, 3b, and 4b) were less potent than the desmethyl compounds, but all of these compounds have potent PDE III inhibiting activity and the ability to increase cardiac force in an anesthetized dog preparation when given iv.

Canine cardiac muscle contains a type IV cyclic AMP (cAMP) phosphodiesterase (PDE) that is composed of two subtypes. One subtype is sensitive to rolipram inhibition (RSPDE), whereas the other is not inhibited significantly by rolipram (RIPDE). The RIPDE is inhibited by several cardiotonic agents operating by a PDE-inhibitory mechanism. Bemoradan [RWJ-22867; 7-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)-2H-1,4-benzoxazin -3(4H)-one], a novel, potent positive inotropic agent, demonstrated biphasic inhibition of the fraction III enzyme from canine cardiac muscle. Inhibition by rolipram of the RSPDE converted the IC50 curves of bemoradan, indolidan, pimobendan, and imazodan to sigmoidal, monophasic curves. Lineweaver-Burk analysis yielded competitive inhibition KI values of 0.023, 0.09, 0.065 and 0.60 microM, respectively, for these compounds. The cardiotonic compounds, however, were not potent inhibitors of the Type I and Type II cAMP PDEs found in canine ventricular muscle. The order of potency for inhibiting the RIPDE cAMP PDE subtype was bemoradan greater than pimobendan greater than indolidan greater than imazodan. Bemoradan is, therefore, a potent inhibitor of the cardiac muscle cAMP PDE which could, in part, be responsible for its cardiotonic activity.

A synthetic program of rational drug design was undertaken to develop a series of quinazoline-3-oxides as pulmonary-selective inhibitors of ovalbumin-induced, leukotriene-mediated bronchoconstriction. The most active and selective compounds contained a methyl group at the 4-position, a medium sized branched alkyl group at the 2-position, and a small electron donating group on the phenyl ring. Significant enhancement in selectivity was observed in comparing the pulmonary versus cardiovascular effects of these new bronchodilators with the effects of theophylline.

A series of 6-benzoxazinylpyridazin-3-ones was prepared and evaluated for inhibition of cardiac phosphodiesterase (PDE) fraction III in vitro and for positive inotropic activity in vivo. 6-[3,4-Dihydro-3-oxo-1,4(2H)-benzoxazin-7-yl]-2,3,4,5-tetrahydro-5 - methylpyridazin-3-one (bemoradan) was found to be an extremely potent and selective inhibitor of canine PDE fraction III and a long-acting, potent, orally active inotropic vasodilator agent in various canine models. Additional benzoxazin-6-yl and -8-yl compounds were also prepared. Altering the pyridazinone substitution from the 6-position to the 7-position produced a 14-fold increase in the iv cardiotonic potency (ED50) from 77 to 5.4 micrograms/kg while substitution at the 8-position reduced potency. Methyl substitution at various sites in the molecule was also examined. Positive inotropic activity was maintained for between 8 and 24 h after a single oral dose (100 micrograms/kg) of bemoradan in dogs, thus making it one of the most potent and long-acting orally effective inotropes yet described. Bemoradan is currently under development as a cardiotonic agent for use in the management of congestive heart failure.

The synthesis, cardiac fraction III cyclic nucleotide phosphodiesterase (PDE-III) inhibition, and positive inotropic activity of a series of 2(1H)-quinazolinones are reported. A general synthesis of the series involved the cyclization of 2-aminoacetophenones with potassium cyanate in acetic acid. Modifications at the 4-position of the quinazoline nucleus were best achieved by formation of the intermediate N1-acyl-N3-phenylurea from the substituted phenyl isocyanate and appropriate carboxamide. PPA was used to ring close to the quinazoline product. Generally the SAR for the series paralleled the five-point model previously published for PDE-III inhibition. The most active analogue of the series was 5,6-dimethoxy-4-methyl-2(1H)-quinazolinone (1) (ORF 16600), which had about twice the intravenous potency of amrinone. Compound 1 is currently under development as an orally active cardiotonic.