1,3-Diarylcycloalkanopyrazoles and diphenyl hydrazides as selective inhibitors of cyclooxygenase-2.

Novel 1,3-diarylcycloalkanopyrazoles 1, and diphenyl hydrazides 2 were identified as selective inhibitors of cyclooxygenase-2. The 1,3-diaryl substitution pattern of the pyrazole ring in 1 differentiates these compounds from most of the known selective COX-2 inhibitors that contain two aryl rings at the adjacent positions on a heterocyclic or a phenyl ring. Similarly, the two phenyl rings in 2 are also separated by three atoms. SAR of both phenyl rings in 1 and 2, and the aliphatic ring in 1 will be discussed.

RWJ 67657, a potent, orally active inhibitor of p38 mitogen-activated protein kinase.

Tumor necrosis factor-alpha (TNF-alpha), a cytokine secreted by activated monocytes/macrophages and T lymphocytes, has been implicated in several disease states, including rheumatoid arthritis, inflammatory bowel disease, septic shock, and osteoporosis. Monocyte/macrophage production of TNF-alpha is dependent on the mitogen-activated protein kinase p38. RWJ 67657 (4-[4-(4-fluorophenyl)-1-(3-phenylpropyl)-5-(4-pyridinyl)-1H-imidazol -2-yl]-3-butyn-1-ol) inhibited the release of TNF-alpha by lipopolysaccharide (a monocyte stimulus)-treated human peripheral blood mononuclear cells with an IC(50) of 3 nM, as well as the release of TNF-alpha from peripheral blood mononuclear cells treated with the superantigen staphylococcal enterotoxin B (a T cell stimulus), with an IC(50) value of 13 nM. This compound was approximately 10-fold more potent than the literature standard p38 kinase inhibitor SB 203580 in all p38 dependent in vitro systems tested. RWJ 67657 inhibited the enzymatic activity of recombinant p38alpha and beta, but not gamma or delta, in vitro and had no significant activity against a variety of other enzymes. In contrast, SB 203580 significantly inhibited the tyrosine kinases p56 lck and c-src (IC(50) = 5 microM). RWJ 67657 did not inhibit T cell production of interleukin-2 or interferon-gamma and did not inhibit T cell proliferation in response to mitogens. RWJ 67657 inhibited TNF-alpha production in lipopolysaccharide-injected mice (87% inhibition at 50 mg/kg) and in rats (91% inhibition at 25 mg/kg) after oral administration. Based on these favorable biological properties, RWJ 67657 may have use as a treatment for inflammatory diseases.

N-hydroxyurea and hydroxamic acid inhibitors of cyclooxygenase and 5-lipoxygenase.

Two series of compounds (1 and 2) having structural features of the dual COX/5-LO inhibitor tepoxalin and the 5-LO inhibitor ABT-761 were prepared. Many of these hybrid compounds are potent COX and 5-LO inhibitors; two compounds (1a and 2t) inhibit eicosanoid biosynthesis in an ex vivo assay.

Evaluation of the antiinflammatory activity of a dual cyclooxygenase-2 selective/5-lipoxygenase inhibitor, RWJ 63556, in a canine model of inflammation.

Sterile perforated polyethylene spheres (wiffle golf balls) were implanted s.c. in beagle dogs. A local inflammatory reaction was elicited within the spheres by injecting carrageenan. Changes in leukocyte count, prostaglandin E2, thromboxane B2 and leukotriene B4 levels were monitored in fluid samples collected over a 24-hr period. Blood samples were also collected at various time points and analyzed for prostaglandin E2 and leukotriene B4 production after ex vivo calcium ionophore treatment. Effects of standard antiinflammatory agents (aspirin, indomethacin, dexamethasone, tenidap and zileuton) and newer cyclooxygenase-2 (COX-2) selective agents (nimesulide, nabumetone and SC-58125) were determined after oral administration. Ex vivo inhibition of cyclooxygenase product synthesis (prostaglandin E2, thromboxane B2) in whole blood was used as an indicator of activity for the constitutive COX-1 isoform, although inhibition of the synthesis of these mediators in the chamber exudate during an inflammatory process is believed to represent COX-2 inhibition. Treatment effects on leukotriene B4 production were also determined both ex vivo in whole blood and in the fluid. All of the compounds tested, except aspirin, inhibited leukocyte infiltration into the fluid exudate. Inhibitors that exert their effects on both isozymes of cyclooxygenase attenuate production of cyclooxygenase metabolites in both the inflammatory exudate and in peripheral blood ex vivo, although COX-2 selective inhibitors only demonstrated activity in the exudate. A 5-lipoxygenase inhibitor (zileuton), a corticosteroid (dexamethasone) and a dual COX-2 selective/5-lipoxygenase inhibitor (RWJ 63556) had similar profiles in that they all inhibited cell infiltration and eicosanoid production in the fluid and also attenuated leukotriene B4 production in both the fluid and blood.

Nitroarylhydroxymethylphosphonic acids as inhibitors of CD45.

A series of nitroarylhydroxymethylphosphonic acids was synthesized and evaluated as inhibitors of CD45. It was discovered that both the alpha hydroxy and nitro groups are essential for activity. Potency is enhanced by the addition of a large lipophilic group on the aryl ring adjacent to the phosphonic acid moiety. Kinetics studies have shown that these compounds are competitive inhibitors and thus bind at the active site of this enzyme.

Tepoxalin: a dual cyclooxygenase/5-lipoxygenase inhibitor of arachidonic acid metabolism with potent anti-inflammatory activity and a favorable gastrointestinal profile.

Tepoxalin [5-(4-chlorophenyl)-N-hydroxy-(4-methoxyphenyl)-N-methyl-1H- pyrazole-3-propanamide] is a potent inhibitor of sheep seminal vesicle cyclooxygenase (CO) (IC50 = 4.6 microM), rat basophilic leukemia cell (RBL-1) lysate CO (IC50 = 2.85 microM) and CO from intact RBL-1 cells (IC50 = 4.2 microM). The compound inhibits the production of thromboxane B2 (TxB2) in Ca++ ionophore A-23187-stimulated human peripheral blood leukocytes (HPBL; IC50 = 0.01 microM) and human whole blood (IC50 = 0.08 microM) and is a potent inhibitor of epinephrine-induced human platelet aggregation (IC50 = 0.045 microM). Tepoxalin inhibits lipoxygenase (LO) in RBL-1 lysates (IC50 = 0.15 microM) and intact RBL-1 cells (IC50 = 1.7 microM) and inhibits the generation of leukotriene B4 (LTB4) in calcium ionophore A-23187-stimulated HPBL (IC50 = 0.07 microM) and human whole blood (IC50 = 1.57 microM). Human platelet 12-LO (IC50 = 3.0 microM) is inhibited, but 15-LO is only weakly so (IC50 = 157 microM). In vivo, tepoxalin, administered orally, demonstrated potent anti-inflammatory activity in the established adjuvant arthritic rat (ED50 = 3.5 mg/kg) and potent analgesic activity in the acetic acid abdominal construction assay in mice (ED50 = 0.45 mg/kg). In an ex vivo whole blood eicosanoid production assay, tepoxalin produces a dose-related inhibition of prostaglandin (PG) and LT production in dogs (PGF2 alpha - ED50 = 0.015 mg/kg; LTB4 - ED50 = 2.37 mg/kg) and adjuvant arthritic rats following oral administration. In adjuvant arthritic rats, tepoxalin is devoid of ulcerogenic activity within its anti-inflammatory therapeutic range (1-33 mg/kg p.o.) and does not exhibit ulcerogenic activity in normal rats at doses lower than 100 mg/kg (UD50 = 173 mg/kg p.o.). Tepoxalin represents a new class of anti-inflammatory drugs which may exhibit less gastrointestinal toxicity and may be efficacious in immunoinflammatory disease states where excessive PG and LT production has been implicated and may offer a significant alternative to nonsteroidal and corticosteroidal anti-inflammatory therapy.

Synthesis and antifertility activity of zoapatanol analogues.

The synthesis of and guinea pig contragestational screening data for several oxepane and 3,8-dioxabicyclo[3.2.1]octane analogues of zoapatanol (1) are described and their structure-activity relationships discussed. Conversion of the 5-keto group on the nonenyl side chain of 1 into a hydroxyl function enhanced the potency. Further significant enhancement in the potency was realized with the transformation of several oxepanes into the 3,8-dioxabicyclo-[3.2.1]octane-1-acetic acid derivatives. Detailed, comparative contragestational evaluation of the three most potent compounds 9, 33, and 37 is presented, which led to the selection of 33 (ORF 13811) for further biological evaluation.

Lumi-mestranol and epi-lumi-mestranol.

Treatment of lumi-estrone 3-methyl ether (I) with acetylene gave the C-17-epimeric compounds lumi-mestranol (3-methoxy-17 alpha-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 beta-ol, III ) and epi-lumi-mestranol (3-methoxy-17 beta-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 alpha-ol, IV). The structures of the two isomers were assigned on the basis of their molecular rotations and shift-reagent experiments in the NMR. The irradiation of estrone 3-methyl ether (II) to provide compound I was investigated in two solvent systems. Minor products of these reactions were the seco-steroids VII, VIII and X.