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Leukotriene biosynthesis inhibitors have potential as new therapeutic agents for asthma and inflammatory diseases. A series of novel substituted 2-cyanoquinolines have been synthesized and the structure activity relationships were evaluated with respect to their ability to inhibit the formation of leukotrienes via the 5-lipoxygenase enzyme. [1S,5R]-2-Cyano-4-(3-furyl)-7-¿3-fluoro-5-[3-(3 alpha-hydroxy-6,8-dioxabicyclo[3.2.1]-octanyl)]phenoxymethyl ¿quinoline (L-746,530) 3 represents a distinct class of inhibitors and possesses in vitro and in vivo potency comparable or superior to naphthalenic analog (L-739,010) 2.

Chalcones and their derivatives were synthesized and evaluated for their anti-inflammatory activity. In vitro, chalcones 2, 4, 8, 10 and 13 inhibited degranulation and 5-lipoxygenase in human neutrophils, whereas 11 behaved as scavenger of superoxide. Only four compounds (4-7) inhibited cyclo-oxygenase-2 activity. The majority of these samples showed anti-inflammatory effects in the mouse air pouch model.

Several thiazolyl derivatives are reported to act as lipoxygenase inhibitors affecting inflammation and/or psoriasis. Two series of new thiazolyl and benzothiazolyl Schiff bases have been designed, synthesized and identified. RM values were determined as an expression of lipophilicity. The compounds were screened for their reducing activity (with the stable free radical 1,1-diphenyl-2-picrylhydrazyl DPPH), for radical scavenging activity (with the xanthine/xanthine oxidase system for O2.-) and for inhibition of soybean lipoxygenase (LO). Anti inflammatory activity was examined in vivo, using the carrageenin induced mice paw edema (24-71.8% inhibition was observed). The results are discussed in terms of structural and physicochemical characteristics of the compounds. Comparing the results among all tests, the benzothiazolyl derivatives seem to be more potent.

An efficient and convergent synthesis has been developed for the production of 3,4-dihydroxy-5-[4-(2-((2Z)-hexenyl)phenyl)-3-(1Z)-but enyl]-2 (5H)-furanone (12d). This hydrophobic antioxidant is a stable conformationally constrained mimic of arachidonic acid (AA) (1) and its respective aci-reductone analogue (2). Pd(0)-catalyzed cross-coupling of 5-(3-butynyl)-3,4-dihydroxy-2(5H)-furanone (7) with 2-((2Z)-hexenyl)iodobenzene (8d) followed by Lindlar catalyzed hydrogenation produces 12d. Butynyl intermediate 7 is prepared from 2-(benzyloxy)-5-deoxyascorbic acid (15) by iodination (I2, PPh3, Imd), iodo substitution with lithium acetylide ethylenediamine complex (LiAEDA, HMPA, -5 degrees C), and benzyl group cleavage (Ac2O, Pyr, BCl3). The utility of this synthetic method was demonstrated by the synthesis of analogues 10e-k. Biological testing revealed that certain of these antioxidants inhibit both cyclooxygenase (COX) and 5-lipoxygenase (5-LO) with comparable efficacy as reported for aspirin and zileuton, respectively. The antioxidant activity of these aci-reductones, measured as a function of their inhibitory effect on CCl4-induced lipid peroxidation of hepatic microsomes, exceeds that produced by alpha-tocopherol. Synthetic routes and initial structure-activity relationships (SAR) for these novel mixed functioning antioxidants are presented.

The aim of our study was to investigate structure activity relationship following the replacement of the 6-phenyl substituent at the 6,7-diaryl-2,3-dihydropyrrolizine template by various heteroaromatic residues. In this context we developed a new, efficient, and highly sensitive test method for the screening of dual cyclooxygenase-1 (COX-1) and 5-lipoxygenase (5-LOX) inhibitors. We used human platelets as a source of COX-1 and human PMNLs as a source of 5-LOX. Both cell types were isolated from the same volume of blood. PGE2 and LTB4 respectively were determined by highly selective and sensitive ELISA kits, using monoclonal antibodies. For a single determination at most 0.5 mL whole blood is needed.

Dioxabicyclooctanyl naphthalenenitriles have been reported as a class of potent and nonredox 5-lipoxygenase (5-LO) inhibitors. These bicyclo derivatives were shown to be metabolically more stable than their tetrahydropyranyl counterparts but were not well orally absorbed. Replacement of the phenyl ring in the naphthalenenitrile 1 by a pyridine ring leads to the potent and orally absorbed inhibitor 3g (L-739,010, 2-cyano-4-(3-furyl)-7-[[6-[3-(3-hydroxy-6,8-dioxabicyclo[3.2.1] octanyl)]-2-pyridyl]methoxy]naphthalene). Compound 3g inhibits 5-HPETE production by human 5-LO and LTB4 biosynthesis by human PMN leukocytes and human whole blood (IC50S of 20, 1.6, and 42 nM, respectively). Derivative 3g is orally active in the rat pleurisy model (inhibition of LTB4, ED50 = 0.3 mg/kg) and in the anesthetized dog model (inhibition of ex vivo whole blood LTB4 and urinary LTE4, ED50 = 0.45 and 0.23 microgram/kg/min, respectively, i.v. infusion). In addition, 3g shows excellent functional activity against ovalbumin-induced dyspnea in rats (60% inhibition at 0.5 mg/kg, 4 h pretreatment) and Ascaris-induced bronchoconstriction in conscious sheep (50% and > 85% inhibition in early and late phases, respectively at 2.5 micrograms/kg/min, i.v. infusion) and, more particularly in the conscious antigen sensitive squirrel monkey model (53% inhibition of the increase in RL and 76% in the decrease of Cdyn, at 0.1 mg/kg, po). In rats and dogs, 3g presents excellent pharmacokinetics (estimated half-lives of 5 and 16 h, respectively) and bioavailabilities (26% and 73% when dosed as its hydrochloride salt at doses of 20 and 10 mg/kg, respectively, in methocel suspension). Based on its overall biological profile, compound 3g has been selected for preclinical animal toxicity studies.

A series of 2-aryl-pyrrolobenzothiazoles with additional functional groups was synthesized and characterized. Mainly ring opening and less substitution of the pyrrole moiety was observed reacting the heterocyclic system with diazoethyl acetate. In general all compounds inhibit 5-lipoxygenase more effectively than cyclooxygenase but one of them is a well balanced dual inhibitor. A structure-activity relationship and the enzyme selectivity are discussed.

Compound 4k N-[5-(4-fluoro)phenoxythien-2-yl]methanesulfonamide is representative of a new class of potent inhibitors of 5-lipoxygenase (5-LO). These versatile compounds exhibit dose-dependent inhibition of 5-LO with IC50s ranging from 20-100 nM in the rat basophilic leukemia (RBL-1) cell homogenate assay and submicromolar IC50s in both the RBL-1 and human peripheral blood leukocyte (PBL) whole cell assays. Compound 4k also showed significant anti-inflammatory activity in the adjuvant arthritic rat at an oral dose of 3 mg/kg.

Six substituted aryloxy diamines, synthesized as potential new antiinflammatory agents, were tested in vivo and in vitro in order to evaluate their biological activities. These derivatives reduced significant carrageenin rat paw edema and showed antiproteolytic activity. The in vitro inhibition of soybean lipoxygenase ranged from 41-77%. The results are discussed from the view of structural modifications.

Cyclization reactions of alpha-ketoarylhydrazonoyl chlorides with various dinucleophiles lead to new 1,4-benzothiazine, quinoxaline, tetrahydropyrazine, thiazole, and thiadiazoline derivatives of methyl butanoate or methyl 5-oxopentanoate. The inhibition of 5-lipoxygenase (LO) was determined by monitoring the leukotriene B4 (LTB4) formation of human polymorphonuclear leukocytes (PMNL). The IC50 values for the most active compounds with an arylhydrazone structure were found to lie between 0.7 and 7.5 microM.

A series of substituted indolylalkoxyiminoalkylcarboxylates were found to be potent leukotriene biosynthesis inhibitors. The structure-activity relationships were investigated. Representative potent inhibitors identified were the quinolyl 3a (A-86885) and pyridyl 3b (A-86886) congeners with in vitro IC50s of 21 and 9 nM and in vivo leukotriene inhibition in the rat with oral ED50s of 0.9 and 1.7 mg/kg, respectively.

Representative nonsteroidal anti-inflammatory drug (NSAID) cyclooxygenase inhibitors such as ibuprofen, naproxen, and indomethacin were used as orally bioavailable scaffolds to design selective 5-lipoxygenase (5-LO) inhibitors. Replacement of the NSAID carboxylic acid group with a N-hydroxyurea group provided congeners with selective 5-LO inhibitory activity.

Synthetic routes were developed to access a variety of novel 1-aryl-2H,4H-tetrahydro-1,2,4-triazin-3-one analogs which were evaluated as 5-lipoxygenase (5-LO) inhibitors. The parent structure, 1-phenylperhydro-1,2,4-triazin-3-one (4), was found to be a selective inhibitor of 5-LO in broken cell, intact cell, and human blood assays with IC50 values of 5-21 microM. In a rat anaphylaxis model, 4 blocked leukotriene formation with an ED50 = 7 mg/kg when administered orally. Compound 4 exhibited selectivity for inhibition of 5-LO with little activity against related enzymes: 12-LO from human platelets, 15-LO from soybean, and cyclooxygenase (COX) from sheep seminal vesicle. In pilot subacute toxicity testing, 4 did not produce methemoglobinemia in rats (400 mg/kg po daily for 9 days) or in dogs (200 mg/kg po daily for 28 days). These results indicated that the triazinone structure provided a 5-LO inhibitor template devoid of the toxicity problems observed in the related phenidone (1) and pyridazinone (3) classes of 5-LO inhibitors. The parent compound 4 is a selective, orally bioavailable 5-LO inhibitor which can serve as a useful reference standard for in vivo pharmacological studies involving leukotriene-mediated phenonmena.

The synthesis of a series of 1,8-dihydroxy-9(10H)-anthracenones bearing sulfur-linked substituents in the 10-position is described. These compounds were evaluated for their ability to inhibit the growth of the human keratinocyte cell line HaCaT and the 5- and 12-lipoxygenase enzymes in bovine polymorphonuclear leukocytes and mouse epidermal homogenate, respectively. In addition, the following redox properties of the compounds were determined: reactivity against 2,2-diphenyl-1-picrylhydrazyl, generation of hydroxyl radicals as measured by deoxyribose degradation, and inhibition of lipid peroxidation in model membranes. Compounds 4e and 4h of this series compare favorably in the cellular assays with the antipsoriatic anthralin. They have the combined inhibitory action against leukotriene B4 and 12(S)-HETE formation and are highly potent antiproliferative agents against keratinocyte growth. In contrast to anthralin, 4h, 1,8-dihydroxy-10-[(4-hydroxyphenyl)thio]-9(10H)-anthracenone, is not cytotoxic as documented by the LDH activity released from cytoplasm of keratinocytes and does not enhance lipid peroxidation in model membranes.

As part of our research for the development of novel antiinflammatory drug candidates, we have designed and synthesized a series of (E)-3-(1,4-benzoquinonyl)-2-[(3-pyridyl)alkyl]-2-propenoic acid derivatives as dual inhibitors of 5-lipoxygenase (5-LO) and thromboxane (TX) A2 synthetase. In order to increase the absorption after oral administration, we introduced a carboxylic acid moiety into the 1,4-benzoquinone skeleton, which has 5-LO-inhibitory character. Introduction of a 3-pyridylalkyl group at the double bond of the 1,4-benzoquinonyl propenoic acid moiety afforded good to moderate inhibitory activities against the production of leukotriene (LT) B4 and TXA2 while not significantly inhibiting that of prostaglandin E2 by glycogen-induced peritoneal cells of rat (in vitro). The length of the methylene chain of the 3-pyridylalkyl group influenced the inhibition of LTB4 and TXB2 production. An increase of lipophilicity by introducing a more lipophilic alkoxy group did not markedly increase the inhibitory activity on LTB4 production. The position of alkoxy group on the 1,4-benzoquinone skeleton played an important role in TXA2 synthetase inhibition. Compounds such as 20c (E6700) with an appropriate alkoxy group and proper length of methylene side chain, together with a polar substituent (carboxylic acid), showed good inhibition of both 5-LO and TXA2 synthetase and possess a variety of pharmacologically beneficial effects.

The synthesis of 2-substituted anthracenonyl acetic acid (2-AA) derivatives is described. The key step is the Marschalk reaction of 1-hydroxy-8-methoxy-anthracenedione with glycolic acid. After protection of the resulting 2-anthracenonyl acetic acid derivative, the 2-monoalkylated derivatives are selectively obtained by direct alkylation. The methodology proves quite general and allows for the introduction of various substituents onto the 2-position of the carboxylic side chain. Reduction of the anthracenediones proceeds with concomitant protecting group removal and provides final 2-AA products in good yields. The results of initial biological studies demonstrate enhanced 5-lipoxygenase inhibition compared to anthralin.

Hydroxylamine and hydroxamic acid derivatives of a known nonsteroidal antiinflammatory dibenzoxepine series display both cyclooxygenase (CO) and 5-lipoxygenase (5-LO) inhibitory properties. Many of these new dual CO/5-LO inhibitors also exhibit potent topical antiinflammatory activity in the arachidonic acid-induced murine ear edema model. On the basis of their promising profile of in vitro and in vivo activities, hydroxamic acids 24h, 3-(6,11-dihydro-11-oxodibenz[b,e]oxepin-2-yl)-N-hydroxy-N-++ +methylpropanamide (HP 977), and 25, 3-(6,11-dihydrodibenz[b,e]oxepin-2-yl)-N-hydroxy-N- methylpropanamide (P10294), were selected as developmental candidates for the topical treatment of inflammatory skin disorders.

Azole phenoxy hydroxyureas are a new class of 5-lipoxygenase (5-LO) inhibitors. Structure-activity relationship studies have demonstrated that electronegative substituents on the 2-phenyl portion of the oxazole tail increased the ex vivo potency of these inhibitors. Similar substitutions on the thiazole analogs had only minor contribution to the ex vivo activity. The trifluoromethyl-substituted oxazole 24 was the best compound of the oxazole series in both the ex vivo (6 h pretreated rats) and in vivo (3 h pretreated rats) RPAR assay with ED50 values of approximately 1 and 3.6 mg/kg, respectively, but was weakly active in the allergic guinea pig assay. Oxazole 50 was equally active in both the RPAR and guinea pig in vivo models and was similar to zileuton. The unsubstituted thiazole 52 was the best compound of the thiazole series, by inhibiting the leukotriene B4 biosynthesis in the RPAR assay (3 h pretreated rats) by 99%, at an oral dose of 10 mg/kg, and the bronchoconstriction in the allergic guinea pig by 50%, at an intravenous dose of 10 mg/kg. Oxazole 24 demonstrated high and selective 5-LO inhibitory activity in the in vitro assays, with IC50 values ranging from 0.08 microM in mouse macrophages to 0.8 microM in human peripheral monocytes to 1.2 microM in human whole blood. This activity was selective for 5-LO, as concentrations up to 15 microM in mouse macrophages did not affect prostaglandin formation. Oxazole 59 was the most active inhibitor in the human monocyte assay with an IC50 value of 7 nM.

The arachidonic acid and the ATP binding sites of human 5-lipoxygenase were characterized using photoaffinity labeling and immobilization of the enzyme on ATP-agarose. Photoaffinity labeling of the active site of 5-lipoxygenase was achieved with a novel thiopyranoindole inhibitor containing a 4-azido-3-iodobenzenesulfonyl moiety (L-708,714). This probe was found to inhibit the activity of 5-lipoxygenase (IC50 = 0.3 microM) and to covalently label the enzyme after UV light irradiation. The labeling was inhibited by arachidonic acid, N-hydroxyurea, and dihydrobenzofuranol inhibitors which have been shown to reduce the non-heme iron center of 5-lipoxygenase. Photoaffinity labeling of 5-lipoxygenase by L-708,714 was dependent on the presence of both Ca2+ ions and phospholipids and was independent of ATP. It occurred at similar levels using native (Fe2+), oxidized (Fe3+), or H2O2-inactivated enzyme, but was abolished by heat inactivation of the enzyme. Competition of the labeling by various thiopyranoindoles and other inhibitors such as L-697,198,ZD-2138, and zileuton was found to be related to their inhibitory potency. Immobilized 5-lipoxygenase on ATP-agarose was found to be selectively eluted by adenine nucleotides (ATP > ADP > AMP) but not by solutions containing high salt concentrations, mild detergents, arachidonic acid, or inhibitors. 5-Lipoxygenase inhibitors were selectively retained on the immobilized enzyme and eluted by buffer containing arachidonic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of a novel dual inhibitor of thromboxane A2 synthetase and 5-lipoxygenase, 5,7-dimethyl-6-hydroxy-2-methylamino-4-(3- pyridylmethyl)benzothiazole (E3040), was accomplished via a new coupling reaction, in which a key intermediate, (3,6-dihydroxy-2,4-dimethylphenyl)-(3-pyridyl)methanol, was easily synthesized in a high yield from 2,6-dimethyl-1,4-benzohydroquinone and 3-pyridinecarboxaldehyde in 6 N hydrochloric acid. The regio isomers of 3-pyridinecarboxaldehyde also gave the corresponding coupling products in high yields.

1,3-Dioxolanes have been described as chiral inhibitors of 5-lipoxygenase (5LO). In the present work, this series has been developed further to provide agents which showed comparable or superior potency in vivo to ZD2138, a methoxytetrahydropyran inhibitor of 5LO, which is currently undergoing clinical evaluation. An asymmetric synthesis was developed to these dioxolanes based on asymmetric dihydroxylation. (S)-N-Methyl-4'-[[4-(2,2,4- trimethyl-1,3-dioxolan-4-yl)thien-2-yl]thio]acetanilide ((S)-10d) inhibited leukotriene B4 (LTB4) synthesis in A23187-stimulated human whole blood in vitro with IC50 0.039 microM, 25-fold more potent than (R)-10d. In vivo, (S)-10d inhibited LTB4 synthesis by 70% in zymosan-inflamed air pouch exudate in rat 10 h after an oral dose of 1.5 mg/kg. Structure-activity relationship considerations suggested that the dioxolane and methoxytetrahydropyran series are related, a conclusion which can be supported by molecular modeling.

2-Phenylsulfenyl- (1b), 2-phenylselenenyl- (1c) and 2-phenyltellurenyl-1-naphthol (1d) were prepared and their antioxidative properties evaluated in comparison with 2-benzyl-1-naphthol (1a; DuP 654). 2-Phenyltellurenyl-1-naphthol had a significantly lower (1.00 V versus SCE) oxidation potential than the other three compounds (1.24, 1.27 and 1.25 V, respectively, versus SCE for compounds 1a, 1b and 1c) as determined by cyclic voltammetry. In contrast to the other materials, compound 1d was able to catalyze the reduction of hydrogen peroxide in the presence of thiols as stoichiometric reducing agents. The organotellurium compound was also the most efficient inhibitor of azo-initiated peroxidation of linoleic acid in a two-phase model system. Ab initio geometry optimization at the 3-21G(*) level revealed infinitesimal changes in the molecular conformations of the carbon, sulfur, selenium and tellurium analogues. As judged by their ability to inhibit stimulated LTB4 biosynthesis in human neutrophils, compounds 1a-1d all turned out to be highly potent 5-lipoxygenase inhibitors with IC50-values ranging from 0.40 microM for 2-benzyl-1-naphthol (1a) to 0.063 microM for 2-phenyltellurenyl-1-naphthol (1d).

alpha-Carbonyl carboxylic acid arylhydrazonochlorides obtained by Japp-Klingemann reaction are the starting substances for the synthesis of alpha-carbonyl carboxylic acid arylhydrazonoamides, -esters and -thioesters. The inhibiting activity of these compounds against 15- and 5-lipoxygenase is described. Reactions of derivatives of amidrazones with formaldehyde give triazole, triazoline and unexpected benzotriazepine derivatives.

N-Hydroxyureas based on the 1,4-benzodioxan template were prepared from appropriately substituted 1,4-benzodioxan-2-methanols as the key intermediates and evaluated in the in vitro guinea pig polymorphonuclear leukocyte 5-lipoxygenase (5-LO) assay for their 5-LO inhibitory activity. Placement of a 7-phenoxy or 7-p-fluorophenoxy substituent resulted in a dramatic increase in in vitro potency. Selected compounds were subsequently assayed in an ex vivo dog model of LTB4 synthesis at a dose of 1.0 mg/kg. The 7-phenoxy derivatives 16 and 17 showed modest duration of action (DA) in this dog model. The 6-regioisomers 21 and 22 were less potent. Replacement of the 7-phenoxy group of 16 with the p-fluorophenoxy moiety enhanced the DA dramatically. Compound 18 (CGS 25667), which had an IC50 value of 100 nM in the in vitro guinea pig 5-LO assay, had a DA of 8.5 h (zileuton, DA = 8.5 h) at the oral dose of 1.0 mg/kg. Optical antipodes (24, 26) of 18 were independently synthesized in high (> 95%) enantiomeric purity from commercially available optically active glycidyl tosylates and evaluated. In the in vitro assay, the 2S-(-)-enantiomer (24, CGS 25997, IC50 = 85 nM) was found to be twice as active as the 2R-(+)-counterpart (26, CGS 25998, IC50 = 180 nM). In the ex vivo experiment, 24, which dose dependently inhibited plasma 5-LO activity, was shown to be significantly longer acting than 26, with a DA of 8.4 h when dosed orally at 1.0 mg/kg.

Some 2-[4-(heteroarylmethyl)phenyl]propanoic acids and phenylacetic and benzoic analogues has been synthesized. All above acids were tested for their inhibitory activity on lipoxygenase and cyclooxygenase, in comparison with NDGA and tolmetin. 2-[4-(Thien-2-ylmethyl)phenyl]propanoic acid 2, strictly related with suprofen, was found the most interesting compound, giving rise to a 79% inhibition of the cyclooxygenase activity at 10(-4) M concentration.

As part of our search for novel antiinflammatory drug candidates, we have designed and synthesized a series of 3-pyridylmethyl-substituted 2-amino-6- hydroxybenzothiazoles. Introduction of a 3-pyridylmethyl group into the 2-amino group (type-A) or the benzene ring (type-B) of 2-amino-6-hydroxybenzothiazoles imparted dual inhibitory activity against the production by glycogen-induced peritoneal cells of rat (in vitro) of leukotriene B4 (LTB4) and thromboxane A2 (TXA2), while not significantly inhibiting that of prostaglandin E2 (PGE2). The observed inhibition of the former two arachidonic acid metabolites was indicated to be the result of a direct action on 5-lipoxygenase and TXA2 synthetase by a cell-free in vitro assay. On the other hand, the inhibitory activities against PGE2 production were for most compounds very weak, indicating that they did not inhibit cyclooxygenase. Structure-activity relationship studies concerning the position of the 3-pyridylmethyl group revealed that type-B compounds generally showed about 10-fold stronger inhibitory activity against TXA2 synthetase than type-A compounds. The position of the 3-pyridylmethyl group played an important role in TXA2 synthetase inhibition. When some of these compounds (8, 13a, 26a (E3040), 26b, 27b, and 28b) were orally administered in the rat TNB/ethanol-induced chronic colitis model (100 mg/kg), the production of both LTB4 and TXB2 in the rat colon was reduced (ex vivo). In addition, one type-B compound, 6-hydroxy-5,7-dimethyl-2-(methylamino)-4-(3-pyridylmethyl)benzothiazole (26a), demonstrated a therapeutic effect at treatments of 100 mg/kg po once daily for 11 days and showed almost comparable activity to sulfasalazine at a dose of 500 mg/kg, the reference drug for inflammatory bowel diseases, in this in vivo model.

Two series of compounds, substituted benzoselenazolinones and their opened analogs, diselenides, were prepared. The diselenides were designed according to the available SAR about glutathione peroxidase mimics and were expected to have activity. An initial series of tests was performed in order to assess the glutathione peroxidase and antioxidant activity of the diselenides compared to their cyclized analogs. The diselenides were shown to be very potent (up to 3 times the activity of ebselen), whereas the benzoselenazolinones were inactive, thus confirming our hypothesis. A second series of tests was done to determine the anti-inflammatory potency of the two series. Both were found to be potent on cyclooxygenase and 5-lipoxygenase pathways (up to 95% inhibition at 10(-5) M). Some compounds were selective, and the variations in the activity allowed us to draft some structure-activity relationships. The most interesting compound of each series, 6-benzoylbenzoselenazolinone and bis[(2-amino-5-benzoyl)phenyl] diselenide, was tested in vivo on the rat foot edema induced with different phlogistic agents and was shown to have some anti-inflammatory properties.

Structure-activity relationships in the inhibitory effects of 4-acylaminophenol derivatives on the 5-lipoxygenase (5-LOX) from RBL-1 cells and leukotriene B4 (LTB4) production by guinea pig neutrophils were studied. When the N-acyl group was n-octanoyl or 2-thiophenecarbonyl and the size of the two ortho substituents of phenol was varied, the substituents bulkier than isopropyl, i.e., 2,6-di-tert-butyl and 2,6-dicyclohexyl, substantially weakened the inhibitory activity in both enzymatic and cellular systems. Among the 2,6-dimethyl derivatives with an acyl group of various carbon-chain lengths (C1-13), those with a n-alkyl chain of C5 to C12 showed similarly potent inhibitory activities toward 5-LOX with an IC50 ranging from 0.27 to 0.66 microM; in contrast, maximal inhibitory activities toward LTB4 production were observed in a narrower range of the serial compounds: i.e., those with a n-hexyl, n-heptyl, or n-octyl chain on the carbonyl carbon formed by far the most inhibitory group of the series and the inhibitory activity sharply decreased on either side of the chain length. Nearly all the active compounds also inhibited cyclooxygenase (COX), but the IC50 values for COX inhibition were more than ten times higher than the corresponding IC50 values for 5-LOX inhibition in most cases, indicating that the acylaminophenols are relatively selective 5-LOX inhibitors.

6-(4-Chlorophenyl)-7-phenyl-2,3-dihydro-1H-pyrrolizines with functional groups at position 5 of the heterocyclic moiety were synthesized and tested. To determine their antiinflammatory activity bovine blood was used as enzyme source for the cyclooxygenase and 5-lipoxygenase, respectively. The iminoxy acetic acid derivative and the iminotetrazole selectively inhibit the 5-lipoxygenase, all the other compounds show medium or low affinity to the active sites of cyclooxygenase and 5-lipoxygenase. In general all compounds inhibit 5-lipoxygenase more effectively than cyclooxygenase. Concerning the inhibition of 5-lipoxygenase the most active compounds found are equipotent to the corresponding propionic acid compounds, but they aren't well balanced dual inhibitors as shown for the carboxylic derivatives. A structure activity relationship and the enzyme selectivity are discussed.

1'-Hydroxyeugenol- and epoxy-Z-coniferyl alcohol esters from Coreopsis species as well as synthetic derivatives of these natural compounds were examined as lipoxygenase inhibitors and as LDL (low density lipoprotein)-stabilizing agents. Most of the compounds displayed inhibitory activity on the formation of leukotrienes (LTB4 and LTC4) in a cellular (RBL-1 cells) assay as well as in a cell-free 5-lipoxygenase assay at concentrations of 4-24 mumol/l. No effect of selected compounds was observed on mammalian lipoxygenases with other specificity (12- and 15-lipoxygenase). The more lipophilic derivatives also effectively reduced Cu(2+)-mediated oxidation of LDL. The findings are discussed on the base of structure-activity relationships.

Piperazinealkanol ester derivatives of indomethacin were prepared and tested for inhibitory activities against 5-lipoxygenase (5-LO) and cyclooxygenase (CO). They inhibited 5-hydroxyeicosatetraenoic acid (5-HETE) formation by the cytosol of guinea pig polymorphonuclear leukocytes and thromboxane B2 (TXB2) formation by washed rabbit platelet suspension. Of the test compounds, 2-[4-(2-hydroxyethyl)-1-piperazinyl]-1-phenylethyl 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-3-indolylacetate dimaleate (II-8) was found to be the most active dual inhibitor of 5-LO and CO, and its inhibitory potency was higher than that of 2-[4-(3-hydroxypropyl)-1-piperazinyl]-ethyl [1-(4-chlorobenzoyl)-5-methoxy-2-methyl]-3-indolyacetate (CR-1015) (I), the lead compound.

Combinations of structural elements found in (methoxyalkyl)thiazole 1a and methoxytetrahydropyran 2a with a naphthalenic lignan lactone produce the potent 5-lipoxygenase (5-LO) inhibitors 3 and 4. While the nature of link Y-Z has a major effect on the in vitro activity of compounds 1 and 2, inhibitors 3 and 4 retain their potencies with either an oxymethylene (Y = O, Z = CH2) or a methyleneoxy (Y = CH2, Z = O) link. Compound 4b inhibits the oxidation of arachidonic acid to 5-hydroperoxyeicosatetraenoic acid by 5-LO (IC50 = 14 nM) and the formation of leukotriene B4 in human polymorphonuclear leukocytes (IC50 = 1.5 nM) as well as in human whole blood (IC50 = 50 nM). Compound 4b is a selective 5-LO inhibitor showing no significant inhibition of human 15-lipoxygenase or porcine 12-lipoxygenase or binding to human 5-lipoxygenase-activating protein up to 10 microM and inhibits leukotriene biosynthesis by a direct, nonredox interaction with 5-LO. Compound 15, the open form of lactone 4b, is well absorbed in the rat and is transformed into the active species 4b. In addition, 15 is orally active in the rat pleurisy model (ED50 = 0.6 mg/kg) and in the functional model of antigen-induced bronchoconstriction in allergic squirrel monkeys (95% inhibition at 0.3 mg/kg).

Tetrahydro-2H-benz[b]azepin-2-ones as starting substances are synthesized by Beckmann rearrangement of Schmidt reaction. The tetrahydrobenzazepinones are transformed into the thiones, thiolactim ethers and phenylhydrazones. The compounds are tested as inhibitors of soja lipoxygenase.

A variety of benzylideneoxazoles, -thiazoles, and -imidazoles derived from 2,6-di-tert-butylphenol were prepared and evaluated as dual inhibitors of 5-lipoxygenase and cyclooxygenase in rat basophilic leukemia (RBL-1) cells. The target compounds exhibit varying degrees of selectivity toward the two enzymes. Several compounds are orally active in the rat carageenan footpad edema (CFE) and mycobacterium footpad edema (MFE) antiinflammatory models. Structure-activity relationships are discussed. From this work, (Z)-5-[[3,5-bis(1,1-dimethylethyl)-4- hydroxyphenyl]-methylene]-2-imino-4-thiazolidinone methanesulfonate salt (CI-1004) was identified as a potent dual inhibitor of 5-lipoxygenase (IC50 = 0.77 microM) and cyclooxygenase (IC50 = 0.39 microM), with oral activity (ID40 = 0.6 mg/kg) in the rat MFE model of inflammation.

Pursuing our researches on quinolizidinyl derivatives of phenothiazine and on the ground of antidepressive, diuretic, antianginal and antiarrhythmic activities of several 10-(3-dialkylamino) propionylphenothiazines (as chloracizine, moricizine, etc.), six 10-homolupinanoyl-2-R-phenothiazines were prepared and subjected to a broad pharmacological screening with in vivo and in vitro assays. Most of these compounds exerted strong antiarrhythmic activity (compounds 1, 3 and 5 were comparable or superior to lidocaine and quinidine in three tests), calcium antagonism on guinea pig ileum and left atria, antagonism to smooth muscle contractile responses induced by several agents and inhibition of rabbit platelet aggregation induced by PAF and ADP. A few other activities were characteristic of single compounds, as antagonism to central and peripheral effects of oxotremorine 1, moderate antihypertensive activity 5, local anesthetic activity and antagonism to substance P 2, antiinflammatory activity with low or absent gastric irritation 2, 3, powerful saluretic action 6, inhibition of arachidonate induced platelet aggregation 1 and antagonism to PAF induced mortality 1, 4. The last activity is very unusual and deserves further investigation. The capacity of compound 1 to displace specific ligands from several receptors was also investigated. Significant binding for M1 (IC50 = 0.03 microM), M3 (IC50 = 10 microM), sigma receptors and Na+ channels (IC50 = 1 microM) were evidentiated.

Thiopyrano[2,3,4-c,d]indoles are a new class of 5-lipoxygenase (5-LO) inhibitors. SAR studies have demonstrated that the thiopyran ring, the 5-phenylpyridine substituent, and an acidic functional group on a four-carbon C-2 side chain are all required for optimal inhibitor potency. In contrast, the indolic nitrogen may be substituted with a variety of lipophilic groups. As a result of the SAR investigation, 44 (L-691,816; 5-[3-[1-(4-chlorobenzyl)-4-methyl-6-[(5-phenylpyridin-2-yl)methoxy ]- 4,5-dihydro-1H-thiopyrano[2,3,4-c,d]indol-2-yl]-2,2-dimethylpro pyl]-1H- tetrazole) has been identified as a potent inhibitor of the 5-LO reaction both in vitro and in a range of in vivo models. Compound 44 inhibits 5-HPETE production by both rat and human 5-LO and LTB4 synthesis in human PMN leukocytes (IC50s 16, 75, and 10 nM, respectively). The mechanism of inhibition of 5-LO activity by compound 44 appears to involve the formation of a reversible deadend complex with the enzyme and does not involve reduction of the nonheme iron of 5-LO. Compound 44 is highly selective for 5-LO when compared to the inhibition of human FLAP, porcine 12-LO, and also ram seminal vesicle cyclooxygenase. In addition, 44 is orally active in a rat pleurisy model (inhibition of LTB4, ED50 = 1.9 mg/kg; 8 h pretreatment) as well as in the hyperreactive rat model of antigen-induced dyspnea (ED50 = 0.1 mg/kg; 2-h pretreatment). Excellent functional activity was also observed in both the conscious allergic monkey and sheep models of asthma. In the latter case, the functional activity observed correlated with the inhibition of urinary LTE4 excretion.

N-Arylanthranilic acids, known generically as the fenamates, are nonsteroidal antiinflammatory drugs (NSAIDs) that block the metabolism of arachidonic acid by the enzyme cyclooxygenase (CO). Substitution of the carboxylic acid functionality of several fenamates with acidic heterocycles provided dual inhibitors of CO and 5-lipoxygenase (5-LO) activities when tested in an intact rat basophilic leukemia (RBL-1) cell line. Compound 5b (IC50 = 0.77 microM (5-LO), 0.27 microM (CO)) which contains an 1,3,4-oxadiazole-2-thione replacement and 10b (IC50 = 0.87 microM (5-LO), 0.85 microM (CO)) which contains a 1,3,4-thiadiazole-2-thione are the most potent inhibitors of 5-LO and CO activities from these series. Both of these heterocyclic analogs of flufenamic acid are also active in carageenin-induced rat footpad edema (CFE), a model of acute inflammation. When dosed orally the ID50s for 5b and 10b in CFE are 8.5 and 4.7 mg/kg, respectively.

The synthesis of some amidrazones as bioisosteric diazaallyl radicals is described starting from the reaction mechanism of the lipoxygenases which postulates the existence of a radical after hydrogen abstraction from the arachidonic acid, N1,N3-diaryl-, N1-aryl-N3-alkyl-benzamidrazones and N1-arylacetamidrazones are strong inhibitors of the soja lipoxygenase.

The synthesis of furo[2,3-b]pyridine formamidines (D/1-D/11, F) was realized by the reaction of the 3-amino-furo[2,3-b]pyridines C/1-C/11 and E, substituted in position 2 with a carbonyl moiety with dimethylformamide/phosphoroxide chloride or with N-formyl-piperidine or N-formyl-morpholine and phosphoroxide chloride. The acetamidines H were yielded from 4-oxo-4H-3-methyl-pyrido[3',2':4,5]furo[3,2-d]1,3-oxazines with aminoethanol. The 4-oxo-4H-3-amino-3,4-dihydro-pyrido[3',2':4,5]furo[3,2-d]pyrimidines K and M reacted with dimethylformamide/phosphoroxide chloride to give the tricyclic formamidines L and K. The described amidines showed antianaphylactic activity.

New alkenyl-1,4-benzoquinones, ardisianones A (1) and B (2), and the known maesanin (3) as 5-lipoxygenase inhibitors have been isolated from the rhizome of Ardisia japonica. Their structures have been elucidated as 2-methoxy-6-[(Z)-10'-pentadecenyl]-1,4-benzoquinone and 5-hydroxy-2-methoxy-6-[(Z)-8'-tridecenyl]-1,4-benzoquinone, respectively, on the basis of spectroscopic data and chemical degradation. Ardisianone A (1), maesanin (3) and belamcandol A (7) have been synthesized starting from belamcandol B (6), readily prepared by Wittig reaction between 9-(2-tetrahydropyranyloxy)nonanal and 3,5-dimethoxybenzyltriphenylphsophonium bromide followed by selective demethylation with sodium thioethoxide.

A series of 19 N-alkyl-diarylpyrrolyl-acetic and-propionic acid derivatives was synthesized and tested. Using bovine blood as enzyme source the inhibition of cyclooxygenase and 5-lipoxygenase, respectively, was applied to determine the antiinflammatory activity. In general all compounds tested inhibit 5-lipoxygenase more effectively than cyclooxygenase. A structure-activity relationship is discussed.

4-Oxo-4H-pyrido[3',2':4,5]thieno[3,2-d]1,3-oxazines react with secondary cycloaliphatic amines to give besides the expected bisamides the amine salts of N-(2-carboxy-thieno[2,3-b]pyridine-3-yl)amidines. These compounds showed inhibitory activity against different lipoxygenases, but a small chemical stability.

Vinylogous hydroxamic acids (3-(N-hydroxy-N-alkylamino)-2-propen-1-ones, VHA) were prepared as antiinflammatory agents. The synthesis, chemical properties, and in vitro biological activities of these relatively unexplored compounds are described. The VHAs were prepared by condensation of the appropriate N-substituted hydroxylamine with any of the three reagents: a 1,3-dicarbonyl compound (method A); a vinylogous amide (method B); or an alkynone (method C). The VHAs exist as one or more tautomers in solution with the relative proportions of each being dependent upon the structure of the VHA, solvent, and pH. VHAs undergo some of the typical reactions of hydroxamic acids as well as those of vinylogous amides. VHAs are active as inhibitors of 5-lipoxygenase and of IL-1 biosynthesis in vitro, which do not inhibit other enzymes of the arachidonic acid cascade. They have been shown by ESR studies to bring about inhibition of soybean type 1 15-lipoxygenase by reduction of the active site iron.

A novel series of N-[(2-benzothiazolylthio)alkyl]-N'-hydroxyurea derivatives (9-25) was synthesized and evaluated for biological activity as inhibitors of 5-lipoxygenase both in vivo (mouse zymosan peritonitis assay) and in vitro (Ca2+ ionophore-stimulated human peripheral blood leukocyte model). The compounds of this series were based on the corresponding hydroxamic acid derivatives (1, 3, 4, and 5) which were moderately active in vitro but inactive in vivo. A number of compounds in the hydroxyurea series exhibited oral activity for 5-lipoxygenase inhibition. Results of studies relating structure to in vivo and in vitro 5-lipoxygenase activity are reported.

Leukotrienes are potent biological mediators of allergic and inflammatory diseases and are derived from arachidonic acid through the action of the 5-lipoxygenase. In this study, the syntheses and comparative biological activities of three series of 2,3-dihydro-2,6-disubstituted-5-benzofuranols with various substituents on position 3 are described. Compounds from each series were evaluated for their ability to inhibit the production of leukotriene B4 (LTB4) in human peripheral blood polymorphonuclear (PMN) leukocytes and the 5-lipoxygenase reaction in cell-free preparations from rat PMN leukocytes. The structure-activity relationships of each series in vitro and in vivo are presented. The bioavailability, metabolism, and toxicity profile of each series are discussed. The series with no substituent at position 3 was the most potent and among the compounds in that series 2,3-dihydro-6-(3-phenoxypropyl)-2-(2-phenylethyl)-5-benzofuranol (46, L-670,630) was chosen for further development.

Inhibition of 5-lipoxygenase by anthralin (1) and 41 derivatives is determined: the acids 38 and 39, the lactones 40-42 and 9-anthrone (8) are the most potent inhibitors, the lactone 41 reaching the efficacy of nordihydroguaiaretic acid (NDGA). The results were correlated with the hydrophilic/lipophilic balance of the test compounds and their clinical efficacy as far as known. There is no correlation between the "minimum structure" of Krebs and Schaltegger concerning antipsoriatic activity and the inhibitory effects against 5-lipoxygenase.

Various catechol derivatives (beta-substituted 3,4-dihydroxystyrenes, 1-substituted 3,4-dihydroxybenzenes, and 6-substituted 2,3-dihydroxynaphthalenes) were synthesized and their inhibition of 5-lipoxygenase was assayed. Their structure-activity relationships were examined quantitatively with substituent and structural parameters and regression analysis. The variations in the inhibitory activity were explained in bilinear hydrophobic parameter (log P) terms, and steric (molecular thickness) and electronic (proton nuclear magnetic resonance (1H-NMR) chemical shift of the proton adjacent to the catechol group) parameter terms. The hydrophobicity of the inhibitor molecule was important, and the optimum value of logP was about 4.3-4.6, beyond which inhibition did not increase further. A lower electron density of the aromatic ring containing the catechol group and the greater thickness of the lipophilic side chains were unfavorable to the activity. The results added a physicochemical basis for the selection of candidate compounds for developmental studies.

Previously, the conversion of a CO inhibitor, naproxen, into an orally active 5-LO inhibitor, Wy-50,295, by covalent attachment of a quinoline group was reported. The authors now report the extension of this transformation to other CO inhibitors. Replacement of an existing substituent or a hydrogen in sulindac, etodolac, carprofen, diclofenac, oxaprozin, des-alpha-methyl-ketoprofen, or des-alpha-methyl-flurbiprofen by a methoxyquinoline group afforded new hybrid structures which were orally active 5-LO inhibitors in the rat RPAR (reverse passive Arthus reaction) assay. In contrast to Wy-50,295 which is a selective 5-LO inhibitor, some of these new hybrids were dual inhibitors of 5-LO and CO. For example, the quinoline-etodolac hybrid WAY-120,739, (1,8-diethyl-1,3,4,9-tetrahydro-6-(2-quinolinylmethoxy)pyrano [3,4-b]indole-1-acetic acid) was a dual inhibitor of 5-LO and CO (91% and 47% inhibition, respectively at 10 microM, rat PMN). In contrast, the quinoline-flurbiprofen hybrid WAY-121,006, (3-fluoro-4'-(2-quinolinylmethoxy)-[1,1'-biphenyl]-4-acetic acid), the quinoline-oxaprozin hybrid, WAY-120,460, (5-phenyl-4-[4-(2- quinolinylmethoxy)phenyl]-2-oxazolepropanoic acid) and the quinoline-carprofen hybrid WAY-120,429 (alpha-methyl-6-(2-quinolinylmethoxy)-9-(2-quinolinylmethoxy)-9H- carbazole-2-acetic acid) were purely 5-LO inhibitors (100%, 96% and 92% inhibition of 5-LO at 10 microM, rat PMN, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)