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A new class of anti-inflammatory (AI) cupferron prodrugs was synthesized wherein a diazen-1-ium-1,2-diolato ammonium salt, and its O(2)-methyl and O(2)-acetoxyethyl derivatives, nitric oxide (NO) donor moieties were attached directly to an aryl carbon on a celecoxib template. The percentage of NO released from the O(2)-methyl and O(2)-acetoxyethyl compounds was higher (18.0-37.8% of the theoretical maximal release of one molecule of NO/molecule of the parent compound) upon incubation in the presence of rat serum, relative to incubation with phosphate buffer saline (PBS) at pH 7.4 (3.8-11.6% range). All compounds exhibited weak inhibition of the COX-1 isozyme (IC(50)=5.8-17.0 microM range) in conjunction with weak or modest inhibition of the COX-2 isozyme (IC(50)=1.6-14.4 microM range). The most potent AI agent 5-[4-(O(2)-ammonium diazen-1-ium-1,2-diolato)phenyl]-1-(4-sulfamoylphenyl)-3-trifluoromethyl-1H-pyrazole exhibited a potency that was about fourfold and twofold greater than that observed for the respective reference drugs aspirin and ibuprofen. These studies indicate that use of a cupferron template constitutes a plausible drug design approach targeted toward the development of AI drugs that do not cause gastric irritation, or elevate blood pressure and induce platelet aggregation that have been associated with the use of some selective COX-2 inhibitors., (Copyright 2010 Elsevier Ltd. All rights reserved.)

A new group of acetic acid (7a-c, R(1) = H), and propionic acid (7d-f, R(1) = Me), regioisomers wherein a N-difluoromethyl-1,2-dihydropyrid-2-one moiety is attached via its C-3, C-4, and C-5 position was synthesized. This group of compounds exhibited a more potent inhibition, and hence selectivity, for the cyclooxygenase-2 (COX-2) relative to the COX-1 isozyme. Attachment of the N-difluoromethyl-1,2-dihydropyrid-2-one ring system to an acetic acid, or propionic acid, moiety confers potent 5-LOX inhibitory activity, that is, absent in traditional arylacetic acid NSAIDs. 2-(1-Difluoromethyl-2-oxo-1,2-dihydropyridin-5-yl)acetic acid (7c) exhibited the best combination of dual COX-2 and 5-LOX inhibitory activities. Molecular modeling (docking) studies showed that the highly electronegative CHF(2) substituent present in 7c, that showed a modest selectivity for the COX-2 isozyme, is oriented within the secondary pocket (Val523) present in COX-2 similar to the sulfonamide (SO(2)NH(2)) COX-2 pharmacophore present in celecoxib, and that the N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore is oriented close to the region containing the LOX enzyme catalytic iron (His361, His366, and His545). Accordingly, the N-difluoromethyl-1,2-dihyrdopyrid-2-one moiety possesses properties suitable for the design of dual COX-2/5-LOX inhibitory drugs., (2010 Elsevier Ltd. All rights reserved.)

A new group of hybrid nitric oxide (NO) releasing anti-inflammatory (AI) coxib prodrugs (NO-coxibs) wherein the para-tolyl moiety present in celecoxib was replaced by a N-(4-nitrooxybutyl)piperidyl 15a-b, or N-(4-nitrooxybutyl)-1,2,3,6-tetrahydropyridyl 17a-b, NO-donor moiety was synthesized. All compounds released a low amount of NO upon incubation with phosphate buffered saline (PBS) at pH 7.4 (2.4-5.8% range). In comparison, the percentage NO released was higher (3.1-8.4% range) when these nitrate prodrugs were incubated in the presence of L-cysteine. In vitro COX-1/COX-2 isozyme inhibition studies showed this group of compounds are moderately more potent, and hence selective, inhibitors of the COX-2 relative to the COX-1 enzyme. AI structure-activity relationship data acquired showed that compounds having a MeSO2 COX-2 pharmacophore exhibited superior AI activity compared to analogs having a H2NSO2 substituent. Compounds having a MeSO2 COX-2 pharmacophore in conjunction with a N-(4-nitrooxybutyl)piperidyl (ED50=132.4 mg/kg po), or a N-(4-nitrooxybutyl)-1,2,3,6-tetrahydropyridyl (ED50=118.4 mg/kg po), moiety exhibited an AI potency profile that is similar to aspirin (ED50=128.7 mg/kg po) but lower than ibuprofen (ED50=67.4 mg/kg po)., (Copyright 2010 Elsevier Ltd. All rights reserved.)

A novel class of phenylacetic acid regioisomers possessing a N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore attached to its C-2, C-3 or C-4 position was designed for evaluation as anti-inflammatory (AI) agents. A number of compounds exhibited a combination of potent in vitro cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitory activities. 2-(1-Difluoromethyl-2-oxo-1,2-dihydropyridin-4-yl)phenylacetic acid (9a) exerted the most potent AI activity among this group of compounds. Molecular modeling studies showed that the N-difluoromethyl-1,2-dihydropyridin-2-one moiety present in 9a inserts into the secondary pocket present in COX-2 to confer COX-2 selectivity, and that the N-difluoromethyl-1,2-dihydropyrid-2-one group (9a) binds close to the region of the 15-LOX enzyme containing catalytic iron (His361, His366). Accordingly, the N-difluoromethyl-1,2-dihyrdopyrid-2-one moiety possesses properties that make it an attractive pharmacophore suitable for the design of dual COX-2/5-LOX inhibitory AI drugs., (Copyright (c) 2009 Elsevier Ltd. All rights reserved.)

A novel class of salicylic acid and N-acetyl-2-carboxybenzenesulfonamide regioisomers possessing a N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore attached to its C-4 or C-5 position was designed for evaluation as anti-inflammatory (AI) agents. Replacement of the 2,4-difluorophenyl ring in diflunisal by the N-difluoromethyl-1,2-dihydropyrid-2-one moiety provided compounds showing dual selective cyclooxygenase-2 (COX-2)/5-lipoxygenase (5-LOX) inhibitory activities. AI structure-activity studies showed that the C-4 (14a) and C-5 (14b) salicylate regioisomers were 1.4- and 1.6-fold more potent than aspirin, and the C-5 N-acetyl-2-carboxybenzenesulfonamide regioisomer (22b) was 1.3- and 2.8-fold more potent than ibuprofen and aspirin, respectively. In vivo ulcer index (UI) studies showed that the 4- and 5-(N-difluoromethyl-1,2-dihydropyrid-2-one-4-yl)salicylic acids (14a and 14b) were completely non-ulcerogenic since no gastric lesions were present (UI=0) relative to aspirin (UI=57) at an equivalent mumol/kg oral dose. The N-difluoromethyl-1,2-dihydropyridin-2-one moiety provides a novel 5-LOX pharmacophore for the design of cyclic hydroxamic mimetics for exploitation in the development of dual COX-2/5-LOX inhibitory AI drugs.

A new group of hybrid nitric oxide (NO) releasing anti-inflammatory (AI) ester prodrugs (NONO-NSAIDs) wherein a 1,3-dinitrooxy-2-propyl (12a-c), or O(2)-acetoxymethyl-1-[2-(methyl)pyrrolidin-1-yl]diazen-1-ium-1,2-diolate (14a-c), NO-donor moiety is directly attached to the carboxylic acid group of aspirin, indomethacin or ibuprofen were synthesized. NO release from the dinitrooxypropyl, or diazen-1-ium-1,2-diolate, ester prodrugs was increased substantially upon incubation in the presence of l-cysteine (12a-c) or rat serum (14a-c). The ester prodrugs (12a-c, 14a-c), which did not inhibit the COX-1 isozyme, exhibited modest inhibitory activity against the COX-2 isozyme. The NONO-NSAIDs 12a-c and 14a-c exhibited in vivo AI activity that was similar to that exhibited by the parent drug aspirin, indomethacin or ibuprofen when the same oral dose (micromol/kg) was administered. These similarities in oral potency profiles suggest these NONO-NSAIDs act as classical prodrugs that require metabolic activation by esterase-mediated hydrolysis. Hybrid NO-donor/anti-inflammatory prodrugs of this type (NONO-NSAIDs) offer a potential drug design concept targeted toward the development of anti-inflammatory drugs with reduced adverse gastrointestinal effects.

A hitherto unknown class of linear acetylene regioisomers were designed such that a SO(2)Me or SO(2)NH(2) group was located at the ortho-, meta- or para-position of the acetylene C-1 phenyl ring, and a N-difluoromethyl-1,2-dihydropyridin-2-one moiety was attached via its C-5 position to the C-2 position on an acetylene template (scaffold). All three SO(2)Me regioisomers, and the 4-SO(2)NH(2) analog, were potent inhibitors of 5-lipoxygenase (5-LOX IC(50)=3.2-3.5 microM range) relative to the reference drug caffeic acid (IC(50)=4.0 microM). The SO(2)Me regioisomers exhibited weak cyclooxygenease-1 (COX-1) and -2 (COX-2) inhibitory activity with a modest COX-2 selectivity index. The most potent 3-SO(2)Me, 4-SO(2)Me and 4-SO(2)NH(2) compounds, with respective ED(50) values of 66.1, 68.5 and 86.5 mg/kg po, exhibited comparable oral anti-inflammatory (AI) activity to that of the reference drug ibuprofen (ED(50)=67.4 mg/kg po). The N-difluoromethyl-1,2-dihydropyridin-2-one moiety provides a novel pharmacophore for the design of cyclic hydroxamic mimetics capable of inhibiting 5-LOX for exploitation in the development of 5-LOX inhibitory AI drugs.

A hitherto unknown class of celecoxib analogs was designed for evaluation as dual inhibitors of the 5-lipoxygenase/cyclooxygenase-2 (5-LOX/COX-2) enzymes. These compounds possess a SO(2)Me (11a), or SO(2)NH(2) (11b) COX-2 pharmacophore at the para-position of the N(1)-phenyl ring in conjunction with a 5-LOX N-hydroxypyrid-2(1H)one iron-chelating moiety in place of the celecoxib C-5 tolyl group. The title compounds 11a-b are weak inhibitors of the COX-1 and COX-2 isozymes (IC(50)=7.5-13.2 microM range). In contrast, the SO(2)Me (11a, IC(50)=0.35 microM), and SO(2)NH(2) (11b, IC(50)=4.9 microM), compounds are potent inhibitors of the 5-LOX enzyme comparing favorably with the reference drug caffeic acid (5-LOX IC(50)=3.47 microM). The SO(2)Me (11a, ED(50)=66.9 mg/kg po), and SO(2)NH(2) (11b, ED(50)=99.8 mg/kg po) compounds exhibited excellent oral anti-inflammatory (AI) activities being more potent than the non-selective COX-1/COX-2 inhibitor drug aspirin (ED(50)=128.9 mg/kg po) and less potent than the selective COX-2 inhibitor celecoxib (ED(50)=10.8 mg/kg po). The N-hydroxypyridin-2(1H)one moiety constitutes a novel pharmacophore for the design of cyclic hydroxamic mimetics capable of chelating 5-LOX iron for exploitation in the design of 5-LOX inhibitory AI drugs.