Design, synthesis and in vitro study of 5,6-diaryl-1,2,4-triazine-3-ylthioacetate derivatives as COX-2 and ß-amyloid aggregation inhibitors.

In order to find novel cyclooxygenase (COX)-2 inhibitors for treating inflammatory-based diseases such as Alzheimer's disease (AD), an ethyl carboxylate side chain was added to 5-(4-chlorophenyl)-6-(4-(methylsulfonyl)phenyl)-3-(methylthio)-1,2,4-triazine (lead compound II) to maintain residual inhibition of COX-1 through interacting with Arg120. A preliminary molecular docking study on both the COX-1/COX-2 active sites truly confirmed our hypothesis. Accordingly, a series of ethyl 5,6-diaryl-1,2,4-triazine-3-ylthioacetate derivatives were synthesized and their chemical structures were confirmed by NMR, IR and MS spectra. Further in vitro COX-1/COX-2 evaluations revealed that compound 6c (COX-2 IC50 = 10.1 µM, COX-1 IC50 = 88.8 µM) is the most selective COX-2 inhibitor while maintaining residual inhibition of COX-1. In order to evaluate their potential use against AD, an in vitro evaluation of ß-amyloid fibril formation was performed. The results indicated that the prototype compounds 6 are effective ß-amyloid destabilizing agents while compound 6c could inhibit 94% of the ß-amyloid fibril formation after 48 h. Finally, the in silico assessment results of their blood-brain barrier permeability were satisfactory.

1,2-Diaryl-2-hydroxyiminoethanones as dual COX-1 and ß-amyloid aggregation inhibitors: biological evaluation and in silico study.

To find out new agents for treating inflammatory-involved diseases such as Alzheimer's disease, a series of 1,2-diaryl-2-hydroxyiminoethanones containing vicinal diaryl pharmacophore of COX inhibitors were tested by a set of in vitro, in vivo, and computational studies. The in vivo study of compounds indicated their prominent anti-inflammatory ability at the doses of 10 and 20 mg/kg comparable to celecoxib (10 mg/kg). Further in vitro COX-1/COX-2 evaluations revealed that 4-methoxy derivative 3 had a high selective COX-1 inhibitory activity (COX-1, IC50=0.12 µm, SI>833). To evaluate their potential use against Alzheimer's disease, in vitro evaluation of ß-amyloid fibril formation using Aß(1-40) and Aß(1-42) peptides was performed. The evaluation of their antiaggregation ability gave impressive results and comparable to rifampicin and indomethacin. Conformational study of compound 3 and subsequent docking of its restrained analogs on both active sites of COX-1 and COX-2 could provide a proof of its COX-1 selectivity as well as molecular dynamic simulation could elucidate and give more insight into the amyloid disaggregation mechanisms leading to rational design of inhibitors.

Synthesis and antimycobacterial activities of some new thiazolylhydrazone derivatives.

This Letter reports the synthesis and evaluation of some thiazolylhydrazone derivatives for their in vitro antimycobacterial activities against Mycobacterium tuberculosis H37Rv. The cytotoxic activities of all compounds were also evaluated. The compounds exhibited promising antimycobacterial activity with MICs of 1.03-72.46 µM and weak cytotoxicity (8.9-36.8% at 50 µg/mL). Among them, 1-(4-(1H-1,2,4-triazol-1-yl)benzylidene)-2-(4-(4-nitrophenyl)thiazol-2-yl)hydrazine 10 was found to be the most active compound (MIC of 1.03 µM) with a good safety profile (16.4% at 50 µg/mL). Molecular modeling studies were done to have an idea for the mechanism of the action of the target compounds. According the docking results it can be claimed that these compounds may bind most likely to TMPK than InhA or CYP121.

1-(4-Methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-3-carboxamides: synthesis, molecular modeling, evaluation of their anti-inflammatory activity and ulcerogenicity.

A series of novel 1-(4-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-3-carboxamides were synthesized and confirmed with different spectroscopic techniques. The prepared compounds exhibited remarkable anti-inflammatory activity that represents 38%-100% of indomethacin activity and 44%-115% of celecoxib activity after 3 h. The anilides 5a-l and hydrazide 6 exhibit low incidence of gastric ulceration compared to indomethacin which was confirmed with histopathological investigation. In vitro COX-1/COX-2 inhibition studies showed compounds 4b (COX-1 IC50 = 45.9 µM; COX-2 IC50 = 68.2 µM) and 6 (COX-1 IC50 = 39.8 µM; COX-2 IC50 = 46.3 µM) are the most potent COX inhibitors in the tested compounds. The binding mode for some of the tested compounds to the enzymes was predicted using docking studies.

Synthesis, cyclooxygenase inhibitory effects, and molecular modeling study of 4-aryl-5-(4-(methylsulfonyl)phenyl)-2-alkylthio and -2-alkylsulfonyl-1H-imidazole derivatives.

A series of 4-aryl-5-(4-(methylsulfonyl)phenyl)-2-alkylthio and 2-alkylsulfonyl-1H-imidazole derivatives were synthesized. All compounds were tested in human blood assay to determine COX-1 and COX-2 inhibitory potency and selectivity. Among the synthesized compounds, 2-alkylthio series were more potent and selective than 2-sulfonylalkyl derivatives. In molecular modeling, interaction of 2-sulfonylalkyl moiety with Arg120 in COX-1 and an extra hydrogen bond with Tyr341 in COX-2 increased the residence time of ligands in the active site in 2-sulfonylalkyl and 2-alkylthio analogs, respectively.

Synthesis, molecular modeling and evaluation of novel N'-2-(4-benzylpiperidin-/piperazin-1-yl)acylhydrazone derivatives as dual inhibitors for cholinesterases and Aß aggregation.

To develop new drugs for treatment of Alzheimer's disease, a group of N'-2-(4-Benzylpiperidin-/piperazin-1-yl)acylhydrazones was designed, synthesized and tested for their ability to inhibit acetylcholinesterase, butyrylcholinesterase and aggregation of amyloid beta peptides (1-40, 1-42 and 1-40_1-42). The enzyme inhibition assay results indicated that compounds moderately inhibit both acetylcholinesterase and butyrylcholinesterase. ß-Amyloid aggregation results showed that all compounds exhibited remarkable Aß fibril aggregation inhibition activity with a nearly similar potential as the reference compound rifampicin, which makes them promising anti-Alzheimer drug candidates. Docking experiments were carried out with the aim to understand the interactions of the most active compounds with the active site of the cholinesterase enzymes.

Molecular modeling, synthesis and screening of some new 4-thiazolidinone derivatives with promising selective COX-2 inhibitory activity.

In order to develop new selective cyclooxygenase-2 inhibitors, a series of novel 2-aryl-3-(4-sulfamoyl/methylsulfonylphenylamino)-4-thiazolidinones were designed. Molecular modeling studies with COX-2 enzyme were performed by using MOE program. The designed compounds with reasonable binding modes and high docking scores were synthesized. Their COX-1/COX-2 inhibitory activities were evaluated in vitro, using NS-398 and indomethacine as reference compounds. Compounds possessing methyl group (3d and 4d) on the phenyl ring exhibited highly COX-2 inhibitory selectivity and potency.

Trimethyl-4-oxo-4,5,6,7-tetrahydroindazole-1-acetic acid: a new lead compound with selective COX-2 inhibitory activity.

A novel series of 3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydroindazole-1-acetic acid derivatives was designed and synthesized by a new one-step pathway. Structure elucidation of the synthesized compounds was confirmed by various spectral and elemental analyses. The prepared compounds were evaluated for their ability to inhibit cyclooxygenase-2 (COX-2) and cyclooxygenase-1 (COX-1) enzymes in vitro. Among the synthesized compounds, the 2-(3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydroindazol-1-yl)acetic acid 4 emerged as the most potent COX-2 inhibitor (IC(50) value: 150 nM) with the highest selectivity index (COX-1/COX-2 inhibition ratio: 570.6). Docking studies of compound 4 in the active site of COX-2 recognized its potential binding mode to the enzyme. Based on the preliminary results, compound 4 was considered as a lead compound for further optimization.

Synthesis and biological evaluation of isoxazolo[4,5-d]pyridazin-4-(5H)-one analogues as potent anti-inflammatory agents.

In this study, eighteen new isoxazolo[4,5-d]pyridazin-4(5H)-one derivatives possessing either a 1,3,4-thiadiazole or a 1,2,4-triazole-5-thione moiety were synthesized and tested for anti-inflammatory activity in vitro (COX-1/COX-2, 5-LOX) and in vivo (rat paw edema assay). Compounds 15, 16, 25, 26 and 28-30 showed dual COX-2 (IC(50)'s in the 2.1-10.9 µM range), and 5-LOX (IC(50)'s in the 6.3-63.5 µM range) inhibitory activity. When administered orally to rats, dual COX-2/5-LOX inhibitors showed higher anti-inflammatory activity in vivo (30-45% reduction of the inflammatory response) than the reference drug ibuprofen (18%). Among dual COX-2/5-LOX inhibitors, the most potent compound (28) exhibited the best anti-inflammatory profile by inhibiting both COX-2 (IC(50)=2.1 µM) and 5-LOX (IC(50)=6.3 µM) enzymes. We investigated the binding interactions of compound 28 by an enzyme-ligand molecular modeling (docking) studies, which showed favorable binding interactions in both COX-2 and 5-LOX active sites. Furthermore, the dual acting COX-2/5-LOX compound 28 exhibited a superior gastrointestinal safety profile (ulcer index=0.25) compared to the reference drug ibuprofen (UI=7.0) when administered orally at the same molar dose. These observations suggest that isoxazolo[4,5-d]pyridazin-4(5H)-one analogs represent a new scaffold to design potent, effective, and safe anti-inflammatory agents possessing dual COX-2/5-LOX inhibitory activity.

Synthesis and biological activities of some thiazolidin-4-ones.

In this study, fifteen 2,3-disubstituted-4-thiazolidinone derivatives were synthesized by the reaction of Schiff bases and alpha-mercaptoacetic acid. The structures of the compounds were elucidated by IR, 1H-NMR, 13C-NMR, mass spectral data and elementary analysis. The antihistaminic and anticholinergic activities of the compounds were determined by tests performed on isolated guinea pig trachea in comparison with aminophylline (CAS 317-34-0). Compound 15 (3-[3-(2-methyl-piperidine-1-yl)propyl]-2-(4-methyl-phenyl)thiazolidin-4-one hydrochloride) showed the highest inhibition (53 %).