Analgesic and antiinflammatory activity screening of 6-acyl-3-piperazinomethyl-2-benzoxazolinone derivatives

Synthesis and analgesic activities of some new 5-chloro-2(3H)-benzoxazolone derivatives

Affordable and practical synthesis methods in drug development have always been very attractive. Herein, microwave assisted synthesis was utilized to prepare piperazine substituted 5-chloro-2(3H)-benzoxazolone derivatives in 5 minutes. Structural characterization of these 5-chloro-2(3H)-benzoxazolone derivatives was achieved by IR, NMR, ESI-MS and elemental analysis. Since these types of compounds have been shown to have anti-inflammatory and analgesic activities there biological activities were also examined. Indomethacin (INDO) and acetylsalicylic acid (ASA) were used as reference. Carrageenan-induced hind paw edema in mice test was used to study anti-inflammatory activity. Compound 1 (100 mg / kg dose) showed the longest anti-inflammatory activity among the title compounds synthesized. For the analgesic activities, both hot-plate and tail-flick tests were employed. Compound 3 was found to have the highest activity in the hot-plate test whereas in the tail-flick test, compounds 1 and 2 showed higher anti-nociceptive activity.

Combretastatin A-4 analogues with benzoxazolone scaffold: Synthesis, structure and biological activity

In order to design and synthesize a new class of heterocyclic analogues of natural combretastatin A-4 and its synthetic derivative AVE8062, the benzoxazolone ring was selected as a scaffold for a bioisosteric replacement of the ring B of both molecules. A library of 28 cis- and trans-styrylbenzoxazolones was obtained by a modified Wittig reaction under Boden's conditions. Structures of the newly synthesized compounds bearing the 3,4,5-trimethoxy-, 3,4-dimethoxy-, 3,5-dimethoxy-, and 4-methoxystyryl fragment at position 4, 5, 6 or 7 of benzoxazolone core were determined on the basis of spectral and X ray data. The in vitro cytotoxicity of styrylbenzoxazolones against different cell lines was examined. Stilbene derivative 16Z, (Z)-3-methyl-6-(3,4,5-trimethoxystyryl)-2(3H)-benzoxazolone, showed highest antiproliferative potential of the series, with IC50 of 0.25 μM against combretastatin resistant cell line HT-29, 0.19 μM against HepG2, 0.28 μM against EA.hy926 and 0.73 μM against K562 cells. Furthermore, the results of flow cytometric analysis confirmed that 16Z induced cell cycle arrest in G2/M phase in the cell lines like combretastatin A-4. This arrest is followed by an abnormal exit of cells from mitosis without cytokinesis into a pseudo G1-like multinucleate state leading to late apoptosis and cell death. Accordingly, synthetic analogue 16Z was identified as the most promising potential anticancer agent in present study, and was selected as lead compound for further detailed investigations.

Molecular modeling, synthesis, characterization and pharmacological evaluation of benzo[d]oxazole derivatives as non-steroidal anti-inflammatory agents

A series of N-(2-(4-chlorobenzyl)benzo[d]oxazol-5-yl)-3-substituted-propanamide (3a–3n) were synthesized and evaluated for their acute and chronic anti-inflammatory potential. The structure of the compounds was elucidated by elemental and spectral (IR, ¹H NMR and MS) analysis. The synthesized compounds (at a dose of 20 mg/kg b.wt. p.o.) have shown their ability to provide 45.1–81.7% protection against carrageenan-induced paw edema, in comparison with diclofenac sodium (69.5%) and ibuprofen (64.7%). The most active compounds 3a, 3l and 3n were screened for chronic anti-inflammatory activity (cotton-pellet-induced granuloma) and to study their ulcerogenic activity. Compounds 3a, 3l and 3n showed 48.4%, 39.3% and 44.0% protection against cotton pellets-induced granuloma compared to diclofenac sodium (60.2%). The tested compounds were less ulcerogenic than the ibuprofen. Molecular modeling studies suggest that these compounds have strong interaction with the COX-2 enzyme, which is responsible for the activity.

Novel pyrazolopyrimidine derivatives targeting COXs and iNOS enzymes; design, synthesis and biological evaluation as potential anti-inflammatory agents

A novel set of 4-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidine and 5-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidin-4-one derivatives were synthesized and evaluated as potential anti-inflammatory agents. The newly prepared compounds were assessed through the examination of their in vitro inhibition of four targets; cyclooxygenases subtypes (COX-1 and COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor kappa B (NF-κB). Compounds 8a, 10c and 13c were the most potent and selective ligands against COX-2 with inhibition percentages of 79.6%, 78.7% and 78.9% at a concentration of 2 μM respectively, while compound 13c significantly inhibited both COX subtypes. On the other hand, fourteen compounds showed high iNOS inhibitory activities with IC50 values in the range of 0.22-8.5μM where the urea derivative 11 was the most active compound with IC50 value of 0.22 μM. Most of the tested compounds were found to be devoid of inhibitory activity against NF-kB. Moreover, almost all compounds were not cytotoxic, (up to 25 μg/ml), against a panel of normal and cancer cell lines. The in silico docking results were in agreement with the in vitro inhibitory activities against COXs and iNOS enzymes. The results of in vivo anti-inflammatory and antinociceptive studies were consistent with that of in vitro studies which confirmed that compounds 8a, 10c and 13c have significant anti-inflammatory and analgesic activities comparable to that of the control, ketorolac. Taken together, dual inhibition of COXs and iNOS with novel pyrazolopyrimidine derivatives is a valid strategy for the development of anti-inflammatory/analgesic agents with the probability of fewer side effects.

Synthesis of novel 1,2,3-triazole based benzoxazolinones: their TNF-α based molecular docking with in-vivo anti-inflammatory, antinociceptive activities and ulcerogenic risk evaluation

A library of novel bis-heterocycles containing benzoxazolinone based 1,2,3-triazoles has been synthesized using click chemistry approach. The compound 3f exhibited potent selective COX-2 inhibition of 59.48% in comparison to standard drug celecoxib (66.36% inhibition). The compound 3i showed significant (p < 0.001, 50.95%), TNF-α inhibitory activity as compared to indomethacin (p < 0.001, 64.01%). The results of the carrageenan induced hind paw oedema showed that compounds 3a, 3f, 3i, 3o, and 3e exhibited potent anti-inflammatory activity in comparison to Indomethacin. The molecular docking studies revealed that 3i exhibits strong inhibitory effect due to the extra stability of the complex because of an extra π-π bond. The histopathology report showed that none of the compounds caused gastric ulceration.

Ab initio HF, DFT and experimental (FT-IR) investigation of vibrational spectroscopy of 3-(2-(4-isopropylpiperazin-1-yl)-2-oxoethyl)-6-(4-methoxybenzoyl)benzo[d]thiazol-2(3H)-one

FT-IR spectra was recorded for 3-(2-(4-isopropylpiperazin-1-yl)-2-oxoethyl)-6-(4-methoxybenzoyl)benzo[d]thiazol-2(3H)-one molecule (abbreviated as IOMBT) sample in solid state. Conformational analysis of IOMBT was performed to determine the most stable conformer. Potential energy curves of IOMBT were obtained performing a relaxed scan of D1-7 dihedral angels at B3LYP/6-311++G(d,p) level of theory. Geometrical parameters of these structures were optimized by using the same method. The molecular geometry of IOMBT was reoptimized at DFT(B3LYP) and HF methods using 6-311++G(d,p), 6-311+G(d), 6-311G(d,p), 6-311G(d) and 6-31++G(d,p) basis sets for the lowest energy conformer. The vibrational frequencies, IR intensities were calculated at DFT(B3LYP) and HF methods. The thermodynamic parameters (such as zero-point vibrational energy, EHOMO, ELUMO, thermal corrections to energy, enthalpy and Gibbs free energy, and entropy) have also been computed. The LUMO-HOMO energy gap of IOMBT shows that the energy gap reflects the chemical reactivity and the level of conductivity of the molecule.

Synthesis, analgesic and antiinflammatory properties of certain 5-/6-acyl-3-(4-substituted-1-piperazinylmethyl)-2-benzoxazolinones derivatives

The synthesis of a novel series of Mannich bases of 5-/6-acyl-5-methyl-2-benzoxazolinones has been described. The structures attributed to compounds 2a, 3a, 4a, 4b, 9a, 9b, 5a-5g, 6a-6g, 10a, 10g, 11a, 11g have been elucidated using IR and (1)H NMR spectroscopic techniques besides elemental analysis. The compounds have been evaluated for their in vivo analgesic and antiinflammatory activities using the p-benzoquinone-induced writhing test and the carrageenan hind paw oedema test in mice, respectively. In addition, the ulcerogenic effects of the compounds were determined. Among the tested derivatives most promising results were obtained for the compounds bearing a 6-(4-chlorobenzoyl) at C-6 position and 2-/4-fluorophenyl at C-3 position of 2-benzoxazolinone ring (11c, 11d).

Synthesis of 3-(4-substituted benzoylmethyl)-2-benzoxazolinones and screening antimicrobial activities

A number of 3-(4-substituted benzoylmethyl)-2-benzoxazolinones have been synthesized by reacting with 2-benzoxazolinone and 4-substituted phenacyl bromide in ethanol. Their chemical structures were confirmed by IR, 1H NMR and elemental analysis. For screening antimicrobial activity, minimum inhibitory concentration (MIC) values were determined against two Gram positive, one Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) and three yeast-like the fungi (Candida albicans, Candida krusei, Candida parapsilosis).

Synthesis of some novel 3-methyl-6-(2-substituted propanoyl/propyl)-2-benzoxazolinone derivatives and anti-nociceptive activity

In this study, 12 new 3-methyl-6-(2-substituted aminopropanoyl)-2-benzoxazolinone and 3-methyl-6-(1-hydroxy-2-substituted aminopropyl)-2-benzoxazolinone derivatives have been prepared. Their structures have been elucidated by IR, 1H NMR spectra and by elementary analysis. The anti-nociceptive activity of these compounds has been investigated by using a modified Koster test. It was found that most compounds are capable of inducing anti-nociception in animals.

Synthesis of N-substituted 4,6-dioxo-imidazo[3,4-c] thiazoles and their analgesic activity in mice

A new series of N-substituted dioxo-imidazo[3,4-c]thiazoles have been prepared and evaluated for their analgesic activity. The structures of these new derivatives were confirmed by lR, 1H NMR and 13C NMR spectra, and by elemental analysis. When administered intraperitoneally to mice all derivatives were devoid of any toxic effect, even at the high dose of 800 mg kg(-1). In the phenylbenzoquinone-induced abdominal constriction test in mice, eight of the nine synthesized compounds exhibited significant antinociceptive properties with ED50 values (50% effective dose) ranging from 46.7 to 104.7 mg kg(-1) intraperitoneally. Further investigation demonstrated that analgesic activity of the most effective derivatives 5e and 5f partly involved opioidergic and/or noradrenergic pathways.

Analgesic activity of acylated 2-benzoxazolinone derivatives

Ten new benzoxazolinone derivatives having a disubstituted benzoyl group at the six position of the ring were synthesized by reacting 2-benzoxazolinone with aromatic carboxylic acids in the presence of polyphosphoric acid. The structure of the compounds were elucidated by IR, 1H NMR, MS and elemental analysis. Analgesic activity was evaluated by a modified Koster test. Seven compounds showed analgesic activities higher than that of acetylsalicylic acid.

Synthesis of thiazolotriazine derivatives and their antinociceptive effects in mice

Ans raci A series of 2-(4-arylpiperazin-1-yl-methyl)-4-methyl-1-oxo-5,6,8,8a-tetrahydro -thiazolo[3,4-d] [1,2,4]triazines was prepared and tested for antinociceptive activity. The compounds were prepared by the Mannich reaction from the corresponding 2-unsubstituted thiazolotriazines. When administered intraperitoneally most were found to have potent analgesic activity in the mouse during tests of phenylbenzoquinone-induced abdominal constriction; ED50 values (doses resulting in half the maximum effect) ranged from 10 to 87 mg kg(-1). Derivatives with a 3-chloro- or 4-fluorophenylpiperazinylmethyl side-chain in the 2-position of the bicyclic system were, when administered intraperitoneally at doses greater than 25 mg kg(-1), also effective in the hot-plate test without associated sedative effects. The compounds have a large therapeutic index; intraperitoneal LD50 values (doses which result in the death of half the animals) were > 700 mg kg(-1). Naloxone attenuated the analgesic activity of the 3-chloro derivative, suggesting the participation of micro-receptors in the antinociceptive effects of this drug. In addition, a nonopioid mechanism, probably related to enhancement of the release of 5-hydroxytryptamine and noradrenaline, or inhibition of the neuronal re-uptake of these compounds, has been evinced to explain the analgesic properties of the 3-chloro or 4-fluoro derivatives. These results provide evidence for the involvement of noradrenergic and 5-hydroxytryptaminergic pathways in the analgesic activity of 3 and 4. Because of their potential effectiveness, the 3-chloro- or 4-fluorophenylpiperazinylmethyl derivatives might be suitable for treatment of a wide variety of painful conditions and could be attractive reserve agents for patients dissatisfied with opioids.