Synthesis of some new 2-(substituted-phenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazoles: a safer anti-inflammatory and analgesic agents

A series of 2-(substituted-phenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazoles (3-15) were synthesized. The compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation actions. The percentage inhibition in edema at different time intervals indicated that compounds 8, 11, 12, 14 and 15 exhibited good anti-inflammatory potential. The results illustrate that 2-(2-acetoxyphenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazole (15) and 2-(3,4-dimethoxyphenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazole (12) showed best anti-inflammatory activity among the series tested. Furthermore, activity is higher in case of chloro substitution as compared to methyl substitution. The compounds synthesized were also evaluated for their ulcerogenic and lipid peroxidation action and showed superior GI safety profile along with reduction in lipid peroxidation as compared to that of ibuprofen.     

Non-carboxylic analogues of naproxen: design, synthesis, and pharmacological evaluation of some 1,3,4-oxadiazole/thiadiazole and 1,2,4-triazole derivatives

A series of substituted 1,3,4-oxadiazole (2-7 and 14-19), 1,2,4-triazole (20-25), and 1,3,4-thiadiazole (26-31) derivatives of naproxen have been synthesized by cyclization of 2-(6-methoxy-2-naphthyl)propanoic acid hydrazide 1 and N(1)[2-(6-methoxy-2-naphthyl) propanoyl]-N(4)-alkyl/aryl-thiosemicarbazides (8-13) under various reaction conditions. All the compounds were screened for their anti-inflammatory activity by carrageenan-induced rat paw edema test method. Compounds showing high anti-inflammatory activity were also tested for their analgesic, ulcerogenic, and lipid peroxidation. Few of the synthesized compounds showed significant anti-inflammatory and analgesic activities along with reduced ulcerogenic effect and lipid peroxidation.     

Studies on fused heterocyclic 3,6-disubstituted-1,2,4-triazolo-1,3,4-thiadiazoles: synthesis and biological evaluation

In this study, a series of 3,6-disubstituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazoles (5a–t) were synthesized by condensing 4-amino-3-mercapto-(4H)-1,2,4-triazoles (4a–c) with different aromatic or aroyl acids through one-pot reaction. The compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic, and lipid peroxidation actions. Some of the newly synthesized compounds showed very good anti-inflammatory activity with low GI toxicity and reduced lipid peroxidation. These compounds also showed interesting profile of analgesic activity in acetic acid-induced writhing test. The findings of the study indicate that the synthesized compounds have superior GI safety profile along with reduction in lipid peroxidation as compared to that of the standard.     

Synthesis and pharmacological evaluation of N-(6-chlorobenzo[d]thiazol-2-yl)hydrazine carboxamide derivatives of benzothiazole

A series of 6-substituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole (6a–g) and 1,3,4-oxadiazole (7a–g, 8) derivatives of benzothiazole were synthesized in satisfactory yield and pharmacologically evaluated for their anti-inflammatory, analgesic, ulcerogenic, and lipid peroxidation activities by known experimental models. All the synthesized compounds were in good agreement with elemental and spectral data. Some of the synthesized compounds have significant anti-inflammatory and analgesic activities. Ulcerogenic and irritative action on the gastrointestinal mucosa, in comparison with standard are low.     

Synthesis and Biological Evaluation of ��-Aroylpropionic acid based 1,3,4-Oxadiazoles

In the present investigation, two new series, 1-(4-benzylphenyl)-3-(5-substituted-1,3,4-oxadiazol-2-yl)-1-propanone and 1-(4-ethylphenyl)-3-(5-substituted-1,3,4-oxadiazol-2-yl)-1-propanone from β-(4-benzylbenzoyl)propionic acid and β-(4-ethylbenzoyl)propionic acid, respectively, were synthesized and tested for antiinflammatory, analgesic, lipid peroxidation, ulcerogenic and antibacterial actions. A fair number of compounds were found to have good antiinflammatory activity in carrageenan-induced rat paw edema test, while a few compounds showed significant antibacterial activity. The newly synthesized compounds showed very low ulcerogenic action.     

Synthesis and anti-inflammatory activity of 1-acylthiosemicarbazides, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazole-3-thiones

Sixteen 1-(2-naphthyloxyacetyl)-4-substituted-3-thiosemicarbazide, 2-(2-naphthyloxymethyl)-5-substitutedamino-1,3,4-oxadiazole, 2-(2-naphthyloxymethyl)-5-substitutedamino-1,3,4-thiadiazole and 5-(2-naphthyloxymethyl)-4-substituted-1,2,4-triazole-3thione derivatives have been prepared and evaluated as orally active anti-inflammatory agents with reduced side-effects. The structures of the compounds were confirmed by IR and 1H NMR spectral data and microanalysis. The anti-inflammatory and ulcerogenic activities of the compounds were compared with naproxen, indomethacin and phenylbutazone. In carrageenan-induced foot pad edema assay, 2-(2-naphthyloxymethyl)-5-methylamino-1,3,4-oxadiazole, 5-(2-naphthyloxymethyl)-4-methyl-1,2,4-triazole-3-thione and 5-(2-naphthyloxymethyl)-4-ethyl-1,2,4-triazole-3-thione showed an interesting anti-inflammatory activity. In the air-pouch test, 1,3,4-oxadiazole and 1,2,4-triazole-3-thione derivatives reduced total number of leukocytes of the exudate that indicates excellent inhibition of prostaglandin production. Side effects of the compounds were examined on gastric mucosa, liver and stomach and none of the compounds showed significant side effects compared with reference nonsteroidal anti-inflammatory drugs (NSAIDs).     

Anti-inflammatory and gastro sparing activity of some new indomethacin derivatives

Indomethacin is a non-steroidal anti-inflammatory drug but its use is associated with high degree of gastric toxicity therefore it is prescribed only in severe conditions. In order to reduce the gastric toxicity of indomethacin, various oxadiazole, triazole, thiadiazole and triazine derivatives have been synthesized. Out of thirteen cyclized derivatives, eleven were screened for anti-inflammatory activity by Winter et al. method. Four compounds showed highly significant activity and were further tested for analgesic, ulcerogenic and lipid peroxidation activities. The tested compounds showed anti-inflammatory activities in the range from about 32% to 85% as compared to that of indomethacin of about 96%. The compounds showing high anti-inflammatory activity also exhibited reduction in severity index. These compounds also produced less malondialdehyde content in gastric mucosa than the standard drug indomethacin. The study showed that the compounds inhibited the induction of gastric mucosal lesions and it can be suggested from our results that their protective effects may be related to inhibition of lipid peroxidation in the gastric mucosa.     

2-Amino-5-sulfanyl-1,3,4-thiadiazoles: a novel series of anti-inflammatory and analgesic agents

2-Amino-5-sulfanyl-1,3,4-thiadiazole derivatives were synthesized via the interaction of 2-amino-5-sulfanyl-1,3,4-thiadiazole, Ar-Cl, and benzene sulfonamide/benzene sulfonyl chloride. Twelve compounds were synthesized, out of which six compounds show significant anti-inflammatory and analgesic activity and were devoid of gastrointestinal side effects (ulcerogenic effect), which zre the most frequent adverse reactions associated with orally ingested anti-inflammatory or antiarthritic agents.     

Synthesis,analgesic and anti-inflammatory activities of new methyl-imidazolyl-1,3,4-oxadiazoles and 1,2,4-triazoles

Background

Long-term clinical employment of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with significant side effects including gastrointestinal (GI) lesions and kidney toxicity. In this paper we designed and synthesized new imidazolyl-1,3,4-oxadiazoles and 1,2,4-triazoles by molecular hybridization of previously described anti-inflammatory compounds in the hope of obtaining new safer analgesic and anti-inflammatory agents.

Methods

The target structures were synthesized by preparation of 5-methyl-1H-imidazole-4-carboxylic acid ethyl ester 5. The reaction of hydrazine hydrate with this ester afforded the 5-methyl-1H-imidazole-4-carboxylic acid hydrazide 6 which was converted to target compounds 7-15 according to the known procedures. In silico toxicity risk assessment and drug likeness predictions were done, in order to consider the privileges of the synthesized structures as drug candidates.

Results and discussion

The analgesic and anti-inflammatory profile of the synthesized compounds were evaluated by writhing and carrageenan induced rat paw edema tests respectively. Compounds 8, 9 and 11-13 and 15 were active analgesic agents and compounds 8, 9 and 11-13 showed significant anti-inflammatory response in comparison with control. Compounds 11 and 13 were screened for their ulcerogenic activities and none of them showed significant ulcerogenic activity. The active Compounds 11 and 12 showed the highest drug likeness and drug score.

Conclusions

The analgesic and anti-inflammatory activities of title compounds were comparable to that of standard drug indomethacin with a safer profile of activity. The results revealed that both of oxadiazole and triazole scaffolds can be determined as pharmacophores. The in silico predictions and pharmacological evaluations showed that compounds 11 and 12 can be chosen as lead for further investigations.     

Synthesis of some thiazolo[3,2-b]-1,2,4-triazole-5(6H)-ones and their novel Michael addition products with anti-inflammatory activities.

In this study, 21 new compounds having 2-methyl-6-benzylidenethiazolo[3,2-b]-1,2,4-triazol-5(6H)-one (2-4) and 2-methyl-6-(alpha-aminobenzyl)thiazolo[3,2-b]-1,2,4-triazole-5-ol (2a-4g) structures were synthesized. The structures of the compounds were proved by spectral and elemental analysis. All of the compounds synthesized were tested for their anti-inflammatory actively and ulcerogenic potential in mice at 10, 20 and 40 mg/kg dose levels. Compound 4b showed higher anti-inflammatory activity than the analogue derivatives and indometacin (CAS 53-86-1), used as a reference drug, at 10 mg/kg dose level. Generally, the compounds were found to be more reliable than indometacin since they did not cause any reaction in the stomach.     

Synthesis and anti-inflammatory activity of some pyrazole derivatives

A novel series of pyrazoles containing benzenesulfonamides, 1,3,4-oxadiazole-2-thiones, 4-substituted-1,2,4-triazole-3-thiones, and 2-substituted-1,3,4-thiadiazoles has been synthesized. Anti-inflammatory activity of some synthesized compounds was evaluated in vivo utilizing a standard acute carrageenan-induced paw edema method. The most active anti-inflammatory agents 3, 8f, and 10f were evaluated for ulcerogenic liability in rats compared to indomethacin and celecoxib as reference standards. Molecular modeling studies were initiated herein to validate the attained pharmacological data and provide understandable evidence for the observed anti-inflammatory behavior.     

Design, synthesis and molecular docking of some new 1,2,4-triazolobenzimidazol-3-yl acetohydrazide derivatives with anti-inflammatory-analgesic activities

The present work describes the synthesis and evaluation of some new acetohydrazones, 1,3,4-oxadiazoles and 1,2,4-triazoles of 1,2,4-triazolo[1,5-a]benzimidazole as anti-inflamm atory-analgesic agents. Structure elucidation of these compounds was confirmed by IR, ¹H NMR, and mass spectrometry along with elemental microanalyses. Most compounds exhibited significant anti-inflammatory activity in comparison to indomethacin. Further, some compounds were tested for their analgesic effects where two compounds showed results comparable to indomethacin at 4 h interval. The most active anti-inflammatory and analgesic compounds (4c and 11a) were examined on gastric mucosa and didn’t show any gastric ulcerogenic effect compared with the reference indomethacin. Moreover, LD₅₀ of compounds (4c and 11a) were determined in mice; they were found non toxic up to 240 and 300 mg/kg (i.p.). Also, docking simulation of some compounds into COX active sites was studied.     

Novel 3,6‐Disubstituted 7H‐1,2,4‐Triazolo[3,4‐b][1,3,4]thiadiazines: Synthesis,Characterization, and Evaluation of Analgesic / Anti‐inflammatory,Antioxidant Activities

In this study, the synthesis of a new series of 3,6‐disubstituted‐7H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazine 1a – 4c compounds derived from 4‐amino‐3‐substituted‐1,2,4‐triazole‐5‐thiones 1 – 4 is described. All of the synthesized compounds were screened for their possible analgesic / anti‐inflammatory, antioxidant activities and gastric toxicity. The compound 2c was found to have both significant analgesic and consistent anti‐inflammatory activity without inducing any gastric lesions along with minimal lipid peroxidation. A deep insight into the structures of the active compounds revealed that the compounds carrying an electron withdrawing group (a chloride or fluoride) on the phenyl ring at 6‐position of the condensed heterocyclic derivatives exhibited noticeable higher activity.     

Design and synthesis of 3-[3-(substituted phenyl)-4-piperidin-1-ylmethyl/-4-morpholin-4-ylmethyl-4,5-dihydro-isoxazol-5-yl]-1H-indoles as potent anti-inflammatory agents

The synthesis of new indole derivatives bearing isoxazoline moiety (3a–d and 4a–d) has been described. IR, ¹H NMR, and mass spectral data supported the structures of synthesized compounds. The compounds were tested in vivo for their anti-inflammatory activity by carrageenin-induced rat paw edema method. The compounds that showed good anti-inflammatory activity were screened for their ulcerogenic and lipid peroxidation activities. The most active compound of this series is 3-[3-(4-methoxyphenyl)- 4-morpholin-4-ylmethyl)-4,5-dihydro-isoxazol-5yl]-1H-indole 4d.     

Pharmacological screening for anti-inflammatory, analgesic activity of pyrazolyl derivatives along with molecular docking studies

The pyrazole derivatives were synthesized and pharmacologically evaluated for analgesic (tail flick) and anti-inflammatory (based on carrageenan-induced paw edema) activities. Compound 4k showed high potency as an anti-inflammatory agent after 3 and 4-h time intervals (P?<?0.001) equipotent to indomethacin. They were devoid of ulcerogenic potential when administered at a dose of 30?mg/kg. The compounds, which showed less ulcerogenic action, also showed reduced malondialdehyde content (MDA), which is one of the byproduct of lipid peroxidation. Further docking studies of titled compounds was done to understand key interactions responsible for observed inhibition of COX enzyme. The most active compound 4k was found to have ?11.192?kcal/mol, as the free energy of binding. Various other key interactions between the synthesized molecules and active site of COX-2 enzyme, responsible for the obtained pharmacological results were also reported. Most of the active compounds were docked well into the active sites of the receptor.     

Design and one-pot and microwave-assisted synthesis of 2-amino/5-aryl-1,3,4-oxadiazoles bearing a benzimidazole moiety as antioxidants

In this study, two new series of 2-amino-1,3,4-oxadiazoles and 5-aryl-1,3,4-oxadiazoles carrying a benzimidazole moiety were synthesized. The antioxidant properties of these compounds were investigated in vitro by the determination of the microsomal NADPH-dependent inhibition of lipid peroxidation levels (LP), the microsomal ethoxyresorufin O-deethylase activity (EROD), and DPPH radical scavenger effects. Among the tested compounds, 2-[(2-(4-chlorophenyl)-1H-benzo[d]imidazole-1-yl)methyl]-5-(4-fluorophenyl)-1,3,4-oxadiazole (9) was found to be the most active compound in all three in vitro systems.     

Synthesis and pharmacological activity of 1,2,4-triazolo[4,3-a]quinolines

The synthesis of a series of 1,2,4-triazolo[4,3-a]quinoline derivatives is described; their structures were assigned by 1H NMR and analytical data. The new compounds were tested in vivo for their antiinflammatory and analgesic activities, as well as for their ulcerogenic action. Some of the tested triazoles showed an analgesic activity in the acetic acid writhing test and antiinflammatory properties on carrageenan paw edema assay.     

Synthesis and pharmacological activity of imidazolyn-5-ones

A new series of imidazolyn-5-one derivatives were synthesized. These compounds were screened for their analgesic, anti-inflammatory and antipyretic activities, as well as for their ulcerogenic potential, for behavioural effects and acute toxicity. Some of them showed higher analgesic activity than phenylbutazone (PBZ), but lower anti-inflammatory activity. Their ulcerogenic effect was lesser than that of the reference drug.     

Synthesis and pharmacological evaluation of some 3-(4-methylphenyl)-2-substituted amino-3H-quinazolin-4-ones as analgesic and anti-inflammatory agents

A variety of 3-(4-methyl phenyl)-2-substituted amino-3H-quinazolin-4-ones were synthesized by reacting the amino group of 2-hydrazino-3-(4-methyl phenyl)-3H-quinazolin-4-one with a variety of aldehydes and ketones. The starting material 2-hydrazino-3-(4-methyl phenyl)-3H-quinazolin-4-one was synthesized from 4-methyl aniline. The title compounds were investigated for analgesic, anti-inflammatory, and ulcerogenic index activities. While the test compounds exhibited significant activity, compounds Al, A2, and A3 showed more potent analgesic activity and the compound A3 showed more potent anti-inflammatory activity when compared to the reference standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic potential when compared to aspirin.     

Design and synthesis of some new thiazolo [3,2-b]-1,2,4-triazole-5(6H)-ones substituted with flurbiprofen as anti-inflammatory and analgesic agents

In the course of our ongoing studies, a series of thiazolo[3,2-b]-1,2,4-triazole-5(6H)-ones substituted with flurbiprofen (CAS 5104-49-4) has been prepared. The compounds were synthesized by the cyclization of the 3-[(2-fluoro-4-biphenyl)ethyl]-5-mercapto-1,2,4-triazole (3) with chloroacetic acid and relevant benzaldehydes in the presence of acetic acid, acetic anhydride and anhydrous sodium acetate in one step. The product of this one-pot synthesis that precipitated on cooling of the reaction mixture was identified undoubtedly by X-ray crystallographic analysis as thiazolo[3,2-b]-1,2,4-triazole. In-vivo anti-inflammatory and analgesic activities of the compounds were assessed by carrageenan-induced hind paw edema and p-benzoquinone-induced abdominal constriction tests in mice, respectively. In addition, the ulcerogenic risks were evaluated. It is worthy of saying that the compounds which maintained analgesic/antiinflammatory activity of the starting compound were found to be safer with regard to gastric lesion risks at 100 mg/kg oral dose when compared with flurbiprofen. Among the synthesized compounds 3d showed the highest analgesic and antiinflammatory activity without inducing any gastric lesion and deserves further attention in order to develop new lead drug candidates.