A number of N-(4,6-substituted diphenylpyrimidin-2-yl) semicarbazones (4a-t) were synthesized and tested for their anticonvulsant activity against the two seizure models, maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ). All the synthesized compounds possessed the four essential pharmacophoric elements for good anticonvulsant activity. Most of the compounds displayed good anticonvulsant activity with lesser neurotoxicity. To assess the unwanted effects of the compounds on liver, estimation of enzymes and proteins was carried out.

A series of 4-thiazolidinones bearing a sulfonamide group (4a-w) were prepared by cyclizing various 5-bromo-2-methoxy-N'-[(1E)-arylmethylene/arylethylidene]benzenesulfonohydrazides. All the compounds were characterized by IR,(1)H NMR, and elemental analysis. The compounds were tested for their anticonvulsant activity utilizing MES and scPTZ animal models. The majority of the compounds exhibited significant activity against both animal models; however, compounds 4c, 4m, and 4o displayed promising activity and could be considered as leads for further investigations.

A series of 2-(substituted phenyl)-3-[3-(2-oxo-2H-chromen-3-yl)-5-thioxo-1,5-dihydro-4H-1,2,4-triazol-4-yl]-1,3-thiazolidin-4-ones, 8a-n, were synthesized and evaluated for their antimicrobial activity. The structures of the compounds were confirmed on the basis of their elemental analysis and spectral data. Compounds 8k, 81 and 8m showed significant inhibition against S. aureus, compound 8m showed significant inhibition against E. coli and compounds 8b, 8e, 8i, 8j, 8k, 81 and 8m showed significant inhibition against C. albicans.

Various N-(5-chloro-6-substituted-benzothiazol-2-yl)-N'-(substituted phenyl)-[1,3,4]thiadiazole-2,5-diamines (5a-t) were designed and synthesized starting from substituted acetophenones. Structures of all the compounds were confirmed on the basis of spectral and elemental analyses. All the newly synthesized compounds were screened for their anticonvulsant activity and were compared with the standard drug phenytoin sodium. Interestingly, all the compounds showed protections against seizures in the range 50-100% indicative of the promising nature of the compounds against seizure spread. Compounds 5b and 5c showed complete protection against MES induced seizures.

A number of new 8-substituted-4-(2/4-substituted phenyl)-2H-[1,3,5]triazino[2,1-b][1,3]benzothiazole-2-thiones (4a-t) were synthesized and evaluated for their anticonvulsant, anti-nociceptive, hepatotoxic, and neurotoxic properties. The titled compounds (4a-t) were obtained by cyclization of N-{[6-substituted-1,3-benzothiazol-2-yl)amino]carbonothioyl}-2/4-substituted benzamides (3a-t) by refluxing in n-butanol. All the newly synthesized compounds were screened for their anticonvulsant activity in a mouse seizure model and were compared with the standard drug phenytoin. Compounds 4a, 4c, 4f, and 4l showed complete protection after time periods of 0.5 h and 4 h. Some of the selected compounds were evaluated for their neurotoxic and hepatotoxic effects, and none of these showed any sign of neurotoxicity or hepatotoxicity. Compounds 4a-t were also evaluated for their anti-nociceptive activity by a thermal stimulus technique using diclofenac as standard. Compounds 4o, 4q, and 4t displayed highly potent analgesic activity with p < 0.01.

Several heteroaryl semicarbazones were prepared by the reaction of heteroaryl hydrazine carboxamide with aryl aldehydes or ketones. The structures of the synthesized compounds were confirmed by spectral data and elemental analyses. Compounds were tested for anticonvulsant activity utilizing pentylenetetrazole-induced seizure (PTZ) and maximal electroshock seizure (MES) tests at 30, 100 and 300 mg/kg dose levels. Neurotoxicity of the compounds was also assessed at the same dose levels. Three compounds of the series, 6d, 6i and 6n, exhibited significant anticonvulsant activity at 30 mg/kg dose level comparable to the standard drug, phenytoin.

A series of 4-(5-bromo-1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-butyryl N-(substituted phenyl) amides (3a-I) were synthesized and evaluated for their anticonvulsant activity in MES test according to the protocols of Antiepileptic Drug Development (ADD) programme of National Institutes of Health (NIH, Bethesda, USA).The most active compounds of the series were 3a, 3c, 3d, 3f, 3g, 3i and 3k at the dose of 30 mg/kg (i.p.) 0.5 h and 4 h after administration. In neurotoxic screen (NT), 3d, 3i and 3k were less toxic when compared with the other compounds.

A series of 3-(4-acetyl-5H/methyl-5-substituted phenyl-4,5-dihydro-1,3,4-oxadiazol-2-yl)-2H-chromene-2-ones (6a-j) were synthesized and evaluated for anticonvulsant activity and neurotoxicity. The structures of the synthesized compounds were confirmed on the basis of their spectral data and elemental analysis. A majority of the compounds was active in MES tests. Compound (6e) was found to be potent and had activity at lower dose of 30 mg/kg in MES-test. All the compounds were less toxic as compared with the standard drug phenytoin.

A series of 1,3-benzothiazol-2-yl benzamides (11-30) were prepared in satisfactory yield and evaluated for their anticonvulsant, neurotoxicity, CNS depressant study and other toxicity studies. All the synthesized compounds were in good agreement with elemental and spectral data. Majority of the compounds were active in MES and scPTZ screen and showed the decrease in the immobility time. None of the compounds had shown neurotoxicity or liver toxicity.

The significance of this study was to prepare various oxadiazole derivatives by introducing the 1,3,4 oxadiazole core into several molecules to explore the possibilities of some altered biological activities. Series of (Z)-N-(1-(2-(2-amino-3-((dimethylamino) methyl)phenyl)-5-phenyl-1,3,4,oxadiazol-3(2H)-yl)ethanone derivatives were prepared in satisfactory yield and pharmacologically evaluated for their antimicrobial and antioxidant activities. The results revealed that all synthesized compounds have a significant biological activities. Among the synthesized derivative 7c (Z)-N-(1-(2-(2-amino-3-((dimethylamino)methyl)phenyl)-5-phenyl-1,3,4-oxadiazol-3(2H)-yl)ethylidene)-4-chloroaniline 7g (Z)-N-(1-(2-(2-amino-3-((dimethylamino)methyl)phenyl)-5-phenyl-1,3,4-oxadiazol-3(2H)-yl)ethylidene)-4-nitroaniline and 7i (Z)-N-(1-(2-(2-amino-3-((dimethylamino)methyl)phenyl)-5-phenyl-1,3,4-oxadiazol-3(2H)-yl)ethylidene)-4-methoxyaniline were found to be most effective antimicrobial compounds. While the compounds 7c and 7g were the most potent antioxidant compounds with significant hydrogen peroxide scavenging activity.

Several 2,5-disubstituted-1,3,4-oxadiazoles (4a-f) and 3,6-disubstituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles (7a-f) were synthesized and characterized by elemental analyses and spectral data. These compounds were screened for their anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation activities. Compound 7c showed excellent anti-inflammatory and remarkable analgesic activity with reduced ulcerogenic and lipid peroxidation activity when compared with ibuprofen.

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.

A series of 6-substituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole (3a-g) and 1,3,4-oxadiazole (4a-g, 5) derivatives of isoniazid were synthesized in satisfactory yield and pharmacologically evaluated for their in vitro antimicrobial activity. All the synthesized compounds were in good agreement with elemental and spectral data. A majority of the tested compounds showed good to moderate antimicrobial activity against all tested pathogenic bacterial and fungal strains.

A series of pyridazinone derivatives (19-34) were synthesized with an aim to synthesize safer anti-inflammatory agents. The compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation (LPO) actions. The percentage inhibition in edema at different time intervals indicated that compounds 20, 26, 28 and 34 exhibited good anti-inflammatory potential, comparable with that of ibuprofen (85.77%) within a range of 67.48-77.23%. The results illustrate that 5-(4-fluoro-benzyl)-3-(4-chloro-phenyl)-1,6-dihydro-6-pyridazinone (26) and 5-(4-chloro-benzyl)-3-(4-chloro-phenyl)-1,6-dihydro-6-pyridazinone (20) showed best anti-inflammatory activity. Furthermore, activity is more in case of chloro substitution as compared with methyl-substitution. The compounds synthesized were also evaluated for their ulcerogenic and LPO action and showed superior gastrointestinal safety profile along with reduction in LPO as compared with that of the ibuprofen.

In this paper, we report the synthesis and pharmacological evaluation of pyrazine N-acylhydrazone (NAH) derivatives (2a-s) designed as novel analgesic and anti-inflammatory drug candidates. This series was planned by molecular simplification of prototype 1 (LASSBio-1018), previously described as a non-selective cyclooxygenase inhibitor. Derivatives 2a-s were evaluated in several animal models of pain and inflammation, standing-out compound 2o (2-N'-[(E)-(3,4,5-trimethoxyphenyl) methylidene]-2-pyrazinecarbohydrazide; LASSBio-1181), that was also active in a murine model of chronic inflammation (i.e., adjuvant-induced arthritis test in rats) and can be considered a new analgesic and anti-inflammatory lead for drug development.

A series of substituted azole derivatives (3a-e, 4a-e and 5a-e) were synthesised by the cyclisation of N(1)(diphenylethanoyl)-N(4)-substituted phenyl thiosemicarbazides under various reaction conditions. These compounds were tested in vivo for their anti-inflammatory activity. The compounds which showed activity comparable to the standard drug ibuprofen, were screened for their analgesic, ulcerogenic and lipid peroxidation activities. The compounds 5-(diphenylmethyl)-N-(4-fluorophenyl)-1,3,4-oxadiazol-2-amine (3b) and 5-(diphenylmethyl)-N-(3-chloro-4-fluorophenyl)-1,3,4-oxadiazol-2-amine (3c) emerged as the most active compounds of the series, and were moderately more potent than the standard drug, ibuprofen.(This abstract was published in Inflammation Research, Supplement 2, Volume 56, page A101, 2008.).

The pyrroles Ia-c were used as precursor for the preparation of pyrrolo [2, 3-d] pyrimidine-2 and/or 4 thione derivatives IIa-f. A series of 8-Aryl-pyrrolo [2, 3-d] thiazolo[3,2-a]pyrimidine VI and VII were prepared. Alkylation of the thione compounds in basic medium afforded the pyrrolo [2, 3-d] pyrimidine IV. Also, some 2-amino pyrrolo [2, 3-d]pyrimidines V were obtained. Some newly synthesized compounds were examined for their in vitro anti-inflammatory. Also, all new compounds were examined for their in vivo anti-microbial activity. Several derivatives, showed a promising anti-inflammatory activity in compared to ibuprofen. In this paper, we examine and discuss the structure-activity relationships and anti-inflammatory activities of these compounds.

A new series of 9-deazaxanthine derivatives with various substituents at the heterocyclic system were synthesized and evaluated for their binding affinities for the four human recombinant adenosine receptors, A(1)-A(3) subtypes. A number of the 9-deazaxanthines derivatives 3a-m showed moderate-to-high affinity for hA(2B) receptors, with compound 3f showing a 32-fold selectivity for A(2B) over A(1) and a 2750-fold selectivity for A(2B) over A(2A).

A series of 1,8-dihydro-1-aryl-8-alkyl pyrazolo(3,4-b)indoles 4a-j, 5a-j and 6a-j has been synthesized and tested for their anti-inflammatory and anticonvulsant activities. Formation of the pyrazoloindole derivatives was achieved by treating arylhydrazones of N-alkyl indole-3-carbox-aldehydes 1a-j, 2a-j and 3a-j with ten times their mass of polyphosphoric acid as a condensing agent. The newly synthesized compounds were evaluated for their anti-inflammatory, analgesic and anticonvulsant activities compared to indomethacin, flufenamic acid and diazepam as positive controls. Detailed synthesis, spectroscopic and toxicity data are reported.