Synthesis and molecular modeling of some novel hexahydroindazole derivatives as potent monoamine oxidase inhibitors.

A novel series of 2-thiocarbamoyl-2,3,4,5,6,7-hexahydro-1H-indazole and 2-substituted thiocarbamoyl-3,3a,4,5,6,7-hexahydro-2H-indazoles derivatives were synthesized and investigated for the ability to inhibit the activity of the A and B isoforms of monoamine oxidase (MAO). The target molecules were identified on the basis of satisfactory analytical and spectra data (IR, (1)H NMR, (13)C NMR, (2)D NMR, DEPT, EI-MASS techniques and elemental analysis). Synthesized compounds showed high activity against both the MAO-A (compounds 1d, 1e, 2c, 2d, 2e) and the MAO-B (compounds 1a, 1b, 1c, 2a, 2b) isoforms. In the discussion of the results, the influence of the structure on the biological activity of the prepared compounds was delineated. It was suggested that non-substituted and N-methyl/ethyl bearing compounds (except 2c) increased the inhibitory effect and selectivity toward MAO-B. The rest of the compounds, carrying N-allyl and N-phenyl, appeared to select the MAO-A isoform. The inhibition profile was found to be competitive and reversible for all compounds. A series of experimentally tested (1a-2e) compounds was docked computationally to the active site of the MAO-A and MAO-B isoenzyme. The autodock 4.01 program was employed to perform automated molecular docking. In order to see the detailed interactions of the docked poses of the model inhibitors compounds 1a, 1d, 1e and 2e were chosen because of their ability to reversibly inhibit the MAO-B and MAO-A and the availability of experimental inhibition data. The differences in the intermolecular hydrophobic and H-bonding of ligands to the active site of each MAO isoform were correlated to their biological data. Observation of the docked positions of these ligands revealed interactions with many residues previously reported to have an effect on the inhibition of the enzyme. Excellent to good correlations between the calculated and experimental K(i) values were obtained. In the docking of the MAO-A complex, the trans configuration of compound 1e made various very close interactions with the residues lining the active site cavity these interactions were much better than those of the other compounds tested in this study. This tight binding observation may be responsible for the nanomolar inhibition of form of MAOA. However, it binds slightly weaker (experimental K(i)=1.23 microM) to MAO-B than to MAO-A (experimental K(i)=4.22 nM).

Synthesis and studies on antidepressant and anticonvulsant activities of some 3-(2-thienyl)pyrazoline derivatives.

In this study, the synthesis of twelve 3-(2-thienyl)pyrazoline derivatives are described. The structures of all compounds were confirmed by UV, IR, (1)H-NMR, mass spectral data, and microanalyses. In the pharmacological studies, antidepressant and anticonvulsant activities of these compounds have been screened. The antidepressant activities of the compounds were investigated by Porsolt's behavioral despair test (forced swimming) on albino mice and compared with tranylcypromine. Among the compounds examined, the compounds 9 and 12 showed significant antidepressant activity. Anticonvulsant activities of the compounds were determined by maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (metrazol) (scMet.) tests, neurotoxicities were determined by rotarod toxicity test on albino mice. Compound 8 was found to be protective against MES in the range of 30-300 mg/kg dose levels at four hours. None of the synthesized compounds showed neurotoxicity at 30-300 mg/kg dose levels.

A new therapeutic approach in Alzheimer disease: some novel pyrazole derivatives as dual MAO-B inhibitors and antiinflammatory analgesics.

The increasing life expectancy in our population makes Alzheimer's disease (AD) a growing public health problem. There is a great need to find a way to prevent and delay the disease. It was shown that monoamine oxidase-B (MAO-B) inhibitors and antiinflammatory agents might be effective in treating AD. Therefore, a novel series of 1-thiocarbamoyl-3-substituted phenyl-5-(2-pyrrolyl)-4,5-dihydro-(1H)-pyrazole derivatives as promising MAO-B inhibitors was synthesized and investigated for the ability to inhibit selectively the activity of the A and B isoforms of monoamine oxidase (MAO). Most of the synthesized compounds showed high activity against both the MAO-A (compounds 3e-3h) and the MAO-B (compounds 3i-3l) isoforms. All the synthesized compounds were also tested for their in vivo antiinflammatory activity by two different bioassays namely, carrageenan-induced oedema and acetic acid-induced increase in capillary permeability in mice. In addition, analgesic and ulcerogenic activities were determined. The combined antiinflammatory data from in vivo animal models showed that compound 3k exhibited anti-inflammatory activity comparable to that of indomethacin with no ulcerogenic effects. Since compound 3k exhibits both antiinflammatory-analgesic activity and MAO-B inhibition, it needs further detailed studies.

Synthesis and studies on antidepressant and anticonvulsant activities of some 3-(2-furyl)-pyrazoline derivatives.

Twelve 1-phenyl-, 1-thiocarbamoyl- and 1-N-substituted thiocarbamoyl-3-(2-furyl)-5-phenyl/(2-furyl)-2-pyrazoline derivatives were synthesized. The chemical structures of the compounds were proved by IR, (1)H NMR, Mass spectrometric data and microanalyses. The antidepressant activities of the compounds were investigated by Porsolt's behavioural despair (forced swimming) test on albino mice. 1-N-Ethylthiocarbamoyl-3-(2-furyl)-5-phenyl-2-pyrazoline (6) and 1-N-allylthiocarbamoyl-3,5-di(2-furyl)-2-pyrazoline (11) reduced 33.80-31.42% duration of immobility times at 10 mg kg(-1) dose level. Anticonvulsant activities of the compounds were determined by maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (metrazol) (scMet.) tests, neurotoxicities were determined by rotarod toxicity test on albino mice. 1,5-Diphenyl-3-(2-furyl)-2-pyrazoline (2), 1-N-allylthiocarbamoyl-3-(2-furyl)-5-phenyl-2-pyrazoline (7), 1-N-allylthiocarbamoyl-3,5-di(2-furyl)-2-pyrazoline (11) and 1-N-phenylthiocarbamoyl-3,5-di(2-furyl)-2-pyrazoline (12) were active at 100-300 mg kg(-1) dose levels. 1-Thiocarbamoyl-3,5-di(2-furyl)-2-pyrazoline (4), 1-N-methylthiocarbamoyl-3,5-di(2-furyl)-2-pyrazoline (9) and 1-N-ethylthiocarbamoyl-3,5-di(2-furyl)-2-pyrazoline (10) were found protective against MES and scMet. at 30-300 mg kg(-1) dose levels.

1-N-Substituted thiocarbamoyl-3-phenyl-5-thienyl-2-pyrazolines: a novel cholinesterase and selective monoamine oxidase B inhibitors for the treatment of Parkinson's and Alzheimer's diseases.

Twelve 1-N-substituted thiocarbamoyl-3-phenyl-5-thienyl-2-pyrazoline derivatives were synthesized and their biological interactions with human plasma and erythrocyte acetylcholinesterase (AChE) and butrylcholinesterase (BuChE) enzymes were assessed. Compounds 3i-3l of newly synthesized N-substituted pyrazolines, which were presented as selective and irreversible MAO-B inhibitors in our previous report, were found to inhibit human erythrocyte and plasma AChE activities selectively and non-competitively suggesting that these compounds may interact with a region close to the peripheral site of the enzyme molecule which could shift the proper positioning of the catalytic center. Compounds 3e-3h inhibited both AChE and BuChE activities of human erythrocytes, but the inhibitory potencies of these compounds towards BuChE were found to be higher than that of towards AChE. Inhibition was found to be non-competitive and reversible. These data suggested that newly synthesized N-substituted pyrazoline derivatives can be evaluated as both MAO-B and cholinesterase inhibitors which may have promising features in the treatment of Alzheimer's and Parkinson's diseases.

1-N-substituted thiocarbamoyl-3-phenyl-5-thienyl-2-pyrazolines: synthesis and evaluation as MAO inhibitors.

Twelve new 1-N-substituted thiocarbomoyl-3-phenyl-5-thienyl-2-pyrazoline derivatives were synthesized and evaluated their for antidepressant, anxiogenic and mammalian monoamine oxidase (MAO)-A and Binhibitory activities by in vivo and in vitro tests. MAO was isolated and purified from the mitochondrial pellet of bovine liver homogenates and human platelets. All of the new compounds inhibited the total MAO activity of liver homogenates and the inhibition was found to be time-dependent. Four compounds (3 i-3 l) inhibited MAO-B selectively and irreversibly in a classical non-competitive manner with IC(50) values in the range of 22.00-91.50 microM. The rest of the compounds appeared to be non-selective reversible inhibitors. It was suggested that the p-methoxy group on the phenyl ring in the compounds increased the inhibitory effect and selectivity toward MAO-B. The reversible and unselective inhibition of MAO by the remaining compounds was suggested to be related to their properties of acting ability to act as both as substrate and inhibitor at the same time. However, none of the novel compounds showed antidepressant activity as expected suggesting formation of inactive metabolites. We conclude that the compounds appeared as which functioned as selective MAO-B inhibitors might have promising features as therapeutic properties in the treatment of Parkinson disease. In vivo studies are needed to verify this hypothesis.