A. Altan Bilgin

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 Alzheimers and Parkinsons diseases.

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, 1H‐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 Porsolts 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.

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).

Interaction of rat lung SSAO with the novel 1-N-substituted thiocarbamoyl-3-substituted phenyl-5-(2-pyrolyl)-2-pyrazoline derivatives

SummaryInteractions of twelve new synthesized 1-N-substituted thiocarbamoyl-3-substituted phenyl-5-pyrolyl-2-pyrazoline derivatives with rat lung semicarbazide-sensitive amine oxidase (SSAO) were assessed. Pyrazoline derivatives were synthesized according to previous methods and SSAO was purified from the crude microsomal fractions of rat lung.Three compounds (3e, 3f, 3k) with a p-methoxy group at the phenyl ring inhibited rat lung SSAO non-competitively and irreversibly, and showed higher affinity towards SSAO when expressed in terms of IC50 for SSAO/Monoamine oxidase B (MAO-B). Since these novel pyrazoline derivatives have been found to act as suicide inhibitors of SSAO, the semicarbazide group in these molecules may be responsible for the SSAO inhibitory action. It is suggested that these compounds cannot enter the first small active site cavity of SSAO and may interact tightly with another binding site or with some other reactive groups present in the molecule. Compound 3e showed the highest inhibitory activity on rat lung SSAO. The novel pyrazoline derivatives may be used to discriminate between Cu- and FAD-containing amine oxidases and may have promising features as anti-Parkinson agents if the SSAO-inhibitory effects can be supported by in vivo studies.

1-(2-Furyl)-3-phenyl-2-propen-1-one

The molecule of the title compound, C13H10O2 is nearly planar; the furyl and and phenyl rings are only slightly twisted with respect to each other, making a dihedral angle of 8.56 (6)°. The crystal structure is stabilized by weak intermolecular C—H⋯O contacts and C—H⋯π interactions.