Antimicrobial and Cytotoxic Evaluation of New Quinazoline Derivatives.

The synthesis of nine new quinazoline derivatives (2a-2i) and evaluation of their antimicrobial and cytotoxic activities were aims of the present work. For the synthesis of the compounds, 2-chloro-6,7-dimethoxyquinazolin-4-amine was used as the initial starting material. The intermediate product, 2-hydrazinyl-6,7- dimethoxyquinazolin-4-amine, was reacted with appropriate aromatic aldehydes to obtain 2-(2-benzylidenehydrazinyl)-6,7-dimethoxyquinazolin-4-amine derivatives as final compounds. The structures of the compounds were elucidated by (1)H- and (13)C-NMR, IR, and-MS analyses. The new pure compounds were evaluated for their potential antimicrobial and cytotoxic activities using in vitro microdilution and cell culture techniques, respectively. The compounds 2e and 2f may be promising candidates for the treatment of fungal infections with their activity and cytotoxicity.

Synthesis and evaluation of new 1,5-diaryl-3-[4-(methyl-sulfonyl)phenyl]-4,5-dihydro-1H-pyrazole derivatives as potential antidepressant agents.

In an effort to develop potent antidepressant agents, new pyrazoline derivatives 2a-s were synthesized and evaluated for their antidepressant-like activity by tail suspension test (TST) and modified forced swimming test (MFST). The effects of the compounds on spontaneous locomotor activity were also investigated using an activity cage apparatus. Among these derivatives, compounds 2b, 2d, 2f, 2o, and 2r decreased both horizontal and vertical activity number of the mice. On the other hand, compounds 2a, 2h, 2j, 2k, 2l, 2m, and 2n, which did not induce any significant change in the locomotor activity, significantly shortened the immobility time of mice in TST and MFST, representing the presence of the antidepressant-like effect. Additionally, the same compounds increased the swimming time of mice in MFST without any change in climbing duration, similar to the reference drug fluoxetine (10 mg/kg). In the light of previous papers examining the effects of pyrazolines on central nervous system, this study, once more, pointed out remarkable antidepressant activity potential of pyrazoline derivatives.

Synthesis and evaluation of new indole-based chalcones as potential antiinflammatory agents.

In the present work, new indole-based chalcone derivatives were obtained via the reaction of 5-substituted-1H-indole-3-carboxaldehydes/1-methylindole-3-carboxaldehyde with appropriate acetophenones. The synthesized compounds were investigated for their in vitro COX-1 and COX-2 inhibitory activity. The most effective COX inhibitors were also evaluated for their in vivo antiinflammatory and antioxidant activities in LPS induced sepsis model. Furthermore, the CCK-8 assay was carried out to determine cytotoxic effects of all compounds against NIH/3T3 mouse embryonic fibroblast cells. 3-(5-Bromo-1H-indol-3-yl)-1-(4-cyanophenyl)prop-2-en-1-one (6) can be considered as a non-selective COX inhibitor (COX-1 IC50 = 8.1 ± 0.2 µg/mL, COX-2 IC50 = 9.5 ± 0.8 µg/mL), whereas 3-(5-methoxy-1H-indol-3-yl)-1-(4-(methylsulfonyl)phenyl)prop-2-en-1-one (1) inhibited only COX-1 (IC50 = 8.6 ± 0.1 µg/mL). According to in vivo studies, these compounds also displayed antiinflammatory and antioxidant activities.

Synthesis and biological evaluation of some thiazole derivatives as new cholinesterase inhibitors.

In the present study, some thiazole derivatives were synthesized via the ring closure reaction of 1-[2-(2-oxobenzo[d]thiazol-3(2H)-yl)acetyl]thiosemicarbazide with various phenacyl bromides. The chemical structures of the compounds were elucidated by (1)H NMR, (13)C NMR and mass spectral data and elemental analyses. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellman's spectrophotometric method. The compounds were also investigated for their cytotoxic properties using MTT assay. The most potent AChE inhibitor was found as compound 4e (IC(50) = 25.5 ± 2.12 µg/mL) followed by compounds 4i (IC(50) = 38.50 ± 2.12 µg/mL), 4c (IC(50) = 58.42 ± 3.14 µg/mL) and 4g (IC(50) = 68 ± 2.12 µg/mL) when compared with eserine (IC(50) = 0.025 ± 0.01 µg/mL). Effective compounds on AChE exhibited weak inhibition on BuChE (IC(50) > 80 µg/mL). MTT assay indicated that the cytotoxic dose (IC(50) = 71.67 ± 7.63 µg/mL) of compound 4e was higher than its effective dose.

Synthesis and antinociceptive activities of some pyrazoline derivatives.

In the present study, some pyrazoline derivatives were synthesized to investigate their potential antinociceptive activities. 1-[(Benzoxazole/benzimidazole-2-yl)thioacetyl]pyrazoline derivatives were obtained by reacting 3,5-diaryl-1-(2-chloroacetyl)pyrazolines with 2-marcaptobenzoxazole/benzimidazole. The chemical structures of the compounds were elucidated by IR, (1)H NMR and FAB(+)-MS spectral data and Elemental Analyses. All of the compounds (100 mg/kg) exhibited significant antinociceptive activities in both hot plate and acetic acid-induced writhing tests. Naloxone (5 mg/kg) pre-treatment reversed the antinociceptive activities suggesting the involvement of opioid system in the analgesic actions. None of the compounds impaired motor coordination of animals when assessed in the Rota-Rod model. These results support the previous papers reporting the opioid sensitive antinociceptive activities of various benzoxazole/benzimidazole-pyrazoline derivative compounds.

Synthesis of some 4-arylidenamino-4H-1,2,4-triazole-3-thiols and their antituberculosis activity.

The increasing clinical importance of drug-resistant mycobacterial pathogens has lent additional urgency to microbiological research and new antimycobacterial compound development. For this purpose, new triazoles were synthesized and evaluated for antituberculosis activity. A series of 4-arylidenamino-4H-1,2,4-triazole-3-thiol derivatives (2a-n) were synthesized from the treatment of 4-amino-4H-1,2,4-triazoles-3-thiol (1) with the respective aldehydes and were evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv (ATCC 27294), using the BACTEC 460 radiometric system and BACTEC 12B medium. Compound 2k showed an intereting activity at 6.25 microg/mL with a 87 percentage inhibition.