Pyrazole derivatives were used for all kinds of biological celerity like used for a core structure in a large of compounds that possess important pharmacological agents such as a potent anti-inflammatory, anti-obesity drug rimonabant, antitumor and analgesic. Various bis-pyrazole derivatives were introduced a great contribution not only in the synthetic chemistry but also used in the healthful chemistry field. In this review, we reported the different methods have been used for synthesis of pyrazole derivatives with some of them being used in the biological field.

A new series of 2,5-disubstituted-1,3,4-thiadiazole derivatives (1-8) was synthesized from the 5-(4-Chloro-phenyl)-[1,3,4]thiadiazol-2-ylamine. The reaction of the starting material with isocyanate and isothiocyanate derivatives afforded 1,3,4-thiadiazole containing urea and thiourea derivatives (1-3), respectively. Reaction of 1,3,4-thiadiazole with p-nitrobenzaldehyde produced new Schiff base 4. It cyclized thiazolidin-4-one (5) and azetidin-2-one (6) derivatives by the action of thioglycolic acid and chloroacetyl chloride. Compound 7 was synthesized by a reaction of 1,3,4-Thiadiazole with chloroacetyl chloride. Cyclization of compound 7 with ammonium thiocyanate produced compound 8. The Synthesized derivatives were characterized using spectral analysis. All the derivatives were In vitro screened against Escherichia coli, Klebsiella SPP (gram negative), Staphylococcus aureus, Streptococcus SPP (gram positive) and also Candida albicans and showed moderate to effective inhibition activity.

A novel derivative of 3,5-disubstituted-2-isoxazolines (3-11) have been synthesized and characterized by spectral analysis. All the synthesized derivatives were screened qualitatively for their antioxidant property using TLC technique and the percent DPPH radical scavenging activity of the potent derivatives (5, 11) were evaluated. The 2-pyrazolines (3-11) were in vitro screened against different bacterial strains as well as candida albicans and found exhibiting moderate to potent activity. Docking study of 2-isoxazoline derivative 11 against glucosamine-6-phosphate synthase, the target enzyme for the antimicrobial agents, was explored to study the interactions of the discovered hit (11) within the binding pocket residues of the enzyme.

The standard heat of formation (ΔHof) and binding energy (ΔEb) for the free compound and their derivatives are calculated by using the PM3 method at 273K of Hyperchem.-8.07 program. The compound is more stable than their derivatives. furthermore to investigate the reactive site of the molecules the electrostatic potential of free derivatives is measured and pm3 is used to evaluate the vibrational spectra of the free derivatives, the frequencies are obtained approximately agreed with those values experimentally found; in addition, the calculation helps to assign clearly the most diagnostic bands .