SYNTHESIS AND CHARACTERIZATION OF 1, 3, 5-(TRI-SUBSTITUTED)-2-PYRAZOLINES BEARING HOMOLOGOUS ALKOXY GROUPS AND STUDY OF THEIR BIOLOGICAL AND FLUORESCENCE PROPERTIES

Abstract

In the present research work the following one series of 4-alkoxybenzaldehyde, four series of 4-alkoxychalcones and six series of 1,3,5-trisubstituted-2-pyrazolines bearing homologous alkoxy groups and some other subsituents have been synthesized. Each series is comprised of twelve compounds due to the variation of the alkoxy group ranging from CH 3 to C 12 H 25 . As a result a total of one hundred and thirty two (132) compounds were prepared out of which 110 are new and are being reported here for the first time. 4-Alkoxybenzaldehydes A-Series 4-Alkoxybenzaldehydes 4-Alkoxychalcones B-Series (E)-1-Phenyl-3-(4-alkoxyphenyl)prop-2-en-1-ones C-Series (E)-1-(4-bromophenyl)-3-(4-alkoxyphenyl)prop-2-en-1-one D-Series (E)-1-(4-chlorophenyl)-3-(4-alkoxyphenyl)prop-2-en-1-one E-Series (E)-1-(4-fluorophenyl)-3-(4-alkoxyphenyl)prop-2-en-1-one 1,3,5-trisubstituted -2-Pyrazolines F-Series 1-Acetyl-3-phenyl-5-(4-alkoxyphenyl)-2-pyrazolines G-Series 1-Propionyl-3-phenyl-5-(4-alkoxyphenyl)-2-pyrazolines H-Series 1-(3, 4-Dimethylphenyl)-3-phenyl-5-(4-alkoxyphenyl)-2-pyrazolines I-Series 1-(3,4-Dimethylphenyl)-3-(4-bromophenyl)-5-(4-alkoxyphenyl)-2- pyrazolines J-Series 1-(3,4-Dimethylphenyl)-3-(4-chlorophenyl)-5-(4-alkoxyphenyl)-2- pyrazolines K-Series 1-(3,4-Dimethylphenyl)-3-(4-fluorophenyl)-5-(4-alkoxyphenyl)-2- pyrazolines All compounds were obtained in good yields and their purity was ascertained by thin layer (TLC) and gas chromatography (GC). The synthesized compounds were characterized by physical data, spectroscopic techniques, elemental analysis and single crystal x-ray crystallography. The synthesized 1,3,5-trisubstituted-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible VIspectrum when irradiated with ultra violet radiation. The fluorescence behavior of these compounds was studied by UV-Vis Spectroscopy and Emission Spectroscopy performed at room temperature. The synthesized compounds were also subjected to biological activity analysis such as antifungal, anti-inflammatory and cytotoxicity. Many of the lead compounds showed significant level of activity as compared to the standard drugs used as references. Some of the 1,3,5-trisubstituted-2-pyrazolines showed broad spectrum antifungal behavior against the tested fungi strains. In case of in vitro anti-inflammatory activity of 1,3,5-trisubstituted-2-pyrazolines high anti-inflammatory activity with IC 50 values comparable to the standard drug was observed. The brine shrimp lethality assay of the 4-Alkoxychalcones, especially that of some of the E-series compounds exhibited highest degree of cytotoxicity with LD 50 values much lower than the LD 50 values of the standard drug. All the synthesized 4-Alkoxychalcones and 1,3,5-trisubstituted-2-pyrazolines were devoid of any antibacterial activity.