Abstract
Some aryl-aryl 1H pyrazoles have been synthesised by cyclization of aryl chalcones and hydrazine hydrate in the presence of SOCl2. The yields of the pyrazoles are more than 85%. These pyrazoles are characterized by their physical constants and spectral data. The infrared, NMR spectral group frequencies of these pyrazolines have been correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses the effects of substituent on the spectral frequencies have been studied. The antimicrobial activities of all synthesised pyrazolines have been studied using Bauer-Kirby method. KEY WORDS: SOCl2, 1H Pyrazolines, IR spectra, NMR spectra, Hammett substituent constants, Antimicrobial activities Bull. Chem. Soc. Ethiop. 2014, 28(2), 271-288. DOI: http://dx.doi.org/10.4314/bcse.v28i2.11
Highlights
The prominent nitrogen containing five membered heterocyclic compounds, such as pyrazolines are extensive important synthons [1] in the synthetic organic chemistry and drug designing
Five new 1,3,5-triphenyl-2-pyrazolines have been synthesized by reacting 1,3-diphenyl-2-propene-1-one with phenyl hydrazine hydrochloride and another five new 3-(2"-hydroxy naphthalen-1"-yl)-1,5-diphenyl-2-pyrazoline have been synthesized by reacting 1-(2'-hydroxylnaphthyl)-3-phenyl-2-propene-1-one with phenyl hydrazine hydrochloride [21]
Some new 1,3,5-triphenyl-2-pyrazolines have been synthesized by reacting 1,3-diphenyl-2-propene-1-one with phenyl hydrazine hydrochloride and another five new 3-(2"-hydroxy naphthalen-1"-yl)-1,5-diphenyl-2-pyrazoline have been synthesized by reacting 1-(2'-hydroxylnaphthyl)-3-phenyl-2-propene-1-one with phenyl hydrazine hydrochloride [22]
Summary
The prominent nitrogen containing five membered heterocyclic compounds, such as pyrazolines are extensive important synthons [1] in the synthetic organic chemistry and drug designing. Pyrazoline refers to both the classes of simple aromatic ring organic compounds of the heterocyclic series characterized by a five membered ring structure composed of three carbon atoms and two nitrogen atoms in adjacent positions, and the unsubstitued parent compound These pyrazolines have played an important role in the development of theoretical heterocyclic chemistry and organic synthesis. The reaction of hydrazine and its derivatives with α,β-unsaturated ketones and α,β-epoxy ketones is one of the preparative methods for the synthesis of pyrazolines and pyrazoles derivatives [15]. The effect of substituents on the group frequencies have been studied, through UV-Vis, IR, 1H and 13C NMR spectra of ketones [23], unsaturated ketones [24,25,26,27,28], acyl bromides-esters [29] and naphthyl and 5-bromo-2-thienyl pyrazolines [30] by spectral analysts and organic chemists. 199-200 (199)[31] 218-219 (217)[31] 214-215 (212-214)[32] 184-185 (183-184)[32] 235-236 (234-236)[32] 215-215 (215)[31] 250-251 (248-250)[31] 245-246 (244-245)[31] 220-221 (217)[31] 231-232 (230-232)[31] 222-223 (220-222)[31] 237-238 (236-237)[32] 234-235 (233-234)[32] 184-185
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