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Synthesis and Crystal Structures of N-Substituted Pyrazolines
Crystallography Unit, School of Physics, Universiti Sains Malaysia, Penang 11800 USM, Malaysia
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
Department of Studies in Chemistry, Mangalore University, Mangalagangotri-574 199, India
Department of Chemistry, P.A. College of Engineering, Nadupadavu, Mangalore-574 153, India
* Author to whom correspondence should be addressed.
Received: 12 December 2012; in revised form: 2 February 2013 / Accepted: 7 February 2013 / Published: 20 February 2013
Abstract: Four pyrazole compounds, 3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde (1), 5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-carbaldehyde (2), 1-[5-(4-chlorophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone (3) and 1-[3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]propan-1-one (4), have been prepared by condensing chalcones with hydrazine hydrate in the presence of aliphatic acids, namely formic acid, acetic acid and propionic acid. The structures were characterized by X-ray single crystal structure determination. The dihedral angles formed between the pyrazole and the fluoro-substituted rings are 4.64(7)° in 1, 5.3(4)° in 2 and 4.89(6)° in 3. In 4, the corresponding angles for molecules A and molecules B are 10.53(10)° and 9.78(10)°, respectively.
Keywords: synthesis; X-ray diffraction; pyrazole; crystal structure
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Loh, W.-S.; Quah, C.K.; Chia, T.S.; Fun, H.-K.; Sapnakumari, M.; Narayana, B.; Sarojini, B.K. Synthesis and Crystal Structures of N-Substituted Pyrazolines. Molecules 2013, 18, 2386-2396.
Loh W-S, Quah CK, Chia TS, Fun H-K, Sapnakumari M, Narayana B, Sarojini BK. Synthesis and Crystal Structures of N-Substituted Pyrazolines. Molecules. 2013; 18(2):2386-2396.
Loh, Wan-Sin; Quah, Ching K.; Chia, Tze S.; Fun, Hoong-Kun; Sapnakumari, Majal; Narayana, Badiadka; Sarojini, Balladka K. 2013. "Synthesis and Crystal Structures of N-Substituted Pyrazolines." Molecules 18, no. 2: 2386-2396.