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Pyrazoles are one of the important classes of biologically active compounds.In particular, they are used as antitumor, antibacterial, anti-fungal, anti-parasitic, anti-tubercular and insecticidal agents. 1,2 Some of these compounds also have antiinflammatory, anti-diabetic, anaesthetic and analgesic properties. 3 The synthesis of some of these 3,5-disubstitituted-4,5-dihydro-1H-pyrazoles has already been reported by the condensation of α,β-unsaturated ketones with hydrazine and methyl hydrazine. 4 The investigated compound (Fig. 1), m.p. 173˚C, was characterized by spectral data (IR,UV, NMR, MS) as 3-(2′-hydroxy-5′-methoxy-phenyl)-5-(3-methoxy-4-hydroxyphenyl)-4,5-dihydro-1H-pyrazole. To further confirm the attachment of positions of the hydroxy and methoxy groups on the phenyl rings and to obtain more detailed structural information on the conformation of the molecule in the crystalline state, an X-ray structure determination was carried out; the results are presented here.Crystals suitable for diffraction were prepared by recrystallization from ethanol. All of the hydrogen atoms were found from difference Fourier maps and were refined with isotropic temperature factors.The bond lengths and bond angles of the title compound are comparable to those found in other pyrazole derivatives. It has been reported that the N-N bond length in the pyrazoline ring varies over a wide range, from 1.234 (8)

Benzopyran derivatives R 0350 Intramolecular Low-Temperature 1,3-Dipolar Cycloadditions of Nitrones: Synthesis of Chromano-Heterocycles. -The cycloaddition reaction of formyl chromones (I) with N-methyl hydroxylamine in methylene chloride at ice-cold temperature allows the preparation of the desired fused isoxazolidines (III) as major products. -(SINGH, G.; ISHAR*, M. P. S.; GUPTA, V.; SINGH, G.; KALYAN, M.; BHELLA, S. S.; Tetrahedron 63 (2007) 22, 4773-4778; Dep. Pharm. Sci., Guru Nanak Dev Univ., Amritsar 143 005, India; Eng.) -Klein 37-135