Structures of aminopyrazole derivatives

1-[(2RS,3RS)-4-Acetyl-2-hydroxy-3-(5-methoxy-4-methyl-3-phenylpyrazol-1-ylamino)-2,5-dimethyl-2,3-dihydrofuran-3-yl]ethanone

“…Atom N1 is pyramidal with the lone pair antiperiplanar with the N2ÐN3 bond [torsion angles N3ÐN2ÐN1ÐH1 À70.5 (3) and N3Ð N2ÐN1ÐC2 58.5 (3) ]. This con®rms a feature already observed for N-amino-pyrazole (Jimenez et al, 1999) and some simple derivatives (Yamaguchi et al, 1989).…”

“…The pyrazole ring is planar [maximum deviation from mean plane 0.010 (2) A Ê ], and the bond lengths and angles do not differ signi®catly from those of similar compounds (Yamaguchi et al, 1989). The mean plane of the pyrazole ring makes an angle of 40.0 (1) with the phenyl ring bonded at C13 and is perpendicular to the C21ÐO5 bond of the methoxy group at C11 [torsion angle C21ÐO5ÐC11ÐC12 91.4 (4) ].…”

The structure of N-aminopyrazole in the solid state and in solution: an experimental and computational study

“…Although NÈHÉ É ÉN interactions dominate the packing in many aminopyrazoles, it is worth noting that the hydrogen bonding pattern is inÑuenced by substituents in the ring. 25 The di †erent HB network between aniline and AMPZ is also apparent in their IR spectra (liquids between two disks of NaCl). peratures where experiments were performed a well resolved doublet is observed around 6.7 ppm for both protons of the amino group, characterized by a coupling constant of 1J(1HÈ15N) \ 71 Hz.4 When temperature is lowered the doublet is shifted downÐeld which strongly indicates that the amino group of AMPZ forms hydrogen bonds preferentially at low temperatures.…”