Crystal structures of (5 RS )-( Z )-4-[5-(furan-2-yl)-3-phenyl-4,5-di-hydro-1 H -pyrazol-1-yl]-4-oxobut-2-enoic acid and (5 RS )-( Z )-4-[5-(furan-2-yl)-3-(thio-phen-2-yl)-4,5-di-hydro-1 H -pyrazol-1-yl]-4-oxobut-2-enoic acid

• Published in: Acta crystallographica. Section E, Crystallographic communications Crystallographic communications, 2016-11, Vol.72 (Pt 11), p.1557-1561
• Main Authors: Borisova, Kseniya K, Toze, Flavien A A, Yagafarov, Nniyaz Z, Zubkov, Fedor I, Dorovatovskii, Pavel V, Zubavichus, Yan V, Khrustalev, Victor N
• Format: Article
• Language: English
• Subjects: crystal structure; furan; intramolecular Diels–Alder reaction; Research Communications; thiophene
• ISSN: 2056-9890; 2056-9890
• DOI: 10.1107/S2056989016013992

The title compounds, C H N O (I) and C H N O S (II), possess very similar mol-ecular geometries. In both mol-ecules, the central 1,3,5-tris-ubstituted di-hydro-pyrazole ring adopts an envelope conformation. The oxobutenoic acid fragment has an almost planar conformation [r.m.s. deviations of 0.049 and 0.022 Å, respectively, for (I) and (II)] which is determined by the both bond conjugation and the strong intra-molecular O-H⋯O hydrogen bond. The substituents in positions 1 and 3 of the di-hydro-pyrazole ring [oxobutenoic acid and phenyl in (I) and oxobutenoic acid and thienyl in (II)] are nearly coplanar with its basal plane [the corresponding dihedral angles are 6.14 (9) and 2.22 (11)° in (I) and 6.27 (12) and 3.91 (11)° in (II)]. The furyl ring plane is twisted relative to the basal plane of the di-hydro-pyrazole ring by 85.51 (8) and 88.30 (7)° in (I) and (II), respectively. In the crystal of (I), mol-ecules form zigzag hydrogen-bonded chains along [001] by C-H⋯O hydrogen bonds, which are further packed in stacks along [100]. Unlike (I), the crystal of (II) contains centrosymmetric hydrogen-bonded dimers formed by pairs of C-H⋯S hydrogen bonds, which are further linked by weak C-H⋯O hydrogen bonds into a three-dimensional framework.