title: Crystal structures of (5RS)-(Z)-4-[5-(furan-2-yl)-3-phenyl-4,5-di-hydro-1H-pyrazol-1-yl]-4-oxobut-2-enoic acid and (5RS)-(Z)-4-[5-(furan-2-yl)-3-(thio-phen-2-yl)-4,5-di-hydro-1H-pyrazol-1-yl]-4-oxobut-2-enoic acid.
abstract: The title compounds, C17H14N2O4(I) and C15H12N2O4S (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 planarZconformation [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.
authors.affiliation: Organic Chemistry Department, Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklay St., Moscow 117198, Russian Federation.
authors.forename: Kseniya K
authors.initials: KK
authors.lastname: Borisova
authors.affiliation: Department of Chemistry, Faculty of Sciences, University of Douala, PO Box 24157, Douala, Republic of , Cameroon.
authors.forename: Flavien A A
authors.initials: FA
authors.lastname: Toze
authors.affiliation: Organic Chemistry Department, Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklay St., Moscow 117198, Russian Federation.
authors.forename: Nniyaz Z
authors.initials: NZ
authors.lastname: Yagafarov
authors.affiliation: Organic Chemistry Department, Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklay St., Moscow 117198, Russian Federation.
authors.forename: Fedor I
authors.initials: FI
authors.lastname: Zubkov
authors.affiliation: National Research Centre "Kurchatov Institute", 1 Acad. Kurchatov Sq., Moscow 123182, Russian Federation.
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Dorovatovskii
authors.affiliation: National Research Centre "Kurchatov Institute", 1 Acad. Kurchatov Sq., Moscow 123182, Russian Federation.
authors.forename: Yan V
authors.initials: YV
authors.lastname: Zubavichus
authors.affiliation: Inorganic Chemistry Department, Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklay St., Moscow 117198, Russian Federation; X-Ray Structural Centre, A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., B-334, Moscow 119991, Russian Federation.
authors.forename: Victor N
authors.initials: VN
authors.lastname: Khrustalev
keywords: crystal structure; furan; intra­molecular Diels–Alder reaction; thio­phene