In the title fluorinated pyrrolidine derivative, C₁₀H₁₀F₄N₂, the dihedral angle between the best planes of the benzene and pyrrolidine rings is 62.6 (1)°. The crystal packing features inter­molecular N—HF hydrogen bonds.

The title compound, C₁₆H₁₇O₅P, was obtained by the reaction of benzoyl chloride and dimethyl (hydroxy­phenyl­meth­yl)­phos­phon­ate. The mol­ecular packing is stabilized by van der Waals forces.

The title compound, C₉H₁₃O₄P, has been obtained by the reaction of dimethyl phosphite and benzaldehyde. In the crystal structure, inter­molecular O—HO hydrogen bonds link the mol­ecules into infinite chains.

The title compound, C₁₉H₁₇O₄P, was obtained as colorless block-shaped crystals by the reaction of diphenyl phosphite and benzaldehyde. The crystal structure is stabilized by strong inter­molecular O—HO hydrogen bonds.

The title compound, C₂₀H₂₂ClNO₃, was synthesized by the reaction of 3-chloro­benzaldehyde, 5,5-dimeth­yl-1,3-cyclo­hexane­dione and meth­yl 2-amino­crotonate in an ionic liquid medium. The X-ray analysis reveals that the nitro­gen-containing ring adopts a boat conformation and the cyclo­hexene ring has a half-chair conformation. Inter­molecular N—HO bonds in the structure lead to the formation of chains.

The title compound, C₁₆H₁₆N₂O₃, was synthesized by the reaction of phenyl­methyl­idene­malono­nitrile and ethyl aceto­acetate in the presence of triethyl­benzyl­ammonium chloride in an aqueous medium. The pyran ring adopts a boat conformation. The phenyl ring and the basal plane of the pyran ring make a dihedral angle of 94.5 (2)°. Intermolecular N—HO and N—HN hydrogen bonds link the mol­ecules into ribbons along the a axis.

The title complex, [Pr₂(C₄H₂O₄)₃(C₄H₄O₄)(H₂O)₂]_n, was synthesized by reaction of praseodymium(III) nitrate hexa­hydrate with fumaric acid in a water–ethanol (4:1) solution. The asymmetric unit comprises a Pr³⁺ cation, one and a half fumarate dianions (L²⁻), one half-mol­ecule of fumaric acid (H₂L) and one coordinated water mol­ecule. The carboxyl­ate groups of the fumarate dianion and fumaric acid exhibit different coordination modes. In one fumarate dianion, two carboxyl­ate groups are chelating with two Pr³⁺ cations, and the other two O atoms each coordinate a Pr³⁺ cation. Each O atom of the second fumarate dianion binds to a different Pr³⁺ cation. The fumaric acid employs one O atom at each end to bridge two Pr³⁺ cations. The Pr³⁺ cation is coordinated in a distorted tricapped trigonal–prismatic environment by eight O atoms of fumarate dianion or fumaric acid ligands and one water O atom. The PrO₉ coordination polyhedra are edge-shared through one carboxyl­ate O atom and two carboxyl­ate groups, generating infinite praseodymium–oxygen chains, which are further connected by the ligands into a three-dimensional framework. The crystal structure is stabilized by O—HO hydrogen-bond inter­actions between the coordin­ated water mol­ecule and the carboxyl­ate O atoms.

The title compound, C₂₀H₁₇NO₅, was prepared by the reaction of 3-acetyl-2-oxo-2H-chromen-7-yl acetate with benzyl­oxy­amine. The mol­ecule adopts an E configuration with respect to the C=N double bond. The dihedral angles between the coumarin ring system, the phenyl ring and the C=N—O—C plane of the oxime unit are 35.83 (6), 35.8 (2) and 69.99 (15)°, respectively. In the crystal, a two-dimensional supra­molecular network is assembled through weak inter­molecular C—HO hydrogen-bonding inter­actions.

The asymmetric unit of the title compound, C₁₄H₁₂F₈N₂, contains one tetra­fluoro­pyrrolidine system and one half-mol­ecule of benzene; the latter, together with a second heterocyclic unit, are completed by symmetry, with a twofold crystallographic axis crossing through both the middle of the bond between the C atoms bearing the heterocyclic rings and the opposite C—C bonds of the whole benzene mol­ecule. The pyrrolidine ring shows an envelope conformation with the apex at the N atom. The dihedral angle between the least-squares plane of this ring and the benzene ring is 36.9 (5)°. There are intra­molecular C—HN inter­actions generating S(6) ring motifs. In the crystal structure, the mol­ecules are linked by C—HF inter­actions, forming chains parallel to [010].

The structure of the title compound, C₁₃H₁₀O₄, which was synthesized by the reaction of salicylaldehyde and 4-hydr­oxy-6-meth­yl-2H-pyran-2-one in the presence of triethyl­benzyl­ammonium chloride in aqueous media, was previously determined at room temperature [March, Moreno-Manas, Roca, Germain, Piniella & Dideberg (1986). J. Heterocycl. Chem. 23, 1511–1153]. As in the present determination, the X-ray analysis revealed that the title compound is in the enol form, which was confirmed by ¹H NMR data. Weak inter­molecular C—HO inter­actions connect mol­ecules into a two-dimensional framework.

The title compound, C₁₉H₁₂N₃O₂·C₃H₇NO, was synthesized by the reaction of 1-(4-chloro­phen­yl)-3-phenyl­prop-2-en-1-one and 6-amino­uracil in the presence of KF–alumina in ethyl alcohol; its crystal structure was determined at low temperature [193 (2) K]. The crystal structure is stabilized by N—HO, C—HO and C—HCl hydrogen bonds.

The title compound, C₂₀H₁₅N₃O₆·C₃H₇NO, was synthesized by the reaction of methyl 2-cyano-3-(3-nitro­phenyl)­acryl­ate and 4-hydroxy­quinolin-2-one in ethanol, catalysed by KF-alumina. X-ray analysis reveals that the pyran ring adopts a boat conformation.

The title compound, C₂₀H₁₅N₃O₆·C₃H₇NO, was synthesized by the reaction of methyl cyano­acetate, 4-nitro­benz­aldehyde and 4-hydroxy­quinolin-2-one in EtOH catalysed by KF-alumina, followed by crystallization from dimethylformamide. X-ray analysis reveals that the pyran ring adopts a boat conform­ation.

The title compound, C₂₄H₂₅N₃O₅, was synthesized by the reaction of methyl 2-cyano-3-(4-methyl­phenyl)-1-acryl­ate and 4-hydroxy­quinolin-2-one in the presence of triethyl­benzyl­ammonium chloride in aqueous media. X-ray analysis reveals that the pyran ring adopts a boat conformation.