Diastereoisomers of a prednisolone derivative

The crystal and molecular structures of two synthetic corticosteroid diastereoisomers were determined by X-ray diffraction methods. (22R)-21-acetoxy-16,17-furfurylidenedioxy-11-hydroxy-pregna-1,4-diene-3,20-dione, C₂₈H₃₂O₈, crystallized in the orthorhombic system, space group P2₁2₁2₁,a=6.346(1),b=14.106(2),c=27.901(3) Å, andZ=4. (22S)-21-acetoxy-16, 17-furfurylidenedioxy-11-hydroxy-5 pregna-1,4-diene-3,20-dione ethanolate, C₂₈H₃₂O₈ ·C₂H₅OH, crystallized in the monoclinic system, space group C2,a=20.382(5),b=8.331(1),c=17.346(4)Å, =103.43(2)°, andZ=4. A change of configuration at the C(22) chirality center has influence on the remote parts of the molecules. The long-range effects appear in the ability to form intermolecular hydrogen bonds by different atoms and consequently in the solvation of the (S) diastereoisomer.     

Synthesis and crystal structures of 5-amino-1-(2-hydroxyethyl)imidazole-4-carboxamide and 5-amino-1-(2-chloroethyl)-4-cyanoimidazole

Both 5-amino-1-(2-hydroxyethyl)imidazole-4-carboxamide (AHIC) and 5-amino-1-(2-chloroethyl)-4-cyanoimidazole (ACCI) have been synthesized and crystallized in the monoclinic space group P2₁/c, Z = 4, with a = 8.420(2), b = 9.759(2), c = 10.583(2) Å, = 111.80(2)° for AHIC and a = 6.139(1), b = 8.522(2), c = 15.156(3) Å, = 96.71(2)° for ACCI. Differences in the molecular geometries of the two compounds are attributed to the differences in the substituents at the 1- and 4-positions of the imidazole ring. The molecular conformation of AHIC is stabilized by intramolecular hydrogen bonding between the 5-amino and the vicinal carboxamide moiety, resulting in an extended planar structural pattern. The presence of the cyano group in the 4-position of ACCI prevents the formation of such an intramolecular hydrogen bond. Both the crystal structures are stabilized by networks of intermolecular hydrogen bonds.     

Crystal structure of a novel inner salt 4-guanidino-2-hydroxybenzoic acid

The guanidinium compound 4-guanidino-2-hydroxybenzoic acid, crystallizes in the orthorhombic space group Pbac with a = 8.090(2) Å, b = 12.470(3) Å, c = 16.430(3) Å, and Φ_calc = 1.564 Mg/m³ for Z = 8. The three-dimensional network is constructed through hydrogen bonds, electrostatic interactions and weak π–π stacking interaction among the guanidinium, carboxyl and hydroxy groups in the title compound.     

Supramolecular assembly in the chiral N-carbamoyl compound 2-ureido-pentanedioic acid

The compound 2-ureido-pentanedioic acid was synthesized and characterized by FT-IR and NMR spectra. Its molecular structure was solved by single crystal X-ray diffraction. In the title compound, C₆H₁₀N₂O₅, the chiral structure is stabilized by intermolecular O–H···O and N–H···O hydrogen bonds in a supramolecular assembly formed by infinite chains parallel to the bc plane with graph set C(4) connected by amide-acid dimers R²₂(8) into a three-dimensional network.     

Neutron diffraction structure of Y2V10O28·24H2O at 297 and 60 K

The structure of yttrium-decavanadate-24-hydrate, [Y₂V₁₀O₂₈·24H₂O], was determined by neutron diffraction at temperatures of 297 and 60 K. Space group P-1, triclinic, Z = 2; at 297 K : a = 9.36(1), b = 9.86(1), c = 23.53(3) Å, = 98.79(2), = 98.15(2), = 89.30(2), V = 2123(5); at 60 K : a = 9.19(3), b = 9.85(3), c = 23.31(12) Å, = 99.03(3), = 98.99(6), = 89.39(6)°, V = 2058(13). Final R factors of 10 and 9.4% were obtained using 1955 and 1100 observed structure factors at both temperatures, respectively. The position of the 24 water molecules was determined and the characteristics of the hydrogen bonds were analyzed at both temperatures.     

Synthesis and crystal structure of N-benzylmethy- lammonium pentachlorothallate (III), [C6H5CH2NH2CH3]2TlCl5

N-Benzylmethylammonium pentachlorothallate (III) salt crystallizes in the monoclinic system P2₁/c with the following unit cell dimensions: a = 10.9540 (8), b = 12.559(1), c = 18.099(2)Å, = 112.1(3)° and Z = 4. The examination of the structure shows an alternate stacking of inorganic layers of pentachlorothallate (III) anions and organic layers of [C₆H₅CH₂NH₂CH₃]⁺ cations parallel to the c axis. The cohesion forces of the packing of N-benzylmethylammonium units in the layer and between two adjacent layers are provided by hydrogen bonds (N—HsCl) and van der Waals contacts.     

Three‐Dimensional Structure Constructed via Hydrogen Bonds and π‐π Stacking Interaction. Crystal Structure of [Cu(AFO)2(H2O)2](ClO4)2.2(AFO).2H2O (AFO = 4,5‐Diazafluoren‐9‐one)

The structure of the title complexes [Cu(AFO)₂(H₂O)₂](ClO₄)₂.2(AFO).2H₂O (AFO = 4,5‐Diazafluoren‐9‐one)has been established by single‐crystal X‐ray diffraction. The complex crystallizes in the triclinic space group P‐1 with cell constants a = 7.659(3) Å, b = 11.066(3) Å, c = 14.203(5) Å, alpha = 75.16(3)°, β = 79.87(3)°, gamma = 85.71(3)°, Z = 1. The structure was solved by direct methods and refined to R₁ = 0.0595 (wR₂ = 0.1164). The X‐ray analysis reveals that a pair of AFO ligands chelate to a Cu(II) atom in an asymmetric fashion with one Cu‐N bond being much longer than the other, the Cu(II) atom is further coordinated by a pair of aqua ligands to form an elongated octahedral geometry. In the crystal of the complex, the mononuclear complex cations [Cu(AFO)₂(H₂O)₂]²⁺, uncoordinated AFO molecules, lattice water molecules and perchlorate anions are assembled into 3‐D structure via hydrogen bonds and π‐π stacking interaction.     

Structure and conformation of the monohydrate of N-t-boctyrosyl-proline (Boc-Tyr-Pro·H2O)

The structure and conformation of the monohydrate of N-t-boc-tyrosyl-proline (Boc-Tyr-Pro·H₂O) (C₁₉H₂₆O₆N₂·H₂O) has been investigated with X-ray crystallographic and spectroscopic methods. Boc-Tyr-Pro crystallized in an extendedtrans conformation in the space group P2₁2₁2₁ with cell dimensionsa=8.566(1),b=9.996(1),c=24.734(1). The conformation of Boc-Tyr-Pro reflex -helix type prolines. Three intermolecular hydrogen bonds are observed. Crystal water is involved in two hydrogen bonds (to the hydroxyl group of the C-terminal of the proline residue; to the carbonyl group of the t-Boc functionality) while the hydroxyl group of the tyrosyl residue (to the carbonyl group of the amide bond) is involved in one hydrogen bond. The puckering mode of the pyrrolidine ring of the proline residue is similar to what has been previously observed for other proline-containing peptides.Cis-trans isomerism is observed in the NMR spectra of Boc-Tyr-Pro with a predominance for the extended side chain for the tyrosyl residue.     

Crystal structure of terephthalaldehyde

Terephthalaldehyde forms monoclinic crystals, space group P2 ₁ /a, a = 12.698(6), b = 3.845(2), c = 14.764(3) Å, = 116.53(3)°, Z = 4, V = 645(1) ų, and Dx = 1.381(2) g cm^–3. There are two independent molecules, each located at a center of symmetry and approximately related to each other by pseudo-symmetry. In both molecules the rings are planar within experimental error. In one molecule the CHO groups are twisted out of the plane of the ring by 1.3(1)°, in the other by 0.6(1)°. Weak C–H···O hydrogen bonds occur at both independent aldehyde hydrogen atoms.     

Crystal structures of two substituted key intermediates of phenothiazine derivatives

The key intermediates, in the synthesis of phenothiazines, 5-hydroxy-5-methyl 3(phenyl) 2,4-N-dimethylcarbamoyl cyclohexanone, C₁₇H₂₂O₄N₂ (I), and 5-hydroxy-5-methyl 3(2-methylphenyl) 2,4-N-dimethylcarbamoyl cyclohexanone, C₁₈H₂₄O₄N₂ (II), contain essentially substituted cyclohexanone rings in chair conformation with approximately perpendicular oriented phenyl rings. The carbamoyl groups are aligned in opposite directions to facilitate the formation of intramolecular C–HO interaction and O–HO hydrogen bonding. The molecules are linked in helical fashion by an N–HO type intermolecular hydrogen bonding framework. Crystal data: [I], orthorhombic, space group Pbca, a = 9.278(1), b = 19.094(2), c = 19.802(2) Å, V = 3508.0(6) ų, Z = 8 and d = 1.206 Mg m^–3, R = 0.074 (wR = 0.137) for 208 parameters and 1190 observed reflections with I 2 (I); [II], monoclinic, space group P2₁/n, a = 10.523(1), b = 9.005(1), c = 19.771(2) Å, = 94.96(6)°, V = 1866.5(3) ų, Z = 4 and d = 1.183 Mg m^–3, R = 0.062 (wR = 0.131) for 217 parameters and 2276 observed reflections with I 2 (I).     

Heterocyclic tautomerism. XI. Structures of 5,5′-bitetrazole and 1-methyl-5-(2′-pyridyl)tetrazole at 130 K

The X-ray crystal structures of 5,5-bitetrazole and 1-methyl-5-(2-pyridyl)tetrazole at 130 K are described. 5,5-Bitetrazole exists as the 1 H, 1'H-tautomer and packs in chains held together by pairs of intermolecular hydrogen bonds. It crystallizes in the monoclinic space group P2₁/n witha=4.945(1),b=6.367(1),c=8.491(1) Å and =99.233(7)^o. In 1-methyl-5-(2-pyridyl)tetrazole the two heterocyclic rings are nearly coplanar and the molecular packing is controlled by intermolecular – interactions. It crystallizes in the triclinic space group P1 witha=6.667(1),b=7.135(1),c=9.202(1)Å, =89.59(1), =69.08(1), and =66.62(1)^o.     

Crystal structure of a 26-membered hexaaza macrocycle bearing hydroxyethyl pendants containing p-xylyl spacers

The new macrocyclic compound bearing hydroxyethyl pendant arms containing p-xylyl spacers, 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)-tricyclo[22,2,2,2^11,14] triaconta-1,11,13,24,27,29-hexaene, crystallizes in the monoclinic space group P2₁/c with a = 8.700(2) Å, b = 18.301(4) Å, c = 11.766(2) Å, = 108.57(2)°. The two hydroxyethyl pendants are at the opposite sides of the macrocyclic plane. Benzene rings in macrocycle are parallel and exist the - weak interaction with distance of 4.28 Å. The crystal packing of the macrocycle is stabilized by the hydrogen bonds.     

Syntheses,characterization and crystal structures of two structurally similar Schiff bases isonicotinic acid [1-(3-methoxy-2-hydroxyphenyl)methylidene]hydrazide and isonicotinic acid [1-(4-dimethylaminophenyl)methylidene]hydrazide monohydrate

The Schiff base compounds, isonicotinic acid [1-(3-methoxy-2-hydroxyphenyl) methylidene]hydrazide (C₁₄H₁₃N₃O₃, 1) and isonicotinic acid [1-(4-dimethylaminophenyl) methylidene]hydrazide monohydrate (C₁₅H₁₆N₄O·H₂O, 2) have been synthesized by the condensation of equimolar 3-methoxysalicylaldehyde or 4-dimethylaminobenzaldehyde with isonicotinic acid hydrazide in MeOH or EtOH. The compounds were characterized by elemental analysis, IR, ¹HNMR spectra, and single crystal X-ray diffractions. Compound 1 crystallizes in the monoclinic space group P-1 with unit cell dimensions a = 7.662(1) ?, b = 16.249(2) , c = 10.874(2) ?, β = 110.426(3)°, V = 1268.7(3) ′³, Z = 4, R ₁ = 0.0644, and wR ₂ = 0.1283. Compound 2 crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell dimensions a = 7.388(1) ?, b = 11.812(1) ?, c = 17.197(2) ?, V = 1500.7(2) ′³, Z = 4, R ₁ = 0.0585, and wR ₂ = 0.1143. X-ray structure determinations revealed that the molecules of both compounds display trans configurations with respect to the C=N double bonds. In the crystal structure of 1, molecules are linked through N–H···N intermolecular hydrogen bonds, forming layers parallel to the bc plane, while in the crystal structure of 2, molecules are linked through N–H···O, O–H···O, and O–H···N intermolecular hydrogen bonds, forming a network. Supplementary material CCDC-615072 and 620235 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge at http://www.ccdccam. ac.uk/const/retrieving.html or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223–336033 or e-mail: deposit@ccdc.cam.ac.uk.     

Synthesis, crystal structure, and spectroscopy of (azido-N1)bis(2,2′-bi-imidazoline)copper(II) perchlorate

The compound [Cu(biz)₂(N₃)](ClO₄) (biz = 2,2-bi-imidazoline) has been synthesized and characterized by X-ray crystallography and infrared spectroscopy. In addition, EPR and magnetic measurements have been performed. The compound crystallizes in the monoclinic space group P2₁/c, with a = 9.2716(2), b = 27.6454(4), c = 7.4285(1) Å, = 102.1417(6)°, V = 1861.46(5) ų, and Z = 4. The coordination geometry around the Cu(II) ion is distorted square pyrimidal, with 4 nitrogen atoms of 2 bis-chelating ligand molecules in the basal plane and one nitrogen of the azide molecule in the apical position. The perchlorate ion is noncoordinating. In the infrared the vibrations of the coordinated azide anion are observed at 2050, 1286, and 620 cm^–1, while the vibrations of the free perchlorate anion are observed at 1071, 1035, and 919 cm^–1; Cu—N vibrations are observed at 418 and 336 cm^–1. The molecules are connected in the lattice via relatively strong hydrogen bonding between the N—H groups at the back of the biz ligand and the N1 and N3 atoms of the azide ligand forming layers. No intermolecular magnetic interaction was observed for this compound.     

Synthesis and crystal structures of the bis-Schiff bases of 2-(methylthio)aniline with isophthaldehyde, terephthaldehyde, and para-diacetylbenzene

The crystal structures of the new compounds 1,3-bis(((2-methylthio)phenylimino)methyl)benzene (1), 1,4-bis(((2-methylthio)phenylimino)methyl)benzene (2), and 1,4-bis(1-((2-methylthio)phenylimino)ethyl)benzene (3) were obtained by single crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pna2₁ with a=16.8250(13) ?, b=18.1068(13) ?, c=6.3086(5) ?; and Z=4. Compound 2 crystallizes in the triclinic space group with a=6.7532(7) ?, b=9.4433(9) ?, c=15.2473(15) ?; and α=86.339(2)°, β=80.609(2)°, γ=80.962(2)°; and Z=2. Compound 3 crystallizes in the triclinic space group with a=6.787(3) ?, b=7.517(3) ?, c=10.653(4) ?; and α=89.998(7)°, β=72.341(7)°, γ=75.998(7)°; and Z=1. Details of the synthesis, structures, and spectroscopic results are discussed.     

The crystal and molecular structures of rac-threo-ifenprodil and two other 4-benzylpiperidinyl derivatives

The crystal structures of threo-ifenprodil [threo-2-(4-benzyl-piperidin-1-yl)-1-(4-hydroxyphenyl)-propan-1-ol] (1), potent NMDA receptor antagonist, and two related, biologically active compounds: threo-2-(4-benzyl-piperidin-1-yl)-1-(4-fluorophenyl)-propan-1-ol (2) and 4-benzyl-1-phenethyl-piperidinium chloride (3) have been determined by X-ray structure analysis of single crystals. Compound 1 crystallizes in an orthorhombic system, with a space group Pna2₁ (a = 34.843(3) Å, b = 6.0261(13) Å, c = 8.9343(9) Å), compound 2 – in a monoclinic space group P2₁/c (a = 14.194(1) Å, b = 6.2831(6) Å, c = 20.948(1) Å, = 101.762(6)), and compound 3 – in an orthorhombic space group Pbca (a = 10.4627(8) Å, b = 11.2166(6) Å, c = 31.669(2) Å). The piperidine rings are close to ideal chair conformations, the substituents are in equatorial positions. Overall shapes of the molecules, defined by the dihedral angles between the terminal aromatic rings, are very similar in all three cases. In 1 and 3 the crystal packing is mainly determined by the hydrogen bonds, while in case of 2 – by weak van der Waals interactions. The molecules of 1 and 3 are disordered, and the disorder is caused by a rotation around the N–C bond.     

Synthesis and X-ray crystallographic analysis of 17α-hydroxy-17-methylandrost-4-ene-17-one

17α-Hydroxy-17-methylandrost-4-ene-17-one is a complex of two steroid molecules with water and its crystal structure has been determined by X-ray crystallographic techniques. The transparent plate-like crystals of this compound crystallized in the orthorhombic space group P2₁2₁2₁, with unit cell parameters: a = 6.382(2), b = 12.841(5), c = 43.350(2) ?, λ(Mo Kα) = 0.71073 ?, Z = 8. The structure has been solved by direct methods and refined to R = 0.047, wR = 0.086. There are two crystallographically independent molecules, I and II, in the asymmetric unit. In both the molecules, rings A and D adopt a distorted half-chair conformation while rings B and C exist in chair conformation. The crystal structure is stabilized by intermolecular O−H⋯O and C−H⋯O hydrogen bonds.     

Very strong hydrogen bonds in hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids: L·HClO4·H2O and L·HNO3·H2O [L=cis-(p-Me2N+C5H4N)2C2(COO−)2]

The hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids, L·HClO₄·H₂O I and L·HNO₃·N₂O2 [L=cis-(p-Me₂N⁺C₅H₄N)₂C₂(COO^–)₂], have been shown to be nearly isostructural by X-ray crystallography and infrared spectroscopy. The common cationic unit HL⁺ of both compounds exhibits significant semi-quinonoid character and possesses symmetrym, ist two coplanar carboxylate groups being linked by a very strong, nearly linear intramolecular O–H–O hydrogen bond [O...O 2.397(9)Å and O–H–O 167.1° for1; 2.388(7)Å and 167.4° for2]. The HL⁺ units are further connected by intermolecular O–H...O hydrogen bonds between the exocyclic carboxyl oxygen atoms and the water molecules to generate polymeric zigzag chains running parallel to thec axis, and the disordered ClO₄ or NO ₃ ^– anions occupy channels running parallel to thea axis in the resulting host lattice.     

Ether cleavage of [2.2.2]cryptand: synthesis and X-ray crystal structure of [NH(CH2CH2I)3][I5]

Treatment of [2.2.2]cryptand1 in toluene with HI(g) has resulted in the formation of a twophase liquid clathrate solution from which the complex [NH(CH₂CH₂I)₃][I₅]2 has been isolated and crystallographically characterized. Crystal data for2: triclinic, space group $P\bar 1$ ,a=9.301(3) Å,b=10.419(3) Å,c=11.078(3) Å, α=90.20(2)^o, β=103.28(2)^o γ=96.50(2)^o,D _c =3.57g/cm³,Z=2,R _f =0.054,R _w =0.054. The salt is a product of an ether cleavage of the macrobicycle. The crystal structure of2 contains [NH(CH₂CH₂I)₃]⁺ ions and zigzag chains of [I₅]^? ions which self-assemble to form alternating layers, of cations and anions.