The crystal structure of eudesma-4(15),7(11)-dien-8α, 12-olide: a sesquiterpene lactone fromTrattinickia rhoifolia Willd

The title compound, formula C₁₅H₂₀O₂, is orthorhombic, P2₁2₁2₁ witha=8.747(2),b=12.025(3),c=12.554(3)Å,Z=4, andD _m =1.32(2)g/ml. The structural analysis shows that the compound corresponds to eudesma-4(15),7(11)-dien-8,12-olide, a sesquiterpene lactone previously isolated fromAster umbellatus but whose crystal structure was unknown.     

Structures of 8α-(2′-methylbutyryloxy)-9α-hydroxymontahibisciolide,a new skeletal type of sesquiterpene lactone,and of its precursor 8α-isobutyryloxy-9-oxo-germacra-4E, 1(10)Z-dien-6β,12-olide

The structures of a new skeletal type of sesquiterpene lactone, containing a seven, five, fivering system, and of its putative precursor, a 9-oxo-melampolide, have been confirmed by single crystal X-ray structure determination. The central 5-membered ring of the new skeleton istrans-fused to the cycloheptene ring andcis-fused to the lactone ring. Transannular interactions and the geometry of thetrans carbon-carbon double bond of the oxo-melampolide and the keto-group at C9, suggest that the new seven, five, five tricyclic skeleton-type of montahibisciolide can easily be reached by a transannular cyclization process. The isobutyrloxy group of the oxo-melampolide is disordered into two partially populated conformations. 8-(2-Methylbutyryloxy)-9-hydroxymontahibisciolide,3, C₂₀H₂₈O₅, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=8.294(2),b=9.740(2),c=22.675(1) Å,V=1832(1)ų,Z=4. The structure was refined toR=0.043 andR _w=0.048 for 2898 observed reflections with CuK radiation. 8-isobutyryloxy-9-oxo-germacra-4E, 1(10)Z-dien-6, 12-olide,4, C₁₉H₂₄O₅, crystallizes in monoclinic space groupC2 witha=32.879(7),b=5.793(2),c=9.884(4)Å, =99.01(3)°,V=1859.5(9)å³,Z=4. The structure was refined toR=0.054 andR _w=0.064 for 1010 observed reflections with MoK radiation.     

Novel manganese(III) oxidation chemistry: X-ray crystal structures of (1α,2α,4β)-1,2-diacetoxy-4-(4-methoxyphenyl)-6-methoxy-1,2,3,4-tetrahydronaphthalene (compound A) and (1α,2α,4β)-1,2-diacetoxy-4-(2-methoxyphenyl)-8-methoxy-1,2,3,4-tetrahydronaphthalene (compound B)

CompoundA is (1,2,4)-1,2-diacetoxy-4-(4-methoxyphenyl)-6-methoxy-l,2,3,4-tetrahydronaphthalene, C₂₂H₂₄O₆,M _r=384.43, monoclinic, P2₁/n, witha=11.074(3),b=10.353(4),c=17.616(4)Å,=94.96(2)°,V=2012.1ų,D _calc=1.27 g cm^–3 and=0.55 cm^–1 forZ=4. Least-squares refinement of 1371 observed [F ₀5 (F ⁰)] reflections led to the final agreement index ofR=0.052. A twofold disorder was observed for the 1-acetoxy group whereas the 2-acetoxy group was ordered. CompoundB, (1,2,4)-1,2-diacetoxy-4-(2-methoxyphenyl)-8-methoxy-l,2,3,4-tetrahydronaphthalene, C₂₂H₂₄O₆,M _r=384.43, crystallizes in the monoclinic space group, P2₁/c, witha=16.209(2),b=10.076(1),c=13.357(4)Å,=111.41(2)°,V=2030.9ų,D _calc=1.26 g cm^–3 and=0.54 cm^–1 forZ=4. A final agreement index ofR=0.045 was realized by least-squares refinement of 1486 observed [F _o5 (F _o)] reflections. Intermolecular interactions in the cell lattices of compoundsA andB are noted. The title compoundsA andB were prepared by manganese(III) acetate oxidative dimerization of two molecules of 4-methoxystyrene and 2-methoxystyrene, respectively.     

Synthesis and Crystal Structure of Benzoyloxymethyl (4α,8β,13β)-13-methyl-16-oxo-17-norkauran-18-carbonate Ester

Abstract  Isosteviol derivative: benzoyloxymethyl (4α,8β,13β)-13-methyl-16-oxo-17-norkauran-18-carbonate ester was synthesized by esterification of isosteviol with chloromethyl benzoate and its crystal structure was determined by X-ray diffraction method. The compound crystallizes in the triclinic space group P1 with unit cell parameters: a = 8.784(3) ?, b = 9.079(3) ?, c = 15.950(6) ?, α = 79.343(6)°, β = 79.061(5)°, γ = 89.849(5)°, Z= 2. The conformation of rings A and B is chair, whereas the conformation of ring C is unsymmetrical twist chair. The carbonyl group at the C20 is coplanar with the benzene ring. The fragment of the ester group occupying the pseudoaxial site of C1 position adopts a zigzag conformation. Index Abstract  Isosteviol derivative: benzoyloxymethyl (4α,8β,13β)-13-methyl-16-oxo-17-norkauran -18-carbonate ester was synthesized and its crystal structure was determined by X-ray diffraction method.      

Crystal structure of a (25R)-2α,3α-epoxy-5α-spirostan-6, 23-dione hemi-ethyl acetate solvate

The compound (25R)-2,3-epoxy-5-spirostan-6,23-dione, crystallizes as a hemi-ethyl acetate solvate, having two host molecules of similar conformation per molecule of ethyl acetate, in the asymmetric unit. The O atom of the epoxy group is -oriented. The presence of the epoxy group disturbs the chair conformation in the ring A of the steroidal nucleus. Ring A has a C5,C10 half-chair conformation. The six-membered rings B, C, and F have chair conformation as expected. The D ring adopts a C14-envelope conformation and the E ring is midway between a C22,O3 half-chair and a C22-envelope conformations. The A/B, B/C, and C/D ring junctions are trans. Crystal data: C₂₇H₃₈O₅·1/2C₄H₈O₂, Monoclinic, space group P2₁, a = 7.7363(18) b = 28.769(12) c = 12.038(6) Å, = 90.88(5), V = 2679.0(10) ų, Z = 4. The packing of the molecules is assumed to be dictated by van der Waals interactions and by intermolecular C—H ··· O hydrogen bonds.     

The Synthesis and Crystal Structure of (4α,8β,13β,16β)-13-Methyl-16,18-diol-17-Norkaurane: A Simultaneous Reduction Product of Isosteviol

Abstract  

(4α,8β,13β,16β)-13-methyl-16,18-diol-17-norkaurane was synthesized by esterification and reduction of isosteviol, respectively. The structure of the title compound was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell parameters: a = 7.3705 (14) ?, b = 13.508 (3) ?, c = 20.139 (4) ?, V = 2005.1 (7) ?³, Z = 4. The conformation of rings A and B is chair, whereas the conformation of ring C is unsymmetrical distorted chair. The stereochemistry of the A/B and B/C ring junctions is trans, while the five-membered ring D adopts an envelope conformation.     

Molecular structure of 3α-ethoxy-8α-acetoxy-13-hydroxy-lactar-6(7)en-5-oic acid γ-lactone

The structure of the title compound has been investigated in the solid state by X-ray diffraction. The crystals are tetragonal, space groupP4₁2₁,2 (No. 92), with cell dimensions:a=10.463(1),c=34.603(8)Å. The structure was solved by direct methods and refined with 3634 unique reflections by a full-matrix, least-squares procedure givingR=0.0460,R _w=0.0472 (w=1/ _F ² . The stereochemical analysis of the molecule confirmed the expectations based on earlier NMR investigations of the title compound and its precursors.     

Structure of 1-(2′-tosyloxyethoxy)-8-tosyloxy-9,10-anthraquinone

The title compound crystallizes in the monoclinic space group, P2₁/c;a=12.938(1),b=11.041(1),c=19.285(2) Å, =104.314(8)°,Z=4. Refinement based on 1660 unique observed reflections converged toR=0.054. The anthraquinone moiety is distorted due to intramolecular steric hindrance from the tosylate groups.     

Crystal structure of aminoguanidinium hexahydro-closo-hexaborate dihydrate, (CN4H7)2B6H6 · 2H2O

The (HAgu)₂B₆H₆ · 2H₂O compound was synthesized and its crystal structure was determined [R = 0.0385 for 2018 reflections with I > 2σ(I)]. The structure consists of HAgu ⁺ cations, centrosymmetric B₆H ₆ ^2? anions, and water molecules. The anions have an almost regular octahedral structure. The bond lengths and angles lie within the following narrow ranges: B-B, 1.715–1.726(2) Å; B-H, 1.08–1.14(2) Å; B-B-B, 59.72°–60.29(9)° and 89.63°–90.20(11)°; and B-B-H, 133.2°–137.0(9)°. The HAgu ⁺ cations and water molecules are involved in the O-H?O, N-H?O, and N-N?N hydrogen bonds and participate in numerous (N, O)-H?H-B specific interactions with the B₆H ₆ ^2? anions, which results in splitting and high-frequency shift of the band of B-H stretching vibrations in the IR spectrum.     

Synthesis NMR Characterization and Crystal Structure of Methyl 3α,7α-diacetoxy-12-oxo-13-oxa-C-homo-5β-cholanate

Journal of Chemical Crystallography - The crystal structure and NMR characterization of methyl 3α,7α-diacetoxy-12-oxo-13-oxa-C-homo-5β-cholanate. The title compound which was...     

Crystal Structure of 9α,11-Epoxy-7α-(methoxycarbonyl)-3-oxo-17α-pregn-4-ene-21,17-carbolactone

Abstract  The title compound (common name eplerenone), C₂₄H₃₀O₆, is an aldosterone receptor antagonist. From the isopropyl acetate solution the compound crystallizes in monoclinic space group P 21 with a = 8.811(1) ?, b = 11.250(1) ?, c = 11.079(1) ?, β = 93.822(12)°, Z = 2. The molecule contains three six membered rings, two five membered rings and one three membered ring. Both five membered rings display envelope conformation, whereas three six membered rings show different conformation: chair, half-chair and envelope. In the crystal the eplerenone molecules link to one another via intermolecular weak C–H···O hydrogen bonding to form the smaller cavity of 12.0(1) ?³ between eplerenone molecules, no solvent molecule filled in this cavity. Index Abstract  In the title molecule three six-membered rings show different conformation. Weak C–H···O hydrogen bonding links adjacent molecules to form the small cavity 12.0(1) ?³, no solvent molecule filled in the cavity.      

Mesophase-Preceding Crystal Packing of 4,4'-Dialkyl-Substituted Salicylideneanilines; C10H21O–C6H3(OH)–CH=N–C6H4–С7Н13) Structure

Crystallography Reports - The crystal structure of 4,4'-substituted salicylideneaniline C10H21O–C6H3(OH)–CH=N–C6H4–C7H13 has been investigated by X-ray diffraction. A...     

Molecular structure and absolute configuration of (+)-(1R, 2S, 6R, 7S, 1′R)-5-(1′-phenylethylamino)-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one

The crystal and molecular structure of (+)-(1R, 2S, 6R, 7S, 1R)-5-(1-phenylethylamino)-endo-tricyclo[5.2.1.0^2,6]deca-4,8-dien-3-one is described. Based on the known absolute configuration (R) of the -phenylethylamine moiety the X-ray analysis revealed the absolute configuration of the title compound. The structure was refined to R ₁ = 0.0298 for 1950 reflections (with I > 2(I)). Crystal data: C₁₈H₁₉NO, monoclinic, space group P2₁, a = 6.7406(4), b = 9.959(2), c = 11.3123(8)Å, = 102.969(5), V = 740.0(2)ų, and Z = 2.     

Synthesis and Crystal Structure of 3-Quinuclidinyl α-(Cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate

Abstract The title compound 3-quinuclidinyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate was obtained by the reaction of methyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate with 3-quinuclidinol in n-heptane. Its structure was characterized by ¹H, ¹³C NMR, MS and X-ray single-crystal diffraction techniques: C₂₀H₂₅NO₃, M _r = 327.41, orthorhombic, space group P2₁2₁2₁ with a = 8.547(2), b = 11.428(4), c = 18.288(5) ?, V = 1786.3(9) ?³, Z = 4. The title compound comprises a tertiary α-hydroxy acid and a bicyclo[2.2.2]octan moiety. The crystal structure shows the presence of the intermolecular O(1)–H(1)···N(1) hydrogen bonds. Index Abstract The title compound, 3-quinuclidinyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate was obtained by the reaction of methyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate with 3-quinuclidinol in n-heptane and its crystal structure determined. The title compound comprises a tertiary α-hydroxy acid and a bicyclo[2.2.2]octan moiety. The crystal structure shows the presence of the intermolecular O(1)–H(1)···N(1) hydrogen bonds.      

Structure of tetrazole steroid analogues,IV: Structure of 7a-aza-B-homocholest-5-eno [7a, 7-d]tetrazol-3β-yl-acetate (HS503)

The crystal and molecular structure of the steroidal tetrazole 7a-aza-B-homocholest-5-eno[7a,7-d]tetrazol-3-yl acetate (C₂₉H₄₆N₄O₂) has been determined by vector verification, and refined to a finalR of 0.087 for 3454 observed reflections. The compound crystallizes in space groupP2₁ with cell dimensionsa=7.352(3),b=25.950(8),c=15.408(6) Å,=91.22(3)°;Z=4,D _x=1.33 g cm^–3, (CuK)=4.87 cm^–1. The two independent molecules exhibit similar overall topography, ringsA, B, C, andD adopting chair, butterfly (Husainet al., 1981), sofa, and distorted envelope conformations respectively in both molecules.Steroids and Related Studies, Part 74.     

Crystal and molecular structure of 7α, 8α, 13-trihydroxy-marasman-5-oic acid γ-lactone,C15H22O4

The structure of the title compound has been investigated by X-ray diffraction methods. The crystals are monoclinic, space groupP2₁, with cell dimensions:a=9.802(3),b=6.192(1),c=12.392(2) Å, and=112.40(2)°. The structure was solved by direct methods, and refined with 1492 unique reflections by a full-matrix, least-squares procedure givingR=0.0450. Thetrans arrangement of H-8 and H-9 hydrogens as deduced from earlier¹H NMR experiments was fully confirmed by the X-ray investigations.     

The crystal and molecule structure of three 2,4,6-trinitrobenzene derivatives:α,α,α-trifluoro-2,4,6-trinitrotoluene (C7H2F3N3O6), 2,4,6-trinitrobenzamide (C7H4N4O7), 2,4,6-trinitrobenzoic acid (C7H3N3O8)

The crystal and molecular structures of three 2,4,6-trinitrobenzene derivatives have been determined. Forα,α,α-trifluoro-2,4,6-trinitrotoluene (1): monoclinic,P2₁/n,a=7.510(2),b=9.273(2),c=14.984(0) Å,β=99.02(2)°,V=1028.1(4)° ų,Z=4,D=1.816 g cm^?3,R(F)=0.051, andR(wF)=0.055. For 2,4,6-trinitrobenzamide (2): orthorhombic,Pbca,a=9.248(3),b=14.377(6),c=17.729(4) Å,V=1958(1) ų,Z=8,D=1.737 g cm^?3,R(F)=0.073, andR(wF)=0.077. For 2,4,6-trinitrobenzoic acid (3): orthorhombic,P2₁2₁2₁,a=6.553(1),b=11.405(2),c=12.796(2) Å,V=956.3(3) ų,Z=4,D=1.785 g cm^?3,R(F)=0.045, andR(wF)=0.046.1 crystallizes as discrete molecules,2 as weakly hydrogen-bonded dimers and3 as a chiral polymer of hydrogen-bonded helices. In1, the presence of the nonplanar CF₃ substituent causes a large twisting of theα-nitro groups out of the plane of the benzene ring, whereas the nearly planar C(O)NH₂ and C(O)OH substituents in2 and3 are perpendicular to the benzene plane and do not cause a significant rotation of theα-nitro groups.     

(20R,22R)-6α,7α-Epoxy-5α,27-dihydroxy-1-oxowitha-2,24-dienolide in Leaves of Withania somnifera: Isolation and its Crystal Structure

Abstract  (20R,22R)-6α,7α-Epoxy-5α,27-dihydroxy-1-oxowitha-2,24-dienolide (27-hydroxy-withanolide B) was isolated from Withania somnifera. The structure of the withanolide was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell parameters: a = 9.2163(3), b = 11.1828(4), c = 23.6146(9) ?, Z = 4. The crystal structure was refined to R = 0.0495 for 3,284 observed reflections. All the rings of the steroid skeleton are trans connected. Rings A and B exist in a half-chair conformation, ring C a chair, and five membered ring D is intermediate between a half-chair and an envelope. The δ-lactone ring E adopts a distorted sofa conformation. The twist along the length of the steroid nucleus is −6.5°. The characteristic pattern observed in the packing diagram is the appearance of twisted chains of molecules packed together to form layers. Index Abstract  Isolation and crystal structure analysis of (20R,22R)-6α,7α-epoxy-5α,27-dihydroxy-1-oxowitha-2,24-dienolide.      

Structure of 9-oxa-2,3-(4′-methoxy)-benzo bicyclo[4,3,0]non-1(6)-ene-7,8-dione: C13H10O4

The crystal and molecular structure of the title compound: C₁₃H₁₀O₄,M _r=230.22, determined by single crystal X-ray diffraction is reported. Crystals are monoclinic, space groupP2_l/c,a=3.991(3),b=21.381(4),c=12.289(4)Å,b=91.15(1)°,V=1048(1)Å₃,z=4,D _x=1.46Mg m^–3, (MoK)=0.7107 Å,m=0.87 mm^–1,F(000)=480,T=298 K. The structure was solved by direct methods and the finalR value is 0.071 (wR=0.055) for 795 independent observed reflections. The cyclohexadienic moiety of the molecule adopt a twist conformation.