Isolation and Crystal Structure of 6α,7α-Epoxy-5α,17α,27-trihydroxy-1-oxo-22R-witha-2,24-dienolide monohydrate-A Withasteroid from Withania somnifera Leaves

Abstract  

(5R,6S,7S,8S,9S,10R,13S,14S,17S,20R,22R)-6α,7α-epoxy-5α,17α,27-trihydroxy-1-oxo-22R-witha-2,24-dienolide has been isolated from Withania somnifera leaves. Three-dimensional X-ray intensity data were collected at 293 K on Bruker CCD area-detector diffractometer equipped with graphite-monochromated MoKα radiation (λ = 0.71073 ?). The compound crystallizes in monoclinic space group P21 with unit cell parameters: a = 6.4540(2), b = 11.3656(4), c = 17.4982(5) ?, β = 90.730 ^o(2), Z = 2. The crystal structure was refined to a final R-value of 0.0419 for 6122 observed reflections. One water solvent molecule was observed. All the rings of the steroid skeleton are trans connected. Rings A and B exists in a half-chair conformation, ring C a chair, and five membered ring D is intermediate between half-chair and envelope. The δ-lactone ring E adopts a distorted sofa conformation. The characteristic pattern observed in the packing diagram is the appearance of twisted chains of molecules. The packing of the molecules in the crystal is stabilized by intra- and intermolecular O–H···O and C–H···O interactions.     

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.      

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.      

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.     

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...     

Synthesis and Crystal Structure of 3β-Acetoxy-5α-bromo-6β-hydroxyandrostan-17-one

Abstract  

The title steroid 3β-acetoxy-5α-bromo-6β-hydroxyandrostan-17-one 1 was synthesized from the reaction of 3β-acetoxy-5-androstene-17-one with N-bromosuccinimide (NBS) and characterized by FT-IR, ¹H-NMR, EI-MS and ESI-HRMS techniques. The structure of the compound was also determined crystallographically. The crystal structure was solved by direct methods and refined by full-matrix least-squares. It crystallized with two molecules in the asymmetric unit in the triclinic space group P1 with a = 7.0518(9), b = 10.1362(16), c = 15.3472(19) ?, α = 100.579(8), β = 99.354(6), γ = 109.267(5)°, V = 988.1(2) ?³, D _x  = 1.436 g cm⁻³, respectively (R ₁ = 0.0262 and wR ₂ = 0.0468 for 5273 reflections [I > 2σ(I)]). Three-six-membered rings A, B and C exist in chair conformation while the five-membered ring D displays an envelope conformation. The intermolecular interactions O–H···O link the molecules into a three dimensional network. The crystal structure was compared with our previously reported similar structures.     

Crystal and molecular structures of (20R)-20-aminopregn-5-en-3β-ol and (20S)-20-aminopregn-5-en-3β-ol hydrochloride

Two epimers of 20-aminopregn-5-en-3-ol differing in configuration at C(20) have been synthesized and their structures have been determined by single crystal X-ray diffraction methods. The (20R)-epimer (1) crystallized in the orthorhombic system, space group P2₁2₁2₁, with a = 9.0432(5) Å, b = 13.3446(7) Å, c = 15.1086(8) Å, and Z = 4. The (20S)-epimer hydrochloride hydrate (2 hydrate) crystallized in the monoclinic system, space group C2, with a = 31.0501(3) Å, b = 11.8221(1) Å, c = 11.9703(2) Å, = 98.5140(10)°, and Z = 8. The absolute configurations at the C(20) chiral centers for the title compounds were unequivocally established for the first time. The asymmetric unit cell of 2 hydrate contained two steroid molecules, A and B, two hydrochloride molecules, and two molecules of water. The crystal packing for both diastereomers was strongly influenced by the presence of intermolecular hydrogen bonding. The molecules of 1 were linked in a head-to-tail fashion via hydrogen bonds between the hydroxyl group of the ring A and the amino group of the side chain of the ring D. The two molecules A and B of 2 hydrate were held together in head-to-head and head-to-tail fashions by a three-dimensional network of hydrogen bonds involving chlorine ions, disordered water molecules, and hydroxyl–amino groups interactions.     

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.     

Structure of 3α,12β-dihydroxy-2β-morpholino-5α-pregnan-20-one,C25H41O4N

The crystal and molecular structure of 3,12-dihydroxy-2-morpholino-5-pregnan-20-one, C₂₅H₄₁O₄N, has been determined:M _r =419.6,P2₁,a=13.5778(8),b=14.4340(8),c=5.8943(5) Å,=94.32(1)°,V _c =1151.9(3) ų,Z=2,D _x =1.21 g cm^–3, (CuK) = 1.5418 Å, =5.6 cm^–1,F(000)=460,R=0.039,R _w =0.040 for 2421 unique observed reflections. All six-membered rings have chair conformations, and theD ring has a 13-envelope conformation. The progesterone side chain has an unusual conformation, and the C16-C17-C20-O20 torsion angle, which defines the conformation, is –152.6(3)°. The unusual conformation seems to be forced by the intramolecular hydrogen bond between the hydroxyl group at C12 and the O20 atom from the side-chain.     

Synthesis,Crystal Structure and Characterization of (Z)-2-N′-hydroxyisonicotinamidine

The compound (Z)-2-N′-hydroxyisonicotinamidine, (2) was synthesized and characterized by ¹H NMR, FT-IR, FAB-Mass, UV-Visible Spectra, and elemental Analysis. Its molecular structure was solved by single crystal X-ray diffraction method. The title molecule, C₆H₇N₃O is crystallized in the orthorhombic crystal system with the space group Pna2₁ and with unit cell parameters a = 12.5664(8) Å, b = 8.8622(6) Å, c = 5.7953(4) Å, α = 90°, β = 90°, γ = 90°, and Z = 4. The molecular and crystal structure of the title molecule is stabilized by an intramolecular interaction of the type N—H···O, and the intermolecular interactions of types N—H···N and O—H···N.     

Crystal and molecular structure of 4,17a-methy1-4, 17a-diaza-5α-androstane (HS353): An intermediate in the design of azasteroid neuromuscular blocking agents

The crystal and molecular structure of 4, 17a-methyl-4, 17a-diaza-5-androstane (HS353), C₂₀N₂H₃₆ has been determined by direct methods and successive electron density calculations. The crystals are triclinic,a=7.419(2),b=20.300(4),c=12.866(2)Å,=105.91(2),=76.33(2),=99.32(2)°, space groupP1,Z=4. Block-matrix least-squares refinement converged toR=0.0660 for 3243 reflections withI3I (CuK radiation). The four independent molecules show only minor conformational variations, all rings being trans-connected chairs. Introduction of N at positions 4 and 17a of ringsA andD creates asymmetry in both conformation and bond angles, producing outward bending of the C-N side groups at both ends of all four molecules.Steroids and related studies, Part 83.     

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 of 7,4′-Bis-(hydroxyl)-8,3′,5′-tris-(hydroxymethyl)isoflavone and Crystal Structure of its Ester

Abstract 7,4′-bis-(hydroxyl)-8,3′,5′-tris-(hydroxymethyl)isoflavone (I) and its ester were synthesized and examined by IR, element analysis and ¹H NMR. The crystal of 7,4′-bis-(acetyl oxide)-8,3′,5′-tris-(acetoxymethyl)isoflavone (II) was studied by X-ray diffraction. (II) crystallizes in the monoclinic with space group P2 ₁ /c. a = 17.987(3) ?, b = 17.972(3) ?, c = 8.4087(11) ?, β = 97.703(3)°, V = 2693.7(6) ?³ and Z = 4. The molecular structure of the ester consists of a benzopyranone moiety, a phenyl moiety, two acetyl oxides and three acetoxymethyl groups. Hydrogen bonds and aromatic stacking interactions link the ester into a two-dimensional structure. Index Abstract 7,4′-bis-(hydroxyl)-8,3′,5′-tris-(hydroxymethyl)isoflavone and its ester were synthesized and examined by IR, element analysis and ¹H NMR. The result of the ester’s crystal structure showed that hydrogen bonding and aromatic π–π stacking assemble the ester into a two-dimensional networking structure.      

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

The crystal and molecular structure of (–)-(1R, 2S, 6R, 7S, 2S)-5-(2-hydroxymethyl-pyrrolidin-1-yl)-endo-tricyclo[5.2.1.0^2,6]deca-4,8-dien-3-one is described. Knowing the absolute configuration of the prolinol moiety (S) the X-ray diffraction study established the absolute configuration of the title compound. The structure was refined to R ₁ = 0.0322 for 1237 reflections (with I > 2(I)). Crystal data: C₁₅H₁₉NO₂, monoclinic, space group P2₁, a = 6.0757(4), b = 11.3473(5), c = 9.5114(7)Å, = 104.686(6)°, V = 634.32(7)ų, and Z = 2.     

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.     

Anticancer agent development. 5. X-ray structure and1H nmr spectral analysis of (1α,2α,5α,6α)-2,6-bis(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3.3.0]octane-4,8-dione

The title compound, C₂₀H₁₄O₈, Mr=382.3, crystallized from chloroform in the centric space group P¯1 witha=6.516(4),b=6.798(3),c=9.545(7) Å,=85.31(5),=73.87(5), =79.59(4)°,V=399.2 ų, and D_calc=1.59 g cm^–3 forZ=1. Least-squares refinement of 1035 observed [F_o5(F_o)] reflections led to the final agreement index ofR=0.074. The molecule resides on a crystallographic center of inversion and is disordered into two different conformations. This manifests itself as a 50/50 disorder at O(4), C(2), and C(3). The observed structure reveals acis relationship between the bridgehead hydrogen atoms and the aryl rings. The 90 MHz¹H nmr spectrum of the title compound exhibits an AAXX spin system with a H(1)C(2) to H(1)C(3) and H(1)C(2) to H(1)C(3) coupling constant of 2.8 Hz. Computer spectral simulation and Karplus equation analysis are utilized to illustrate a relaxation of the torsion angles between H(1)C(2) and H(1)C(3), and H(1)C(2) and H(1)C(3) is solution.