Structure of 6α-methyl-17α-hydroxyprogesterone butanoate,C26H38O4

The title compound crystallizes in space groupP2₁2₁2₁ with lattice constantsa=16.253(3),b=17.107(3), andc=8.486(2) Å. The A ring has 1,2-half-chair conformation. The calculated steric energy of a 6-methyl-17-ester progesterone molecule is lower by about 4 kJ/mol for the normal A-ring conformation. The progesterone side chain has typical conformation for 17-ester steroids; the C(16)-C(17)-C(20)-O(20) torsion angle is –24.9(4)°.     

X-ray elucidation of 17α-pregna-2,4-dien-20-yne-(2,3-d) isoxazole-17β-ol

Synthetic pregnen steroid 17-pregna-2,4-dien-20-yne-(2,3-d) isoxazole-17-ol crystallizes in the orthorhombic space group P2₁2₁2₁, with a = 6.601(4), b = 10.530(4), c = 26.177(9) Å, and Z = 4. The structure was solved from Enraf Nonius CAD4 diffractometer data by direct methods and refined to R = 0.0399 for 2041 observed reflections (I > 2(I)). The molecule contains five rings of which rings A, B, and C are cyclohexene; ring D is cyclopentene; and ring E is heterocyclic cyclopentene. Ring A acquires the conformation of a half-chair; ring B tends toward a half-chair conformation with a bias toward a chair conformation that contains a hydrogen at C8 and an hydrogen at C9. Ring C acquires a near chair conformation with an hydrogen at C14. Ring D is a 13, 14-half chair, and ring E is a O3-envelope. Both the ring junctions A/B and A/E are quasi-trans, whereas the ring junctions B/C and C/D are both trans. The molecule as a whole is slightly convex toward the -side, with an angle of 16.7(2)° between the C10–C19 and C13–C18 vectors. Structural association is due to hydrogen bonding and stacking 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.      

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 and molecular structure of 17-β-methyl-α-isolupanineN-(16)-oxide perchlorate monohydrate

[C₁₆H₂₇N₂O₂]⁺·ClO ₄ ^– ·H₂O,M _r=396.87, orthorhombicP2₁2₁2₁ a=13.708(4),b=16.930(7),c=8.311(3) Å,V=1928.3(13) ų,Z=4,D _x=1.367(2) g cm^–3,(MoK)=0.71068 Å,(MoK)=1.95 cm^–1,F(000)=848,T=292 K,R=0.061 for 1324 unique reflections. RingsA,B,C,D have half-chair, chair, chair and chair conformations, respectively; the quinolizidone moietyA/E has a quasi-trans and the quinolizidine moietyC/D has a trans configuration. The cations are connected into chains along the crystallographic direction [001] by strong hydrogen bonds utilizing the water molecule: C(2)=O(5)O(W)O(6)-N(16) of 2.623(7) and 2.574(7) Å, respectively. The water molecule is also hydrogen-bonded to one oxygen atom of the perchlorate anion: O(W)O(2) is 3.106(10) Å. A very short intramolecular distance between N(1) and O(6) of 2.696(7) Å, due to the quasitrans-trans configuration of the-isolupanine skeleton, is observed.     

Reactivity of 6α,7α-epoxyhimachal-2-ene and crystal structures of 2α,3α-dibromocyclopropanehimachal-5,7-diene and 2α,3α-dibromocyclopropane-6α,7α-epoxyhimachalane

We report here the reactivity of 6,7-epoxyhimachal-2-ene with dibromocarbene generated in situ by phase-transfer catalysis. The stereochemistry of products resulting from dibromocyclopropanation has been established by X-ray crystallography. Compound 3 is orthorhombic P2₁2₁2₁ with a = 7.549 (1), b = 8.432 (1), c = 24.469 (1) Å, V = 1559.8 (5) ų, Z = 4 and compound 5 is monoclinic P2₁ with a = 8.779 (1), b = 15.684 (1), c = 12.111 (1) Å, = 91.869 (1)°, V = 1666.7 (4) ų and Z = 4.     

Structure of 6-methyl-3,20-dioxo-4,6-pregnadien-17α-yl acetate,C24H32O4

The X-ray structure of 6-methyl-3,20-dioxo-4,6-pregnadien-17-yl acetate is reported. The crystals are monoclinic, space groupP2₁,Z=4,a=28.955(7),b=6.597(2),c=11.064(3) Å,/gb=90.80(2) °. The two crystallographically independent molecules have very similar overall geometries. The A rings have intermediate sofa-half-chair conformations and are bent relative to the steroid skeleton. The conformation of the 17-progesterone side chain is stabilized by the 17-ester substituent; the C(16)-C(17)-C(20)-O(20) torsion angle is –19.4(6) and –20.6(7)°.     

Structure of 17α-methyl-testosterone semihydrate,C20H30O2·1/2 H2O

The crystal structure of 17-methyltestosterone hemihydrate, C₂₀H₃₀O₂·1/2H₂O, has been determined:M _r =312.5, space groupP2₁2₁2₁2₁,a=6.374(2),b=12.807(2),c=43.398(5)Å,V _c =3543(2)ų,Z=8,D _x =1.172 mg^–3, CuK radiation ( = 1.54184 Å),(CuK)=5.5 cm^–1,F(000)=1376. The structure was solved usingMultan. The final conventionalR=0.053 (R _w =0.052) for 3634 reflections. The structure contains two crystallographically independent molecules in the asymmetric part of the unit cell that have almost identical geometry.     

Structure of 21-fluoro-4,9(11)-pregnadiene-3,20-dion-17α-yl acetate,C23H29O4F

The crystal and molecular structure of 21-fluoro-4,9(ll)-pregnadiene-3,20-dion-17a-yl acetate has been determined by X-ray diffraction methods;P2₁2₁2₁,a=15.827(4),b=16.912(4),c=7.513(2) Å,Z=4;R=0.062, (R _w =0.065) for 2028 unique observed reflections. The progesterone side chain has an unusual conformation; the C16-C17-C20-O20 torsion angle is 173.1(4)°. Molecular mechanics calculations suggest that this conformation may be cuased by 17-acetoxy substituent and the additional double bond between C9 and C11.Research supported in part by RP.II. 10 grant from the Polish Ministry of National Education (to Z. G., P. G., and Z. W.) and by PHS Grant DK26546 (to WLD).     

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.      

Tb2Fe17和Tb2（Fe,Si）17磁性单晶的生长和相图

利用磁悬浮冷坩埚提拉法技术生长了Tb2Fe17和Tb2(Fe,Si)17的单晶,并用差热分析等方法研究了材料的相图。研究结果表明：Tb2Fe17的相关系并非以往报道的包晶反应。而是同成分熔化。本文还给出了Tb2Fe17化合物附近的新相图。采用优化后的生长条件,获得了缺陷较少的Tb2Fe17和Tb2(Fe,Si)17高质量单晶,分析了Si替代对于化合物结构的影响,测量了Tb2Fe17单晶样品的基本磁性。从材料的一级磁化过程的测量可以看出,在理想配比条件下最容易获得缺陷密度低的单晶样品,这种磁性测量方法为了解单晶的完整性提供了一个有效的间接观察方法。     

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.     

Structure of (1αH,6βH,7αH,8αH)-1α,10α-epoxy-8β-hydroxy-germacr-2,11(13)-dien-6,12-olide (Incomptine B): A sesquiterpenoid lactone

C₁₅H₁₈O₄ is monoclinic,P2₁. Unit-cell dimensions at 293 K area=15.048(5),b=9.756(3),c=15.815(5)Å,=114.18(2)°,V=2118(1)ų,D _x=1.23 g cm^–3, andZ=6. The structure has been determined from single-crystal data collected with a four-circle diffractometer and refined from 2816 observed reflections toR=0.054. The structural features determined from chemical and spectroscopic studies are confirmed and extended. The incomptine B occurs as three independent molecules with different conformations. The stereochemistry at C(6), C(7), and C(8) is 6S, 7R, and 8R. The 10-membered ring has an approximate C₂ symmetry for the A, B, and C molecules. The -methylene -lactone ring adopts a half-chair conformation for molecule A, and a conformation intermediate between-envelope and half-chair for the B and C molecules, respectively. The structures are stabilized by a three-dimensional network of O-HO hydrogen bonds and several C-HO interactions.     

Crystal structure of γ-2-trans-2,6-diphenylthian-1,1-dioxide-4-one oxime, C17H17NO3S

The X-ray crystal structure of -2-trans-2,6-diphenylthian-1,1-dioxide-4-one oxime is determined [C₁₇H₁₇NO₃S, space group P2₁ n, a = 8.177(1) b = 9.574(1)c = 19.730(5) Å, = 97.35(5)°]. The oxime group does not form an oxime dimer, but is involved in an O-H···O=S hydrogen bond.     

α-氰基-α-二茂铁基乙氧三甲硅烷的合成与晶体结构

乙酰基二茂铁与三甲基氰硅烷在CH2Cl2中ZnI2催化下加成,得到产率较高的α-氰基-α-二茂铁基乙氧三甲硅烷,用元素分析、IR和1H NMR进行了表征.经X射线单晶衍射法测试表明,该化合物属正交晶系,Pbca空间群,晶胞内分子数为8,化合物分子式为C16H21FeNOSi,Mr=327.28,a=1.1995(4)nm,b=1.2441(4)m,c=2.2183(7)nm,β=90°,V=3.3103(18)nm3,Dcale=1.313g·cm-3,Z=8,最终偏离因子R=0.0456,ωR=0.0880.分析其结构表明,该化合物含有一个二茂铁基和氰基乙氧三甲基硅烷基,与二茂铁基相连的碳原子是手性原子,分子中存在超共轭效应.     

Crystal structure of N(1)-methyl-α-isosparteine iodide and 1,16-endomethylene-α-isosparteine diiodide

The crystal and molecular structures of mono- and di-quaternary salts ofa-isosparteine have been determined by X-ray analysis. Both N(1)-methyl--isosparteine iodide and 1,16-endomethylene-isosparteine diiodide crystallize in the space groupC222₁. The N-methylation does not change the configuration of parenttrans-cisoid-trans--isosparteine. The crystallographic twofold symmetry axis coincides with molecular symmetry of the diquaternary cation. Thetrans-cisoid-trans-1,16-endomethylene--isosparteine diiodide and its stereoisomer,trans-cisoid-cis-1,16-endo-methylenesparteine diiodide, form isomorphous crystals. Short cation-anion contacts in crystal structures suggest existence of C-H--I^– hydrogen bonds in the solid state. In the N(1)-methyl--isosparteine iodide crystal, 7CI^– distances in the range 3.85-4.15 Å have been found, while 17 distances of this type have been observed in 1,16-endomethylene--isosparteine diiodide.     

Molecular structures of four triterpenoids. X-ray crystallographic analysis of methyl 2α,3β,23α-triacetoxy-19α-hydroxyurs-12-en-28β-oate

A triterpenoid glycoside has been isolated from the roots of a herb used in traditional Chinese medicine. The molecular structure of this compound and its derivatives have been determined by spectroscopic studies and an X-ray analysis of the 2,3,23-triacetoxy-28-methyl ester of the aglycone. This aglycone belongs to the ursene structure series. The hydroxy group on ring E of these triterpenoids is orientated and the side chains at C(2), C(3), C(4) and C(17) are .,, and orientated, respectively. The C ring, which has a double bond at C(12)=C(13), adopts a sofa conformation.     

The crystal and molecular structure of trans-dimethyl 2α-methyl(3αH) perhydro [1,2]oxazolo-[2,3-a]azepine-2α,3α-dicarboxylate: A 7/5-fused ring system

The title compound crystallizes in the monoclinic space group P2₁/n, with a = 6.225(1), b = 14.612 (1), c = 15.520 (1) Å, = 96.6(3)°, Z = 4 and V = 1402.4ų. The stereochemistry of the 7/5-fused ring system is trans, the 7-membered and the 5-membered rings are found to be in the chair and envelope conformations, respectively. This represents the first study of a compound containing the 7/5-ring skeleton shown in (3) below.     

The crystal structure of 5α,9α-peroxyergosta-7,22-dien-6-one-3β-ol acetate

Ergosterol acetate, in pyridine, reacts with hydrogen peroxide and catalytic amounts of FeCl₃ to afford the unusual product 5,9-peroxyergosta-7,22-dien-6-one-3-ol acetate. The peroxide, in the title structure, is seen to bridge the C5 and C9 positions of the sterol backbone. Crystal data: C₃₀H₄₄O₅, orthorhombic, P2₁2₁2₁, a = 6.552(2), b = 11.048(8), c = 37.60(2), V = 2772(3)ų, Z = 4.     

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.