scholarly journals Structure of Equilenin at 100 K: an estrone-related steroid

2017 ◽  
Vol 73 (8) ◽  
pp. 1223-1226
Author(s):  
Christopher S. Frampton ◽  
David D. MacNicol
Keyword(s):  
Hydrogen Bonds ◽  
Resonant Scattering ◽  
Methyl Group ◽  
Axis Direction ◽  
Envelope Conformation ◽  
The Absolute ◽  
Absolute Structure

The structure of the estrone-related steroid, Equilenin, C18H18O2 (systematic name 3-hydroxy-13-methyl-11,12,13,14,15,16-hexahydrocyclopenta[a]phenanthren-17-one), has been determined at 100 K. The crystals are orthorhombic, P212121, and the absolute structure of the molecule in the crystal has been determined by resonant scattering [Flack parameter = −0.05 (4)]. The C atoms of the A and B rings are almost coplanar, with an r.m.s. deviation from planarity of 0.0104 Å. The C ring has a sofa conformation, while the D ring has an envelope conformation with the methine C atom as the flap. The keto O atom and the methyl group are translated 0.78 and 0.79 Å, respectively, from the equivalent positions on 17β-estrone. In the crystal, molecules are linked by O—H...O hydrogen bonds, forming chains parallel to the c-axis direction.

scholarly journals 2′-Methylpyrazolo[4′,3′:16,17]androst-5-en-3β-ol

2009 ◽  
Vol 65 (6) ◽  
pp. o1436-o1436
Author(s):  
Hu-ling Zheng ◽  
Peng Xia ◽  
Ying Chen
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Pyrazole Ring ◽  
Chair Conformation ◽  
Envelope Conformation ◽  
Compound C ◽  
The Absolute ◽  
Absolute Structure

In the title compound, C21H30N2O, there are five fused rings. TheAandCrings adopt chair conformations, ringBadopts an 8β,9α-half-chair conformation and ringDadopts a 14α-envelope conformation. The pyrazole ring is planar. Intermolecular O—H...N hydrogen bonds [H...N = 1.88 (5) Å] help to stabilize the crystal structure. The absolute structure was deduced from those of the starting materials.

scholarly journals Crystal structure of 7β-hydroxyroyleanone isolated fromTaxodium ascendens(B.)

2017 ◽  
Vol 73 (10) ◽  
pp. 1414-1416
Author(s):  
Shicheng Xu ◽  
Xinhua Ma ◽  
Ruifang Ke ◽  
Shihao Deng ◽  
Xinzhou Yang ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Resonant Scattering ◽  
Acta Cryst ◽  
Space Group ◽  
Compound C ◽  
The Absolute ◽  
Absolute Structure

The title compound, C20H28O4[systematic name: (4bS,8aS,10S)-3,10-dihydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthrene-1,4-dione], is an abietane-type diterpene, which was isolated fromTaxodium ascendens(B.). The compound crystallizes in the chiral space groupP21, but it was not possible to determine the absolute structure of the molecule in the crystal by resonant scattering. The molecular structure is stabilized by two intramolecular O—H...O hydrogen bonds, enclosingS(5) andS(6) ring motifs. In the crystal, molecules are linked by O—H...O and C—H...O hydrogen bonds, forming chains along the [010] direction. The crystal structure of the 10Rstereoisomer of the title compound, isolated from the roots ofPremna obtusifolia(Verbenaceae), has been reported. It crystallized in the chiral space groupP212121, and the absolute structure was determined as (4bS,8aS,10R), by resonant scattering using CuKα radiation [Razaket al.(2010).Acta Cryst.E66, o1566–o1567].

scholarly journals Crystal structures of 1-(4-chlorophenyl)-2-(diphenylphosphoryl)ethan-1-one and 1-(diphenylphosphoryl)-3,3-dimethylbutan-2-one

2015 ◽  
Vol 71 (5) ◽  
pp. 523-527
Author(s):  
Erin G. Leach ◽  
Alyssa A. Kulesza ◽  
Richard J. Staples ◽  
Shannon M. Biros
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Resonant Scattering ◽  
Arbuzov Reaction ◽  
Π Interactions ◽  
The Absolute ◽  
Compound Ii ◽  
Absolute Structure

The title compounds, C20H16ClO2P, (I), and C18H21O2P, (II), were synthesizedviaan Arbuzov reaction between an α-bromoketone and isopropoxydiphenylphosphane. In the crystals of both compounds, molecules are linkedviabifurcated C—H...(O,O) hydrogen bonds, forming chains propagating along [100] for (I) and along [010] for (II). The chains are linkedviaC—H...π interactions, leading to the formation of sheets lying parallel to (010) for (I) and (001) for (II). The absolute structure of compound (II) was determined by resonant scattering [Flack parameter = 0.088 (14)].

(3R,4R)-(–)-3-Hydroxymethyl-4-phenyl-2-o-toluoyl-1,2,3,4-tetrahydroisoquinoline

2006 ◽  
Vol 62 (5) ◽  
pp. o1774-o1776 ◽  
Author(s):  
Andrzej Gzella ◽  
Maria Chrzanowska ◽  
Agnieszka Dreas ◽  
Michał S. Kaczmarek ◽  
Zenon Woźniak
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Absolute Configuration ◽  
Title Compound ◽  
Phenyl Ring ◽  
Heterocyclic Ring ◽  
Hydroxymethyl Group ◽  
Envelope Conformation ◽  
Compound C ◽  
The Absolute

The absolute configuration of the title compound, C24H23NO2, has been confirmed as 3R,4R. The hydroxymethyl group and phenyl ring at the asymmetric C atoms exhibit α and β orientations, respectively, and the non-planar heterocyclic ring of the tetrahydroisoquinoline system adopts an envelope conformation. The crystal structure is stabilized through hydrogen bonds.

scholarly journals {(3S,5R)-5-(2,4-Difluorophenyl)-5-[(1H-1,2,4-triazol-1-yl)methyl]tetrahydrofuran-3-yl}methyl 4-methylbenzenesulfonate

IUCrData ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Qing-Shuang Ma ◽  
Xiao-Guang Wang ◽  
Lei Xu ◽  
Sun Bin ◽  
Dao-Hong Xia ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Axis Direction ◽  
Envelope Conformation ◽  
Compound C ◽  
Best Fit

In the title compound, C21H21F2N3O4S, the tetrahydrofuran ring adopts an envelope conformation with the β-C atom positioned at the flap. The triazole, difluorophenyl and tolyl rings of the various substituents on the tetrahydrofuran ring are inclined at 77.88 (12), 83.81 (10) and 81.00 (10)°, respectively, to the best-fit mean plane through the five atoms of the tetrahydrofuran ring. In the crystal, weak C—H...O and C—H...F hydrogen bonds link the molecules into a three-dimensional structure, with molecules stacked along thea-axis direction.

scholarly journals tert-Butyl (2S,3R,4R)-7′-bromo-4-methyl-2′,5-dioxo-4,5-dihydro-3H-spiro[furan-2,3′-indoline]-3-carboxylate

IUCrData ◽  
2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Chen-Hong Meng ◽  
Ai-Bao Xia
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Furan Ring ◽  
Axis Direction ◽  
Tert Butyl ◽  
Envelope Conformation ◽  
Compound C ◽  
The Mean

In the title compound, C17H18BrNO5, the furan ring has an envelope conformation with the carboxylate substituted C atom as the flap. The planar indoline ring is inclined to the mean plane of the furan ring by 87.5 (2)°. In the crystal, molecules are linked by N—H...O and C—H...O hydrogen bonds forming chains propagating along the a-axis direction.

scholarly journals Crystal structure of tetraethyl 27,30-dioxo-7,12,20,25-tetra-tert-butyl-3,16-dioxa-9,22,28,31-tetrathiaheptacyclo[21.3.1.11,5.14,8.110,14.114,18.117,21]dotriaconta-4,6,8(29),10,12,17,19,21(32),23,25-decaene-2,2,15,15-tetracarboxylate

2015 ◽  
Vol 71 (10) ◽  
pp. o778-o779
Author(s):  
Mehmet Akkurt ◽  
Jerry P. Jasinski ◽  
Shaaban K. Mohamed ◽  
Omran A. Omran ◽  
Mustafa R. Albayati
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Membered Ring ◽  
Asymmetric Unit ◽  
Axis Direction ◽  
Tert Butyl ◽  
Envelope Conformation ◽  
Compound C ◽  
A Chain

The asymmetric unit of the title compound, C54H64O12S4, consists of one half of the molecule, which is located on an inversion centre. The heterocyclic six-membered ring adopts a distorted envelope conformation with the spiro C atom as the flap. In the crystal, molecules are linked by weak C—H...O hydrogen bonds with anR22(14) motif, forming a chain along theb-axis direction.

scholarly journals (4S)-5′-Chloro-3,7,7-trimethyl-5,6,7,8-tetrahydro-4H-spiro[1,2-oxazolo[5,4-b]quinoline-4,3′-indole]-2′,5-dione

2014 ◽  
Vol 70 (2) ◽  
pp. o173-o173
Author(s):  
E. Govindan ◽  
PanneerSelvam Yuvaraj ◽  
Boreddy Siva Rami Reddy ◽  
K. Premalatha ◽  
A. SubbiahPandi
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Ring System ◽  
Axis Direction ◽  
Envelope Conformation ◽  
Compound C ◽  
Cyclohexene Ring

In the title compound, C20H18ClN3O3, the five- and six-membered heterocycles fused through a spiro C atom are inclined to each other at an angle of 87.4 (1)°. In the tricyclic ring system, the cyclohexene ring adopts an envelope conformation with the spiro atom as the flap. In the crystal, two sets of N—H...O hydrogen bonds link the molecules into columns containing centrosymmetricR22(7) ring motifs and propagating along theb-axis direction.

scholarly journals 16α,17α-Epoxy-17β-(1H-imidazol-1-yl)androst-4-en-3-one monohydrate

2012 ◽  
Vol 68 (8) ◽  
pp. o2345-o2345
Author(s):  
A. G. Anitha ◽  
R. Hema ◽  
Ranju Bansal ◽  
Sridhar Thota ◽  
S. Rizwana Begum
Keyword(s):  
Hydrogen Bonds ◽  
Water Molecule ◽  
Title Compound ◽  
Methyl Group ◽  
Envelope Conformation ◽  
Compound C

In the title compound, C22H28N2O2·H2O, ringsBandCadopt chair conformations. RingAadopts an envelope conformation, with the non-fused C atom adjacent to the fused C atom bearing a methyl group as the flap atom. RingDalso adopts an envelope conformation, with the fused C atom not bearing a methyl group as the flap atom. The water molecule links the moleculesviaO—H...O and O—H...N hydrogen bonds, forming zigzag chains which run parallel to thecaxis. Weak C—H...O interactions also occur.

scholarly journals 3β-Hydroxy-28-norolea-12,17-dien-11-one

2014 ◽  
Vol 70 (8) ◽  
pp. o842-o842
Author(s):  
Werner Seebacher ◽  
Robert Weis ◽  
Johanna Faist ◽  
Robert Saf ◽  
Ferdinand Belaj
Keyword(s):  
Hydrogen Bonds ◽  
Diffraction Data ◽  
Title Compound ◽  
The Other ◽  
Asymmetric Unit ◽  
Chiral Molecules ◽  
Compound C ◽  
Alkaline Conditions ◽  
The Absolute ◽  
Absolute Structure

The title compound, C29H44O2, was formed by treatment of 11-oxooleanolic acid under strong alkaline conditions. The absolute structure of the chiral molecules could not be determined reliably from the diffraction data, but is known from other triterpenes. The asymmetric unit consists of two molecules, 1 and 2. In both molecules, ringsAandBshow chair conformations. The other rings show mixed forms between envelope and half-chair conformations with atoms in positions 8, 15 and 21 forming the flaps in ringsC,DandE, respectively. RingsDandEof molecule 2 are disordered over two orientations, with occupancies of 0.557 (4) and 0.443 (4), which differ in the direction of the flap in ringE. In the crystal, molecules 1, as well as the molecules 2, are linked by O—H...O hydrogen bonds, forming chains parallel to thebaxis.

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