Crystal and molecular structure of 12α-hydroxy-ent-kaur-16-en-19-oic acid

The crystal and molecular structure of the title compound has been determined by X-ray crystallographic analysis. The 12-hydroxy-ent-kaur-16-en-19-oic acid previously isolated from other sources is found for the first time in a species of theMachaeranthera genus. The unit cell contains three closely similar independent molecules organized into trimers.     

Crystal structure of 14, α-hydroxy,sandarocopimar-7, 15-diene-19-oic acid

C₂₀H₃₀O₃, M _r =318.46, Monoclinic,P2₁,a=12.232(2) ,b=11.491(2) ,c=14.160(3) , =115.2°(3),V=1800.3(7) ³,Z=4,D _x =1.18 Mg m^–3, (CuK)=1.5418 , =5.3 cm^–1,F(000)=696,T=298 K. FinalR=0.044 for 2645 reflections withI>2. The two crystallographically independent molecules in the unit cell adopt essentially similar conformations. The structure reveals atrans relationship between the hydrogen at C(9) and the methyl group at C(20). The stereochemistry at C(13) is S. Apart from van der Waals forces the structure is stabilized by hydrogen bonds.     

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.     

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 14-β-N-pentylaminomorphinone,C22H28N2O3

The crystal and molecular structure of 14--N-pentylaminomorphinone (14--N-PAM), C₂₂H₂₈N₂O₃, has been determined by analysis of single crystal X-ray diffraction data. The compound crystallized at room temperature in the orthorhombic system, space group P2₁2₁2₁ witha=12.4535(8),b=13.7855(8),c=11.710(1) Å,V _c =2010.3(2) ų,Z=4,D _x =1.22 gm/cm³,(Cu K)=6.58 cm^–1, andF(000)=792. The final refinement yieldedR=0.051,R _w =0.059 for 328 variables with 1133 unique observed reflections. The absolute configuration is established via the synthesis from thebaine by the noninvolvement of certain asymmetric centers. The molecule is found to have as its central structure a T shape similar to that found in morphine and codeine. The distinctive feature of the molecule is the 14--N-pentylamino lipophilic side chain. Molecular modeling studies on the alkylamino chain result in the identification of clusters of conformations based on energy and dihedral angle criteria. Selected conformations are compared to 19-propylthevinol (etorphine), another potent analgesic which contains a lipophilic hydroxyalkyl substituent at C19. The enhanced analgesic activity of 14--N-pentylaminomorphinone is postulated to arise from an overall morphine-like contact with the receptor augmented by the interaction of the aliphatic chain with a lipophilic receptor pocket.     

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.     

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.     

Synthesis and structure determination of 3β-hydroxyandrost-5-en-17-one (C19H28O2·CH3OH)

3-Hydroxyandrost-5-en-17-one (C₁₉H₂₈O₂.CH₃OH) has been prepared for undertaking its crystallographic analysis and to investigate the role of intra- and intermolecular interactions in steroids. The title compound crystallizes in the orthorhombic space group C222₁ with unit cell parameters a = 6.7892(17), b = 12.624(2), and c = 41.136(5) Å; V = 3525.7(12) ų and Z = 8. The three-dimensional structure has been solved by direct methods. The final reliability index for the computed structure is 0.050 for 1088 observed reflections. Ring A exist in chair conformation, Ring B in half-chair conformation, and the Ring C assumes a distorted chair conformation. The five-membered Ring D adopts half-chair conformation. The A/B ring junction is quasi-trans while as B/C and C/D are trans-fused. The oxygen atom of the solvent molecule (CH₃OH) is involved in O–H···O intermolecular interaction.     

Organic/inorganic hybrid compound: α-Dodecamolybdophosphoric acid–3-(4,5-diazafluoren-one)-3–water

In the title compound (C₁₁H₆N₂O)₃·H₃PMo₁₂O₄₀·3H₂O(1), the -dodecamolybdophosphoric acid residue has the Keggin structure, with M–O distance ranging between 1.673(5) and 2.464(4) Å. The water molecules are involved in O–H···N and O–H···O intermolecular hydrogen bonds with the diazafluoren moiety and -dodecamolybdophosphoric acid respectively while the diazafluoren moiety and -dodecamolybdophosphoric acid are connected through C–H···O interactions. The O–H···O intermolecular hydrogen bonds form infinite chains of Mo₁₂O₄₀ units in which N···O contacts interconnect the chains to form layers.     

Absolute Configuration Determination of Two Optically Active Cyclopropyl-Ketoacids: (1′S, 3S) 3-(2′,2′-Dichloro-1′-methyl-cyclopropyl)-6-oxo-heptanoic acid and (1′S, 3S) 3-(2′,2′-Dibromo-1′-methyl-cyclopropyl)-6-oxo-heptanoic acid

Abstract  

The title compounds C₁₁H₁₆Cl₂O₃ (III) and C₁₁H₁₆Br₂O₃ (IV) have been prepared from (S)-Limonen. Their crystal structure and absolute configuration have been determined by X-ray analysis which confirmed the 1′S absolute configuration at the cyclopropyl moiety, in agreement with the known absolute configuration of the starting material. Both (III) and (IV) are orthorhombic, space group P2₁2₁2₁ with a = 7.2558(4) ? (for III) 7.4058(6) ? (for IV), b = 9.7885(5) ? (for III) 9.7459(7) ? (for IV), c = 17.7551(10) ? (for III) 18.0354(14) ? (for IV), α = 90°, β = 90°, γ = 90° and Z = 4.     

Growth, structure, and properties of ferroelectric—ferroelastic— superionic K3Nb3B2O12 and K3−x NaxNb3B2O12 crystals

The potassium niobate-borate K₃Nb₃B₂O₁₂ (KNB) crystals and their solid solutions with partial substitution of potassium by sodium (KNB: Na) are grown from flux and their physical properties are studied. The specific feature of the crystals grown is a complicated polymorphism and the unique combination of ferroelectric and ferroelastic properties with superionic conductivity with respect to potassium ions.     

Crystal structure of 2,2,3-trimethyl-3-(2′,4′,5′-tricyanophenyl) cyclopentyl-1-acetic acid, methyl ester, C20H21N3O2

The title compound crystallizes in space group P2₁/n, with a = 14.600(2), b = 7.091(2), c = 18.211(5) Å, and = 103.67(2)°. Owing to the centric space group, both C(1) and C(3) chiral centers are either R or S. The acetate group is equatorial, the H(1) and the methyl group at C(3) are axial and reciprocally trans.     

Synthesis and Structures of Two Functionalized Isobenzofurans: (3aR,7aR,4S,5S)-1,3,3a,4,5,7a-Hexahydro-5-methyl-3-oxoisobenzofuran-4-carboxylic acid and (3aα,4β,7β,7aα)-4-[(Acetyloxy)methyl]-3a,4,7,7a-tetrahydro-7-methyl-1,3-isobenzofurandione

Abstract  

The title compounds, C₁₀H₁₂O₄ and C₁₂H₁₄O₅, were prepared as part of an ongoing study to explore the practical aspects of solventless reaction methods. As confirmed by the crystal structures, treatment of maleic anhydride with (2E,4E)-hexa-2,4-dien-1-ol or its acetate counterpart resulted in cis bicyclo [4.3.0] molecular frameworks. The racemic product derived from the dienol synthon crystallized in chiral space group P2₁2₁2₁ via a pasteurian resolution process with molecules organized by carboxyl⋯carboxyl and C–H⋯O contacts. The acetate derivative crystallizes in space group Cc.     

Unusual Temperature-Dependence of the Cholesteric Pitch of Pure Methyl 3β-Nonanoyloxychol-5-en-24-oate

New derivatives of 3β-hydroxychol-5-enoic acid have been prepared. Their purities were checked by TLC, IR, PMR and DSC. It was found that the cholesteric pitch of methyl 3β-nonanoyloxychol-5-en-24-oate (I) exhibits a non-typical increase with increasing temperature. Since this phenomenon occurs in the visible light range, it may eventually be of great practical importance.     

Annulated bicyclo[2.2.2]octenones: 9-hydroxy-9-chloromethyl-endo-tricyclo[5.2.2.02,6]undeca-4,10-diene-3-spiro(1′-cyclopropane)-8-one and 12-hydroxy-12-chloromethyl-endo-tricyclo [8.2.2.02,9]tetradeca-13-en-11-one

A single crystal X-ray diffraction study of two annulated bicyclo[2.2.2]octenones has been carried out to establish their precise stereostructures. The compounds, with their crystal data, are:1, 9-hydroxy-9-chloromethyl-endo-tricyclo[5.2.2.0^2,6]undeca-4,10-diene-3-spiro(1-cyclopropane)-8-one, C₁₄H₁₅O₂Cl, space group P2₁/c,a=10.540(2),b=9.668(1),c=11.841(4)Å, =95.67(2)°,Z=4, and2, 12-hydroxy-12-chloromethyl-endo-tricyclo[8.2.2.0^2,9]tetradeca-13-en-11-one, C₁₅H₂₁O₂Cl, space group C2/c,a=20.747(8),b=6.498(1),c=20.525(3)Å, =93.04(3)°,Z=8. The molecule of1 has endo stereochemistry at the ring junction and the spirocyclopropane ring is proximal to the hydroxyl group. In2, the eight membered ring deviates from a chair conformation and one ring atom is disordered. Crystals of1 and2 contain centrosymmetric dimers formed by C=O...O–H hydrogen bonds.     

Crystal structure of (ethylenediammonium-N,N′-di-3-propanoic acid) tetrachloropalladate(II) complex

The title compound was obtained by a synthesis from ethylenediamine-N,N-di-3-propanoic acid dihydrochloride (H₂eddp2HCl) and potassium hexachloropalladate(IV) (molar ratio 1:1, in water). Its structure has been determined by single-crystal X-ray diffraction: monoclinic space group P2₁/n, a = 8.198(1), b = 10.282(1), c = 9.080(1) Å, = 103.62(1)°, V = 743.9(2) ų, and Z = 2. The dianionic complex has a square-planar coordination geometry with four chloro ligands, and ethylenediamine-N,N-di-3-propanoic acid as dication in the second coordination sphere. This is the first reported Pd(II) structure with uncoordinated H₂eddp.     

Crystal and molecular structure of 4-(3-indolyl)butyric acid-picric acid 2/2 π complex

The title compound, IBA-PIC, is 2C₁₂H₁₃NO₂·2C₆H₃N₃O₇, triclinic,P¯1,a=7.137(1),b=15.355(4),c=18.282(5) Å,=79.72(2),=79.85(2), =76.87(2)°. The structure was solved by direct methods and refined by least-squares techniques to anR factor of 0.068 for 3395 observed reflections. The IBA-PIC complex occurs as two independent molecules with different conformations. The crystallographic evidence for a prominent overlapping between the phenyl and indole rings corroborates earlier conclusions from UV spectroscopy. Molecules of both IBA and picric acid lie approximately parallel to (100) in layers and -bonding interactions across the 3.55 Å spacing. The angles between the indole ring and carboxyl-group planes are 82.9 and 86.9° for the A and B molecules, respectively.     

新型闪烁晶体Gd3(Al,Ga)5O12:Ce3+的研究进展

无机闪烁晶体在核辐射探测领域有重要的应用,铈掺杂铝酸钆镓(Gd3(Al,Ga)5O12:Ce,缩写为GAGG:Ce)闪烁晶体性能优良,在高能物理、γ相机等应用领域有广阔的应用前景,因此成为了当前闪烁体领域的研究热点.本文总结了GAGG:Ce闪烁晶体近年来主要的研究进展;分析了GAGG:Ce晶体的结构及其稳定性;阐述了反位缺陷对晶体发光性能的影响;通过"带隙工程"理论解释了Gd、Ga离子掺杂消除反位缺陷的机理;总结了近年来GAGG:Ce晶体生长中存在的问题及解决途径;梳理了GAGG:Ce晶体的发光机理、闪烁性能及其影响因素;对各国团队通过阳离子掺杂的"缺陷工程"理论抑制GAGG:Ce晶体闪烁衰减慢分量的研究进行分析总结;展望了GAGG:Ce闪烁晶体发展方向.     

Crystal Structure of Ozagrel Fumarate dihydrate (Ozagrel = (E)-3-[4-(1H-imidiazol-1-ylmethyl)phenyl]-2-propenic acid)

Abstract  

Ozagrel, (E)-3-[4-(1H-imidiazol-1-ylmethyl)phenyl]-2-propenic acid, crystallizes with fumaric acid in absolute ethanol to give the dihydrous fumarate salt, [(C₁₃H₁₃N₂O₂)₂]²⁺ [C₄H₂O₄]²⁻·2H₂O, which crystallizes in the monoclinic space group P2(1)/n with a = 4.7981(19), b = 11.101(6), c = 26.930(11) Å, β = 90.567(16)°, V = 1434.3(11) Å³, Z = 4, C₁₅H₁₆N₂O₅, M _r  = 304.30, D _c  = 1.409 g/cm³. In the crystal structure, fumaric acid transfers two protons to imidazole ring N atoms of ozagrel. And the resulting carboxylate anions are simultaneously hydrogen-boned to carboxylic group and imidazole ring of ozagrel to give rise to a 2D layer structure. Hydrogen-bonding interactions between water and fumarate dianion result in a 3D structure.