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.     

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.     

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 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.     

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.     

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.     

Molecular and crystal structure of two nickel(II) 1,2-dithiooxalato-S,S′ complexes using 1-(Rbenzyl)pyridinium cation (R = 4′-bromo-2′-fluoro or 4′-bromo)

[BrFPy]₂[Ni(dto)₂] (1) and [BrPy]₂[Ni(dto)₂] (2) complexes have been prepared by reaction of Na₂[Ni(S₂C₂O₂)₂] and the corresponding 1-(Rbenzyl)pyridinium bromide salt (R₁ = 4-bromo-2-fluoro, R₂ = 4-bromo). The crystallographic data for 1: monoclinic P2₁/c, a = 14.2192(1) Å, b = 14.2533(4) Å, c = 15.6535(3) Å, = 96.463(1)°, V = 3152.34(11) ų, Z = 4. Two cations, [Br₁F₁Py]⁺ and [Br₂F₂Py]⁺, both adopt a conformation where both the aromatic rings are twisted to the corresponding N(1)–C(10)–C(11) or N(2)–C(22)–C(23) reference plane. Data for 2: triclinic , a = 9.4042(3) Å, b = 9.6814(4) Å, c = 10.3357(4) Å, = 80.155(1)°, = 65.245(1)°, = 64.259(1)°, V = 769.68(5) ų, Z = 1. The [Ni(dto)₂]^2– anion exhibits a quasi-planar structure in both complexes. An extensive hydrogen bond network of C–H O is clearly observed in 1 and 2, and two complexes show similar crystal packing.     

Crystal structure of 1-benzyl-5-bromo-2-oxoindol-3-spiro-2′-(4′-benzoyl-1′-methylpyrrolidin)-3′-spiro-3′′-(1′′-methyl-2′′-oxoindole), C34H28N3O3Br

The title compound crystallizes in space group P-1, with a = 10.574(4) Å, b = 11.262(1) Å, c = 12.536(8) Å, = 90.08(3)°, = 103.63(3)°, = 103.35(2)°. Owing to the centric space group, C3, C3, and C4 chiral centers are either [R, S, S] or [S, R, R].     

Synthesis and crystal structure of (S, S, S, S)-N, N′-bis[N-(P-toluenesulfonamido)-1,2-diphenylethyl]ethylenediamine

(S, S, S, S)-N,N′-bis[N-(p-toluenesulfonamido)-1,2-diphenylethyl] ethylenediamine (C₄₄H₄₆N₄O₄S₂), has been synthesized and structurally characterized by elemental analysis, ¹H-NMR, MS, IR and single-crystal X-ray diffraction. The title compound contains four chiral centers with C atoms in S configuration. Molecules are connected to one another by hydrogen bonds between sulfonamide nitrogen and sulfonyl oxygen to form chains alone a axis.     

Preparation,characterisation, and crystal structure analysis of (2<Emphasis Type="Italic">E</Emphasis>,2′<Emphasis Type="Italic">E</Emphasis>)-3,3′-(1,4-phenylene)bis(1-(2-aminophenyl)prop-2-en-1-one

A novel bis-chalcone, (2E,2′E)-3,3′-(1,4-phenylene)bis(1-(2-aminophenyl)prop-2-en-1-one) is synthesized through a base catalyzed Claisen-Schmidt condensation reaction of terephthalaldehyde with 2-aminoacetophenone. Its structure (sp. gr. P\(\bar 1\), Z = 2) is determined from single crystal X-ray diffraction data. There are two independent centrosymmetric molecules with no significant differences in bond lengths and angles between them. The NMR, IR, HRMS, and UV spectral data of the prepared bis-chalcone are presented.     

Crystal structure of 1,3-(N,N′-benzamide)-2-methyl-1-pentene

Crystals of the title compound are monoclinic (C20H22N2O2): space groupP2₁/n,a=11.800(3),b=13.820(2),c=11.004(3) Å,=92.74(3)°. The structure was solved by direct methods and refined by block-matrix least-squares procedure to giveR=0.078 andRw=0.076 for 1960 reflections above 3(I). The two amide groups are not coplanar with respect to their benzene rings. An intramolecular N-HO hydrogen bond was found in the molecules which are joined in chains by other strong N-HO hydrogen bonds.     

The crystal structure of 2-amino-5,5′-bis(β-cyanoethyl)-1,2-pyrrolenineN-oxide monohydrate

2-Amino-5,5-di(-cyanoethyl)-1,2-pyrrolenineN-oxide monohydrate, C₁₀H₁₄N₄O·H₂O, crystallizes from MeCN in space group P2₁2₁2₁ witha=7.0007(5),b=8.2998(6),c=20.8418(13) Å,V=1211.0(2) ų,Z=4. The structure was refined toR=0.034 andR _w=0.044 for 2325 observed reflections. The pyrrolenine ring adopts a nearly planar conformation, with maximum deviation from planarity 0.089(2) Å. The N–O distance is 1.345(2) Å. The water molecule bridges two pyrrolenine molecules via hydrogen bonds to theirN-oxide oxygen atoms, and also accepts a hydrogen bond from the NH₂ group of another pyrrolenine molecule.     

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 crystal structure of (+)-(2R,3R)-N, N′-bis-trityl-2,3-bis-aziridine

A new C₂ symmetric bis-aziridine derivative was synthesized starting from L-(+)-tartaric acid. The molecular structure of (+)-(2R, 3R)-N, N-bis-trityl-2,3-bis-aziridine 4, was determined by ¹H, ¹³C NMR and elemental analysis and was confirmed by single-crystal X-ray diffraction. Crystal data for 4: C₄₂H₃₆N₂, orthorhombic, space group: P2₁2₁2₁, a = 12.7633(14), b = 14.5661(6), c = 17.4184(14) Å, and Z = 4.     

Crystal structure ofβ-C.I. Solvent Yellow 18, 4(2′,4′-dimethylphenyl hydrazono)-5-methyl-2-phenyl-3H-pyrazol-3-one

The crystal structure of-C.I. Solvent Yellow 18, C₁₈H₁₈N₄O, has been determined by single crystal X-ray diffraction techniques. It crystallizes in the monoclinic system witha=30.948(18)Å,b=4.918(4)Å,c=20.861(9)Å,=91.68(4)°, space groupC2/c,Z=8. The structure has been solved by direct methods and least-squares refinement has been completed on three dimensional data (1237 reflections MoK radiation). The hydrogen atoms have been found but only their positional parameters refined. Final residual 0.092 (all intensity data). The molecule exists as the hydrazone tautomer and intramolecular hydrogen bonding keeps the molecule approximately planar. The molecules are packed in columns parallel to theb axis, while the molecule lies approximately parallel to the (51¯3) plane. The molecules are linked by van der Waals' force.     

Spectroscopic studies and crystal structure of (E)-N′-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide

The structure of compound has also been examined cyrstallographically. It crystallizes in the monoclinic space group P2₁/c with a = 7.673(1), b = 16.251(2), c = 10.874(1) Å, β = 110.42(1)°, V = 1270.7(3) ų, D _x = 1.418 g cm^?3, R ₁ = 0.0349 and wR ₂ = 0.0935 [I > 2σ(I)], respectively. The title compound has been synthesized from the reaction of isonicotinohydrazide with 2-hydroxy-3-methoxybenzaldehyde. It has been characterized by using elemental analysis, MS, IR, ¹H NMR, ¹³C NMR and UV-Visible spectroscopic techniques.     

A structural model for a new class of conformationally constrained retinoid: (2Z,4E)-4-[3′,4′-dihydro-1′(2′H)-naphthalene-1′-ylidene]-2-butenoic acid

Racemic (2Z,4E)-4-[3′,4′-dihydro-1′(2′H)-naphthalene-1′-ylidene]-2-butenoic acid (1) is a polyene chain-shortened analog of (9Z)-retinoic acid (3) which uses a tetrahydronaphthyl ring to conformationally constrain the C6-C7 single bond (retinoic acid numbering). The structure of (1) was obtained to determine the effects of the tetrahydronaphthyl ring on the ring to polyene chain conformation as compared to a published crystal structure for (9Z)-retinal (2). The results reveal significant differences between the solid state structures of (1) and (2), particularly for torsion angles about C6, C7 and C8, C9. The title compound crystallizes in the centrosymmetric monoclinic space groupP2₁/n withZ=4. (Cell dimensions:a=10.863(2) Å,b=7.637(2) Å,c=15.781(3) and β=106.11(3)°.) The structure was refined toR=3.88% for those 1132 unique data with |F _o|>6σ(F _o). In the crystal structure, the molecules adopt a hydrogen bonded dimeric structure.     

X-ray structure investigation of two polymorphic modifications of 1-acetyl-3-(4-nitrophenyl)-5-(2′-furyl)pyrazoline

Two polymorphic modifications of 1-acetyl-3-(4-nitrophenyl)-5-(2′-furyl)pyrazoline (I) are investigated by X-ray diffraction with the purpose of analyzing the factors responsible for the formation of crystal structures of the optical nonlinear organic compounds. Both modifications crystallize simultaneously upon slow evaporation of a solution of compound I in an isopropanol-acetonitrile (3: 1) mixture. It is found that the molecular geometry of the polymorphic modifications is characterized by the rotation of the furan substituent with respect to the plane of the pyrazoline ring. The molecular hyperpolarizabilities (β) of both conformers are calculated.     

Crystal structure of 4-phenyl-3,5-dioxacyclohexyl-1, 1′-cyclopentane-2′,3″-(1,5,8,11-tetraoxacyclotridecane)

The structure of the title compound is determined by X-ray diffraction (DAR-UMB diffractometer, θ-θ/2θ scan mode, MoK _α radiation, direct method). The crystal is monoclinic, a = 24.582(6) Å, b = 22.812(8) Å, c = 8.647(3) Å, γ = 60.64(2)°, ρ _calcd = 1.232 g/cm³ space group A2/a, and Z = 8 for C₂₂H₃₂O₆. The molecule consists of four fragments: 13-crown-4 (A), 1,3-dioxane (B), a five-membered ring (C) acting as a bridge between fragments A and B, and a phenyl ring (D). Introduction of the bulky ring C as a bridge into the molecule results in significant deviations (up to ±0.014 Å) of the ether O atoms from planarity. The conformation of the macrocyclic fragment is [3433] according to the Dale notation. The C—H?O 1,4-interactions, which are energetically favorable occur in the propylene part of 13-crown-4: the C(2)?O(5) and C(4)?O(1) distances are 2.82 Å. The molecules in the structure form planar networks parallel to the xy plane. The intermolecular contacts correspond to the van der Waals interactions.     

A quasi-layer structure of trinuclear molybdenum(IV) cluster, [Mo3S7(S2CNEt2)3]I·S8

The title compound, [Mo₃(₃-S)(-S₂)₃(S₂CNEt₂)₃]I·S₈, was obtained by solid state reaction of (NH₄)₂MoS₄, Et₂NCS₂Na, and Et₄NI at low heating temperature and crystallizes in space group P with a = 13.572(3), b = 13.813(4), c = 13.239(3) Å, = 92.63(3), = 100.15(3), = 117.89(2)°, V = 2136(2) ų, and D _calc. = 2.08 g/cm³ for Z = 2. The structure reveals that it consists of a trinuclear Mo cluster molecule, [Mo₃S₇(S₂CNEt₂)₃]I, and one S₈, which are connected to form a quasi-layer structure by the interaction between S₈ and the S atoms of the cluster molecule.