ABSTRACT
THE TITLE COMPOUND [SYSTEMATIC NAME: (3bS,5aS,7R,8R,10aR,10bS)-7-meth-oxy-10b-methyl-3b,4,5,6,7,8,9,10,10a,10b,11,12-dodeca-hydro-5a,8-methano-5aH-cyclo-hepta-l[5,6]naph-tho[2,1-b]furan-7-methanol], C(21)H(30)O(3), was isolated from the beans of Coffea robusta. The mol-ecule contains five fused rings including a furan ring. The two six-membered rings are in chair conformations, but the third six-membered ring and the five-membered aliphatic ring adopt envelope conformations. Inter-molecular O-Hâ¯O hydrogen bonding is present in the crystal structure.
ABSTRACT
In the title solvate, C(30)H(39)NO(5)·CH(4)O {systematic name: 21-acet-oxy-18,21-dihy-droxy-5,6,16,18-tetra-methyl-10-phenyl-6,7-ep-oxy-[11]cytochalasa-13,19-dien-1-one methanol solvate}, the organic mol-ecule exhibits the tetra-cyclic terpenoid skeleton of cytochalasin, consisting of fused five-, six-, three- and 11-membered rings. The five-membered ring adopts an envelope conformation, while the six-membered ring is in a boat conformation. The ep-oxy O atom on the six-membered ring is pointing away from the five-membered ring. An inter-stitial methanol solvent mol-ecule is hydrogen bonded to the cytochalasin mol-ecules and inter-molecular O-Hâ¯O and N-Hâ¯O hydrogen bonds connect the mol-ecules into infinite chains along the (10) direction.
ABSTRACT
Cluster's last stand: Six chiral reduced Schiff base ligands containing amino acids and seven La(III) ions self-assemble to form a novel heptameric lanthanum supramolecule with the aid of the CO(3)(2-) ion (see picture). The cluster exists as a single chiral triple helix. The CO(3)(2-) ion, which is derived from atmospheric CO(2) , adopts a rare mu(3)-tridentate bridging mode that links three La(III) ions, thus allowing the cluster to efficiently fix CO(2).
ABSTRACT
The title compound, C(20)H(30)O(2), is an ent-atisane diterpenoid which was isolated from the roots of Euphorbia kansuensis. The mol-ecule contains five six-membered rings, among which three six-membered rings of the bicyclo-[2.2.2]octane unit adopt boat conformations and two cyclo-hexane rings adopt chair conformations. In the crystal structure, mol-ecules are connected by inter-molecular O-Hâ¯O hydrogen bonds, forming zigzag chains propagating parallel to [001].
ABSTRACT
A new ligand, N,N'-dibenzylethane-1,2-diamine (L) and its four transition metal(II) complexes, ML(2)(OAc)(2).2H(2)O (M=Cu, Ni, Zn, Co), have been synthesized and characterized by elemental analysis, mass spectra, molar conductivity, NMR and IR. Moreover, the crystals structure of Cu(II) and Ni(II) complexes characterized by single crystal X-ray diffraction showed that the complexes have a similar molecular structure. Ni(II) has an regular octahedral coordination environment complexes, but typical Jahn Teller effect influenced Cu(II) in an elongated octahedral environment. The interaction between complexes and calf thymus DNA were studied by UV and fluorescence spectra measure, which showed that the binding mode of complexes with DNA is intercalation. Under physiological pH condition, the effects of Cu(OAc)(2)L(2).2H(2)O and Ni(OAc)(2)L(2).2H(2)O on human serum albumin were examined by fluorescence. The results of spectroscopic measurements suggested that the hydrophobic interaction is the predominant intermolecular force. The enthalpy change DeltaH(0) and the entropy change DeltaS(0) of Cu(OAc)(2)L(2).2H(2)O and Ni(OAc)(2)L(2).2H(2)O were calculated to be -11.533 kJ mol(-1) and 46.339 J mol(-1)K(-1), -11.026 kJ mol(-1) and 46.396 J mol(-1)K(-1), respectively, according to the Scatchard's equation. The quenching mechanism and the number of binding site (n approximately 1) were also obtained from fluorescence titration data.
Subject(s)
DNA/chemistry , Intercalating Agents/chemistry , Organometallic Compounds/chemistry , Serum Albumin/chemistry , Binding Sites , Cobalt/chemistry , Copper/chemistry , DNA/metabolism , Diamines/chemistry , Humans , Hydrogen-Ion Concentration , Intercalating Agents/metabolism , Kinetics , Ligands , Models, Molecular , Nickel/chemistry , Spectrometry, Fluorescence , Thermodynamics , Transition Elements/chemistry , X-Ray Diffraction , Zinc/chemistryABSTRACT
OBJECTIVE: To study the chemical constituents in the aerial part of Acalypha australis. METHOD: The aerial part of Acalypha australis were extracted with EtOH at room temperature. The compounds were separated by various kinds of chromatographic methods and their structures were identified on the basis of spectroscopic techniques. RESULT: Eleven compounds have been isolated and identified: emodin (1), beta-sitosterol (2), loliolide (3), 2,6-dimethoxy-1,4-benzoquinone (4), nicotinic acid (5), protocatechuic acid (6), daucosterol (7), gallic acid (8), rutin (9), succinic acid (10), brevifolin (11). CONCLUSION: Compounds 1, 3-5, 10 and 11 were obtained from A. australis for the first time.
Subject(s)
Euphorbiaceae/chemistry , Plant Components, Aerial/chemistry , Drugs, Chinese Herbal/chemistry , Ethanol/chemistry , Magnetic Resonance Spectroscopy , Organic Chemicals/analysis , Organic Chemicals/isolation & purification , Spectrometry, Mass, Electrospray IonizationABSTRACT
Two new cucurbitacins, endecaphyllacins A (1) and B (2), together with six known analogues (3-8), were isolated from the tubers of Hemsleya endecaphylla. The structures of 1 and 2 were elucidated by NMR and MS spectroscopic analysis. The relative stereochemistry of 1 was determined by single-crystal X-ray diffraction. Compound 4 (cucurbitacin B) showed potent anti-HIV-1 in C8166 cells (EC=0.09 microg/mL) with a selectivity index of 16.7.
Subject(s)
Anti-HIV Agents/isolation & purification , Anti-HIV Agents/pharmacology , Cucurbitaceae/chemistry , Drugs, Chinese Herbal/isolation & purification , Drugs, Chinese Herbal/pharmacology , HIV-1/drug effects , Plants, Medicinal/chemistry , Triterpenes/isolation & purification , Triterpenes/pharmacology , Anti-HIV Agents/chemistry , Crystallography, X-Ray , Drugs, Chinese Herbal/chemistry , Molecular Structure , Plant Tubers/chemistry , Triterpenes/chemistryABSTRACT
THE TITLE COMPOUND (COMMON NAME: 3ß-acet-oxy-8-epi-sclareolide), C(18)H(28)O(4), is a sclareolide derivative, which was synthesized from 9(11)-en-3ß-acet-oxy-8-epi-sclareolide. In the mol-ecular structure, the two six-membered rings display chair conformations and the five-membered ring displays an envelope conformation. Weak inter-molecular C-Hâ¯O hydrogen bonding is present in the crystal structure.
ABSTRACT
The title compound, C(20)H(26)NO(2) (+)·Br(-), is an N-chiral quaternary ammonium salt synthesized from (2S*)-N-benzyl-N-methyl-tyrosine methyl ester. The dihedral angle between the phenyl ring and the benzene ring is 11.61â (19)°. In the crystal structure, the allyl group is disordered over two positions with site occupancy factors of ca 0.8 and 0.2. The bromide anion links to the quaternary ammonium cations via O-Hâ¯Br hydrogen bonding. An intramolecular O-Hâ¯Br hydrogen bond is also observed.
ABSTRACT
Three novel metal-organic architectures, [Ag3(bta)].1.5H2O (1), [Cd3(bta)2(H2O)7].5H2O (2), and [Cu11(bta)6(Hbta)2(H2O)10].29H2O (3), were obtained by reactions of the corresponding metal salts with a flexible tripodal ligand, benzene-1,3,5-triacetic acid (H3bta), and their structures were determined by single-crystal X-ray diffraction studies. The results revealed that, in complexes 1 and 2, the carboxylate groups of the bta3- ligand adopted varied coordination modes to link metal atoms and further to form three-dimensional structures with open channels occupied by water molecules, while in complex 3, for the first time, the flexible H3bta acted as a secondary building unit to generate a novel nanometer-sized metallocage, which is composed of a Cu(II) paddle wheel (square secondary building units) and bta3-/Hbta2- organic links (triangular secondary building units). The photoluminescence properties of complexes 1 and 2 were investigated, and the results showed that 2 exhibited photoluminescence in the solid state at room temperature.
Subject(s)
Acetates/chemistry , Cadmium/chemistry , Copper/chemistry , Organometallic Compounds/chemistry , Silver/chemistry , Crystallography, X-Ray , Ligands , Luminescence , Models, Molecular , Molecular ConformationABSTRACT
The title compound, [Cu(2)(OH)(2)(C(12)H(8)N(2))(2)(H(2)O)(2)][Cu(C(10)H(9)NO(5)S)(2)].6H(2)O, is comprised of a copper-centred complex cation and a copper-centred complex anion; the cation lies about an inversion centre and in the anion the Cu atom lies on an inversion centre. In the doubly charged bridged dicopper cation, each Cu centre has distorted square-pyramidal geometry. In the square-planar dianion, two sulfonate ligands are trans coordinated to the Cu atom via a deprotonated hydroxyl O atom and an imine N atom, forming two six-membered chelate rings. The structure is stabilized by an extensive hydrogen-bond system and aromatic-ring stacking interactions.
ABSTRACT
The crystal structure of a cholor-bisabolene sesquiterpene has been determined for the absolute configuration. Its structure was elucidated as (-)-(1R,2R,3R,4R,6S,8S,10S)-chloro-2,10-diacetoxy-1,8-diangeloyloxy-3-hydroxy-11-methoxy-bisabol-7(14)-ene. The chlorine atom at C4 is axial in the cyclohexane ring. The molecule shows a stable chair conformation, and crystallizes in the monoclinic space group P2(1) with one molecule in the asymmetric unit.
Subject(s)
Hydrogen-Ion Concentration , Sesquiterpenes/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Bacteria/drug effects , Cell Line, Tumor , Crystallography, X-Ray , Drug Screening Assays, Antitumor , Humans , Microbial Sensitivity Tests , Models, Molecular , Molecular Conformation , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Six noninterpenetrating organic-inorganic hybridized coordination complexes, [Mn(3)(2)(H(2)O)(2)](ClO(4))(2).2 H(2)O (5), [Mn(3)(2)(H(2)O)(2)](NO(3))(2) (6), [Mn(3)(2)(N(3))(2)].2 H(2)O (7), [Cu(3)(2)(H(2)O)(2)](ClO(4))(2) (8), [Mn(4)(2)(H(2)O)(SO(4))].CH(3)OH.5 H(2)O (9) and [Mn(4)(2)](ClO(4))(2) (10) were obtained through self-assembly of novel tripodal ligands, 1,3,5-tris(1-imidazolyl)benzene (3) and 1,3-bis(1-imidazolyl)-5-(imidazol-1-ylmethyl)benzene (4) with the corresponding metal salts, respectively. Their structures were determined by X-ray crystallography. The results of structural analysis of complexes 5, 6, 7, and 8 with rigid ligand 3 indicate that their structures are mainly dependant on the nature of the organic ligand and geometric need of the metal ions, but not influenced greatly by the anions and metal ions. While in complexes 9 and 10, which contain the flexible ligand 4, the counteranion plays an important role in the formation of the frameworks. Entirely different structures of complexes 5 and 10 indicate that the organic ligands greatly affect the structures of assemblies. Furthermore, in complexes 5 and 6, the counteranions located between the cationic layers can be exchanged by other anions. Reversible anion exchanges between complexes 5 and 6 without destruction of the frameworks demonstrate that 5 and 6 can act as cationic layered materials for anion exchange, as determined by IR spectroscopy, elemental analyses, and X-ray powder diffraction.
ABSTRACT
On the basis of the principle that the incorporation of the structurally rigid and conformationally restricted skeleton in beta-amino alcohols is beneficial to the enantioselective diethylzinc addition to imines, a series of chiral oxazolines, which had been designed and conveniently prepared from commercially available (1S,2S)-2-amino-1-phenylpropane-1,3-diol, were applied in the diethylzinc addition to diphenylphosphinoyl imines to give high yields of 68-84% and excellent ee values of 90-95%. The configuration of the product was controlled by the chirality of the carbon bonded to the hydroxyl group in the oxazoline. Oxazolines bearing a para- or meta-substituted phenyl group generally offered higher enantioselectivity than those containing an ortho-substituted phenyl. The X-ray structures of 4f and 4j, in combination with the proposed transition state, preliminarily explained why oxazolines with a para- or meta-substituent on the phenyl group gave higher enantioselectivities than those bearing an ortho-substituent. This successful example using chiral oxazolines to promote the titled reaction implies that a large family of chiral compounds containing an oxazoline ring moiety have the potential to be developed for promoting the highly enantioselective dialkylzinc addition to N-(diphenylphosphinoyl) imines.
ABSTRACT
[(CuimZnL-2H)(CuimZnL-H)](ClO4)3, the first imidazolate-bridged Cu(II)-Zn(II) complex of a unique single macrocyclic ligand with two flexible hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22.2.2.2(11,14)]triaconta-1,11,13,24,27,29-hexaene) has been obtained, in which the macrocyclic ligand with two hydroxyethyl arms possesses a markedly different conformation compared to its dicopper analogue.
ABSTRACT
The adduct of piperazine, o-phthalic acid and water (1:2:2), C20H26N2O10, crystallizes in the monoclinic space group P21/c with a = 6.129(1), b = 12.810(2), c = 13.137(2)A, beta = 95.87(1) degrees, V = 1026.0(3)A3, Z = 2. The piperazinium adopts a chair comformer, and is tied with the hydrogen orthophthalate via a hydrogen bond of the N-H...O type. Because of bifurcated hydrogen bonding of C(sp3)H-O [3.0801(17) and 3.1408(18)A] and the shortest hydrogen bond of C(sp3)H-O [2.9758(17)A], C(sp3)H-O hydrogen bonds play important roles in stablizing the title adduct.
ABSTRACT
In the title supramolecular complex, [Ag(2)Cl(2)(C(4)H(5)N(3))(C(18)H(15)P)(2)](n), a one-dimensional chain is formed by dimeric [Ag(2)Cl(2)(PPh(3))(2)] units bridged by 2-aminopyrimidine moieties. The Ag atoms are four-coordinate, with an AgCl(2)NP core. A crystallographic inversion centre is located in the centre of the Ag(2)Cl(2) chelate ring, while the crystallographic twofold axis bisects the 2-aminopyrimidine ligand.
ABSTRACT
Two 3D supramolecular complexes [Cu(2)(trans-oxpn)(phth)](n)().2nH(2)O, 1, and [Cu(2)(trans-oxpn)(&mgr;-OH)(&mgr;-H(2)O)](n)()Br(n)().2nH(2)O, 2 [H(2)oxpn = N,N'-bis(3-aminopropyl)oxamide, phth = phthalate], were synthesized and characterized by single-crystal X-ray crystallography, thermal analyses, and magnetic measurements. 1 crystallizes in the monoclinic space group P2(1)/c with a = 8.578(2) Å, b = 15.596(2) Å, c = 15.657(2) Å, beta = 101.29(2) degrees, Z = 4; 2 crystallizes in the trigonal space group R&thremacr;c with a = 15.266(2) Å, b = 15.266(2) Å, c = 34.953(5) Å, and Z= 18. The neutral 2D sheetlike coordination polymer [Cu(2)(trans-oxpn)(phth)](n)() in 1 contains alternate trans-oxamidate and phthalate bridges and then is joined together by H(2)O molecules via the hydrogen bond linkage Cu(oxpn).H(2)O.H(2)O.(oxpn)Cu to produce a 3D supramolecular structure. The cationic chains [Cu(2)(trans-oxpn)(&mgr;-OH)(&mgr;-H(2)O)](n)()(n)()(+) in 2 contain alternate trans-oxamidate, &mgr;-OH, and &mgr;-H(2)O bridges and are arranged in three directions, intersecting with one another to yield an extended network via the interchain hydrogen bonds formed by metal-coordinated OH(-) with the linkages Cu(oxpn)-OH.OH-Cu(oxpn). Magnetic calculations showed the presence of antiferromagnetic exchange interactions for both complexes. The 2D magnetic coupling system of 1 was simplified into interacting dimers Cu(trans-oxpn)Cu, with the coupling via phth as an interdimer interaction and the data were interpreted with a modified Bleaney-Bowers equation leading to J = -456.7 cm(-)(1) and theta = 22.0 K. 2 was analyzed qualitatively by an alternating chain model taking into account the interchain interaction in a molecular model with J(1) = -309.6 cm(-)(1), J(2) = -63.5 cm(-)(1), and theta = -12.9 K, where J(1) and J(2) denote the coupling constants of the bridges oxamidate and &mgr;-OH, respectively.