Die kristalline und molekulare Struktur von cis-Coleon D,einem cis-A/B-6,7-Diketo-abietan-Derivat

The Crystal and Molecular Structure of cis-Coleon D, a cis-A/B-6,7-Dioxo Derivative of Abietane. The X-ray analysis of cis-Coleon D ( 1 ) confirmed the postulated position of H? C(5) in the plane of the neighbouring keto group. This situation is unfavourable for enolisation, in contrast to the situation where the H? C(5) is perpendicular to the keto plane, as supposed in trans-Coleon D ( 2 ). The α-diketone moiety has a significant (P)-helicity of about 10 (1)°. The acentric crystal structure of cis-Coleon D was determined by direct methods and refined with 1533 structure amplitudes to R = 0.042. The absolute configuration was determined from the known chirality of the A/B-ring junction.     

Modulation of ionization and structural properties of weak polyelectrolytes due to 1D, 2D,and 3D confinement

What is the impact of reducing the space available to molecules onto their properties is a fundamental question for capillary systems, molecular biology and transport, protein and material sciences. Possibly influenced by space restriction, ionization degree has rarely been studied for confined polyelectrolytes; Monte Carlo titrations and coarse‐grained models are thus used to investigate structural and ionization changes induced on a single polyelectrolyte chain by confinement into slit (1D), cylindrical (2D), or spherical (3D) cavities. Four polyelectrolyte models differing in chain stiffness and the possible formation of charged hydrogen bonds (c? H? bonds) are studied. Low pH effective ionization constants (pK_a ) of confined chains are lower than for the free species if c? H? bonds can be formed. This is especially evident for 3D‐confined stiff chains, a finding rationalized by the impact of global compression onto chain conformations. If no c? H? bonds are allowed, chain ionization is largely unaffected by 1D or 2D confinement, while it is depressed by 3D. Chain confinement Helmholtz energy (ΔA _conf) was computed as a function of both pH and confining width (W) to gauge the impact of ionization‐induced stiffening onto ΔA _conf versus W behavior, the partition coefficient governing absorption, and the average number of c? H? bond formed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 1088–1102     

PALLADIUM DIHALIDE COMPLEXES WITH D,L-ETHIONINE

Abstract

By reaction of palladium halides with D,L-ethionine (D,L-EthH; molar ratio 1:1) in dichloromethane solutions containing an excess of 2,6-dimethyl-4H-pyran-4-one (DMP) [Pd(D,L-EthH)X₂] (X?Cl, Br or I) complexes have been isolated. When the solvent was benzene [Pd(D,L-EthH)X₂].DMP adducts were obtained in which the DMP molecule does not bind to the metal. The complexes have been characterized by infrared and nmr (¹H and ¹³C) spectroscopy and by thermogravimetric measurements (TG, DTG and DTA). The importance of DMP in determining the reaction course is discussed.     

Concerning the acidity and hydrogen bonding of hydroxyphenanthroperylene quinones like fringelite D,hypericin, and stentorin

Summary The strongly enhanced acidity of the bay hydroxyl group as compared to the respectiveperi hydroxyl groups of fringelite D, hypericin, and stentorin could be rationalized on the basis of a vinylogous carboxylic acid and was nicely corroborated by semiempirical calculations of the AM1 type. Experimental data obtained from several independent experimental methods, like polarized absorption spectroscopy, hole burning, and isotope effects, as well as from semiempirical AM1 and 6–31G levelab initio calculations conclusively pointed to dissymmetrical hydrogen bonding systems in both theperi andbay regions of the correspondingbay phenolate ions.

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Zu Acidität und Wasserstoffbrückenbindung von Hydroxyphenanthroperylenchinonen wie Fringelit D, Hypericin und Stentorin

Zusammenfassung Die stark erhöhte Acidität der bay-Hydroxylgruppen gegenüber jener derperi-Hydroxylgruppen von Fringelit D, Hypericin und Stentorin läßt sich auf der Basis einer vinylogen Carbonsäure verstehen und wurde auch durch semiempirische Rechnungen vom AM1-Typ erhärtet. Daten aus unabhängigen Experimenten wie Polarisationsspektroskopie, Lochbrennen und Isotopeneffekte sowie semiempirische AM1- undab initio-Rechnungen auf 6–31G Niveau belegen ein unsymmetrisches Wasserstoffbrückenbindungssystem sowohl für denperi-als auch denbay-Bereich der entsprechendenbay-Phenolationen.

     

Total Synthesis of Aculenes B and D

The first total synthesis of aculene D, a structurally rare nordaucane-type natural product exhibiting quorum sensing inhibitory activity, has been accomplished from a known five-membered hydroxy carboxylic acid. Nucleophilic addition of methallylzinc bromide to a β-keto aldehyde intermediate under Barbier conditions to install the secondary hydroxy group on the seven-membered ring of aculene D gave the corresponding alcohol with an undesired configuration predominantly. On the other hand, the protection of its keto group as the ethylene acetal induced a reversal of diastereoselectivity, affording a desired diastereomer in a selective manner. The construction of the seven-membered ring was realized by ring-closing metathesis using a triethylsilyl-protected monocyclic diene ester precursor. An additional five-step manipulation on the cyclization product including the installation of an ethyl group on the five-membered ring completed the synthesis of aculene D, whose esterification with an N-protected l -proline followed by deprotection also achieved the first total synthesis of aculene B.     

Synthesis and properties of fringelite D (1,3,4,6,8,10,11,13-octahydroxy-phenanthro[1,10,9,8,o,p,q,r,a]perylene-7,14-dione)

Summary Fringelite D was synthesized from 1,3,6,8-tetramethoxyanthracen-9-olvia two different efficient routes. The first one involved demethylation and subsequent dimerization. The other one started with dimerization to yield octamethylfringelite D and subsequent demethylation. The starting material was prepared in four steps from commercially available educts, the key step being a benzamideortho-lithiation. The spectroscopic properties of fringelite D were measured and are discussed. The dissociation, deprotonation, and protonation equilibria of fringelite D were characterized by their respectivepK values in ground and excited states and compared with those of hypericin. Homo- and heteroassociation properties of fringelite D were found to be similar to those of hypericin.

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Synthese und Eigenschaften von Fringelit D (1,3,4,6,8,10,11,13-Octahydroxy-phenanthro[1,10,9,8,o,p,q,r,a]perylen-7,14-dion)

Zusammenfassung Fringelit D wurde auf zwei effizienten Routen aus 1,3,6,8-Tetramethoxyanthracen-9-ol synthetisiert. Die erste umfaßt Demethylierung und anschließende Dimerisierung. Die andere beginnt mit der Dimerisierung zu Octamethylfringelit D und endet mit einer Demethylierung. Das Ausgangsmaterial wurde in vier Stufen aus kommerziell zugänglichen Edukten dargestellt; der Schlüsselschritt ist eineortho-Lithiierung eines Benzamids. Die spektroskopischen Eigenschaften von Fringelit D wurden gemessen und werden diskutiert. Die Dissoziations-, Deprotonierungs- und Protonierungsgleichgewichte wurden durch ihrepK-Werte in Grundzustand und angeregtem Zustand charakterisiert und mit jenen des Hypericins verglichen. Die Homo- und Hetero-assoziationseigenschaften von Fringelit D sind jenen des Hypericins ähnlich.

     

Rastronole A,B, C,D, E,F, G und H; eine Gruppe multioxygenierter Diterpenbitterstoffe der ent-Kauran-Reihe aus Englerastrum scandens ALSTON

Rastronols A, B, C, D, E, F, G, and H, a group of multioxygenated bitter principles with ent-kaur-16-en-15-one structure from Englerastrum scandens ALSTON (Labiatae) We have isolated from the leaves of Englerastrum scandens from Kenya eight new, highly oxygenated ent-kaur-16-en-15-ones named rastronol A, B, C, D, E, F, G, and H, and determined their structures mainly by spectroscopic techniques as 1, 8, 14, 17, 20, 29, 39 , and 51 respectively.     

Total Synthesis and Absolute Configuration of Epicoccamide D,a Naturally Occurring Mannosylated 3‐Acyltetramic Acid

The endofungal metabolite epicoccamide D was synthesised in eighteen steps and 17 % yield as the first member of the family of natural glycotetramic acids. The modular character of the synthesis opens access also to analogues featuring different sugars and spacers. It comprises several high‐yielding key steps. The β‐D ‐mannosyl group was introduced by using an α‐D ‐glucosyl imidate donor with subsequent oxidative‐reductive epimerisation at C‐2′. The pyrrolidine ring was closed quantitatively by a Lacey‐Dieckmann condensation of an N‐(β‐ketoacyl)‐N‐methyl alaninate. The resulting 3‐[ω‐(β‐D ‐mannosyl)octadec‐2‐enoyl]tetramic acid was hydrogenated in the presence of the rhodium catalyst (R,R)‐[Rh(Et‐DUPHOS)][BF₄] to establish the (7S)‐stereocentre. This was possible only after blocking the acyltetramic acid as a BF₂‐chelate to prevent capture of the metal catalyst. We also assigned the hitherto unknown configuration of the natural product as being 5S,7S by comparison of its ¹³C NMR spectroscopic and optical rotation data with those of our two synthetic 5S,7R/S‐diasteromers.     

Design of polylactide-grafted copolymeric stabilizer for dispersion polymerization of D,L-lactide

Poly(D,L-lactide) (PDLLA) microspheres with narrow diameter distribution were prepared by dispersion polymerization of D,L-lactide in xylene/heptane (1:2, v/v) using poly(dodecyl methacrylate)-g-poly(D,L-lactide) (PDMA-g-PDLLA) as a dispersion stabilizer. The particle diameters of PDLLA microspheres were controlled from 200 nm to 5 μm by altering the concentration and the graft chain number of PDMA-g-PDLLA. The effect of the copolymer composition on the particle diameter was investigated to clarify an important factor of the copolymer structure for the control of the particle diameter. As a result, it was necessary for anchor block in diblock copolymer as a dispersion stabilizer to have low solubility in the solution rather than the compatibility with particles. Moreover, we confirmed by dynamic light scattering measurement that PDMA-g-PDLLA formed micelles in the solution. In conclusion, it was clarified that PDLLA microspheres with a wide range of particle diameter were prepared due to the different kinetic stability of micelles.     

Bruceines D,E and H

The absolute stereochemistry of bruceines D, E and H has been confirmed to be 1S, 5S, 7R, 8R, 9R, 10S, 11R, 12S, 13R, 14R, 15R and additionally 2S for bruceine E by a combination of 2D nmr [¹H-¹H and ¹H-¹³C (one-bond and long-range) COSY] nOe and cd spectroscopic analyses.     

Partialsynthese der Grandidone A, 7-Epi-A,B, 7-Epi-B,C, D und 7-Epi-D aus 14-Hydroxytaxodion

Partial Synthesis of Grandidones A, 7-Epi-A, B, 7-Epi-B, C, D and 7-Epi-D, from 14-Hydroxytaxodione Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved.     

Dimension Engineering of Stimuli-Responsive 1D Molecular Crystals into Unusual 2D and 3D Zigzag Waveguides

We demonstrate an innovative technique to achieve organic 2D and 3D waveguides with peculiar shapes from an acicular, stimuli-responsive molecular crystal, (2Z,2′Z)-3,3′-(anthracene-9,10-diyl)bis(2-(3,5-bis(trifluoromethyl)phenylacrylonitrile), Ant-CF₃. The greenish-yellow fluorescent (FL) Ant-CF₃ molecular crystals exhibit laser power-dependent permanent mechanical bending in 2D and 3D. Investigation of a single-crystal using spatially-resolved Raman/FL/electron microscopy, and theoretical calculations revealed photothermal (Z,E)/(E,E) isomerization-assisted transition from crystalline to amorphous phase at the laser-exposed regions. This phenomenon facilitates the dimension engineering of a 1D crystal waveguide into 2D waveguide on a substrate or a 3D waveguide in free space. The bends can be used as interconnection points to couple different optical elements. The presented technique has broader implications in organic photonics and other crystal-related photonic technologies.     

3D Electron Diffraction Structure Determination of Terrylene,a Promising Candidate for Intermolecular Singlet Fission

Herein we demonstrate the prowess of the 3D electron diffraction approach by unveiling the structure of terrylene, the third member in the series of peri-condensed naphthalene analogues, which has eluded structure determination for 65 years. The structure was determined by direct methods using electron diffraction data and corroborated by dispersion-inclusive density functional theory optimizations. Terrylene crystalizes in the monoclinic space group P2₁/a, arranging in a sandwich-herringbone packing motif, similar to analogous compounds. Having solved the crystal structure, we use many-body perturbation theory to evaluate the excited-state properties of terrylene in the solid-state. We find that terrylene is a promising candidate for intermolecular singlet fission, comparable to tetracene and rubrene.     

Lucidumol D,a new lanostane-type triterpene from fruiting bodies of Reishi (Ganoderma lingzhi)

A new lanostane-type triterpenoid, lucidumol D (1) was isolated from the fruiting bodies of Ganoderma lingzhi. Its structure was elucidated on the basis of extensive 1D- and 2D-NMR studies as well as mass spectrometry. The cytotoxicity of lucidumol D against proliferation of several cancer cells were assayed by using MTT method and the obtained result suggested selective anti-proliferative and cytotoxic effects against MCF-7, HepG2, HeLa, Caco-2, and HCT-116. In comparison to lucidumol C (2) isolated previously by our group, the structure-activity relationship indicated that carbonyl function at C-11 is necessary to enhance the cytotoxicity.     

Hydrothermal synthesis, crystal structure and magnetic property of oxalate-bridged iron 1D chain coordination polymer

A novel oxalate-bridged iron coordination polymer, Fe₂(phen)₂(C₂O₄)₂ (1) has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, TGA-DTA analysis, and single-crystal X-ray diffraction. Compound (1) crystallizes in the monoclinic system, space group P2(1), the final R is 0.0486. The tetradentate-chelating coordination mode of oxalate anion creates an infinite 1D iron (II) oxalate chain structure and from which a 2D network is constructed by π–π interactions of phen rings. The temperature-dependent magnetic susceptibility measurement indicates the existence of a weak antiferromagnetic coupling between Fe^II ions.     

A 2D bitriazole-bridging copper(II) polymer: Hydro thermal synthesis, crystal structure, and fluorescence

A new 2D metal-organic coordination polymer [Cu(trtr)₂]_n (1) (Htrtr = 3-(1,2,4-triazolyl-4-yl)-1H-1,2,4-triazole) is synthesized through the hydrothermal reaction of Cu(ClO₄)₂ with Htrtr. The crystal structure of 1 is determined by a direct method from X-ray diffraction data (Rigaku Mercury CCD, MoK _α radiation). 1 crystallizes in the monoclinic C2/c space group with unit cell parameters: a = 14.158(2) ?, b = 9.8050(14) ?, c = 11.413(3) ?, β = 127.9870(10)°, V = 1248.7(4) ?³, Z = 4, D _calc = 1.775 g/cm³. 1 features a 2D grid based on the propagation of 28-membered rings, which is further fabricated into a 3D supramolecular framework via the hydrogen bond linkage. The fluorescence of 1 shows a blue emission at 441 nm with a 14 nm red-shift compared to that of free Htrtr, which can be assigned to LMCT.     

Structure of the smectic D phase

Abstract

The so-called ‘smectic’ D phase of 4′-n-octadecyloxy-3′-cyanobiphenyl-4-carboxylic acid (one of only four materials known to exhibit this phase) has been shown unambiguously by X-ray diffraction to be characterized by a primitive cubic space group. The space group is either P23 or Pm3, and the lattice parameter a ₀ is 86 Å. It is shown that data from previous studies of this phase may be re-intepreted to be consistent with these findings. In view of these conclusions it is clearly inappropriate to refer to the phase as smectic.     

New cyclopeptides from Trichoderma polysporum (Link ex Pers.) Rifai: cyclosporins B, D and E (author's transl)

New Cyclopeptides from Trichoderma polysporum (LINK EX PERS .) RIFAI : Cyclosporins B, D and E Cyclosporins represent a new group of biologically active metabolites produced by Trichoderma polysporum (LINK EX PERS .) RIFAI and other fungi imperfecti. The structures of the main components, cyclosporins A ( 1 ) and C( 3 ) have been determined as neutral cyclic oligopeptides composed of 11 amino acids, among them a new C₉-amino acid [2–4]. In addition, three minor metabolites, cyclosporins B, D and E, have now been isolated and characterized. Chemical investigation, spectroscopic evidence and X-ray analysis led to the structural formulae of cyclosporins B (2) and D (4) . Both compounds have the same sequence of amino acids as cyclosporin A (1) , with the exception of L -α-aminobutyric acid, replaced in cyclosporin B (2) by L -alanine and in cyclosporin D (4) by L -valine, respectively. Cyclosporins undergo a characteristic intramolecular N,O-acyl migration to furnish the corresponding basic isocompounds. The antifungal activities of cyclosporins are reported.     

Macromolecular engineering of polylactones and polylactides. X. Selective end-functionalization of poly(D,L)-lactide

Functional aluminum alkoxides, such as Et_3–pAl(O? CH₂? X)_p, where p = 1,3 and X = a functional group, are very effective initiators for the (D, L)-lactide polymerization in toluene at 70°C. The coordination-insertion type of polymerization is living. Linear polyesters of a predictable molecular weight and a narrow molecular weight distribution are obtained within the period of time required for the total monomer conversion. The functional group (X) associated with the active alkoxy group of the initiator is selectively and quantitatively attached to one chain end, whereas the second end group is systematically a hydroxyl function resulting from the hydrolysis of the living growing site. Asymmetric telechelic polylactides are thus obtained in a perfectly controlled way. A kinetic study has shown that the polymerization is first order in both the monomer and initiator. © 1993 John Wiley & Sons, Inc.     

Solvent‐regulated Assembly of 1D and 2D CdII Coordination Polymers with Tetrafluorophthalate: Syntheses,Structures and Properties

Two new coordination polymers [Cd(1,2‐BDC‐F₄)(H₂O)₂(py)]_n ( 1 ) and {[Cd(1,2‐BDC‐F₄)(H₂O)₂](DMF)}_n ( 2 ) were prepared from the vapor diffusion reactions of Cd^II acetate with tetrafluorophthalic acid (1,2‐H₂BDC‐F₄) under different solvent atmospheres, and structurally characterized by single‐crystal diffraction technique. Both complexes reveal polymeric coordination architectures. Complex 1 is a one‐dimensional (1D) double chain, which crystallizes in the space group, P2₁2₁2₁. In 1 , each Cd^II ion is hexacoordinate by five oxygen atoms from two terminal water and three 1,2‐BDC‐F₄ anions with a μ₃‐bridging mode, as well as one nitrogen donor from one pyridine molecule. Complex 2 is a two‐dimensional (2D) layered network, which crystallizes in the P\bar{1} space group. In 2 , each Cd^II ion is heptacoordinate by seven oxygen atoms from two terminal water and four 1,2‐BDC‐F₄ anions with a μ₄‐bridging mode. The results clearly suggest that the judicious choice of solvent systems does play a critical role in the construction of coordination frameworks with distinct dimensionality and connectivity. Their spectroscopic, thermal, and fluorescence properties have also been investigated.