bluuebunny/crossref_metadata_2025_split huggingface dataset:
Azaborolinyl-Komplexe, XVIII [1]. η5 -1,2-Azaborolinyl-η6 -Aromaten-Sandwichkomplexe des Eisens / Azaborolinyl Complexes, XVIII [1]. η5-1,2-Azaborolinyl-η6 -arene Sandwich Complexes of Iron
Authors: Schmid Günter , Barbenheim Gerd , Boese Roland 
Published: August 2018

Abstract
Bis(1-tert-butyl-2-methyl-η5-1,2-azaborolinyl)iron can be transformed into cationic (1-tert-butyl-2-methyl-η5-1,2-azaborolinyl)-η6-arene-iron sandwich complexes by the reaction with an excess of the arene (benzene (1), toluene (2), o-xylene (3), and mesitylene (4)), AlX3 (X = Cl, Br) and aluminum at 80 °C with 60-70% yield. The sandwich cations are best isolated as PF6
− salts. 1H, 11B, and 13C N|MR data indicate η5 coordinated 1,2-azaborolinyl ligands and η6 bound arenes, in agreement with X-ray structure investigations on 1 and 2, using FeCl4
2 and FeBr4
2- anions because of the better crystal quality compared with the PF6
−salts.
Reduktive Enthalogenierung von (Cl, Br)RP–CH2–PR(Cl, Br) mit Fe2(CO)9– Bildung von Komplexen mit gespannten Diphosphirangerüsten und bifunktionellen Phosphidobrücken (µ2-PR)2CH2 / Reductive Dehalogenation of (Cl, Br)RP–CH2—PR(Cl, Br) with Fe2(CO)9– Formation of Complexes with Strained Diphosphirane Skeletons and Bifunctional Phosphido Bridges (μ2-PR)2CH2
Authors: Bitterer F. , Brauer D. J. , Dörrenbach F. , Gol F. , Knüppel P. C. , Stelzer O. , Krüger C. , Tsay Y.-H. 
Published: August 2018

Reductive dehalogenation of the bifunctional methylene bridged halogenphosphines XRP-CH2—PRX (X = Cl, Br; R = iPr, tBu, 2,4,6-R′3C6H2 (R′ = Me, iPr, tBu), N(SiMe3)2 and 2,6,4-tBu2MeC6H2—O) with diironenneacarbonyl affords phosphido complexes with strained RP—CH2—PR backbones, Fe2(CO)6[(μ2-PR)2CH2] (8a-8g). X-Ray structural analyses of the 2,4,6-iPr3C6H2 (8d) and 2,6,4-tBu2MeC6H2—O derivatives (8g) reveal that the Fe2P2C skeletons have remarkably small P—C—P angles (83,7(4)° (8d), 78,6(1)° (8g)).
The dehalogenation of XRP—CH2—PRX with Fe,(CO)9 is preceded by the formation of iron carbonyl complexes (RXP—CH2—PRX)[Fe(CO)4]n (n = 1, 2). For derivatives with bulky substituents R complex formation proceeds diastereoselectively. In case of 3 b the diastereoisomers could be separated and a crystallographic examination of the racemic form showed that the P—C—P backbone possesses C2 symmetry with an approximately trans conformation of the P—C—P fragment. The P-atoms occupy the equatorial position within the Fe(CO)4P units.
The chloro-phosphido bridged complex Fe2(CO)6(μ2-Cl)(µ2-PR—CH2—PRCl—Fe(CO)4) (4a), formed by oxidative addition of a P—Cl bond to Fe(0), or diphosphiranes and their complexes [(RP)2CH2][Fe(CO)4]n (n = 0-2; 5-7) have been isolated as intermediates of the XRP-CH2—PRX dehalogenation. The diphosphiranes 5 were synthesized independently by reduction of the halogenphosphines XRP—CH2—PRX with lithium or magnesium. An X-ray examination of 4a showed that it contains a μ2-PR—CH2—PRCl backbone which bridges Fe2(CO)6(μ2-Cl) and Fe(CO)4 units, the P—C—P angle being remarkably large, 127,3(1)°.
Preparation and Crystal Structure of Hg9As4O16, a Mercury Arsenate(V) with Triangular Hg3
4+ Cations
Authors: Wessels Annemarie L. , Jeitschko Wolfgang , Möller Manfred H. 
Published: August 2018

Abstract
The new compound Hg9As4O16 has been prepared by thermal decomposition o f the mercury(I) arsenate(V) (Hg2)3(AsO4)2 in the presence of HgO in an evacuated, sealed silica tube. It crystallizes with a rhombohedral structure (R3c, Z = 6), which has been determined from two single-crystal diffractometer data sets collected at 295 K (a = 1665.3(1) pm, c = 1083.8(1) pm, R = 0.051 for 2353 structure factors and 62 variable parameters) and 170 K (a = 1660.3(2) pm, c = 1083.0(1) pm, R = 0.037 for 1681 F-values). It corresponds to the formula (Hg3
4+)3(AsO4
3-)4 with almost equilateral mercury triangles and nearly perfect ASO4 tetrahedra. The average Hg-Hg bond distance of 267.5 pm is considerably greater than the average Hg-Hg distance of 251.3 pm round in mercury(I) compounds, reflecting the atoms.
Synthese, Kristallstruktur und Eigenschaften von 1,1,3,3,3-Pentaaminol- 1-thio-1 λ5,3λ5-diphosphaz-2-en (NH2)2P(S)N=P(NH2)3 / Synthesis, Crystal Structure, and Properties of 1,1,3,3,3-Pentaam 1-thio-1 λ5,3λ5-diphosphaz-2-en (NH2)2P(S)N=P(NH2)3
Authors: Horstmann Stefan , Schnick Wolfgang 
Published: August 2018

Abstract
(NH2)2P(S)N=P(NH2)3 has been prepared by a two step synthesis. Suitable single crystals were obtained from an acetonitrile solution in a temperature gradient between 60 °C and room temperature. The crystal structure of (NH2)2P(S)N=P(NH2)3 has been determined by single crystal X-ray methods (P21/c, a = 998.27(9) b = 762.78(8), c = 1007.70(15) pm, β = 107.340(7)°, Z = 4). In the crystal structure each hydrogen atom is subject to a hydrogen bond. Four N-H -N hydrogen bonding interactions per molecule build up a framework connecting two molecules in eight-membered rings. Each sulfur atom shows six distances N-H···S in the range of weak hydrogen bonding interactions.
Kristallstrukturen von (n-Bu4N)[B6Cl6], (n-Bu4N)[B6Br6] und (Ph3P=N=PPh3)[B6I6] sowie Schwingungsspektren und Normalkoordinatenanalyse der Hexahalogeno-c/osö-Hexaboratradikalanionen [B6X6]-, X = Cl, Br, I / Crystal Structures of (n-Bu4N)[B6Cl6], (n-Bu4N)[B6Br6], and (Ph3P=N=PPh3)[B6I6], and Vibrational Spectra and Normal Coordinate Analysis of the Hexahalogeno-closo-hexaborate Radical Anions [B6X6]- , X = Cl, Br, I
Authors: Lorenzen V. , Preetz W. 
Published: August 2018

Abstract
Oxidation of hexahalogeno-closo-hexaborates [B6X6]2-, X = Cl, Br, I, with (NH4)2[Ce(NO3)6] in ethanol yields coloured radical ions [B6X6]-. X-ray structure determina­ tions have been performed on single crystals of (n-Bu4N)[B6Cl6] (1) (monoclinic, space group P21/c,a = 13.144(2),6 = 12.594(2),c = 17.688(5) Å, β = 107.29(2)°,Z=4),(n-Bu4N)[B6Br6] (2) (monoclinic, space group P21/c, a = 13.529(5), b = 13.096(5), c = 17.863(5) Å, β = 107.20(5)°, Z = 4) and (Ph3P=N=PPh3)[B6I6] (3) (triclinic, space group P1̄, a = 9.3137(8), b = 10.6988(10), c = 11.8760 Å , a = 102.220(7), β = 99.34J(8), 7 = 96.030(7)°, Z = 1). The average B-B distances are nearly equal (1.733 Å (1), 1.728 Å (2), 1.728 Å (3)) while the B-X distances increase (1.762 Å (1), 1.912 Å (2), 2.120 Å (3)). Using the molecular parameters, normal coordinate analyses have been performed and a good agreement of observed and calculated frequencies of 10B and 11B labelled derivatives has been achieved. The valence force constants fd(BB) and fd(BX) of [B6X6]- are 1.17 and 4.17 (X = Cl), 1.18 and 3.34 (Br) and 1.18 and 2.60 mdyn/Å (I), respectively.
Untersuchungen zur thermischen Zersetzung von Ammoniumlanthanhalogeniden/Investigation on the Thermal Decomposition of Ammonium Halides
Authors: Morgenstern A. , Oppermann H. 
Published: August 2018

Abstract
The decomposition equilibria of Ammonium Lanthanum Halides (NH4)2LaX5 were determined by total pressure measurements in a membrane zero manometer. The phases (NH4)2LaX5 decompose in one step to give solid LaX3 and gaseous NH3 and HX. From the decomposition functions the enthalpies of formation and the standard entropies of the phases are derived.
ΔH°B (NH4)2LaCl5,f,298) = -411 ,7 ± 2,2 kcal/mol; S°((NH4)2LaCl5,f,298) = 86,7 ± 2,3cal/Kmol;
ΔH°B (NH4)2LaBr5,f,298) = -351,6 ± 3,8 kcal/mol; S°((NH4)2LaBr5,f,298) = 101,1 ± 1,8 cal/Kmol;
ΔH°B (NH4)2LaI5,f,298)= -268 ,9 ± 3,9 kcal/mol; S°((NH4)2LaI5,f,298) = 115,5 ± 4,3 cal/Kmol.
Difluorphosphorylcyclosilazane -Synthese und Kristallstruktur/Difluorophosphorylcyclosilazanes -Syntheses and Crystal Structure
Authors: Klingebiel Uwe , Noltemeyer Mathias , Rakebrandt Hans-Jörg 
Published: August 2018

Abstract
The reaction of lithiated 1,3-bis(fluorodimethyl)cyclotrisilazane with PF3 leads to the formation of a PF2-substituted six-membered Si-N ring (1). 1,5-Bis(difluorophosphanyl)-2,2,4,4,6,6,8,8-octamethyl-cyclotetrasilazane (2) is obtained in the reaction of the dilithium derivative of the cyclic tetrasilazane with trifluorophosphane in a molar ratio 1:2. The crystal structure of (F2P-N-SiMe2-NH-SiMe2)2 (2) has been determined.
Ein [Ba(Ca,Mn)O6]-Gerüst mit eingelagerten V-O-V-Gruppen in der Kristallstruktur von Ba(Ca0.6Mn0.4)V2O7 /A [Ba(Ca,Mn)O6] Framework with Incorporated V-O-V Groups in the Crystal Structure of Ba(Ca0.6Mn0.4)V2O7
Authors: Rettich R. , Müller-Buschbaum Hk. 
Published: August 2018

Abstract
Single crystals of Ba(Ca0.6Mn0.4)V2O7 have been prepared by crystallization from melts. X-ray investigations revealed a new quaternary vanadium oxide of the type BaMV2O7. The M positions are occupied statistically by Ca2+ and Mn2+. The compound crystallizes with orthorhombic symmetry, space group D2h
16-Pnma, a = 15.429(2), b - 5.7005(12), c = 7.364(2) Å, Z = 4. The crystal structure can be interpreted as a [Ba(Ca,Mn)O6] network with incorporated V-O- V groups. Considering the nearest O2- neighbours of the incorporated vanadium, the V-O-V groups are complemented to give V2O7 divanadate units. Ba(Ca0.6Mn0.4)V2O7 is isotypic to BaMV2O7 (M=Ca,Cd) but not to BaMnV2O7.
Synthesis and X -Ray Crystal Structure of the Heterobimetallic Complex [FeRh (μ-CO)(CO)3((μ-PBut
2)((μ-Ph2PCH2PPh2)]
Authors: Böttcher Hans-Christian , Merzweiler Kurt , Bruhn Clemens 
Published: August 2018

Abstract
The reaction of the phosphido-bridged metal carbonyl [FeRh(CO)6(μ-PBut
2)] (1) with dppm [dppm = bis(diphenylphosphino)methane] leads to the heterobimetallic complex [FeRh(μ-CO)(CO)3(μ-PBut
2)(μ-dppm)] (2) in good yields. The molecular structure of 2 was determined at room temperature [triclinic, space group P1̄, a = 9.509(6), b = 13.637(5), c = 14.926(8) Å, α = 81.38(4), β = 82.75(4), γ = 71.25(4)°]. The compound acts as a homogeneous catalyst precursor in the hydroformylation reaction of ethylene, but it decomposes during this process.
Synthese und Kristallstruktur von [(Cl3Si)2N]2TiCl2 -ein perchloriertes N-Silyl-titanamid /Synthesis and Crystal Structure of [(Cl3Si)2N]2TiCl2 -a Fully Chlorinated N-Silyl Titanium Amide
Authors: Schwarze Bernd , Milius Wolfgang , Schnick Wolfgang 
Published: August 2018

Abstract
The chlorinated titanium amides [(Cl3Si)2N]2TiCl2 (1) and (Cl3Si)2NTiCl3 have been syn­thesized selectively from hexachlorodisilazane lithium and TiCl4. The crystal structure of 1 was determined by single crystal X-ray methods at room temperature (P212121, a = 1232.4(2), b = 1265.5(2), c -1469.1(2) pm, Z = 4). The central titanium atom of 1 is bound to two nitrogen atoms and two Cl atoms and is weakly coordinated further by two Cl atoms of the trichlorosilyl groups.
Synthesis of C2B3 X-Heterocycles (X = C, N, P, O, S) from 1,3,5-Triborapentanes
Authors: Deforth T. , Kaschke M. , Stock H. , Pritzkow H. , Siebert W. 
Published: August 2018

Abstract
The hydroboration of acetylene with HBCl2 yields the products (Cl2B)2CHMe (1a), (Cl2BCHMe)2BCl (2a), (Cl2BCHMeBCl)2CHMe (3a), and (ClBCHMe)3 (4a). The crystal structure of 4a as well as of the pentaiodo derivative 2b were determined. A mechanism for the formation of the different hydroboration products is proposed. The 1,3,5-triborapentane 2a serves as precursor for the synthesis of derivatives of 1,3,5-triboracyclohexanes, 1,3,5-tribora-2-aza-cyclohexanes, 1,3,5-tribora-2-phospha-cyclo-hexanes, and 1,3,5-tribora-2-thia-cyclohexanes. Their constitutions have been derived from spectroscopic studies. The crystal structure of the 1,3,5-tribora-2-oxa-cyclohexane derivative was also determined.
Ein neues Verfahren zur numerischen Berechnung des Madelung-Anteils der Gitterenergie ionischer Kristalle / A New Method for the Numerical Calculation of the Madelung Contribution of the Lattice Energy in Ionic Crystals
Authors: Marx Veit 
Published: August 2018

Abstract The Madelung contribution to the lattice energy of simple binary crystal structures and lanthanide oxide fluorides with different types of disorder has been calculated by summation of Coulomb interactions and additional consideration of surface effects. In the case of NaCl, CsCl, ZnS and CaF2 the agreement with mathematically exactly calculated values is better than 1 %. For the cubic high temperature modification of YOF it could be shown that a structure with long range order and short range disorder is more favourable from the energetic point of view than a stochastic distribution of the anions over all anion sites of the crystal.
Kurze O-O-Abstände einer gemeinsamen Polyederkante bei Verknüpfung von PO4-Tetraedern mit VO6-Oktaedern im Vanadyl-Orthophosphat CaNi(VO)(PO4)2 / Short O-O Distances in Edge Sharing PO4 Tetrahedra and VO6 Octahedra of the Vanadyl- Orthophosphate CaNi(VO)(PO4)2
Authors: Meyer S , Müller-Buschbaum Hk 
Published: August 2018

Abstract Single crystals of the new compound CaNi(VO)(PO4)2 have been prepared by solid state reactions below the melting point of the oxide mixture in evacuated quartz tubes. X-ray investigations led to orthorhombic symmetry, space group D2h16-Pnma, a =14.113(1), b =6.408(1), c = 7.364(1) Å, Z = 4. The crystal structure shows 1∞[NiO4] and 1∞[VO6P2O3] polyhedra chains closely related to analogous chains in the isotypic compound CdV2O(PO4)2. The short V -O distance of 1.66 Å indicates a vanadyl group as the main difference to CdV2O(PO4)2. The short O-O distance of 2,395 Å of the edge-sharing PO4 tetrahedra and VO6 octahedra is discussed.
Synthesis of AM15C5 Bonded Merrifield Peptide Resin and its Separating Properties
Authors: Kim Dong Won , Kang Byung Moo , Lee Nam-Soo , Kim Chang Suk , Ryu Haiil , Hong Young Guan 
Published: August 2018

Abstract
A 2-aminomethyl-15-crown-5 (AM15C5) bonded Merrifield peptide resin was synthesized. The capacity of this crown ion exchanger was 2.25 meq/g of dry resin. The heavier isotopes of magnesium were enriched in the solution phase, while the lighter isotopes were enriched in the resin phase. The hydration and isotope mass effects dominated over those of the complexation and properties of the exchanger. The separation factors of 24Mg2+/25Mg2+, 24Mg2+/26Mg2+, and 25Mg2+/26Mg2+ isotope pair fractionations were 1.0012, 1.0023, and 1.0011, respectively.
An Improved Synthesis of Nickel-bis[5,6-dihydro-1,4-dioxine- 2,3-dithiolate], Ni(edo)2
Authors: Papavassiliou G. C. , Mousdis G. A. , Anyfandis G. C. 
Published: August 2018

Abstract
Starting from 2,3-dichloro-1,4-dioxane, the title compound was prepared by a five-step chemical procedure, instead of a eight-step procedure reported recently.
Reaktionen von Vanadium(V)- und Tantal(V)-Komplexen Mit Kinetisch Stabilisierten Phosphaalkinen. Einfache Synthese von 1,3,4-Thia- und 1,3,4-Selenadiphospholen / Reactions of Vanadium(V) and Tantalum(V)-Complexes with Kinetically Stabilized Phosphaalkynes. A Simple Synthesis of 1,3,4-Thia and 1,3,4-Selenadiphospholes
Authors: Peters Christoph , Fischbeck Uwe , Tabellion Frank , Regitz Manfred , Preuss Fritz 
Published: August 2018

Abstract
A simple synthetic pathway to the unknown 1,3,4-thiadiphospholes 3 and 1,3,4- selenadiphospholes 4 has been developed involving reactions of the azaphosphavanada(V)- cyclobutenes 2, generated in situ from the imidovanadium(V) complex tBuN = VCl3 and the phosphaalkynes 1a - d, with an excess of elemental sulfur or grey selenium, respectively. The reactions of the phosphaalkynes 1a,b with TaOCl3 or VOCl3 · DME furnish the 1,2-dichloro-phosphaalkenes 5a,b and 1,2,3,4-tetrachloro-3,4-di-tert-butyl-1,1-diphosphethane 7a. The metallacyclic species 2e - h with secondary or primary alkyl groups on the ring nitrogen atom are unstable and undergo quantitative conversion to the 1H-1,2,4-azadiphospholes 8, whereas in the presence of an excess of phenylacetylene the 1H-1,2-azaphospholes 9e - h, are formed selectively. A catalytic reaction course has been demonstrated for the cyclotrimerization of phenylacetylene and 2-butyne initiated by small amounts of TaSCl3. The syntheses of the vanadium(IV) complexes [tBuN = VCl2 · 2Py] and [tBuN = VCl2 · TMEDA] are also described starting from tBuN = VCl3 and phosphaalkene 12.
The Hexakis(N,N'-Dimethylurea)Cobalt(Ii) Cation: A Flexible Building Block for the Construction of Hydrogen Bonded Networks
Authors: Papaefstathiou Giannis S. , Keuleers Robby , Milios Constantinos J. , Raptopoulou Catherine P. , Terzis Aris , Desseyn Herman O. , Perlepes Spyros P. 
Published: August 2018

Abstract
The ligand N.N'-dimethylurea (DMU) is used to propagate the octahedral coordination geom- etry of [Co(DMU)6]2+ into 1D and 2D assemblies via a combination of coordinative bonds and interionic hydrogen-bonding. Compounds [Co(DMU)6](ClO4)2 (1), [Co(DMU)6](BF4)2 (2) and [Co(DMU)6](NO3)2 (3) have been prepared from the reactions of DMU and the appropriate hydrated cobalt(II) salts in EtOH. MeCN or Me2CO (only for 1) in the presence of 2,2-di- methoxypropane. Crystal structure determinations demonstrate the existence of [Co(DMU)6]2+ cations and CIO4
- , BF4
- or NO3
- counterions. The great stability of the [Co(DMU)6]2+ cation in the solid state is attributed to a pseudochelate effect which arises from the existence of strong intracationic N-H···O(DMU) hydrogen bonds. The [Co(DMU)6]2+ cations and counterions self- assemble to form a hydrogen-bonded ID architecture in 1, and different 2D hydrogen-bonded networks in 2 and 3. The precise nature of the resulting supramolecular structure is influenced by the nature of the counterion. Two main motifs of intermolecular (interionic) hydrogen bonds have been observed: N-H ···O(ClO4
-, NO3
-) or N-H ··· F(BF4
-) and weak C-H F(BF4
- ) or C-H-O(NO3
- ) hydrogen bonds. The complexes were also characterized by vibrational spec- troscopy (IR, far-IR. low-frequency Raman). The spectroscopic data are discussed in terms of the nature of bonding and the know;n structures.
Preparation, Crystal and Magnetic Structure of the Double Perovskites Ca2TWO6 (T = Co, Ni)
Authors: Martínez-Lope M.J. , Alonso J.A. , Casais M.T. , Fernández-Díazb M.T. 
Published: August 2018

Abstract
Ca2TWO6 (T = Co, Ni) perovskites have been prepared in polycrystalline form by thermal treatment, in air, of previously decomposed citrate precursors. These materials have been studied by X-ray (XRD) and neutron powder diffraction (NPD) data. Our results show that these compounds crystallize, at room temperature, in the monoclinic space group P21/n. The two perovskites contain divalent T (T = Co, Ni) cations. The low temperature antiferromagnetic ordering has been followed from sequential NPD data. Peaks of magnetic origin appear at the NPD patterns below temperatures of TN = 36 K and TN = 56 K for the Co and Ni compounds, respectively. The magnetic structures are both defined by a propagation vector k = (1/2, 0, 1/2), and can be described as an array of ferromagnetic layers of Co(Ni) moments, perpendicular to the [101] directions, coupled antiferromagnetically.
Zur gezielten Synthese funktionell substituierter Oligosilane aus Silyltriflaten und Aminosilyllithiumverbindungen / Tailor-Made Synthesis of Functional Substituted Oligosilanes from Silyl Triflates and (Aminosilyl)Lithium Compounds
Authors: Uhlig Wolfram 
Published: August 2018

Abstract
Diethylamino substituted silyllithium compounds have been prepared in situ from the corresponding phenylchlorosilanes and lithium. These reagents undergo coupling reactions with triflate derivatives of silanes and oligosilanes. Exchange processes analogous to metal halogen exchange and Si-Si bond cleavage, which are side reactions with chlorosilanes, were not observed. Based on the coupling reaction and the amino-to-triflate transformation, functionalized tri-, tetra-, penta- und hexasilanes have been synthesized. α,ω-Triflate substituted oligosilanes containing π-systems have also been obtained. These compounds are useful building blocks for new organosilicon polymers. The formation of the silicon polymers at low temperatures, in short reaction times, and with high yields is reported. The 29Si NMR spectra indicate a regular, alternating arrangement of the building blocks in the polymer backbone.
High-Pressure Preparation, Crystal Structure, and Properties of RE4B6O15 (RE = Dy, Ho) with an Extension of the “Fundamental Building Block”-Descriptors
Authors: Huppertz Hubert 
Published: August 2018

High-pressure/high-temperature conditions of 8 GPa and 1000°C were used to synthesize
the new rare earth oxoborates RE4B6O15 (RE = Dy, Ho) in a Walker-type multianvil apparatus.
The single crystal X-ray structure determination of Ho4B6O15 revealed the following
data: C2/c, a = 1164.1(1), b = 436.7(1), c = 1882.5(1) pm, β = 96.71(1)°, Z = 4, R1 = 0.0291, wR2 = 0.0505 (all data). The two isotypic compounds exhibit a new structure type built up from corrugated layers of BO4 tetrahedra. In contrast to all known oxoborates the linking
of the BO4 tetrahedra is partially realized via common edges. Regarding the “fundamental
building block”-concept, we introduce a new descriptor “

” for edge-sharing BO4 tetrahedra.
Temperature-resolved in situ powder diffraction measurements and IR/Raman-spectroscopic
investigations on Dy4B6O15 are also reported.
A New Prenylated Hydroquinone from the Roots of Garcinia atroviridis Griff ex T. Anders (Guttiferae)
Authors: Permana Dharma , Lajis Nordin Hj. , Shaari Khozirah , Ali Abdul M. , Mackeen Mukram M. , Kitajima Mariko , Takayama Hiromitsu , Aimi Norio 
Published: August 2018

A continuing study on the phytochemical constituents of Garcinia atroviridis Griff ex T. Anders (Guttiferae) has led to the isolation of a new prenylated hydroquinone from the roots of the plant. The compound has been elucidated to be 4-methylhydroatrovirinone, primarily by the use of gradient NMR and mass spectroscopy. The roots also yielded the known morelloflavone and its 7-O-β-D-glucopyranoside, fukugiside, together with 14-cis-docosenoic
acid.
Synthesis of Some New (Nα-Dipicolinoyl)-bis-L-leucyl-DL-norvalyl Linear tetra and Cyclic octa Bridged Peptides as New Antiinflammatory Agents
Authors: Abo-Ghalia Mohamed H. , Amr Abd El-Galil E. , Abdalah Mohamed M. 
Published: August 2018

In continuation to our search for new amino acid and peptide based anti-inflammatory agents, the suggestion, synthesis, structure elucidation of some Nα -bis-dipicolinoyl amino acids, linear tetra and cyclic octa bridged peptides 1-9, of which four are new compounds 6-9, were herein realized. Accordingly, Nα -bis-dipicolinoyl-L-leucine methyl ester 1, the corresponding acid 2, its bis-DL-norvalyl methyl ester homologue 3, the acid 4 and hydrazide 5 analogues were conventionally prepared.
The tetrachlorophthalic acid hydrazine conjugate 6, anisaldehyde hydrazone 7, the benzenetetracarboxylic acid and naphthalenetetracarboxylic acid bis-L-leucyl-DL-norvalyl cyclic octa bridged peptides 8 and 9 respectively, were newly synthesized via condensation of the hydrazide 5 with the corresponding aldehyde or anhydride.
The chromatographic, IR, NMR and mass spectral analysis confirmed the identities of the synthesized compounds.
Comparable to the two reference antiinflammatory drugs indomethacin® and voltaren® (100%), the determined antiinflammatory potency of the candidates (carrageenan® induced paw edema in rats) revealed a general significant activity (66 - 94%), except for the practically inactive 6 (∼1.5 % activity).
In particular, the potency of the (Nα -dipicolinoyl)-bis-L-leucyl-DL-norvalyl anisaldehyde hydrazone 7 was of 94 and 87%, comparable to the reference drugs. However, 7 also showed 58% protection against ulcer formation, comparable to null for indomethacin®. Additionally, an acceptable acute toxicity was observed (LD50: 2833 mg/kg, comparable to 2700 and 2850 for indomethacin® and voltaren® respectively).