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Naphthacenes (2):
Recent article
Naphthacenes
Abstract
Large area chiral supramolecular self-assembly of rubrene has been achieved on Au(111) surface at room temperature. The basic building block of such self-assembled layers consists of two double-layered Y-shape supramolecular structures containing eight twisted rubrene molecules. Chirality is maintai...
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PMID: 20820574
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PDF is available here.
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Abstract
We present a new contrast agent for imaging hydrogen peroxide, termed the chemiluminescent poly(ethylene glycol)-b-poly(e-caprolactone) (PEGPCL) micelles (CPMs), which can detect hydrogen peroxide at nanomolar concentrations and chemiluminesce in the near IR range (676 nm) in the presence of hydroge...
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PMID: 19402235
PDF is available here.
PDF is available here.
Abstract
We demonstrate that the system developed in this work is operational for solid-state NMR with hyperpolarized nuclear-spin systems in static organic materials, and also discuss the application of our system....
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PMID: 19405684
PDF is available here.
PDF is available here.
Abstract
BF(2) complexes containing tetracene and perylene moieties were synthesized as new types of electron-deficient arene compounds. These compounds exhibit long wavelength absorption and high electron affinities, as revealed through spectral and electrochemical studies, due to their quadrupolar structur...
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PMID: 19053501
PDF is available here.
PDF is available here.
The Journal of Chemical Physics (129)17 2008
Abstract
Our analysis shows that discrete branch and bound methods provide robust strategies for inverse chemical design involving diverse chemical structures. Based on the linear combination of atomic potentials, a hybrid discrete-gradient optimization strategy significantly improves the performance of the...
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PMID: 19045331
PDF is available here.
PDF is available here.
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment and General Theory (112)37 2008
Abstract
I r/ I f), suggesting noncovalent interactions between the solvent and the nonemitting ECL partner. Specifically, the reaction of an aromatic luminophore with 1,4-naphthoquinone in acetonitrile/benzotrifluoride showed a 1.03-1.63-fold increases in ECL efficiency over that of acetonitrile/benzene. Sl...
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PMID: 18729443
PDF is available here.
PDF is available here.
Abstract
Self-assembly of the binary molecular system of pentacene and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on Ag(111) has been investigated by low-temperature scanning tunneling microscopy, molecular dynamics (MD), and density functional theory (DFT) calculations. Well-ordered two-dimensiona...
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PMID: 18722423
PDF is available here.
PDF is available here.
Journal of Food Science (73)6 2008
Abstract
Effects of phosphatidylcholine (PC) on the oxidation of oil by singlet oxygen in a W/O microemulsion and an emulsion food model containing tocopherol-stripped sunflower oil (TSSO) have been studied. The W/O microemulsion consisted of methylene chloride, butanol, and sodium dodecyl sulfate with PC (0...
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PMID: 19241542
PDF is available here.
PDF is available here.
Abstract
The growth of pentacene films on different metal (Ga, Pb, Bi, Ag) induced Si(111)-(square root(3) x square root(3))R30 degrees surfaces is investigated by scanning tunneling microscopy. On surfaces with high atomic surface roughness, such as GaSi-square root(3), beta-PbSi-square root(3), and alpha-B...
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PMID: 18647034
PDF is available here.
PDF is available here.
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment and General Theory (112)25 2008
Abstract
We ascribed this term to a predominantly in-plane libration. In this manuscript, we present molecular dynamics simulations for the motions of perylene and tetracene using the CHARMm molecular dynamics program (version c29b2). Both rotational correlation functions contain subpicosecond decay terms th...
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PMID: 18507364
PDF is available here.
PDF is available here.
The Journal of Chemical Physics (128)15 2008
Abstract
The full UV-visible dielectric tensor and the corresponding directions of the principal axes of triclinic tetracene crystals are reported as deduced either by polarized absorption and ellipsometry measurements or by calculations based on the molecular and crystallographic data. The results allow the...
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PMID: 18433260
PDF is available here.
PDF is available here.
Abstract
These results strongly suggest that the regiospecific cyclizations of the first two rings and subsequent aromatizations take place in the interior pocket. The chemical insights gleaned from this work pave the foundation toward defining the molecular rules for the ARO/CYC cyclization specificity, who...
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PMID: 18388203
PDF is available here.
PDF is available here.
Abstract
We show that the detailed molecular packing in thin organic semiconductor films can be solved through a combination of grazing incidence X-ray diffraction (GIXD), near-edge X-ray absorption spectra fine structure (NEXAFS) spectroscopy, energy minimization packing calculations, and structure refineme...
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PMID: 18293975
PDF is available here.
PDF is available here.
Abstract
Monolayers of 1,1'-bi-2-naphthol (BN) derivatives, of which the two naphthalene rings are twisted along the carbon(1)-carbon(1') single bond, were studied for their conformational effect on the growth of pentacene crystals on their monolayer surface. BN monolayers with H and Br at 6,6'-positions (H-...
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PMID: 18288840
PDF is available here.
PDF is available here.
Abstract
We report the fabrication of an extended 2D C60 nanomesh featuring a well-ordered nanocavity array by controlling the binary molecular phases of C60 and pentacene on Ag(111). Using low-temperature scanning tunneling microscopy, we demonstrate that the C60 nanomesh can serve as an effective template...
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PMID: 18266368
PDF is available here.
PDF is available here.
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment and General Theory (112)4 2008
Abstract
The investigations were made on photoinduced electron transfer (ET) from the singlet excited state of rubrene (1RU*) to p-benzoquinone derivatives (duroquinone, 2,5-dimethyl-p-benzoquinone, p-benzoquinone, 2,5-dichloro-p-benzoquinone, and p-chloranil) in benzonitrile (PhCN) by using the steady state...
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PMID: 18173251
PDF is available here.
PDF is available here.
Abstract
We decreased the temperature of rubreneperoxides, most of the molecules migrate to the lowest vibrational and rotational energy levels of the ground electronic state. Similar migration is also observed for the lowest triplet state. Therefore at 77 K, we can get the clean absorption an emission spect...
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PMID: 17561439
PDF is available here.
PDF is available here.
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment and General Theory (111)49 2007
Abstract
The electronic properties of a single layer (SL) of pentacene molecules are investigated by high-resolution UV photoemission and near-edge X-ray absorption spectroscopy in different configurations of the SL, either standing up on an aromatic self-assembled monolayer or planar on a bare Cu(001) subst...
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PMID: 17988104
PDF is available here.
PDF is available here.
Abstract
Journal of Physical Chemistry B (111)32 2007
Abstract
We also determined the energy level alignment of the pentacene-rubrene interface by using X-ray and ultraviolet photoelectron spectroscopy. From these comparisons, it is found that the electronic structure of the pentacene-rubrene interface has a strong dependence on interface characteristics which...
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PMID: 17658782
PDF is available here.
PDF is available here.
Abstract
We found that it is generally possible to deduce the KR regiospecificity (C-9, C-15, C17) from the amino acid sequence and thus to predict the nature of the aromatic polyketide (e.g., angucycline, anthracycline, benzoisochromanequinones). We hypothezised that the new clade of KRs is characteristic f...
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PMID: 17625850
PDF is available here.
PDF is available here.
Journal of Organic Chemistry (72)13 2007
Abstract
3-Phenylsulfanylphthalides (e.g. 8a) readily react with p-benzoquinones in the presence of LiOtBu in THF to furnish 1,4-dihydroxyanthraquinones in good yields and one-pot operations.
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PMID: 17511506
PDF is available here.
PDF is available here.
Abstract
We found a novel oscillating phenomenon associated with surface wetting during the vacuum deposition of an organic semiconductor (rubrene) on a liquid film (bis(2-ethylhexyl)sebacate, B2EHS). In-situ observations by an optical microscope revealed that the oscillation was associated with the growth o...
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PMID: 17497904
PDF is available here.
PDF is available here.
Abstract
Our results also further substantiate the potential of metabolic engineering toward polyphenols with altered substituents and ring systems....
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PMID: 17439117
PDF is available here.
PDF is available here.
Abstract
The paper describes synthesis and antibacterial study of biologically active Mannich bases of carboxamide derivative employing Mannich reaction of 4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,6,10,12,12a pentahydroxy naphthacene carboxamide with various sulfonamides/secondary amines .They were...
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PMID: 17110110
PDF is available here.
PDF is available here.
Abstract
Abstract
Thin films of organic molecular crystals have drawn widespread attention for their scientifically interesting and potentially useful electronic, photonic, and chemical properties. However, because their properties are extremely sensitive to structural imperfections, domain size, and crystallographic...
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PMID: 17177373
PDF is available here.
PDF is available here.
Abstract
Aims
To investigate the diffusion and accumulation of doxorubicin metabolites in the ascites of patients with ovarian cancer following intravenous injection, as a model for intraperitoneal accumulation of drugs.
Methods
The concentrations of doxorubicin and its metabolites [Doxorubicinol (Dox-ol)...
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PMID: 17174514
PDF is available here.
PDF is available here.
Abstract
Journal of Organic Chemistry (71)21 2006
Abstract
Multi-substituted pentacenes, such as 1,2,3,4,6,8,9,10,11,13-decasubstituted pentacenes (Type I), 1,2,3,4,6,13-hexasubstituted pentacenes (Type II), 1,2,3,4-tetrasubstituted pentacenes (Type III), and 2,3-disubstituted pentacenes (Type IV), 1,2,3,4,6,11-hexasubstituted naphthacenes (Type V), 1,2,3,4...
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PMID: 17025283
PDF is available here.
PDF is available here.
Abstract
We developed a simple chitosan sheet and examined the possibility of using an adriamycin-containing chitosan sheet as a drug carrier for controlled release. To prepare a carrier consisting only of chitosan, a chitosan suspension was subjected to acid-alkaline treatment, mixed with adriamycin, frozen...
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PMID: 16884897
PDF is available here.
PDF is available here.
Abstract
Combinatorial biosynthesis was applied to Streptomyces deoxysugar biosynthesis genes in order to reconstitute "unnatural natural gene clusters" for the biosynthesis of four D-deoxysugars (D-olivose, D-oliose, D-digitoxose, and D-boivinose). Expression of these gene clusters in Streptomyces albus 16F...
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PMID: 17021216
PDF is available here.
PDF is available here.
Journal of Physical Chemistry B (110)38 2006
Abstract
Our theoretical and experimental results reveal that, while the main contribution to relaxation energy in the ground state of oligoacene systems comes from high-energy vibrations, the excited-state relaxation energies show a significant redistribution toward lower-frequency vibrations. A direct corr...
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PMID: 16986882
PDF is available here.
PDF is available here.
Abstract
We study the growth and structure of thin films of the organic semiconductor rubrene during organic molecular beam deposition (OMBD) on silicon oxide in situ and in real time using X-ray scattering. Using in situ grazing incidence diffraction (GID) we find a small degree of local order but an otherw...
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PMID: 16633669
PDF is available here.
PDF is available here.
Abstract
Benzoic acid priming of the enterocin and actinorhodin type II polyketide synthase complexes was accomplished in vitro via an unprecedented type II nonribosomal peptide synthetase-like mechanism involving the benzoate:acyl carrier protein (ACP) ligase EncN and the ACP EncC. The transfer of the aryl...
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PMID: 16448095
PDF is available here.
PDF is available here.
Abstract
The translational diffusion of rubrene in the fragile molecular glass former, sucrose benzoate (SB) (fragility index m approximately 94), has been studied from T(g)+6 K to T(g)+71 K(T(g)=337 K) by using the technique of holographic fluorescence recovery after photobleaching. In the temperature range...
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PMID: 16409044
PDF is available here.
PDF is available here.
Abstract
We isolated a bioactive streptomycete from marine sediment samples collected at Bay of Bengal, India, during our systematic study of marine actinobacteria. The taxonomic studies indicated that the isolate is related to Strepomyces corchorusii. However, it differed in certain aspects, and, hence, was...
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PMID: 16808176
PDF is available here.
PDF is available here.
Abstract
Abstract
The growth of well-oriented crystalline films of rubrene (C42H28) on SiO2 and Au111 substrates is achieved by employing "hot wall" deposition whereas organic molecular beam deposition (OMBD) only yields rather amorphous layers or poly-crystalline dendritic networks at elevated temperature. This pron...
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PMID: 16189602
PDF is available here.
PDF is available here.
Chemistry & Biology (12)5 2005
Abstract
We report here that purified AknS has very low activity in the absence of the adjacently encoded AknT; however, at a 3:1 ratio, AknT stimulates AknS k(cat) by 40-fold up to 0.22 min(-1) for transfer of L-2-deoxyfucose (2-dF) to the aglycone aklavinone. It is likely that several other Gtfs that glyco...
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PMID: 15911373
PDF is available here.
PDF is available here.
Abstract
L- and D-stereoisomers of amicetose were generated by combining sugar biosynthesis genes from four different antibiotic gene clusters and both sugars were transferred to the elloramycin aglycone by the sugar flexible ElmGT glycosyltransferase.
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PMID: 15770274
PDF is available here.
PDF is available here.
Chemistry & Biology (11)12 2004
Abstract
Sugar biosynthesis cassette genes have been used to construct plasmids directing the biosynthesis of branched-chain deoxysugars: pFL942 (NDP-L-mycarose), pFL947 (NDP-4-deacetyl-L-chromose B), and pFL946/pFL954 (NDP-2,3,4-tridemethyl-L-nogalose). Expression of pFL942 and pFL947 in S. lividans 16F4, w...
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PMID: 15610855
PDF is available here.
PDF is available here.
Ultramicroscopy (101)2-4 2004
Abstract
We have measured the sensitivity of three highly conjugated organic compounds to electron irradiation. Using a 200 keV TEM, loss of crystallinity was determined from quantitative electron-diffraction measurements. Degradation of the molecular ring structure was monitored from fading of the 6 eV pi-e...
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PMID: 15450662
PDF is available here.
PDF is available here.
Journal of Natural Products (67)10 2004
Abstract
Chemical analysis of an Australian Streptomyces species yielded a range of known anthracyclines and biosynthetically related metabolites, including daunomycin (1), epsilon-rhodomycinone (2), 11-hydroxyauramycinone (3), 11-hydroxysulfurmycinone (4), aklavinone (5), bisanhydro-gamma-rhodomycinone (6),...
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PMID: 15497950
PDF is available here.
PDF is available here.
Abstract
The fluorescence and laser properties of seven specially chosen aromatic compounds are studied at 293 degrees C. The quantum yield of fluorescence, gamma, decay times, tauf, of the deaerated and non-deaerated solutions are measured. The oscillator strength, fe, fluorescence rate constants, kf, natur...
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PMID: 15248983
PDF is available here.
PDF is available here.
Organic Letters (6)12 2004
Abstract
[reaction: see text] Irradiation of 5,12-didecyloxytetracene (1) leads to photodimers P(1) (planosymmetric) and P(2) (centrosymmetric). P(1) is characterized by naphthalene excimer fluorescence, whereas P(2) emits naphthalene monomer fluorescence.
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PMID: 15176778
PDF is available here.
PDF is available here.
The Journal of Chemical Physics (120)16 2004
Abstract
We present a multimode vibrational analysis of the gas-phase ultraviolet photoelectron spectra of the first ionization in anthracene, tetracene, and pentacene, using electron-vibration constants computed at the density functional theory level. The first ionization of each molecule exhibits a high-fr...
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PMID: 15267661
PDF is available here.
PDF is available here.
Biochemistry (Washington) (43)15 2004
Abstract
We report the heterologous expression and purification of one of these enzymes, AknK, as well as the preparation of dTDP-L-2-deoxysugar donors, dTDP-L-2-deoxyfucose and dTDP-L-daunosamine, and the monoglycosyl aglycone, rhodosaminyl aklavinone. Our experiments show that AknK catalyzes the addition o...
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PMID: 15078101
PDF is available here.
PDF is available here.
Biochemistry (New York) (68)9 2003
Abstract
We have shown that infrared low intensity laser radiation causes oxygenation of the chemical traps of singlet oxygen dissolved in organic media and water saturated by air at normal atmospheric pressure. The photooxygenation rate was directly proportional to the oxygen concentration and strongly inhi...
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PMID: 14606937
PDF is available here.
PDF is available here.
Abstract
The effects and mechanism of sesamol on the methylene blue- or chlorophyll-sensitized photo-oxidations of soybean oil have been studied. Sesamol showed strong antiphoto-oxidative activity in both methylene blue-and chlorophyll-sensitized photo-oxidations of soybean oil in a dose-dependent manner. Th...
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PMID: 12744684
PDF is available here.
PDF is available here.
Abstract
The preparation and cytotoxic activity of 4'-azido-3'-bromo-3'-deamino-4'-deoxydaunorubicin is described. The new compound was found to be less active in vitro than adriamycin against L1210 and the sensitive cell lines KB-3-1 and MES-SA, but retained interesting cytotoxicity against the adriamycin r...
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PMID: 12443763
PDF is available here.
PDF is available here.
Abstract
Photochemical properties of the lowest triplet pi,pi* state of 5,12-naphthacenequinone (5,12-NQ) have been investigated in solution by means of nanosecond laser flash photolysis at 295 K. The transient absorption spectrum of triplet 5,12-NQ was measured in CCl4 and the molar absorption coefficient w...
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PMID: 12659526
PDF is available here.
PDF is available here.
Journal of Bacteriology (184)22 2002
Abstract
In streptomycete anthracycline biosynthetic gene clusters, small open reading frames are located just upstream of minimal polyketide synthase genes. aknX is such a gene found in the aklavinone-aclacinomycin biosynthetic gene cluster of Streptomyces galilaeus. In order to identify its function, the a...
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PMID: 12399480
PDF is available here.
PDF is available here.
Abstract
The PL and EL spectra of 5,6,11,12-tetraphenyl-tetracene doped 8-hydroxyquinoline are measured. It is found that Alq is host emitter when dopant concentration is low, and a discrete level is introduced by doping Rubrene (guest emitter) in Alq energy gap. As increasing Rubrene concentration, Rubrene...
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PMID: 12938410
PDF is available here.
PDF is available here.
Biochemistry (Washington) (41)33 2002
Abstract
We have shown that sgFabH activity is present in S. glaucescens fermentations during TCM C production, suggesting that it could contribute to initiation of TCM C biosynthesis in vivo. Isotope incorporation studies with [CD3]acetate and [13CD3]acetate demonstrated significant intact retention of thre...
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PMID: 12173933
PDF is available here.
PDF is available here.
Abstract
We have cloned and sequenced polyketide synthase (PKS) genes from the aclacinomycin producer Streptomyces galilaeus ATCC 31,615. The sequenced 13.5-kb region contained 13 complete genes. Their organization as well as their protein sequences showed high similarity to those of other type II PKS genes....
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PMID: 12137949
PDF is available here.
PDF is available here.
Abstract
We report the initial results and structure-activity relationships of our study into a series of thiosemicarbazone derivatives of madurahydroxylactone as potential nonsteroidal inhibitors of the enzyme estrone sulfatase. The most active compound, the cyclohexylthiosemicarbazone, was shown to be a no...
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PMID: 11992772
PDF is available here.
PDF is available here.
Abstract
Continuous-wave time-resolved EPR (cw-TREPR) and pulsed electron nuclear double resonance (ENDOR) studies have been carried out to clarify the electronic structure of the lowest excited triplet (Tl) state of 5,12-naphthacenequinone (5,12-NpQ) as well as 1,4-anthraquinone (1,4-AQ) and 6,13-pentaceneq...
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PMID: 11993468
PDF is available here.
PDF is available here.
Abstract
(+)-4-Demethoxy-1,4-dimethyldaunomycinone 1 was synthesized using a convergent approach. Here, the key tetracyclic compound 10 was assembled by way of a Diels-Alder reaction using the sugar-based diene 8 and the quinizarin-related dienophile 7.
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PMID: 11814850
PDF is available here.
PDF is available here.
Journal of Antibiotics (55)3 2002
Abstract
We studied the effects of hibarimicins and hibarimicin-related compounds produced by Microbispora rosea subsp. hibaria [glycosides (hibarimicins A, B, C, D, E, G, H and I) and aglycon (hibarimicinone)] or compounds produced by its mutants [glycosides (HMP-P4 and -Y6), aglycons (HMP-P1 and -Y1) and s...
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PMID: 12014442
PDF is available here.
PDF is available here.