Publications by authors named "Peter Baran"

Although the management options for psoriasis have progressed with the use of systemic agents, there are few efficacious nonsteroidal topical therapies for patients with limited or lower grade disease. The effects of allopurinol (Allo) and glutathione (GSH) were examined in two different models for psoriasis. In the first model, human immortalized keratinocytes (HaCaT) were treated with M5 cocktail (IL-17A, IL-22, oncostatin M, IL-1, and TNF-) in four interventional groups (control, Allo, oxypurinol (Oxy), and methotrexate (MTX)).

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An intriguing example of a crystallization-induced stereochemical switch in the configuration of aza-Michael reaction products is described. Depending on both the stereochemical purity and stoichiometric ratio of the chiral amine used, the reaction delivers crystalline diastereomers of a different stereochemistry. The optically pure diastereomer smoothly converts to its racemic epimer salt upon the addition of a complementary chiral amine.

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Monolayers of six alkylphosphonic acids ranging from C8 to C18 were prepared by vacuum evaporation and incorporated into low-voltage organic field-effect transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT). Similar to solution-assembled monolayers, the molecular order for vacuum-deposited monolayers improved with increasing length of the aliphatic tail. At the same time, Fourier transform infrared (FTIR) measurements suggested lower molecular coverage for longer phosphonic acids.

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Two water-soluble iron-pyrazolato complexes, [Fe], have been prepared by the introduction of twelve hydroxyalkyl groups to the periphery of the approximately spherical octanuclear molecule and they are contrasted with their two organosoluble chloroalkyl analogues. All four new complexes, - , have been characterized in solution by H-NMR and electrospray ionization mass spectroscopy. The one-electron reduction product of the water-soluble , [Fe], has been structurally characterized by single crystal diffraction methods.

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The practical stereodivergent route to both syn- and anti-diastereomers of 1-substituted 3-aminobutane-1,4-diols based on the crystallization-induced asymmetric transformation (CIAT) approach was completed. This led to the revision of the reported stereochemistry of the first inhibitor of CERT-dependent ceramide trafficking HPA-12 from (R,R)-anti- to the (R,S)-syn-enantiomer. Due to the expeditiousness of production and inexpensive conditions developed, a series of alkyl- and aryl-substituted analogues of HPA-12 is also reported.

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Six [Fe(8)(μ(4)-O)(4)(μ-4-R-pyrazolato)(12)X(4)] complexes containing an identical Fe(8)(μ(4)-O)(4) core have been structurally characterized and studied by Mössbauer spectroscopy. In each case, an inner μ(4)-O bridged Fe(III) cubane core is surrounded by four trigonal bipyramidal iron centers, the two distinct sites occurring in a 1:1 ratio. The Mössbauer spectrum of each of the clusters consists of two quadrupole doublets, which, with one exception (X = NCS, R = H), overlap to give three absorption lines.

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Ten new diterpenes, 1-10, having a dolabellane skeleton were isolated from a Colombian gorgonian coral of the genus Eunicea. Their structures, as well as those of known compounds 11-18, were determined on the basis of spectroscopic analysis and, in some instances, by chemical conversion and X-ray crystallographic analysis. The absolute structure of 7 was established by chemical conversion from 11, a co-occurring dolabellane congener of known absolute structure.

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A formally Fe(III)(7)Fe(II) complex, containing an inner Fe(4)O(4)-cubane and four peripheral Fe centers, is derived from the one-electron reduction of its Fe(III)(8) precursor. Spectroscopic analysis of the former reveals that the redox activity of this Fe(8) system is confined within its cubane core. The resulting (Fe(4)O(4))(3+)-cubane, which is valence-delocalized in the NMR, Mössbauer, and IR spectroscopy time scales but valence-trapped in the X-ray photoelectron spectroscopy (XPS) time scale, is better described as a Robin-Day class-II system by the analysis of its near-infrared (NIR) intervalence charge transfer (IVCT) band profile.

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A polyoxomolybdenum/vanadium-sulfite {M(18)} cluster-based compound, [Mo(VI)(11)V(V)(5)V(IV)(2)O(52)(mu(9)-SO(3))](7-), is reported that exhibits a unique structural motif, arising from the incorporation of five V(V) and two V(IV) ions into a {M(18)} cluster framework templated by SO(3)(2-); this cluster compostion was first identified using cryospray mass spectrometry.

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Industrial water systems often suffer from undesirable inorganic deposits, such as calcium carbonate, calcium phosphate(s), magnesium silicate, and others. Synthetic water additives such as phosphonates and phosphonocarboxylates are the most important and widely utilized scale inhibitors in a plethora of industrial applications. The design of efficient and cost-effective inhibitors, as well as the study of their structure and function at the molecular level are important areas of research.

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A one-pot synthetic procedure yields the octanuclear Fe(III) complexes Fe(8)(micro(4-)O)(4)(micro-pz(*))(12)X(40, where X = Cl and pz(*) = pyrazolate anion (pz = C(3)H(3)N(2)-) (1), 4-Cl-pz (2), and 4-Me-pz (3) or X = Br and pz(*) = pz (4). The crystal structures of complexes 1-4, determined by X-ray diffraction, show an Fe(4)O(4)-cubane core encapsulated in a shell composed of four interwoven Fe(micro-pz(*))(3)X units. Complexes 1-4 have been characterized by 1H NMR, infrared, and Raman spectroscopies.

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A comparison is made between the structural, spectroscopic, electrochemical, and magnetic properties of pyrazolate versus carboxylate complexes [Fe3(mu3(mu3O)(mu-LL)6Cl3]2- containing the Fe3(mu3-O)-motif. While the Fe3(mu3-O)-cores are structurally indistinguishable in the two types of complexes, their magnetic properties deviate from the expected values as a result of a through-pyrazole contribution to the overall antiferromagnetic exchange with J1/hc = -80.1 cm(-1) and J2/hc = -72.

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A simple and efficient methodology for the synthesis of a small library of substituted indolizines with different degrees of saturation starting from the racemic 2-formyl-1,4-DHP reagent was described. The large synthetic possibilities of this reagent as well as of its Knoevenagel corresponding 2-dicyanovinyl-1,4-DHP reagent were investigated using four kinds of activated methylenes as nucleophiles. The key step of the sequential reaction was based on the highly diastereoselective tandem Michael addition/intramolecular amino-nitrile cyclization catalyzed by an organic base, which resulted in the formation of 1,7-dihydroindolizines in a diastereoselective manner.

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Reaction of NH4VO3 with sulfur dioxide affords the hexanuclear cluster (NH4)2(Et4N)[(V(IV)O)6(mu4-O)2(mu3-OH)2(mu3-SO3)4(H2O)2]Cl x H2O (1), and the decapentanuclear host-guest compound (Et4N)5{Cl subset [(VO)15(mu3-O)18(mu-O)3]} x 3 H2O (2). Sequential addition of magnesium oxide to an acidic aqueous solution of NH4VO3 (pH approximately 0) followed by (NH4)2SO3 resulted in the formation of either the non-oxo polymeric vanadium(IV) compound trans-(NH4)2[V(IV)(OH)2(mu-SO3)2] (3) or the polymeric oxovanadium(IV) sulfite (NH4)[V(IV)O(SO3)1.5(H2O)] x 2.

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Background: A reduction in the expression of the pan T-cell markers CD7 and CD62L supports an endogenous T-cell dyscrasia. Previously, clone availability for CD62L restricted its application to frozen tissue sections.

Materials And Methods: A nonavidin/biotin technique to examine CD3, CD62L, and CD7 in paraffin formalin-fixed tissue in non-neoplastic and neoplastic T-cell infiltrates.

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The title compound, [Cu(C(2)N(3))(C(12)H(8)N(2))(2)]ClO(4), represents a relatively rare class of compounds with dicyanamide coordinated in a monodentate manner. The structure is formed by the [Cu{N(CN)(2)}(phen)(2)](+) complex cation (phen is 1,10-phenanthroline) and an uncoordinated ClO(4)(-) anion. The Cu atom is five-coordinate, with a slightly distorted trigonal-bipyramidal environment.

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(R)- and (S)-alpha-phenylethylamine (alpha-PEA: 7) have been used separately to resolve successfully a racemate 2-formyl-1,4-DHP derivative 4. The process was based on the difference of the solubility of both Schiff bases (6) since one of them crystallized out from the solution. These imines obtained by condensation of (R)-alpha-PEA (7) or (S)-alpha-PEA (7) with aldehyde (rac-4) were separated and analyzed by X-ray diffraction, and their exposition to an hydrochloric hydrolysis conditions led to the enantiopure (4R)-4 or (4S)-4 in excellent yields.

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Pyridine fused with a furan ring (fupy), and its dimethyl derivative, have been used for the first time as ligands to synthesize potentially new Werner clathrates. The extended aromatic system of pyridine-like ligands influences considerably the molecular structure of prepared nickel complexes. The molecular structure of tetrakis(furo[3,2-c]pyridine)bis(isothiocyanato)nickel(II) tetrahydrofuran (THF) solvate, [Ni(NCS)(2)(C(7)H(5)NO)(4)].

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Bielschowskysin is a naturally occurring diterpene isolated from the Caribbean gorgonian octocoral Pseudopterogorgia kallos. Its highly oxygenated hexacyclic structure is based on a previously undescribed tricyclo[9.3.

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The reaction of (S)-alpha,alpha-diphenylprolinol with an excess of borane-tetrahydrofuran complex yields a stable crystalline material with the composition C34H38B2N2O2, which features a borane adduct of a spirocyclic structure with two oxazaborolidine rings joined by a central tetrahedral B atom. This dimeric oxazaborolidine complex, viz. 3,3,3',3'-tetraphenyl-1,1'-spirobi(3a,4,5,6-tetrahydro-3H-pyrrolo[1,2-c][1,3,2]oxazaborole)-7-borane, is the dominant product under various reaction conditions; its crystal structure is consistent with 11B, 1H and 13C NMR and IR analyses.

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[structure: see text] Providencin (1) is a naturally occurring cytotoxin isolated from the Caribbean gorgonian octocoral Pseudopterogorgia kallos. Its highly oxygenated hexacyclic structure is based on a previously undescribed bicyclo[12.2.

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The Caribbean alcyonacean Pseudopterogorgia kallos is shown to contain a novel rearranged pseudopterane diterpene, kallosin A (1), possessing several unusual structural features. In addition to having two distinct 2(3H)- and 2(5H)-furanone moieties, kallosin A is based on a new carbon skeleton. The structural assignment of 1 was based mainly on 1D and 2D NMR spectral data and was further supported by accurate mass measurement and single-crystal X-ray diffraction analysis.

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The secondary metabolite composition of the gorgonian octocoral Eunicea pinta from San Andrés Island, Colombia, is described for the first time. This investigation has resulted in the isolation of eight new gamma-cembranolide-type diterpenes, namely, compounds 3-10, and a new saponin, 13, possessing a pregnene-derived aglycon. In addition, two previously known alpha-methylene-gamma-lactone cembranolides, euniolide (1) and succinolide (2), were also isolated.

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A triangular homoleptic complex, [Pd(mu-3-Ph-pz)2]3, is prepared by the stepwise formation of an open-chain trimer and subsequent ring-closure; D3 molecular symmetry results from the one-directional arrangement of the unsymmetrically substituted pyrazolato ligands; the palladium atoms are held in close proximity, with Pd-Pd distances of 2.997(1)-3.087(1) A.

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