410 research outputs found
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A neutral low-coordinate heterocyclic bismuth-tin species
The reaction of distannadiazane bearing bulky RAr*-groups (RAr* = C6H2{C(H)Ph2}2R-2,6,4; R = iPr, tBu) with ECl3 (E = Sb, Bi) was studied resulting in the isolation of previously unknown N,N-bis(dichloropnictino)amines (3) and a novel heterocyclic carbenoid bismuth species (4) bearing a Bi(III) and a Sn(IV) center. The structure and bonding was investigated by means of X-ray structure elucidations and DFT calculations
Ethyl 4-chloro-2′-fluoro-3-hydroxy-5-methylbiphenyl-2-carboxylate
In the title compound, C 16H 14ClFO 3, the dihedral angle between the mean planes of the two benzene rings is 71.50 (5)°. Due to an intramolecular O - H⋯O hydrogen bond between the hydroxy group and the carbonyl O atom of the ethyl ester group, the ethyl ester group lies within the ring plane. The crystal structure is consolidated by intermolecular C - H⋯O and C - H⋯F interactions
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An efficient route to 1,3,5-triazido-2,4,6-tricyanobenzene
An efficient synthetic route starting from 1,3,5-trimethylbenzene is described for binary 1,3,5- triazido-2,4,6-tricyanobenzene. Besides 1,3,5-triazido-2,4,6-tricyanobenzene, all intermediates have been isolated and fully characterized
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Methyl 5-chloro-2-hydr-oxy-3-(4-methoxyphenyl)-4,6-dimethylbenzoate
In the title compound, C17H17ClO4, the dihedral angle between the mean planes of the two benzene rings is 65.92 (5)°. The methyl ester group lies within the ring plane [deviations of O atoms from the plane = -0.051 (2) and 0.151 (2) Å] due to an intra-molecular O - H⋯O hydrogen bond. In the crystal, molecules are held together by rather weak non-classical inter-molecular C - H⋯O hydrogen bonds, resulting in dimeric units about inversion centers, forming eight- and ten-membered ring systems as R22(8) and R2 2(10) motifs. © Adeel et al. 2009
Genetic Analysis of Cytokine Promoters in Nonhuman Primates: Implications for Th1/Th2 Profile Characteristics and SIV Disease Pathogenesis
The shift from a predominant synthesis of prototype
Th1 cytokines to Th2 or Th0 type of cytokines by antigen
activated PBMC's from HIV infected humans and SIV infected
disease susceptible rhesus macaques (RM) has been shown to
be associated with disease progression. Paradoxically, antigen
activated PBMC's from sooty mangabeys (SM), which are naturally
infected with SIV and are disease resistant despite high viral loads,
maintain a predominant Th2 cytokine profile. It has been reasoned
that the resistance to perturbations of cytokine synthesis by slow
and/or nonprogressor HIV infected patients and SIV infected disease
susceptible RM is secondary to inherited polymorphisms within
the promoter regions for cytokines. Similar promoter polymorphisms
could also contribute to the cytokine profile of PBMC's from SM. To
address this issue promoter regions for the major Th1/Th2 cytokines
from RM and SM were cloned and sequenced. Sequence analysis
of promoter fragments of IL-4, IL-10, IL-12 p40, IFN-gamma and
TNF-alpha from the two monkey species showed varying degree of
homology ranging from high degree of homology detected for
IFN-gamma promoter (>99%) to relatively high degree of polymorphism
detected for TNF-alpha promoter (94% homology). In addition, several
variable regions within the promoters of IL-12 p40, IL-10 and
TNF-alpha in the two species contain polymorphisms in sequences
that constitute binding sites of known transcription factors (TF). Such
differences are likely to differentially bind TF and thus either
qualitatively and/or quantitatively affect the regulation of cytokine
synthesis in these two species and potentially
contribute to disease progression and/or resistance
Synthesis and reactivity of 5-polyfluoroalkyl-5-deazaalloxazines
Reaction of 6-arylamino-1,3-dialkyluracils with anhydrides of polyfluorocarboxylic acids in the presence of pyridine and subsequent cyclization with concentrated H2SO4 gave the corresponding 1,3-dialkyl-5-(polyfluoroalkyl)pyrimido[4,5-b]quinoline-2,4(1H,3H)-diones (5-polyfluoroalkyl-5-deazaalloxazines). The reactivity of these compounds towards nucleophilic reagents, such as sodium cyanoborohydride, acetophenone, nitromethane, potassium cyanide, indole and p-thiocresol, as well as Suzuki and Sonogashira couplings are described. The nucleophilic addition takes place at the 5-position of the 5-deazaalloxazine system and is in many cases irreversible to give 5,10-dihydropyrimido[4,5-b]quinoline-2,4(1H,3H)-dione derivatives in good to excellent yields.© 2013 The Royal Society of Chemistry
Efficient synthesis of novel thieno[3,2-b]-, [2,3-c]- and [3,2-c]pyridones by Sonogashira coupling of bromothiophenes with terminal alkynes and subsequent intramolecular C-N bond-forming reaction
The coupling of bromothiophenes with terminal alkynes using triethylamine or diisopropyl amine under Sonogashira conditions (PdCl2(PPh 3)2, CuI) followed by subsequent addition of amines or ammonium to the intermediate thienyl acetylenes represents a novel access to a wide range of thieno[3,2-b]-, [2,3-c]-, and [3,2-c]pyridones under basic conditions and in excellent yields. © 2013 Elsevier Ltd. All rights reserved
IL-21 enhances influenza vaccine responses in aged macaques with suppressed SIV infection.
Natural aging and HIV infection are associated with chronic low-grade systemic inflammation, immune senescence, and impaired antibody responses to vaccines such as the influenza (flu) vaccine. We investigated the role of IL-21, a CD4+ T follicular helper cell (Tfh) regulator, on flu vaccine antibody response in nonhuman primates (NHPs) in the context of age and controlled SIV mac239 infection. Three doses of the flu vaccine with or without IL-21-IgFc were administered at 3-month intervals in aged SIV+ NHPs following virus suppression with antiretroviral therapy. IL-21-treated animals demonstrated higher day 14-postboost antibody responses, which associated with expanded CD4+ T central memory cells and peripheral Tfh-expressing (pTfh-expressing) T cell immunoreceptor with Ig and ITIM domains (TIGIT), expanded activated memory B cells, and contracted CD11b+ monocytes. Draining lymph node (LN) tissue from IL-21-treated animals revealed direct association between LN follicle Tfh density and frequency of circulating TIGIT+ pTfh cells. We conclude that IL-21 enhances flu vaccine-induced antibody responses in SIV+ aged rhesus macaques (RMs), acting as an adjuvant modulating LN germinal center activity. A strategy to supplement IL-21 in aging could be a valuable addition in the toolbox for improving vaccine responses in an aging HIV+ population
Efficient synthesis of novel benzo[b][1,8]naphthyridin-4(1H)-ones and pyrido[2,3-b]quinoxalin-4(1H)-ones from alkynones and primary amines
An efficient palladium-catalyzed cyclization of o-chlorohetaryl ynones with aliphatic and aromatic primary amines represents a simple access to a wide range of benzo[b][1,8]naphthyridin-4(1H)-one and pyrido[2,3-b]quinoxalin-4(1H)- one derivatives in good to excellent yields. © 2013 Elsevier Ltd. All rights reserved
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