The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
J. Derek Woollins - One of the best experts on this subject based on the ideXlab platform.
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Formation of new organoselenium heterocycles and ring reduction of 10-membered heterocycles into seven-membered heterocycles
Polyhedron, 2011Co-Authors: Guoxiong Hua, Amy L. Fuller, Alexandra M. Z. Slawin, J. Derek WoollinsAbstract:Abstract Reacting 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide [{PhP(Se)(μ-Se)}2], Woollins’ reagent, with an equivalent of Aromatic Diol in refluxing toluene afforded 10-membered phosphorus–selenium heterocycles 1 and 2 with an O–P(Se)–Se–Se–P(Se)–O linkage. Two equivalents of Aromatic Diol and Woollins’ reagent in refluxing toluene gave seven-membered phosphorus–selenium heterocycles 3 and 4 with an O–P(Se)–O linkage together with 10-membered phosphorus–selenium heterocycles 1 and 2. It was also found that the diphosphorus species O–P(Se)–Se–Se–P(Se)–O rings 1 and 2 could be readily ring contracted into the monophosphorus rings 3 and 4 in almost quantitative yields via further reaction with another equivalent of corresponding Aromatic Diol. One representative X-ray structure is reported.
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Novel Five- to Ten-Membered Organoselenium Heterocycles from the Selenation of Aromatic Diols
European Journal of Organic Chemistry, 2010Co-Authors: Guoxiong Hua, Amy L. Fuller, Alexandra M. Z. Slawin, J. Derek WoollinsAbstract:Reaction of Woollins' reagent - WR, 2,4-bis(phenyl)-1,3-di-selenadiphosphetane 2,4-diselenide [{PhP(Se)(μ-Se)} 2 ] - with Aromatic Diols in refluxing toluene afforded a series of novel five- to ten-membered phosphorus-selenium heterocycles 1-10 with an O-P(Se)-O or O-P(Se)-Se-P(Se)-O or O-P(Se)-O-P(Se)-O linkage in 12-74 % isolated yields. It was found that the diphosphorus species O-P(Se)-Se-P(Se)-O rings could be readily reduced into the monophosphorus species O-P(Se)-O rings in almost quantitative yields via further reaction with another equivalent of corresponding Aromatic Diol. All new compounds have been characterized by IR, 1 H NMR, 13 C NMR, 31 P NMR, 77 Se NMR, mass spectrometry and elemental analysis or accurate mass measurement. Seven representative X-ray structures are reported.
Guobao Xu - One of the best experts on this subject based on the ideXlab platform.
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Tris(2,2′-bipyridyl)ruthenium(II) electrochemiluminescent detection of coreactants containing Aromatic Diol group by the interaction between Diol and borate anion
Electrochemistry Communications, 2007Co-Authors: Haijuan Li, Guobao XuAbstract:Previous studies show that Aromatic Diols inhibited Ru(bpy)(3)(2+) electrochemiluminescence (ECL), and all reported Ru(bpy)(3)(2+) ECL methods for the determination of Aromatic Diols-containing coreactants are based on inhibition of Ru(bpy)(3)(2+)/tripropylamine ECL. In this study, the interaction between Diol and borate anion was exploited for Ru(bpy)(3)(2+) ECL detection of coreactants containing Aromatic Diol group using epinephrine as a model analyte. The interaction prevented from the inhibition of Ru(bpy)(3)(2+) ECL by Aromatic Diol group of epinephrine. As a result, epinephrine was successfully detected in the absence of tripropylamine simply by using borate buffer solution as the supporting electrolyte. Under the optimum conditions, the log of the ECL intensity increases linearly with the log of epinephrine concentrations over the concentration range of 1.0x10(-9)-1.0x10(-4) M. The detection limit is 5.0x10(-10) M at a signal-to-noise ratio of three. The proposed method exhibit wider dynamic range and better detection limit than that by inhibited Ru(bpy)(3)(2+) ECL method. The relative standard deviation for 14 consecutive determinations of 5 mu M epinephrine was 3.5%. The strategy by interaction with borate anion or boronate derivatives is promising for the determination of coreactants containing Aromatic Diol group or Aromatic hydroxyl acid group. Such interaction can also be used to avoid interference from Aromatic Diols or Aromatic hydroxyl acids.
Wenxin Niu - One of the best experts on this subject based on the ideXlab platform.
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Tris(2,2' -bipyridyl )ruthenium(II) electrochemiluminescent detection of coreactants containing Aromatic Diol group by the interaction between Diol and borate anion
Electrochemistry Communications, 2007Co-Authors: Xiaoqing Liu, Lihong Shi, Wenxin NiuAbstract:Previous studies show that Aromatic Diols inhibited Ru(bpy)(3)(2+) electrochemiluminescence (ECL), and all reported Ru(bpy)(3)(2+) ECL methods for the determination of Aromatic Diols-containing coreactants are based on inhibition of Ru(bpy)(3)(2+)/tripropylamine ECL. In this study, the interaction between Diol and borate anion was exploited for Ru(bpy)(3)(2+) ECL detection of coreactants containing Aromatic Diol group using epinephrine as a model analyte. The interaction prevented from the inhibition of Ru(bpy)(3)(2+) ECL by Aromatic Diol group of epinephrine. As a result, epinephrine was successfully detected in the absence of tripropylamine simply by using borate buffer solution as the supporting electrolyte. Under the optimum conditions, the log of the ECL intensity increases linearly with the log of epinephrine concentrations over the concentration range of 1.0x10(-9)-1.0x10(-4) M. The detection limit is 5.0x10(-10) M at a signal-to-noise ratio of three. The proposed method exhibit wider dynamic range and better detection limit than that by inhibited Ru(bpy)(3)(2+) ECL method. The relative standard deviation for 14 consecutive determinations of 5 mu M epinephrine was 3.5%. The strategy by interaction with borate anion or boronate derivatives is promising for the determination of coreactants containing Aromatic Diol group or Aromatic hydroxyl acid group. Such interaction can also be used to avoid interference from Aromatic Diols or Aromatic hydroxyl acids.
Guoxiong Hua - One of the best experts on this subject based on the ideXlab platform.
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Formation of new organoselenium heterocycles and ring reduction of 10-membered heterocycles into seven-membered heterocycles
Polyhedron, 2011Co-Authors: Guoxiong Hua, Amy L. Fuller, Alexandra M. Z. Slawin, J. Derek WoollinsAbstract:Abstract Reacting 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide [{PhP(Se)(μ-Se)}2], Woollins’ reagent, with an equivalent of Aromatic Diol in refluxing toluene afforded 10-membered phosphorus–selenium heterocycles 1 and 2 with an O–P(Se)–Se–Se–P(Se)–O linkage. Two equivalents of Aromatic Diol and Woollins’ reagent in refluxing toluene gave seven-membered phosphorus–selenium heterocycles 3 and 4 with an O–P(Se)–O linkage together with 10-membered phosphorus–selenium heterocycles 1 and 2. It was also found that the diphosphorus species O–P(Se)–Se–Se–P(Se)–O rings 1 and 2 could be readily ring contracted into the monophosphorus rings 3 and 4 in almost quantitative yields via further reaction with another equivalent of corresponding Aromatic Diol. One representative X-ray structure is reported.
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Novel Five- to Ten-Membered Organoselenium Heterocycles from the Selenation of Aromatic Diols
European Journal of Organic Chemistry, 2010Co-Authors: Guoxiong Hua, Amy L. Fuller, Alexandra M. Z. Slawin, J. Derek WoollinsAbstract:Reaction of Woollins' reagent - WR, 2,4-bis(phenyl)-1,3-di-selenadiphosphetane 2,4-diselenide [{PhP(Se)(μ-Se)} 2 ] - with Aromatic Diols in refluxing toluene afforded a series of novel five- to ten-membered phosphorus-selenium heterocycles 1-10 with an O-P(Se)-O or O-P(Se)-Se-P(Se)-O or O-P(Se)-O-P(Se)-O linkage in 12-74 % isolated yields. It was found that the diphosphorus species O-P(Se)-Se-P(Se)-O rings could be readily reduced into the monophosphorus species O-P(Se)-O rings in almost quantitative yields via further reaction with another equivalent of corresponding Aromatic Diol. All new compounds have been characterized by IR, 1 H NMR, 13 C NMR, 31 P NMR, 77 Se NMR, mass spectrometry and elemental analysis or accurate mass measurement. Seven representative X-ray structures are reported.
Nicholas E. Geacintov - One of the best experts on this subject based on the ideXlab platform.
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role of hydrophobic effects in the reaction of a polynuclear Aromatic Diol epoxide with oligodeoxynucleotides in aqueous solutions
Chemical Research in Toxicology, 1998Co-Authors: Nikolai Pirogov, Vladimir Shafirovich, Alexander Kolbanovskiy, Kyril M Solntsev, Scott A Courtney, Shantu Amin, Nicholas E. GeacintovAbstract:The need for large-scale direct synthesis of stereochemically defined and site-specific benzo[a]pyreneDiol epoxide−oligodeoxyribonucleotide adducts for detailed NMR and other biochemical and physicochemical studies has necessitated a better understanding of variables that lead to an enhancement of the reaction yields. It is shown that, in aqueous solution, the formation of noncovalent hydrophobic complexes between 7r,8t-dihydroxy-9t,10t-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) and the single-stranded oligonucleotide 5‘-d(CCATCGCTACC) precedes the covalent binding reaction of BPDE with the single deoxyguanosine residue. The yield of covalent reaction products (involving reaction of BPDE at the C10 position with the exocyclic amino group of the dG residue) increases with increasing DNA concentration and tends toward saturation at oligonucleotide single-strand concentrations above ∼3 mM. The addition of NaCl (0.3 M) also tends to enhance the adduct reaction yields. However, organic solvents such as tet...
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NMR solution structures of adducts derived from the binding of polycyclic Aromatic Diol epoxides to DNA
1995Co-Authors: Monique Cosman, Dinshaw J. Patel, Brian E. Hingerty, S. Amin, Suse Broyde, Nicholas E. GeacintovAbstract:Site-specifically modified oligonucleotides were derived from the reactions of stereoisomeric polycyclic Aromatic Diol epoxide metabolite model compounds with oligonucleotides of defined base composition and sequence. The NMR solution structures of ten different adducts studied so far are briefly described, and it is shown that stereochemical factors and the nature of the oligonucleotide context of the complementary strands, exert a powerful influence on the conformational features of these adducts.