- Synthesis of common-sized heterocyclic compounds by intramolecular cyclization over halide cluster catalysts
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Five- to seven-membered common-sized heterocyclic compounds containing an oxygen, sulfur, or nitrogen were synthesized by the intramolecular condensation of α,ω-hydroxy, mercapto, or amino alkanes, respectively, over halide cluster complexes as a thermally stable molecular solid weak acid catalyst in the gas phase at temperatures ≥150 °C. From ω- mercapto and ω-amino alcohols, cyclic sulfides and amines were obtained, respectively. These unimolecular reactions are thermodynamically and kinetically favored.
- Nagashima, Sayoko,Sasaki, Tomoaki,Kamiguchi, Satoshi,Chihara, Teiji
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supporting information
p. 764 - 766
(2015/06/22)
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- AZOLE INHIBITORS OF CYTOKINE PRODUCTION
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Compounds having the formula are useful for treating diseases that are prevented by or ameliorated with Interleukin-2, Interleukin-4, or Interleukin-5 production inhibitors.
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- The first direct oxidative conversion of a selenol to a stable selenenic acid: Experimental demonstration of three processes included in the catalytic cycle of glutathione peroxidase
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(matrix presented) A stable selenenic acid was synthesized by direct oxidation of a selenol bearing a novel bowl-type substituent with H2O2, and its structure was established by X-ray crystallographic analysis. Selenenyl sulfides obt
- Goto, Kei,Nagahama, Michiko,Mizushima, Tadashi,Shimada, Keiichi,Kawashima, Takayuki,Okazaki, Renji
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p. 3569 - 3572
(2007/10/03)
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- Reduction of thiocols to alkanepolythiols with benzeneselenol
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Heating of benzeneselenol with polymethylene disulfides to 40-120°C results in formation of the corresponding alkanedithiols or alkanetrithiols and diphenyl diselenide. Poly(tetramethylene disulfide) reacts with benzeneselenol to give 1,2-dithiane and diphenyl diselenide. A radical mechanism of this reaction is discussed.
- Shilkina,Papernaya,Deryagina
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p. 263 - 265
(2007/10/03)
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- Reduction of thiokols in the system hydrazine hydrate-base as a new route to alkanedithiols
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A new procedure for preparative synthesis of alkanedithiols from simple commercially available products is based on reduction of the S-S bond in appropriate polyalkylene disulfides (thiokols) in the system hydrazine hydrate-base. Thiokols were prepared by reaction of dihaloalkanes with Na2S2 or K2S2 generated from elemental sulfur and alkali in aqueous hydrazine hydrate. Reaction of 1,2-dibromocyclohexane with sodium or potassium disulfide yields bis(2-bromocyclohexyl) sulfide as the only product.
- Alekminskaya,Russavskaya,Korchevin,Deryagina,Trofimov
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p. 732 - 737
(2007/10/03)
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- Degenerate intermolecular thiolate-disulfide interchange involving cyclic five-membered disulfides is faster by ~103 than that involving six- or seven-membered disulfides
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The rate constants for degenerate intermolecular thiolate-disulfide interchange involving 1,2-dithiolane (S(CH2)3S) are higher than those involving 1,2-dithiane (S(CH2)4S) by a factor of ~650 in mixtures of DMSO-d6 and D2O. The extrapolated rate constant for 1,2-dithiolane in DMSO-d6 is fast (k ~ 108 M-1 s-1). The rate constants for cyclic six- and seven-membered disulfides are similar to those for acyclic disulfides. Rate constants for self-exchange were measured by dynamic 1H NMR line-shape analysis. The evolutionary selection of lipoamide as the cofactor in 2-oxo acid dehydrogenases may reflect the fast rate of ring opening of the dithiolane ring by nucleophiles.
- Singh, Rajeeva,Whitesides, George M.
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p. 6304 - 6309
(2007/10/02)
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- Substituent and Steric Effects of Flavin Models in the Reactions of N-Benzyl-1,4-dihydronicotinamide, Butane-1,4-dithiol, Phenylhydrazine, and Nitroethane
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Reactivities of 3-methyl-10-phenyl-8-substituted-, 3-methyl-10-(p-substituted phenyl)-, and 3,6-dimethyl-10-phenylisoalloxazines have been kinetically investigated for oxidations of N-benzyl-1,4-dihydronicotinamide, HS(CH2)4SH, PhNHNH2, and EtNO2 in EtOH containing diazabicycloundecence as a base or in aqueous solution under anaerobic conditions.Substituent effects and the steric hindrance of the 6-methyl group are discussed in connection with the reaction mechanisms.
- Yano, Yumihiko,Nakazato, Michiaki,Ohya, Eiichi
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