- Cu-mediated one-pot three-component synthesis of 3-N-substituted 1,4,2-benzodithiazine 1,1-dioxide derivatives
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A novel and efficient copper-catalyzed one-pot procedure for the synthesis of 3-N-substituted 1,4,2-benzodithiazine 1,1-dioxide derivatives from 2-halobenzenesulfonamides, amines and CS2 is described. The reaction proceeds through Ullmann-type S-arylation, intramolecular addition of NH2 with C[dbnd]S and dehydrosulfide, which provides a new and useful strategy for construction of cyclic aromatic sulfonamides.
- Dong, Wei,Ge, Zemei,Wang, Xin,Li, Ridong,Li, Runtao
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- Utilization of carbon disulfide as a powerful building block for the synthesis of 2-aminobenzoxazoles
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This protocol describes a novel, mild and convenient route to afford 2-aminobenzoxazoles in high yields, and represents a significant advance towards an environmentally friendly strategy. Aliphatic amines are made to react with carbon disulfide to provide intermediate dithiocarbamates (DTC), which in the presence of 2-aminophenol, subsequently undergo successive intermolecular nucleophilic attack and desulfurization to produce 2-aminobenzoxazoles within 3 h.
- Guntreddi, Tirumaleswararao,Allam, Bharat Kumar,Singh, Krishna Nand
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p. 9875 - 9880
(2013/09/02)
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- Metal-sulphur Bond Enthalpy Determination of Di-n-Butyldithiocarbamate Chelates of Zinc, Cadmium and Mercury
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The standard molar enthalpies of formation of crystalline n2)2> (M = Zn, Cd or Hg), determined through reaction-solution calorimetry at 298.15 K, were found to be -471.23 +/- 3.90, -440.74 +/- 3.79 and -319.29 +/- 3.38 kJ mol-1, respectively.The corresponding molar enthalpies of sublimation, 107 +/- 3, 123 +/- 3 and 195 +/- 3 kJ mol-1, were estimated by means of differential scanning calorimetry.From the standard molar enthalpies of formation of the gaseous chelates, -364 +/- 5, 318 +/- 5 and -124 +/- 5 kJ mol-1, the homolytic and heterolytic mean metal-sulphur bond enthalpies were calculated.The homolytic enthalpies decrease from zinc to mercury, while the heterolytic values are almost constant.
- Souza, Antonio G. de,Souza, Jose H. de,Airoldi, Claudio
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p. 1751 - 1754
(2007/10/02)
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- Thermochemical properties of chelates of di-n-butyldithiocarbamate with phosphorus-group elements
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The standard molar enthalpies of formation of crystalline tris(di-n-butyldithiocarbamato)E(III), (E = P, As, Sb, or Bi), determined at 298.15 K by solution-reaction calorimetry, are -(705.5 +/- 7.3), -(443.1 +/- 5.4), -(526.2 +/- 2.5), and -(530.7 +/- 5.5) kJ*mol-1, respectively.The enthalpies of sublimation: (136 +/- 3), (128 +/- 3), (179 +/- 3), and (202 +/- 3) kJ*mol-1, were estimated.From the enthalpies of formation of the gaseous complexes, the homolytic and heterolytic mean standard molar element-sulphur bond enthalpies were calculated.These values are correlated with element-sulphur bond distances, and a larger phosphorus- sulphur bond enthalpy reflects a better overlap of d orbitals in bonding formation.
- Airoldi, Claudio,Souza, Antonio G. de
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p. 283 - 292
(2007/10/02)
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- Enthalpies of formation of crystalline dialkylammoniumdialkyldithiocarbamates: alkyl = ethyl, n-propyl, i-propyl, n-butyl, and i-butyl
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The standard (p0 = 101.325 kPa) molar enthalpies of formation of some crystalline dialkylammoniumdialkyldithiocarbamates were determined at 298.15 K by both solution-reaction calorimetry and by rotating-bomb calorimetry.The values from the two methods agreed to within the limits of experimental error, giving the weighted mean values: R = Ethyl, ΔfH0m(R2NH2S2CNR2, cr): -249.2+/-2.2 kJ*mol-1; R = n-Propyl: -353.2+/-1.3 kJ*mol-1; R = i-Proyl: -349.6+/-1.3 kJ*mol-1; R = n-Butyl: -461.3+/-1.6 kJ*mol-1; R = i-Butyl: -463.8+/-1.4 kJ*mol-1.
- Silva, Manuel A. V. Ribeiro Da,Reis, Ana M. V.,Pilcher, Geoffrey
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p. 837 - 844
(2007/10/02)
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