- Nucleophilic Reactivities of Thiophenolates
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The nucleophilic reactivities of substituted thiophenolates were determined by following the kinetics of their reactions with a series of quinone methides (reference electrophiles) in DMSO at 20 °C. The experimentally determined second-order rate constants were analyzed according to the Mayr-Patz equation log k = sN(N + E) to derive the nucleophile-specific reactivity parameters N and sN for ten thiophenolate ions.
- Jüstel, Patrick M.,Pignot, Cedric D.,Ofial, Armin R.
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supporting information
p. 5965 - 5972
(2021/05/04)
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- Inherent Reactivity of Spiro-Activated Electrophilic Cyclopropanes
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The kinetics of the ring-opening reactions of thiophenolates with geminal bis(acceptor)-substituted cyclopropanes in DMSO at 20 °C was monitored by photometric methods. The determined second-order rate constants of the SN2 reactions followed linear relationships with Mayr nucleophilicity parameters (N/sN) and Br?nsted basicities (pKaH) of the thiophenolates as well as with Hammett substituent parameters (σ) for groups attached to the thiophenolates. Phenyl-substituted cyclopropanes reacted by up to a factor of 15 faster than their unsubstituted analogues, in accord with the known activating effect of adjacent π-systems in SN2 reactions. Variation of the electronic properties of substituents at the phenyl groups of the cyclopropanes gave rise to parabolic Hammett relationships. Thus, the inherent SN2 reactivity of electrophilic cyclopropanes is activated by electron-rich π-systems because of the more advanced C1?C2 bond polarization in the transition state. On the other hand, electron-poor π-systems also lower the energetic barriers for the attack of anionic nucleophiles owing to attractive electrostatic interactions.
- Jüstel, Patrick M.,Ofial, Armin R.,Pignot, Cedric D.,Stan, Alexandra
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supporting information
p. 15928 - 15935
(2021/10/25)
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- PROCESS FOR PREPARATION OF THIOPHENOL DERIVATIVES
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Provided is a process for preparing thiophenol derivatives, using aromatic disulfide as a starting material, and inexpensive sodium bisulfite (NaHSO3) as a reducing agent. The process can be carried out on an industrial scale at low production costs, secures advantageous reaction conditions by using a small amount of water- soluble alcohol solvent. Further, the process can maximize the purity of the products by inhibiting reverse oxidation of the final product by the action of sulfur dioxide (SO2) produced during the preparation process, after solvent extraction of the starting materials present as impurities of the thiophenol derivatives.
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Page/Page column 9-10
(2008/06/13)
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