- Propanolysis of arenesulfonyl chlorides: Nucleophilic substitution at sulfonyl sulfur
-
We have studied the mechanism of solvolysis of arenesulfonyl chlorides by propan-1-ol and propan-2-ol at 303-323 K. Kinetic profiles were appropriately fit by first-order kinetics. Reactivity increases with electron-donating substituents. Ortho-alkyl substituted derivatives of arenesulfonyl chlorides show increased reactivity, but the origin of this “positive” ortho-effect remains unclear. Likely, ortho-methyl groups restrict rotation around the C-S bond, facilitating the attack of the nucleophile. No relevant reactivity changes have been found with propan-1-ol and propan-2-ol in terms of nucleophile steric effect. The existence of isokinetic relationships for all substrates suggests a single mechanism for the series. Solvolysis reactions of all substrates in both alcohols show isokinetic temperatures (Tiso) close to the working temperature range, which is an evidence of the process being influenced by secondary reactivity factors, likely of steric nature in the TS. Solvation plays a relevant role in this reaction, modulating the reactivity. In some cases, the presence of t-Bu instead of Me in para- position leads to changes in the first solvation shell, increasing the energy of the reaction (ca. 1?kJ·mol?1). The obtained results suggest the same kinetic mechanism of solvolysis of arenesulfonyl chlorides for propan-1-ol and propan-2-ol, as in MeOH and EtOH, where bimolecular nucleophilic substitution (SN2) takes place with nucleophilic solvent assistance of one alcohol molecule and the participation of the solvent network involving solvent molecules of the first solvation shell.
- Iazykov, Mykyta,Canle, Moisés,Santaballa, J. Arturo,Rublova, Ludmila
-
-
- Methods for the preparation of biphenyl isoxazole sulfonamides
-
Methods for the preparation of biphenyl isoxazole sulfonamides and intermediates therof. The present invention also relates to the novel intermediates prepared by these methods. The biphenyl isoxazole sulfonamides prepared by the present methods are endot
- -
-
-
- Process for preparation of oxyglutaric acid ester derivatives
-
A process for preparing an oxyglutaric acid ester derivative of the formula: STR1 in which each of R1 and R2 is C1-5 alkoxy, C1-7 aralkyloxy, C7-9 halogenated aralkyloxy or phenyl, R4 is a hydroxyl-protecting group, and R5 is C1-10 alkyl which may have a substituent, comprises the steps of reacting a methyl phosphonate derivative or methyl phosphine oxide derivative with an oxyglutaric acid mono-ester to give a reaction product which comprises an oxyglutaric acid derivative having a phosphorus-containing group and a pentenedioic acid mono-ester (by-product), removing the pendenedioic acid mono-ester from the reaction product to isolate the oxyglutaric acid derivative, and converting the isolated oxyglutaric acid derivative into the oxyglutaric acid ester derivative. A process for obtaining an optically active oxyglutaric acid ester derivative is also disclosed.
- -
-
-
- 2,2-Bis(ethylthio)ethanenitrile: preparation and use as a one or two carbon nucleophile
-
2,2-Bis(ethylthio)ethanenitrile 1 was prepared in high yield from 2,2-bis(ethylthio)ethanal 2.Alkylation of the potassium salt of 1 with various alkylating agents and conjugate addition to cyclic α,β-unsaturated ketones provided high yields of the alkylation products of 1.The potential one and two carbon chain extension capability of this new reagent has been demonstrated.
- Bates, Gordon S.,Ramaswamy, S.
-
p. 2006 - 2009
(2007/10/02)
-
