22891-66-3Relevant articles and documents
A simple, base-free preparation of S-aryl thioacetates as surrogates for aryl thiols
Van Den Hoogenband, Adri,Lange, Jos H. M.,Bronger, Raymond P. J.,Stoit, Axel R.,Terpstra, Jan Willem
experimental part, p. 6877 - 6881 (2011/03/18)
A mild method for the preparation of S-aryl thioacetates by hetero cross-coupling reactions of aryl bromides or aryl triflates with potassium thioacetate is described. The reaction proceeded smoothly in toluene at 110°C, mediated by catalytic Pd2(dba)3 in combination with CyPF-tBu as the ligand. Neither the presence of a base nor microwave conditions were required. The formed S-aryl thioacetate proved to be stable under flash chromatographic conditions and could be rapidly converted into the corresponding thiol under mildly basic conditions.
Leaving Group Effects in Thiolester Hydrolysis. Part 2. On the Possibility of an Elimination-Addition (Keten) Mediated Pathway in S-Acetylcoenzyme A Basic Hydrolysis and Acetyl Transfer
Douglas, Kenneth T.,Yaggi, Norbert F.,Mervis, Cynthia M.
, p. 171 - 174 (2007/10/02)
Alkaline hydrolysis rates (kHO(1-)) at 25 deg C in aqueous solution for a series of S-alkyl and S-aryl thiolacetates, including S-acetylcoenzyme A, were correlated (as their logarithms) with the pKa of the conjugate acid of the thiolate leaving group to give a slope (βl.g.) of -0.33.In comparison with the corresponding oxygen esters, thiolesters are, for the basicity of a given leaving species, one to two orders of magnitude less reactive towards hydroxide ion and show little dispersion into aryl and alkyl leaving groups, ascribed to the lower steric sensitivity of thiolacetate esters compared with the oxygen analogues.The small value of βl.g. and the lower reactivity of S- than O-esters are offered as evidence of a bimolecular associative (BAc2) mechanism for basic hydrolysis.The E2 route is excluded by the lack of deuterium incorporation into the (acetate) product of hydrolysis.In spite of the accepted acidity of thiolacetates, a kinetically insignificant amount of ester conjugate base is formed in aqueous solution even at high, non-physiological pH and thus S-acetylcoenzyme A does not hydrolyse by an E1cB pathway.
