572-51-0Relevant articles and documents
Sustainable access to sulfonic acids from halides and thiourea dioxide with air
Zhang, Hui,Wang, Ming,Jiang, Xuefeng
supporting information, p. 8238 - 8242 (2020/12/29)
A sustainable and mild one-step strategy is explored for the synthesis of aryl and alkyl sulfonic acids using a facile combination of halides and sulfur dioxide surrogates under air. The cheap industrial material thiourea dioxide was employed as an eco-friendly and easy-handling sulfur dioxide surrogate, while air was used as a green oxidant. Both aryl and alkyl sulfonic acids were obtained under transition metal-catalyzed or transition metal-free conditions. Mechanistic studies demonstrated that sulfinate was involved as an intermediate in this transformation. Notably, this protocol has been applied to the late-stage sulfonation of the drugs naproxen, isoxepac and ibuprofen.
Sulfonation of a Series of Bromo- and Methylphenanthrenes with Sulfur Trioxide
Cerfontain, Hans,Koeberg-Telder, Ankie,Laali, Khosrow,Lambrechts, Hans J. A.
, p. 4069 - 4075 (2007/10/02)
The sulfonation of a series of methylphenanthrenes (MPs) and two bromophenanthrenes with SO3 in nitromethane has been studied at O deg C.From the substitution pattern it is evident that steric factors play an important role.Substitution of the 4- and 5-H peri to the methyl does not occur, and that ortho to the 9-methyl is severely reduced.Provided that allowance is made for the steric factors, the positional order of substitution for monosulfonation of a given (methyl)phenanthrene is in agreement with that predicted by the localization energies, calculated by a simple Hueckel MO treatment.The position of substitution of the second sulfo group is governed by two factors, viz., the positional localization energies of the starting MP (which will lead to symmetrical disulfonic acids) and the directing effect of the first (pyro)sulfonic acid group (leading to asymmetrical disulfonic acids).The latter factor is only apparent when the difference in localization energy for the positions of substitution under question of the starting MP are not too large.The formation of disulfonic acids with 2,4,5,7- and 3,4,5,6-TMP when 1 equiv of SO3 is used is ascribed to a mixing-disguised substrate selectivity, as a result of the very high reactivities of both the given TMP and its monosulfonic acid toward SO3.
