88-20-0Relevant articles and documents
Selective Late-Stage Sulfonyl Chloride Formation from Sulfonamides Enabled by Pyry-BF4
Gómez-Palomino, Alejandro,Cornella, Josep
supporting information, p. 18235 - 18239 (2019/11/13)
Reported here is a simple and practical functionalization of primary sulfonamides, by means of a pyrylium salt (Pyry-BF4), with nucleophiles. This simple reagent activates the poorly nucleophilic NH2 group in a sulfonamide, enabling the formation of one of the best electrophiles in organic synthesis: a sulfonyl chloride. Because of the variety of primary sulfonamides in pharmaceutical contexts, special attention has been focused on the direct conversion of densely functionalized primary sulfonamides by a late-stage formation of the corresponding sulfonyl chloride. A variety of nucleophiles could be engaged in this transformation, thus permitting the synthesis of complex sulfonamides, sulfonates, sulfides, sulfonyl fluorides, and sulfonic acids. The mild reaction conditions and the high selectivity of Pyry-BF4 towards NH2 groups permit the formation of sulfonyl chlorides in a late-stage fashion, tolerating a preponderance of sensitive functionalities.
Architectural diversity and elastic networks in hydrogen-bonded host frameworks: From molecular jaws to cylinders
Horner, Matthew J.,Holman, K. Travis,Ward, Michael D.
, p. 14640 - 14660 (2008/09/18)
Guest-free guanidinium organomonosulfonates (GMS) and their inclusion compounds display a variety of lamellar crystalline architectures distinguished by different "up-down" projections of the organomonosulfonate residues on either side of a two-dimensional (2D) hydrogen-bonding network of complementary guanidinium ions (G) and sulfonate moieties (S), the so-called GS sheet. Using a combinatorial library of 24 GMS hosts and 26 guest molecules, a total of 304 inclusion compounds out of a possible 624 possible host-guest combinations were realized, revealing a remarkable capacity of the GMS hosts to form inclusion compounds despite the facile formation of the corresponding guest-free compounds and the absence of "predestined" inclusion cavities like those in related guanidinium organodisulfonate host frameworks. The GS sheets in the inclusion compounds behave as "molecular jaws" in which organomonosulfonate groups projecting from opposing sheets clamp down on the guest molecules, forming ordered interdigitated arrays of the host organic groups and guests. Both the guest-free and inclusion compounds display a variety of architectures that reveal the structural integrity of two-dimensional GS sheet and the unique ability of these hosts to conform to the steric demands of the organic guests. Certain GMS host-guest combinations prompt formation of tubular inclusion compounds in which the GS sheet curls into cylinders with retention of the 2D GS network. The cylinders assemble into hexagonal arrays through interdigitation of the organosulfonate residues that project from their outer surfaces, crystallizing in high-symmetry trigonal or hexagonal space groups. This unique example of network curvature and structural isomerism between lamellar and cylindrical structures, with retention of supramolecular connectivity, is reminiscent of the phase behavior observed in surfactant microstructures and block copolymers. The large number of host-guest combinations explored here permits grouping of the inclusion compound architectures according to the shape of the guests and the relative volumes of the organomonosulfonate groups, enabling more reliable structure prediction for this class of compounds than for molecular crystals in general.
Clean-chemistry sulfonation of aromatics
Corby, Brian W.,Gray, Anthony D.,Meaney, Padraig J.,Falvey, Michael J.,Lawrence, Gregory P.,Smyth, Timothy P.
, p. 326 - 327 (2007/10/03)
A solution of TFAA/H2SO4 is an atom-efficient liquid-phase system for rapid sulfonation of aromatic structures; H2SO4 is consumed stoichiometrically and the spent trifluoroacetic anhydride (TFAA) is readily recovered as trifluoroacetic acid (TFA) which can be recycled to TFAA.
