S(vi) in three-component sulfonamide synthesis: Use of sulfuric chloride as a linchpin in palladium-catalyzed Suzuki-Miyaura coupling
Sulfuric chloride is used as the source of the -SO2- group in a palladium-catalyzed three-component synthesis of sulfonamides. Suzuki-Miyaura coupling between the in situ generated sulfamoyl chlorides and boronic acids gives rise to diverse sulfonamides in moderate to high yields with excellent reaction selectivity. Although this transformation is not workable for primary amines or anilines, the results show high functional group tolerance. With the solving of the desulfonylation problem and utilization of cheap and easily accessible sulfuric chloride as the source of sulfur dioxide, redox-neutral three-component synthesis of sulfonamides is first achieved. This journal is
Wang, Xuefeng,Yang, Min,Ye, Shengqing,Kuang, Yunyan,Wu, Jie
Structure-activity studies have been performed in an attempt to improve the potency of a novel series of azole-based endothelin-A (ET(A)) selective antagonists. Modifications of the hydrophobic group on the terminal urea produced substantial effects on receptor affinity; in particular, the choice of cyclohexyl- or arylureas led to substantial improvements in activity. Conformational restriction of these groups provides an additional benefit. N- Methylation of the indole moiety which is part of the heterocyclic dipeptide surrogate also improves potency. The effects of these two modifications appear to be synergistic, with the best of the resultant doubly modified analogs (e.g. 14q, 15y, and 15ff) exhibiting an 80-200-fold improvement over the original leads.
Von Geldern, Thomas W.,Kester, Jeffrey A.,Bal, Radhika,Wu-Wong, Jinshyun R.,Chiou, William,Dixon, Douglas B.,Opgenorth, Terry J.
p. 968 - 981
(2007/10/03)
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