New antifilarial agents. 1. Epoxy sulfonamides and ethynesulfonamides
摘要:
Two series of 2-substituted 1,2-epoxyethanesulfonamides 2 and ethynesulfonamides 5 were synthesized and evaluated for their antifilarial activity. The trans epoxides 2T were stereospecifically prepared by a Darzens reaction between aldehydes and halomethanesulfonamides. The cis isomers 2c were obtained from ethynesulfonamides 5 by semihydrogenation followed by KOCl epoxidation. 2-Substituted ethynesulfonamides 5 were synthesized from appropriate trans-ethenesulfonamides by a bromination/dehydrobromination sequence. These products, as well as several synthetic intermediates, were evaluated for antifilarial activity against Molinema dessetae either in vivo in its natural host, the rodent Proechimys oris, or in vitro by a new test using cultures of the infective larvae. Most of the epoxides 2T and acetylenic derivatives 5 bearing a 2-aryl substituent were active in vitro. Among these compounds, four epoxides 2T and one acetylenic derivative 5 showed marked macrofilaricidal activity in vivo without any microfilaricidal activity. The differences between the in vivo and in vitro results may be due, in part, to the low chemical stability of the epoxy sulfonamides 2T. Despite this limitation, the activities observed in this reliable animal model suggest further development and testing of both series 2T and 5 as macrofilaricides.
Stereoconvergent Arylations and Alkenylations of Unactivated Alkyl Electrophiles: Catalytic Enantioselective Synthesis of Secondary Sulfonamides and Sulfones
作者:Junwon Choi、Pablo Martín-Gago、Gregory C. Fu
DOI:10.1021/ja506885s
日期:2014.8.27
controlling the stereochemistry of the sulfur-bearing carbon of such targets. In this report, we describe nickel-catalyzed stereoconvergent Negishi arylations and alkenylations of racemic α-bromosulfonamides and -sulfones that furnish the desired cross-coupling product in very good ee and yield for an array of reaction partners. Mechanistic studies are consistent with the generation of a radical intermediate
开发用于生成对映体富集的磺酰胺和砜的有效方法是有机合成和药物化学等领域的重要目标;然而,关于直接催化不对称方法来控制此类目标的含硫碳的立体化学的报道相对较少。在本报告中,我们描述了镍催化的立体收敛 Negishi 芳基化和外消旋 α-溴磺酰胺和 - 砜的烯基化,它们以非常好的 ee 和产率为一系列反应伙伴提供所需的交叉偶联产物。机理研究与自由基中间体的产生一致,该中间体具有足够的寿命以扩散出溶剂笼并环化到侧链烯烃上。
Mn-mediated reductive C(sp3)–Si coupling of activated secondary alkyl bromides with chlorosilanes
作者:Liangliang Qi、Xiaobo Pang、Kai Yin、Qiu-Quan Pan、Xiao-Xue Wei、Xing-Zhong Shu
DOI:10.1016/j.cclet.2022.03.070
日期:2022.12
solution to address this problem, but it typically relies on organometallic species. Herein, we report an Mn-mediated reductive C(sp3)–Si coupling to synthesize these compounds from alkyl and silyl electrophiles. This approach avoids the requirement for activation of Si–Cl by transition metals and thus allows for the coupling of various common chlorosilanes. The reaction proceeds under mild conditions