Bifunctional Phosphonium Salt Directed Enantioselective Formal [4 + 1] Annulation of Hydroxyl-Substituted <i>para</i>-Quinone Methides with α-Halogenated Ketones
作者:Jian-Ping Tan、Peiyuan Yu、Jia-Hong Wu、Yuan Chen、Jianke Pan、Chunhui Jiang、Xiaoyu Ren、Hong-Su Zhang、Tianli Wang
DOI:10.1021/acs.orglett.9b02560
日期:2019.9.20
A highly diastereo- and enantioselective [4 + 1] cycloaddition of para-quinone methides to α-halogenated ketones was realized by bifunctional phosphonium salt catalysis, furnishing functionalized 2,3-dihydrobenzofurans in high yields and excellent stereoselectivities (>20:1 dr and up to >99.9% ee). Mechanistic observations suggested that the reaction underwent a cascade intermolecular substitution/intramolecular
Functionalized benzophenone, thiophene, pyridine, and fluorene thiosemicarbazone derivatives as inhibitors of cathepsin L
作者:G.D. Kishore Kumar、Gustavo E. Chavarria、Amanda K. Charlton-Sevcik、Grace Kim Yoo、Jiangli Song、Tracy E. Strecker、Bronwyn G. Siim、David J. Chaplin、Mary Lynn Trawick、Kevin G. Pinney
DOI:10.1016/j.bmcl.2010.09.026
日期:2010.11
of thiosemicarbazone analogs based on the benzophenone, thiophene, pyridine, and fluorene molecular frameworks has been prepared by chemical synthesis and evaluated as small-molecule inhibitors of the cysteine proteases cathepsin L and cathepsinB. The two most potent inhibitors of cathepsin L in this series (IC50 <135 nM) are brominated-benzophenone thiosemicarbazone analogs that are further functionalized