Benzotriazole-Assisted Preparations of 2-(Substituted amino)pyridines and Pyrid-2-ones
作者:Alan R. Katritzky、Sergei A. Belyakov、Alexander E. Sorochinsky、Scott A. Henderson、Jie Chen
DOI:10.1021/jo970561h
日期:1997.9.1
Base-promoted reactions of benzotriazolyl-containing acetic acid derivatives, 2-(benzotriazol-1-yl)acetonitrile (7a), 2-(benzotriazol-1-yl)acetamide (7b), and (+/-)-2-(benzotriazol-1-yl)propionamide (7c), with alpha,beta-unsaturated ketones 8 give efficient and regioselective access to previously difficult to attain 3-unsubstituted pyridine derivatives: the 2-(substituted amino)pyridines 14a-k and the 4,6-substituted pyrid-2-ones 15a-h. The pyridine rings result from tandem [3 + 3] annulations involving a Michael addition followed by cyclization.
Regioselective Iron-Catalyzed [2 + 2 + 2] Cycloaddition Reaction Forming 4,6-Disubstituted 2-Aminopyridines from Terminal Alkynes and Cyanamides
作者:Nathan A. Spahn、Minh H. Nguyen、Jonas Renner、Timothy K. Lane、Janis Louie
DOI:10.1021/acs.joc.6b02374
日期:2017.1.6
redox-active pyridine dialdimine (PDAI) ligands catalyze the cycloaddition of two terminalalkynes and one cyanamide. The reaction is both chemo- and regioselective, as only 4,6-disubstituted 2-aminopyridine products are formed in moderate to high yields. Isolation of an iron azametallacycle (4) suggests that catalyst deactivation occurs with a large excess of cyanamide over longer reaction times. Fe-catalyzed