Regioselective Synthesis of 2<i>H</i>-Indazoles Using a Mild, One-Pot Condensation–Cadogan Reductive Cyclization
作者:Nathan E. Genung、Liuqing Wei、Gary E. Aspnes
DOI:10.1021/ol5012423
日期:2014.6.6
An operationally simple and efficient one-pot synthesis of 2H-indazoles from commercially available reagents is reported. Ortho-imino-nitrobenzene substrates, generated via condensation, undergo reductive cyclization promoted by tri-n-butylphosophine to afford substituted 2H-indazoles under mild reaction conditions. A variety of electronically diverse ortho-nitrobenzaldehydes and anilines were examined. To further extend the scope of the transformation, aliphatic amines were also employed to form N2-alkyl indazoles selectively under the optimized reaction conditions.
An approach to fused pyrimidine derivativesvia Schiff bases of aromaticortho-nitrocarbaldehydes. An investigation of substituent effects on the reaction course