Concise and Efficient Synthesis of 1<i>H</i>-Pyrazoles: Reaction of [Hydroxy(tosyloxy)iodo]benzene with Ethyl 2,3-Dioxobutanoate-2-arylhydrazones
作者:Himatkumar V. Patel、Kavita A. Vyas、Sudhanshu P. Pandey、Francis Tavares、P. S. Fernandes
DOI:10.1080/00397919108021057
日期:1991.8
Abstract Ethyl 2,3-dioxobutanoate-2-arylhydrazones 1 on treatment with [hydroxy(tosyloxy)iodo]benzene 2 at reflux temperature and followed by heating in the presence of N-ethyldiisopropylamine afforded the cyclized ethyl 1-aryl-4-hydroxy-1H-3-pyrazolecarboxylates 4 in good yield.
Efficient Synthesis of 1-Aryl-4-[(ethoxycarbonyl)oxy]-1<i>H</i>-pyrazole-3-carboxylates
作者:Sergei M. Korneev、Valery A. Polukeev、Peter G. Jones
DOI:10.1002/jhet.1787
日期:2013.7
Two‐step synthesis of N‐aryl 4‐[(ethoxycarbonyl) oxy]‐1H‐pyrazole‐3‐carboxylates is achieved starting from the commercially available ethyl 4‐chloroacetoacetate and aromatic amines. Azo coupling followed by cyclization with ethyl chloroformate–DMAP pair resulted in the formation of new 4‐oxy‐1H‐pyrazole derivatives in high yields.