Base‐Catalyzed Synthesis of Substituted Indazoles under Mild, Transition‐Metal‐Free Conditions1. Issue 29 (5th June 2013)

• Record Type: Journal Article
• Authors: Thomé, Isabelle; Besson, Claire; Kleine, Tillmann; Bolm, Carsten
• Is Part Of: Angewandte Chemie international edition. Volume 52:Issue 29(2013)
• Page Start: 7509
• Page End: 7513
• Publication Date: 2013-06-05
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201300917
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="graphical" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <bold>Back to basics</bold>: A transition‐metal‐free method developed for the synthesis of indazoles involves an inexpensive catalytic system composed of a diamine and K₂CO₃. Various (<italic>Z</italic>)‐2‐bromoacetophenone tosylhydrazones were converted into indazoles at room temperature in excellent yields (see example; Ts=<italic>p</italic>‐toluenesulfonyl). The yield was improved by photoisomerization with UV light when <italic>E</italic>/<italic>Z</italic> isomeric mixtures of the starting material were used.<boxed-text content-type="graphic" position="anchor" orientation="portrait"><graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgg270vv56h" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></boxed-text></p> </abstract>