Synlett

Highly regioselective synthesis of 1-aryl-3, 4, 5-substituted pyrazoles

F Gosselin, PD O'Shea, RA Webster, RA Reamer…

Index: Gosselin, Francis; O'Shea, Paul D.; Webster, Robert A.; Reamer, Robert A.; Tillyer, Richard D.; Grabowski, Edward J. J. Synlett, 2006 , # 19 p. 3267 - 3270

Full Text: HTML

Citation Number: 61

Abstract

We have found that in the cyclocondensation of arylhydrazine hydrochlorides with 1,3-diketones, aprotic solvents with strong dipole moments and dielectric constants consistently gave much improved results relative to polar, protic solvents such as ethanol and acetic acid which are typically used for this type of reaction. [7] Our initial evaluation of solvents for the condensation of aryl-1,3-diketones with phenylhydrazine hydrochloride indicated that amide solvents ...