Recently, while studying the reaction of heteroarylhydrazines with fluorinated β-diketones, [ 1 1. Singh , SP ; Kumar , V. ; Aggarwal , R ; Elguero , J. The reaction of aryl and heteroarylhydrazines with aryl-trifluoromethyl β-diketones . J. Heterocycl. Chem. 2006 , 43 , 1003 – 1014 . [CrossRef] View all references ] we observed that regiochemistry of the products was altered when the reaction medium was changed from neutral to acid. Whereas 5-hydroxy-5- ...