title: A general and regioselective synthesis of 5-trifluoromethyl-pyrazoles.
abstract: Two synthetic approaches to 4-trifluoromethylsydnones, a novel class of these mesoionic reagents, are reported. These compounds undergo regioselective alkyne cycloaddition reactions, thereby providing a general approach to 5-trifluoromethylpyrazoles. This method has been employed in a short formal synthesis of the herbicide fluazolate.
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Foster
authors.forename: Harald
authors.initials: H
authors.lastname: Jakobi
authors.forename: Joseph P A
authors.initials: JP
authors.lastname: Harrity
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D061565:Cycloaddition Reaction; D006540:Herbicides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D006540:Herbicides; D006845:Hydrocarbons, Fluorinated; D006846:Hydrocarbons, Halogenated; D011720:Pyrazoles; C577061:fluazolate