title: Propargyl hydrazides: synthesis and conversion into pyrazoles through hydroamination.
abstract: Pyrazoles direct: propargyl alcohols undergo hydrazination when treated with p-tosyl hydrazide in the presence of catalytic amounts of either Sc(OTf)(3) or La(OTf)(3) (see scheme; Tf=trifluoromethanesulfonyl). Propargyl hydrazides are converted into either N-tosyl or N-H pyrazoles when treated with an acid or a base, respectively. The one-step acid-catalyzed hydrazination/cyclization of propargyl alcohols directly affords pyrazoles in high yields.
authors.affiliation: Department of Chemistry, Faculty of Education, Gifu University, Yanagido, Japan. yoshimae@gifu-u.ac.jp
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yoshimatsu
authors.forename: Katsuki
authors.initials: K
authors.lastname: Ohta
authors.forename: Nami
authors.initials: N
authors.lastname: Takahashi
mesh_terms: D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry; D000586:Amination; D002384:Catalysis; D006834:Hydrazines / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D020005:Propanols / Q000138:chemical synthesis* / Q000737:chemistry; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D006834:Hydrazines; D020005:Propanols; D011720:Pyrazoles; C028255:propargyl alcohol