The Cu-catalyzed direct difluoroalkylation of aldehyde hydrazones with functionalized difluoromethyl bromides is described. The reaction yields stereodefined α,α–difluoro-β-keto hydrazones under mild conditions and can be carried out at a scale that opens up the possibility of practical applications.
Enhydrazine, 6
<sup>1)</sup>
Weitere Enhydrazone, Tetrahydroindazolone und Enhydrazine aus cyclischen β‐Dicarbonylverbindungen
作者:Wolfgang Sucrow、Carl Mentzel、Marion Slopianka
DOI:10.1002/cber.19731060211
日期:1973.2
Aus Dimedon, 1,3-Cyclohexandion und 2-Methyl-1,3-cyclopentandion werden mit Benzaldehyd-alkylhydrazonen weitereEnhydrazone (4e, f, 5a–e, 17b–e) erhalten, die z. T. zu Enhydrazinen (19a, b, 20b, c) hydriert werden. Ferner wird die Darstellung weiterer Tetrahydroindazolone (6e, f, 7a–f, 9, 10, 13, 15) aus Dimedon und 1,3-Cyclohexandion beschrieben.
1-Methyl(or phenyl)-5-(penta-O-acetyl-d-galacto-pentitol-1-yl)pyrazoles from the reactions of 3,4,5,6,7-penta-O-acetyl-1,2-dideoxy-1-nitro-d-galacto-hept-1-enitol with aldehyde methyl(or phenyl)hydrazones
作者:Manuel Gómez-Guillén、José María Lassaletta Simon
DOI:10.1016/0008-6215(91)80121-3
日期:1991.3
hept-1-enitol ( 2 ) reacted with aldehydemethyl(or phenyl)hydrazones in refluxing methanol or butyl acetate to give 1-methyl(or phenyl)-5-(penta- O -acetyl- d - galacto -pentitol-1-yl)pyrazoles in good (for 1-methylpyrazoles) or moderate yields (for 1-phenylpyrazoles). The O -deacetylated products were obtained in high yields. A Michael-type adduct was obtained for the reactions of 2 with p -tolualdehyde
Acid‐Mediated Three Component Assembly of 4‐Fluoropyrazoles from α‐Fluoronitroalkenes, Hydrazines, and Aldehydes
作者:Vladimir A. Motornov、Andrey A. Tabolin、Yulia V. Nelyubina、Valentine G. Nenajdenko、Sema L. Ioffe
DOI:10.1002/ejoc.202000841
日期:2020.8.31
Three‐component one pot assembly of 4‐fluoropyrazoles is described. The method involves formal oxidative [3+2]‐annulation between elusive fluoroalkynes and azomethine imines.