The Efficient Synthesis of 3-Arylsydnones Under Neutral Conditions
作者:Jacqueline Applegate、Kenneth Turnbull
DOI:10.1055/s-1988-27791
日期:——
Various substituted aryl sydnones can be prepared in high yield under mild, neutral conditions by nitrosation of the appropriate aryl glycine with isoamyl nitrite in dimethoxyethane followed by cyclization with trifluoroacetic anhydride.
Acylation of Sydnones with Acetic Anhydride in the Presence of Montmorillonite K-10
作者:Kenneth Turnbull、Jones C. George
DOI:10.1080/00397919608004593
日期:1996.7
Abstract Various 4-acetyl sydnones 2 can be prepared in good yield by reaction of the corresponding 3-arylsydnones (cf. 1) with acetic anhydride at ∼ 110°C catalyzed by Montmorillonite K-10. The reaction fails where an ortho-keto moiety is present; therein sydnone ring cleavage occurs to form the corresponding indazole 3.
Debromination of 3-Aryl-4-bromosydnones with Sodium Borohydride
作者:Kenneth Turnbull
DOI:10.1055/s-1986-31606
日期:——
Debromination of 4-bromo-3-(2-substituted aryl) sydnones 1 with sodium borohydride in methanol occurs readily to give good yields of the corresponding parent sydnones 2, except in those cases where the aryl substituent also reacts. The utility of the process for both sydnone purification and the preparation of novel sydnones has been examined briefly.
and general method for the synthesis of 3-trifluoromethyl-4‑trifluoroacetyl pyrazoles from the cycloaddition of sydnones with 1,1,1,5,5,5-hexafluoropentane-2,4-dione has been established. Using ZnI2/bpy as a catalyst in THF, this protocol proved to be general to prepare a variety of 3-trifluoromethyl-4‑trifluoroacetyl pyrazoles in good yields. Utility of this method was demonstrated by further transformations