Transformation of the sydnone ring into oxadiazolinones. A convenient one-pot synthesis of 3-aryl-5-methyl-1,3,4-oxadiazolin-2-ones from 3-arylsydnones and their antimicrobial activity
作者:Shanta G Mallur、Bharati V Badami
DOI:10.1016/s0014-827x(99)00103-2
日期:2000.1
4-oxadiazolin-2-ones (IIIa-u) by a single-step reaction with bromine in acetic anhydride. In the preliminary screening of all these compounds, the halogen-substituted derivatives have shown antimicrobialactivities equal to those of the standard drugs used.
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.
of 4-trifluoromethyl pyrazoles have been prepared via the copper-catalyzed cycloaddition of 2-bromo-3,3,3-trifluoropropene with a variety of N-arylsydnone derivatives under mild conditions. This new protocol under optimized reaction conditions [Cu(OTf)2/phen, DBU, CH3CN, 35 °C] afforded 4-trifluoromethyl pyrazoles in moderate to excellent yields with excellent regioselectivity.
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