Pseudo-three-component spiro[dihydrofuran-2,3′-oxindoles] synthesis: <i>in situ</i> generation of diazooxindole

Abstract

Upon reaction with N -substituted pyrroloquinoxalinetriones, isatin hydrazone is oxidized to diazooxindole and enters into a formal [4+1] cycloaddition reaction with N -substituted pyrroloquinoxalinetriones to form compounds containing a spiro[dihydrofuran-2,3′-oxindole] fragment, which is interesting for medicinal chemistry. The reaction of diazooxindoles with N -unsubstituted pyrroloquinoxalinetriones afforded analogous substituted spiro[dihydrofuran-2,3′-oxindoles]. The resulting compounds have moderate antimicrobial activity.