The dioxindole is a strong nucleophile for the Michael addition of dioxindoles to nitroalkenes in order to obtain 3, 3-disubstituted oxindole derivatives.
12.
In one study this rearrangement was applied to a 3-N ( CH 3 ) ( C 6 H 5 )-2-oxindole:
13.
The 3-substituted-3-hydroxy-2-oxindole structure holds anti-oxidant, anti-cancer, anti-HIV, and neuroprotective properties.
14.
"' Horsfiline "'is an oxindole alkaloid found in the plant " Horsfieldia superba ", which is used in traditional herbal medicine.
15.
Tandem Wittig-Claisen reaction has also been applied to the construction of the spiro [ pyrrolidin-3, 3-oxindole ] ring system in natural products such as horsfiline.
16.
"' Mitraphylline "', an oxindole derivative, is an active alkaloid in the leaves of the tree " Mitragyna speciosa ", commonly known as kratom.
17.
A secondary amine was combined with an aldehyde to form an intermediate azomethine ylide, which underwent a 1, 3-dipolar cycloaddition with an unsaturated oxindole also present in the reaction mixture.
18.
In the Danishefsky synthesis, an amine derived from tryptophan was condensed with an aldehyde, triggering a Mannich-type reaction wherein the pendant oxindole acted as a nucleophile toward the intermediate iminium species.
19.
The Carreira group made use of a magnesium iodide promoted annulation reaction in their approach toward spirotryprostatin B . An oxindole bearing a cyclopropane was reacted with an imine in the presence of the magnesium iodide, triggering the ring-expansion reaction.
20.
Oxindole derivatives found in natural products are gaining popularity in research because of their structural diversity . 3-substituted-3-hydroxy-2-oxindole is the central structure of a wide variety of biologically important compounds found in natural products.
