§ These authors contributed equally to this manuscript.
A new thermal process to prepare spiroindolin-3-ones from 3-substituted 2,1-benzisoxazoles in good yields (70–85%) is described. The highest yields were observed when microwave irradiation was used. The method does not require the use of any additive or catalyst. A possible reaction mechanism involving a nitrene key intermediate is proposed.
Key words
2-spiroindolin-3-one - (thio)barbiturate - 2,1-benzisoxazole - thermal rearrangement - microwave irradiation