Abstract
Addition of alkyl or aryl α-substituted acetophenones to N- methylisatin in basic media gives diastereomeric mixtures of the corresponding α-substituted 3-benzoylmethyl-3-hydroxy-1-methyloxindole in good yields. Under anhydrous conditions (concentrated sulfuric acid at 0 °C) these adducts eliminate benzoic acid, instead of water, to give pure (E )-3-alkylidene derivatives in quantitative yield. Applying the same treatment to the α-unsubstituted analogue, dehydration took place to give pure (Z )-3-benzoylmethylen-1-methyloxindole.
Key words
indoles - addition reactions - eliminations - rearrangements - isatinylidenes
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