Fischer indolization using bench-stable sodium arylhydrazine sulfonate as a surrogate
of arylhydrazine was developed. The preparation of arylhydrazine sulfonate was also
modified by replacing sodium sulfite reductant with Pd-catalyzed hydrogen transfer.
The straightforward synthesis of tetrahydrocarbazoles from the corresponding anilines
was successfully conducted in a one-pot manner. A practical application of this method
was demonstrated in the formal synthesis of pharmaceutical molecules Rizatriptan and
Zolmitriptan.
Key words
arylhydrazine sulfonate - desulfonation - Fischer indolization - tryptamine - Rizatriptan
- Zolmitriptan