Cryptolepinone (3) was isolated as an artifact of extraction from Cryptolepis sanguinolenta. Previously,this compound had been identified as the natural products hydroxycryptolepine (2) and 3. Synthesis viaan unambiguous pathway has confirmed the structure of cryptolepinone. Spectroscopic studies in varioussolvents have shown that the natural product artifact or its synthetic equivalent can exist in the keto(cryptolepinone) or enol (hydroxycryptolepine) form.
