O12'-Demethylsecoobaberine

Description

This alkaloid is the first isoquinolone-benzylisoquinoline alkaloid to be discovered and occurs in the basic extract from Berberis baluchistanica. It forms colourless crystals when purified by recrystallization from cyc1ohexane-C6H6 and gives an ultraviolet spectrum in EtOH with absorption maxima at 282, 294 and 305 nm, showing a bathochromic shift in acid and alkali due to the presence of a phenolic hydroxyl group in the molecule. Diazomethane in Et20 furnishes the O-methyl ether, m.p. lOS-8°C having an ultraviolet spectrum in EtOH with absorption maxima at 226, 262 and 270 nm and shoulders at 283, 292 and 305 nm. Baluchistanamine itself may be obtained by oxidation of oxyacanthine with dilute potassium permanganate in Me2CO and the methyl ether is also formed by the same method from obaberine. Since both of these latter bases are also present in B. baluchistanica it suggests that baluchistanamine is produced biogenetically by oxidation of oxyacanthine.

References

Shamma, Foy, Miana, J. Amer. Chem. Soc., 96, 7809 (1974)