Hetero analogues of the antimicrobial alkaloids cleistopholine and sampangine.

Hetero analogues of the alkaloids cleistopholine and sampangine were prepared in order to investigate the significance of the (aza)quinoid partial structures for antimicrobial activity. Several analogues containing amino or sulfone groups showed high antimicrobial activities, indicating that the (aza)quinoid partial structures of the alkaloids are not an indispensable requisite for antimicrobial activity.