Natural products are a rich source of bioactive compounds, and numerous natural compounds have found application in cancer chemotherapy. However, unfavorable physicochemical properties often prevent the use of the original natural product as a drug. A prominent example is camptothecin from the Chinese tree Camptotheca acuminata, which shows extraordinary cytotoxic activity based on a specific molecular mode of action (inhibition of human topoisomerase I). Due to its extremely poor solubility, the original natural product cannot be used as a drug. The marketed drug topotecan was developed from this lead structure by semi-synthesis utilizing a Mannich aminomethylation as the crucial step. In this review, the long-distance run leading to this drug and further perspectives are summarized.

Based on the chemotype of canthin‐4‐one alkaloids with moderate antimicrobial activity, a collection of variously substituted canthin‐4‐ones and desaza analogs were synthesized. Key steps in the syntheses were regioselective halogenations of (desaza) canthin‐4‐one, followed by Pd‐catalyzed cross‐coupling reactions. The in vitro screening for antimicrobial activity revealed that two 5‐substituted canthin‐4‐ones (3‐pyridyl, 2‐bromophenyl) exhibit significant activity against Streptococcus entericus, coupled with high selectivity and the lack of cytotoxicity against mammalian cells. The intact canthin‐4‐one ring system was demonstrated to be essential for antibacterial activity.

No abstract

One-Pot Conversion of 1-Bromo--carboline and 1-Bromocarbazole into Pentacyclic Compounds by Suzuki Cross-Coupling Followed by SpontaneousCyclization. -The regioisomer of (VII), 3-formylthiophene-2-boronic acid, fails to give defined products. -(GEHRING, A. P.; TREMMEL, T.; BRACHER*, F.; Synthesis 46 (2014) 7, 893-898, http://dx.

No abstract