New pyridocarbazole alkaloids from Strychnos nitida.

Phytochemical investigation of Strychnos nitida has led to the isolation of three new racemic pyridocarbazole alkaloids, (±)-stritidas A-C (1-3) and three known monoterpenoid indole alkaloids (4-6). Compounds 2 and 3 represent the first examples of pyridocarbazole alkaloids featuring an N-2-hydroxyethyl moiety. Their structures were determined by combined spectroscopic data (MS, UV, IR and NMR) and chemical methods.