Further alkaloids from Strychnos dolichothyrsa.

The isolation of one of the major alkaloids and 11 minor alkaloids from the stem bark of Strychnos dolichothyrsa is described. The major alkaloid was identified as bisnor-C-alkaloid H. Two new dimeric alkaloids derived from this alkaloid were found, dolichocurine and dolichothine. For the former alkaloid a structure is proposed. Furthermore, the following minor alkaloids were identified: bisnor-C-alkaloid H N-oxide and di-N-oxide, Wieland Gumlich aldehyde, 18-deoxy Wieland Gumlich aldehyde, 11-methoxy-diaboline, tubotaiwine, condylocarpine, nor-C-fluorocurarine and nor-macusine B. In the extracts of the stem bark of S. urceolata 11-methoxydiaboline was identified as one of the major alkaloids.