Synthesis of the Corrected Structure Assigned to Clonorosin B, an Alkaloid Obtained from the Soil-derived Fungus Clonostachys rosea YRS-06.

The revised structure, 2 , assigned to the title natural product has been prepared by chemical synthesis using a reaction sequence involving six simple steps starting from 2,3-dimethoxybenzaldehyde and proceeding via intermediates 8 , 12 , and 14 . A comparison of the NMR data acquired on synthetically derived compound 2 with those reported for the natural product reveals an excellent match. Preliminary biological screening of compound 2 along with analogues/precursors 7 , 9 , 10 , 11 , 13 , 14 , and 15 revealed that none exhibited antibacterial, antifungal or cytotoxic effects.