Synthesis and Antibacterial Activity of Calycanthaceous Alkaloid Derivatives

A series of 45 calycanthaceous alkaloid derivatives with the tetrahydropyrroloindole core structure was synthesized from tryptophan in good yields. The synthesized compounds were evaluated against five strains of bacteria (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Escherichia coil, Ralstonia solanacearum, and Pseudomonas aeruginosa). The bioassays indicated that among the synthesized compounds, compounds b3 and b4 exhibited a high degree of activity towards Gram positive B. subtilis. Compounds a14 and a18 displayed a high degree of activity towards R. solanacearum. These results will pave the way for further design, structural modification, and development of calycanthaceous alkaloids as antibacterial agents.