Synthesis of bacillamide 3 and its analogue

The bacillamide 1 is a new algaecide from the marine bacterium Bacillus sp. SY-1. Its analogues bacillamide 3 and alkaloid 4 were firstly synthesized effectively from D-alanine. The key step was a coupling reaction via the mixed anhydride. All structures were confirmed by ~1H NMR and ~(13)C NMR. The final compounds were confirmed by ~1H NMR, ~(13)C NMR and HRMS and the results are consistent with the reported natural products.