Solid-phase synthesis of methyl carboxymycobactin T 7 and analogues as potential antimycobacterial agents

A solid-phase approach for the total synthesis of methyl carboxymycobactins 1a-d, with an on-resin cyclization leading to azopine 5 as the key step, was developed. The iron-affinity of these compounds was assessed by a competitive sulfoxine-binding assay, and antimycobacterial activity was tested against the growth of Mycobacterium avium.