Abstract A total synthesis of cyclothialidine (1), a new DNA gyrase inhibitor isolated from Streptomyces filipinensis, is described. The synthetic concept was tested by preparing the lactone 13 (Scheme 2) which contains the characteristic bicyclic core entity of 1. Key features of the synthesis of 1 are: preparation of 3, 5-dihydroxy-2, 6-dimethylbenzoic acid (23) from 3, 5-dihydroxybenzoic acid (19) by two consecutive Mannich aminomethylation/ ...
