Tricyclic esters derived from bimanes have been synthesized with ring sizes near or equal to that of trypanothione disulfide (T (S) 2), a bis-glutathionylspermidine that is involved in regulating the thiol status of Leishmania and other trypanosomatids. Modest activity for many of the compounds against Leishmania donovani with a maximum at the T (S) 2 ring size suggests that the esters act as T (S) 2 surrogates. However, no inhibition of T (S) 2- ...