Phalloidin derivatives and methods for their synthesis

1. A method for synthesizing a cyclomonomer having actin binding activity, the method comprising the steps of (i) α-protecting the N-terminus of glutamate using base-labile 9-fluorenylmethyloxycarbonyl (Fmoc), (ii) protecting the C-terminal of the Fmoc-protected glutamate using allyl ester to create a modified glutamate, (iii) linking the side chain of the modified glutamate to 2-chlorotrityl polystyrene resin, (iv) linking the N-terminus of the modified glutamate to tryptophan using standard Fmoc chemistry thereby creating a dipeptide, (v) elongating the dipeptide with N-α-protected alanine using standard Fmoc chemistry thereby creating a tripeptide, (vi) elongating the tripeptide with N-α-protected cis-4-hydroxy-proline using standard Fmoc chemistry thereby creating a tetrapeptide, (vii) elongating the tetrapeptide with N-α-protected, S-trityl protected cysteine using standard Fmoc chemistry thereby creating a pentapeptide, (viii) elongating the pentapeptide with N-α-protected D-threonine using standard Fmoc chemistry thereby creating a hexapeptide, (ix) elongating the hexapeptide with N-α-protected alanine using standard Fmoc chemistry thereby creating a heptapeptide, (x) removing the N-terminal Fmoc and the C-terminal allyl ester, (xi) deprotecting the heptapeptide using tetrakis(triphenylphosphine palladium (Pd(PPh 3 ) 4 ), N-methylmorpholine (NMM), acetic acid, dichloromethane (DCM), 20% piperidine, and dimethylfluoride (DMF) thereby creating a modified heptapeptide, (xii) cyclizing the modified heptapeptide using diphenylphosphorylazide (DPPA), N,N-diisopropylethylamine (DIPEA), and DMF thereby creating a cyclomonomer, (xiii) treating the cyclomonomer with I 2 in DMF thereby creating a thioether bond between the cysteine residue (Cys3) and the tryptophan residue (Trp6), wherein S-3→6 represents the thioether bond between Cys3 and Trp6, and resulting in a thioether cyclomonomer, and (xiv) cleaving the thioether cyclomonomer from the resin using 1% TFA in CH 2 Cl 2 , the steps resulting in the synthesis of bicyclo(Ala1-D-Thr2-Cys3-cis-3-hydroxy-Pro-4-Ala5-2-mercapto-Trp6-Glu7) (S 36) having actin binding activity.

2. The method of claim 1 wherein the method further comprises the step of elongating the tripeptide using side chain-protected cis-4-hydroxy-proline.

3. The method of claim 1 wherein the method further comprises the step of elongating the pentapeptide using side chain-protected D-threonine.

4. The method of claim 1 wherein the method further comprises the step of treating the thioether cyclomonomer using 50% TFA in CH 2 Cl 2 .

5. The method of claim 1 wherein the method further comprises the step of treating the thioether cyclomonomer using 50% HF in THF.