合成路线1

The reaction of cyanosafracin B (I) with Boc2O in ethanol gives the amino protected compound (II), which is treated with Mom-Br, DIEA and DMAP in acetonitrile yielding the O-protected compound (III). The demethylation of (III) with NaOH in methanol affords the hydroxyquinone (IV), which is reduced with H2 over Pd/C and cyclized with bromochloromethane and Cs2CO3 in hot DMF providing the methylenedioxy compound (V). The reaction of (V) with acetyl chloride and pyridine in dichloromethane gives the acetate (VI), which is treated with TFA, phenyl isothiocyanate and HCl yielding the primary amine (VII). Finally, this compound is treated with phthalic anhydride (VIII) and CDI in dichloromethane to afford the target phthalimide (phthalascidin Pt-650).