The benzoacridine system (III) was obtained by condensation 3-amino-2-naphthalenecarboxylic acid (I) with phloroglucinol (III) in the presence of p-toluenesulfonic acid in refluxing 1-heptanol. Regioselective O-alkylation of (III) with 3-chloro-3-methylbut-1-yne (IV) in DMF at 65 C gave the intermediate propargyl ether (V), which upon further heating at 130 C underwent Claisen rearrangement to produce the pentacyclic compound (VI). Methylation of (VI) with an excess of dimethyl sulfate in the presence of NaH yielded the O,N-dimethyl derivative (VII). The racemic cis diol (VIII) was obtained by OsO4-catalyzed oxidation of (VII) using N-methylmorpholine-N-oxide. Finally, diol (VIII) esterification with Ac2O in pyridine afforded the title diacetate ester.

The benzoacridine system (III) was obtained by condensation 3-amino-2-naphthalenecarboxylic acid (I) with phloroglucinol (III) in the presence of p-toluenesulfonic acid in refluxing 1-heptanol. Regioselective O-alkylation of (III) with 3-chloro-3-methylbut-1-yne (IV) in DMF at 65 C gave the intermediate propargyl ether (V), which upon further heating at 130 C underwent Claisen rearrangement to produce the pentacyclic compound (VI). Methylation of (VI) with an excess of dimethyl sulfate in the presence of NaH yielded the O,N-dimethyl derivative (VII). The racemic cis diol (VIII) was obtained by OsO4-catalyzed oxidation of (VII) using N-methylmorpholine-N-oxide. Finally, diol (VIII) esterification with Ac2O in pyridine afforded the title diacetate ester.