A New Approach to Methoxyisatins Leading to the Total Synthesis of Ophiuroidine and Other Hydroxytryptanthrins

A new method for the preparation of methoxyisatins from the corresponding methoxyanilines is described. The resulting methoxyisatins were used in the syntheses of several methoxytryptanthrin compounds. The natural product ophiuroidine (4,8,.9-trihydroxytryptanthrin) was obtained from the appropriate trimethoxy precursor using a microwave-mediated Prey demethylation.