Cularine and Related Compounds. XV. : Demethylation of Cularine and Cularimine : Studies on the Syntheses of Heterocyclic Compounds. CLXVII.

Abstract

Demethylation of 10-oxo-oxepine compound (VI) resulted in the cleavage of the three methoxyl groups to produce 2, 3, 6-trihydroxy compound (VII). By utilizing this reaction, attempt was made to obtain cularicine (I) by the preparation of O, O, O-desmethylcularine (II) and O, O, O-desmethylcularimine (III), and demethylation of cularine (IV) and cularimine (V) was carried out. However, in place of the expected II and III, phenolic bases (X and XI) possessing one methoxyl group were obtained. The remaining methoxyl group was found to correspond to that in the 9-position of IV and V through NMR spectral measurements, and it was concluded that the methoxyl groups in 6- and 10-positions were selectively cleaved by demethylation.