Studies on the syntheses of heterocyclic compounds. part CCLXXIX . Synthesis of O‐isobutylcularidine

Abstract
Although various methods of oxepine formation from phenoxybenzene dicarboxylic acids was attempted, only 11‐hydroxy‐4‐isobutoxy‐7,8‐dimethoxydibenz[b,f]oxepin‐l‐ylaeetic acid lactone (XXX) was synthesized successfully. Compound XXX gave O‐isobutylcularidine (XXXVlIb) in a few steps. Our synthetic O‐isobutylcularidine was identical with that prepared from natural cularidine proving the structure for cularidine proposed by Manske. However, dealkylation of synthetic O‐isobutylcularidine was unsuccessful.