Hydrolysis of 1 in strongly basic aqueous solution afforded mono‐ and didemethylated products 2,3 and 4, that are postulated as the metabolites of 1 in some animals. This hydrolytic demethylation was shown to proceed stepwise via mono‐demethylation to give 2 and 3, followed by their further demethylation to 4. The hydrolytic reactivity of 1–3 was rationalized based on MO calculation results and 13C nmr data.