Acetic Acid → Hydrocotarnine

Participants

Reaction Steps

1.19 g (5 mmol) of 4-hydroxy-8-methoxy-2-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline (1) obtained in Reference Example 1 or 2 was dissolved in 15 ml of acetic acid, to which 0.33 ml (6 mmol) of 97% sulfuric acid and 500 mg of 5% palladium on carbon catalyst were added to carry out catalytic reduction at 75° C. for 2 hours. The catalyst was filtered out and 2 ml of 25% aqueous sodium hydroxide solution and 5 ml of water were added to the reaction mixture, which was concentrated under vacuum. 10 ml of water was added to the residue, the solution was made basic with 25% aqueous sodium hydroxide solution and extracted with 10 ml and then 5 ml of methylene chloride successively. The liquid extract was washed with 5 ml of water, dried over anhydrous magnesium sulfate and then concentrated under vacuum to obtain 1.03 g of 8-methoxy-2-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline. Yield 93%.

Provenance & Evidence