Dimethyl Sulfate → 1-(4,5-Dimethoxy-2-methoxycarbonylphenyl)-3,4-dihydroisoquinoline

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Reaction Steps

Dimethyl sulphate (48 cc) is added to a suspension of 12b-hydroxy-10,11-dimethoxy-5,6,8,12b-tetrahydroisoindolo[1,2-a]isoquinol-8-one (80.65 g) in methanol (563 cc) and the reaction mixture is heated under reflux for 6 hours. After concentration to 100 cc and the successive addition of water (300 cc) and then of 10N sodium hydroxide (70 cc), the mixture is extracted three times with ethyl acetate (total 400 cc). The combined organic solutions are washed three times with distilled water (total 400 cc), dried over anhydrous sodium sulphate, treated with decolourising charcoal (1 g), filtered and evaporated. 1-(4,5-Dimethoxy-2-methoxycarbonylphenyl)-3,4-dihydroisoquinoline (67.8 g), melting at 133° C., is thus obtained.

Provenance & Evidence