反应详情

A mixture of 1,2,3,4-tetrahydro-6,7-dimethoxy-3-isoquinolinecarboxylic acid, hydrochloride (S-form) and 600 ml of benzyl alcohol was saturated with hydrogen chloride gas. The temperature rose to 45° C. The mixture was stirred at room temperature for three days. A relatively small amount of solid was filtered off and the filtrate was treated with ca 2-liters of ether to precipitate crude product; wt 37.5 g; yield, 83%. Purification was effected by treatment with excess saturated sodium bicarbonate, extraction of base into ethyl acetate and precipitation of hydrochloride salt with HCl gas. Recrystallization from methanol-ether gave pure product; mp 255°-260° C.; [α]D 23=-81.3° (1.0% MeOH); tlc (20% MeOH-CHCl3SiO2) one spot Rf 0.8.

1. customrose to 45° C
2. filtrationA relatively small amount of solid was filtered off
3. additionthe filtrate was treated with ca 2-liters of ether
4. customto precipitate crude product
5. customyield
6. customPurification
7. extractionwas effected by treatment with excess saturated sodium bicarbonate, extraction of base into ethyl acetate and precipitation of hydrochloride salt with HCl gas
8. customRecrystallization from methanol-ether
9. customgave pure product