Reaktion #95333

Reaktionsgleichung

1,2,3,4-tetrahydro-6,7-dimethoxy-3-isoquinolinecarboxylic acid, hydrochloride

benzyl alcohol

hydrogen chloride

→

1,2,3,4-Tetrahydro-6,7-dimethoxy-3-isoquinolinecarboxylic Acid, Phenylmethyl Ester, Hydrochloride

Lösungsmittel

MeOH

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigerose to 45° C
2. 2
   FiltrationA relatively small amount of solid was filtered off
3. 3
   workup.ADDITIONthe filtrate was treated with ca 2-liters of ether
4. 4
   Sonstigeto precipitate crude product
5. 5
   Sonstigeyield
6. 6
   SonstigePurification
7. 7
   Extraktionwas effected by treatment with excess saturated sodium bicarbonate, extraction of base into ethyl acetate and precipitation of hydrochloride salt with HCl gas
8. 8
   SonstigeRecrystallization from methanol-ether
9. 9
   Sonstigegave pure product

Vorschrift

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.

Quelle