| 摘要 |
Process for preparing the quinolizines (II):- (II) where R = alkyl R' = lower alkyl R2, R3 are the same or different lower alkoxy or R2, R3 together form a methylenedioxy group. Important intermediates in the preparation of the amoebicide (-)-2-dehydroemetine (I), racemic 2-dehydroemetine or homologues thereof. A soln. of Na (0.8 g.) in EtOH (16 ml.) was refluxed with ethyl phthalate (1.8 ml.) for 10 mins. to remove traces of water and then refluxed with IV (R=Et) (2.0 g.) under N2 for 1.25 hrs. The alcohol was evap. in vacuo and the ice-cooled residue was shaken with ice-cold water (125 ml.) and benzene (75 ml.). The benzene layer was separated and washed with 0.1N-hydrochloric acid soln. Gasification and extraction (-)-II (R=Et; R'=C2H5; R2=R3=OMe) (1.84 g.), (alpha)25D -218 deg. (c=2 in EtOH). condensation of this product with homoveratrylamine and 2-hydroxy-pyridine, subsequent cyclisation with POCl3 and reduction (-)-2-dehydroemetine. |
