反应详情

8-Hydroxyjulolidine (1.0 g, 5.29 mmol) and methyl 4,4-dimethyl-3-oxopentanoate (1.0 g, 6.32 mmol) were heated together under nitrogen at 200° C. for 4 hours, after which time more methyl 4,4-dimethyl-3-oxopentanoate (0.5 g, 3.16 mmol) was added and heating was continued for 2 hours. After cooling to room temperature, the reaction mixture was dissolved in dichloromethane and applied to a short column of silica gel (approx. 200 g). Elution with dichloromethane removed non-polar by-products, while subsequent elution with ether afforded 11-[1,1-dimethylethyl]-9-oxo-2,3,6,7-tetrahydro-1H,5H-[1]benzopyrano[6,7,8-ij]quinolizine (1.12 g, 71% yield) as a brown oil which solidified on standing. The structure of this compound was confirmed by mass spectroscopy and by 1H and 13C NMR spectroscopy.

1. temperatureheating
2. washElution with dichloromethane removed non-polar by-products
3. washwhile subsequent elution with ether