反应详情

20.0 g (0.15 mol) of ethylmagnesium bromide are taken as a 40% strength solution in ether, and 27.8 g (0.1 mol) of 3,7-dimethyl-1-(5-oxohexyl)-xanthine in 1 liter of dry ether are metered in dropwise at room temperature, while stirring, whereupon a voluminous precipitate forms. The mixture is heated and is subsequently stirred, while boiling gently under reflux, for one hour. It is then worked up as described in the preceding Example 9 to give 25 g of oily crude product (81.1% of theory), which gradually crystallizes completely and is purified by recrystallization from diisopropyl ether, with the addition of a little ethyl acetate, at the boiling point.

1. customdropwise at room temperature
2. temperatureThe mixture is heated
3. stirringis subsequently stirred
4. temperatureunder reflux, for one hour