2-Bromopropane → 7-Benzyl-3-isopropylxanthine

Participants

Reaction Conditions

Reaction Steps

A solution of 3.5 g (1.45 mmol) of 7-benzylxanthine from Example 6b) in 60 ml of dimethylformamide was heated to 50° C. and treated in portions with 0.35 g (1.45 mmol) of sodium hydride, diluted with 20 ml of dimethylformamide and stirred at 50° C. for one hour. 1.36 ml (1.45 mmol) of 2-bromopropane were added to this suspension and the temperature was increased to 80° C. In the course of the reaction, a total of 4.91 ml (52.3 mmol) of 2-bromopropane were additionally added. After a total of 16 hours at 80° C., 10 ml of water and 2 ml of methanol were added, and the mixture was stirred for 10 minutes, treated with a further 70 ml of water and extracted three times using 70 ml of methyl tert-butyl ether each time. The organic phases were washed with water, dried using magnesium sulfate and concentrated under reduced pressure. The crude product was purified by flash chromatography on a silica gel column, dichloromethane/methanol (19/0.4).

Provenance & Evidence