Dimethylformamide → 7-Benzyl-3-cyclopropylmethylxanthine

Participants

Reaction Conditions

Reaction Steps

A solution of 7 g (29.0 mmol) of 7-benzylxanthine from Example 6 b) in 200 ml of dimethylformamide was heated to 50° C. and treated in portions with 0.69 g (29.0) mmol of sodium hydride and stirred at 50° C. for one hour. 2.76 ml (29.0 mmol) of cyclopropylmethyl bromide were added to this suspension and the temperature was increased to 80° C. After 7 hours at 80° C., 1 ml (11.0 mmol) of cyclopropylmethyl bromide was added again. After a further 6 hours, 24 ml of water and 10 ml of methanol were added, and the mixture was allowed to stand overnight, treated again with 120 ml of water and extracted three times using 300 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 (99/1).

Provenance & Evidence