Dimethyl Sulfoxide → 1-(6-Oxohexyl)-3,7-dimethylxanthine

Participants

Reaction Steps

Dimethyl sulfoxide (156 μl, 172 mg, 2.2 mmol) was slowly added to a solution of oxalyl chloride (103 μl, 150 mg, 1.2 mmol) in dichloromethane at -78° C. A solution of 1-(6-hydroxyhexyl)-3,7-dimethylxanthine (300 mg, 1.1 mmol), prepared in the previous step, in dichloromethane (5 ml) was added to this solution and the resulting reaction mixture stirred for 15 minutes. The cold bath was removed after addition of triethylamine (765 μl, 555 mg, 5.5 mmol). The reaction was added at ambient temperature to 20 ml water and extracted with three 50 ml aliquots of methylene chloride. The combined organic layers were washed with 1% aqueous hydrogen chloride (20 ml), saturated aqueous sodium bicarbonate (20 ml), and saturated aqueous salt solution (20 ml), and then dried over sodium sulfate. Evaporating the solvents and recrystallizing a residue in chloroform/petroleum ether produced 267 mg of 1-(6-oxohexyl)-3,7-dimethylxanthine (87% yield).

Provenance & Evidence