Hydrogen Bromide → 1-(8-Acetoxy-9-bromononyl)-3,7-dimethylxanthine

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Reaction Steps

This example illustrates another method for synthesizing compound no. 1551 (in addition to the method described in Example 1). 1-(8,9-dihydroxynonyl)-3,7-dimethylxanthine (compound no. 1561, 428 mg, 1.3 mmol) was stirred with HBr (777 μl, 1.05 g of a 30% solution in acetic acid, 3.9 mmol) for 90 minutes. The mixture was then added to a flask containing aqueous sodium bicarbonate solution (10 ml, 1.35 g) and dichloromethane (10 ml) and stirred vigorously for 10 minutes. The layers were separated and the aqueous portion was washed with dichloromethane (3×15 ml). The organic portions were combined, dried with sodium sulfate and evaporated to give 1-(8-acetoxy-9-bromononyl)-3,7-dimethylxanthine as a yellow oil (550 mg, 96% yield). Without further purification, the oil was taken up in methanol (5 ml) and treated with a solution of sodium methoxide (prepared from 33 mg, 1.4 mmol sodium and 1.4 ml methanol). After 30 minutes, the reaction mixture was added to water (30 ml) and extracted with dichloromethane (3×40 ml). The organic portions were combined and dried to give an off-white solid. Recrystalization of the remaining solid was recrystalized in dichloromethane/petroleum ether, resulting in 380 mg of 1-(8,9-oxidononyl)-3,7-dimethylxanthine (91% yield).

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