Sulfuric Acid → 3-Methyl-7-(5-oxohexyl)-1-propylxanthine

Participants

Reaction Steps

A suspension of 79.2 g of 3-methyl-7-(5-oxohexyl)-xanthine in a mixture of 120 g of water and 72 g of methanol is brought into solution by the addition of 18 g of sodium hydroxide at about 60° C. 55.5 g of n-propyl bromide are then added. After boiling under reflux for 24 hours, the reaction mixture is treated with 1 ml of concentrated sulphuric acid and cooled. Unreacted 3-methyl-7-(5-oxohexyl)-xanthine is filtered off and the alcohol is distilled off in vacuo. The remaining solution is made alkaline with 4 ml of 50% sodium hydroxide solution and extracted with 350 ml of methylene chloride. 1-n-Propyl-3-methyl-7-(5-oxohexyl)-xanthine with a melting point of 76°-78° C. is obtained in 85% yield from the residue of the methylene chloride solution by recrystallisation from isopropanol. The solubility of the product in ethanol, dimethyl sulphoxide and dimethylformamide is over 10%.

Provenance & Evidence