Ethanol → 9-(5-Carboxypentyl)-1,3-dimethylxanthine

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Reaction Steps

9.3 Grams (0.03 mol) of the formamido derivative (IV) was suspended in 500 ml of o-dichlorobenzene and stirred at reflux under an inert atmosphere for 4 hours. It was cooled and the solvent removed on a rotary evaporator attached to a vacuum pump. The crystalline residue was partitioned between 200 ml of ether and 100 ml of 5% aqueous sodium bicarbonate solution. The aqueous phase was separated, washed with 100 ml of ether, and acidified to pH 3.2 with 5 N HCl. The precipitate was recrystalllized first from aqueous methanol, then from absolute ethanol to give 5.8 g (66% yield) of the xanthine (V) as fine white crystals, mp 177° C.

Provenance & Evidence