Theobromine → 3,7-Dimethyl-1-(4-oxopentyl)purine-2,6-dione

Participants

Reaction Steps

A suspension of 80% sodium hydride in mineral oil (3 g; 0.1 moles) was added in small portions during 10 minutes, to a suspension of 18 g (0.1 moles) of theobromine in 400 ml of anhydrous dimethylformamide. The reaction mixture was heated to 95°-100° C. for 3 hours. Then 13.26 g (0.11 moles) of 5-chloro-2-pentanone were added, and the reaction mixture was maintained at 95°-100° C. for 20 hours more. After filtration, the filtrate was evaporated under reduced pressure, the residue was treated with 150 ml of water and the pH was adjusted to 13-14 with a 10% NaOH aqueous solution. The mixture was extracted with 3×80 ml of methylene chloride, the combined organic extracts were washed with 3×50 ml of water, dried over anhydrous sodium sulfate, filtered and evaporated under vacuum. 2.95 Grams (11.2%) of the title compound were obtained, melting at 109°-111° C., which was directly used in the next step. The 1H-NMR spectrum was consistent with the formula.

Provenance & Evidence