Hydrochloric Acid → 4-(2,6-dioxo-1,3-dipropyl-2,3,6,7-tetrahydro-1H-purin-8-yl)-bicyclo[2.2.2]octane-1-carbaldehyde

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Reaction Steps

8-(4-Hydroxymethylbicyclo[2.2.2]oct-1-yl)-1,3-dipropyl-3,7-dihydropurine-2,6-dione (X, Example 86a, 1 wt) and dimethyl sulphoxide (4 vol) are mixed and stirred under nitrogen; the mixture is stirred for 5 to 15 mins and triethylamine (2.42 vol) is added. A mixture of sulphur trioxide pyridine complex (1.275 wt) in dimethyl sulphoxide (6 vol) is added, maintaining the internal temperature below 30°. The temperature is adjusted to 14 to 20° and the reaction mixture is then stirred at 14 to 20° for 16 to 20 hours until complete by NMR. If there is any starting alcohol remaining sulphur trioxide pyridine complex (0.15 wt) is added and the reaction stirred for a further 2 to 3 hours at 14 to 20°. Ethyl acetate (20 vol) and hydrochloric acid (1 M, 10 vol) are added to the reaction mixture and stirred vigorously for 5 to 15 mins. The phases are separated and the organic phase is washed with hydrochloric acid (1 M, 10 vol). The phases are separated and the organic phase is again washed with hydrochloric acid (1 M, 10 vol). The phases are separated and the organic phase is washed with saline (5 vol), dried over magnesium sulphate (0.5 wt) for 5 to 10 mins and filtered. The filter cake is washed with ethyl acetate (1 vol). The solvent is removed under reduced pressure at 40 to 45° to give the title compound.

Provenance & Evidence