Potassium Carbonate → HCID 19887570, compound

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Reaction Steps

A solution of the crude ethyl 1-benzyl-1-azoniabicyclo[3.2.1]oct-5-ylcarboxylate bromide (D4) in ethanol (200 ml) and 11M hydrochloric acid (5 ml), was hydrogenated over 10% Pd-C (1 0 g) at atmospheric pressure and 40° C. until the uptake of hydrogen was complete. The catalyst was filtered off through kieselguhr and the filtrate concentrated in vacuo to leave a yellow semi-solid, which was treated with 8M hydrochloric acid (150 ml) and heated under reflux for 11 hours. The solution was concentrated to leave a yellow solid, which was basified with saturated potassium carbonate solution and washed with chloroform (3×60 ml). The aqueous solution was acidified with 11M hydrochloric acid and concentrated in vacuo to leave a yellow solid, which was heated under reflux in methanolic hydrogen chloride (140 ml) for 1.5h. The mixture was filtered and the filtrate concentrated to leave a yellow oil, which was treated with saturated potassium carbonate solution and extracted with chloroform (3×70 ml). The combined extracts were dried (Na2SO4) and concentrated in vacuo to give an orange oil, which was purified by column chromatography on silica gel eluting with 10% methanol/chloroform to give a yellow oil (2.50 g). This was converted into the oxalate salt and recrystallised from methanol/ether to give the title compound (E3) as a white solid m.p. 114°-116° C.

Provenance & Evidence