Acetic Acid → 3,4-Dihydro-2-[(5-methyl-1H-imidazol-4-yl)methyl]-[1]benzothieno[3,2-c]pyridin-1(2H)-one maleate

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Reaction Steps

A solution of 3,4-dihydro-[1]benzothieno[3,2-c]pyridin-1(2H)- one (152mg) in dry DMF (3ml) was added dropwise to a stirred, ice-cooled suspension of sodium hydride (78% dispersion in oil; 29mg) in dry DMF (1ml) under nitrogen and stirring was continued at room temperature for 1.5h. A suspension of 4-chloromethyl-5-methyl-1-(triphenylmethyl)-1H-imidazole (560mg) in dry THF (4ml) was added dropwise and stirring was continued at room temperature for 18h. A mixture of acetic acid (5ml), water (5ml) and THF (5ml) was added and the solution was heated at 100° for 1h, cooled, evaporated and treated with 8% aqueous sodium bicarbonate (35ml). The aqueous phase was extracted with ethyl acetate (2×25ml) and the combined, dried organic extracts were evaporated to give an oil. This was purified by SPCC eluting with System A (923:70:7) to give the free base of the title compound as a foam (32 mg). This was further purified by FCC eluting with System A (89:10:1) to give an oil (20mg). This was dissolved in hot ethanol (3ml) and treated with a solution of maleic acid (8mg) in ethanol (1ml). The resultant solution was evaporated to give the title compound (25mg), m.p. 143°-145°, t.l.c. (System A, 89:10:1) Rf 0.27.

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