Dimethylformamide → HCID 22474161, compound

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3-(Benzo[b]thiophen-5-yl)-2-bromo-5,6-dihydroimidazo[2,1-b]thiazole hydrobromide (1.9 g) was added in portions under nitrogen at 0-5° C. to a stirred solution of ethylmagnesium chloride (2M solution in ether; 6.8 ml) in tetrahydrofuran (30 ml), then the mixture was stirred at this temperature for 20 minutes. Dimethylformamide (1.5 ml) was added at <15° C., the mixture was stirred at <15° C. for 20 minutes and at ambient temperature for 1 hour, then it was quenched by the addition of saturated aqueous ammonium chloride solution (10 ml) and water (5 ml). Ethyl acetate (30 ml) was added, the mixture was stirred at ambient temperature for 18 hours, then the organic layer was separated and further product was isolated from the aqueous layer by extraction into ethyl acetate (2×15 ml). The combined ethyl acetate solutions were washed with water (2×30 ml) and saturated aqueous sodium chloride solution (35 ml), then they were dried (MgSO4) and the solvents were removed in vacuo. The residue was purified by flash chromatography over silica using a 9:1 mixture of ethyl acetate and methanol as eluant. Appropriate fractions were combined and the solvents were removed in vacuo to give 3-(benzo[b]thiophen-5-yl)-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxaldehyde (0.7 g) as a yellow solid, m.p. 146° C.

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