Acetaldehyde → tert-butyl 4-(4-(1-hydroxyethyl)-1-(2-(pyrrolidin-1-yl)ethyl)-1H-imidazol-2-yl)piperidine-1-carboxylate

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Reaction Conditions

Reaction Steps

Combine tert-butyl 4-(4-iodo-1-(2-(pyrrolidin-1-yl)ethyl)-1H-imidazol-2-yl)piperidine-1-carboxylate (40.00 g, 82.63 mmol) and tetrahydrofuran (600 mL). Cool to −70° C. under nitrogen. Add 2.5 M n-butyllithium in hexanes (67.76 mL, 2.1 eq) dropwise. Add acetaldehyde (23.22 mL, 5.0 eq) and stir for 15 minutes. Quench over aqueous saturated ammonium chloride (75 mL). Separate the layers. Wash the aqueous phase with methyl tert-butyl ether. Wash the organics with water and aqueous saturated sodium chloride. Dry the organics over anhydrous magnesium sulfate, filter, and concentrate in vacuo. Dissolve in ethanol. Add 85% aqueous phosphoric acid dropwise to achieve a suspension. Stir the mixture overnight at room temperature. Filter and dry the resulting off-white solid under vacuum to give tert-butyl 4-(4-(1-hydroxyethyl)-1-(2-(pyrrolidin-1-yl)ethyl)-1H-imidazol-2-yl)piperidine-1-carboxylate; phosphoric acid (28.00 g, 69%). MS (ES) m/z=393 [M]+.

Provenance & Evidence