tert-butyl 4-[4-(3,6-dihydro-2H-pyran-4-yl)-1-(2-pyrrolidin-1-ylethyl)imidazol-2-yl]piperidine-1-carboxylate → Tert-butyl 4-[1-(2-pyrrolidin-1-ylethyl)-4-tetrahydropyran-4-yl-imidazol-2-yl]piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Add palladium on charcoal, (3.0 g, 50% wet, 0.1 g/g limiting reagent) to a solution of tert-butyl 4-[4-(3,6-dihydro-2H-pyran-4-yl)-1-(2-pyrrolidin-1-ylethyl)imidazol-2-yl]piperidine-1-carboxylate (30 g, 69.67 mmol) in ethanol (210 mL). Stir under a hydrogen atmosphere in a Parr system (200 psi, 65-70° C.) for 27 hours. Add additional palladium on charcoal (0.6 g, 50% wet, 0.02 g/g limiting reagent) and stir under a hydrogen atmosphere in a Parr system (200 psi, 65-70° C.) for five hours. Filter over Celite® and wash with ethanol. Concentrate the filtrate in vacuo and dissolve the residue in ethanol (150 mL). Add palladium on charcoal (0.6 g, 50% wet, 0.02 g/g limiting reagent) and stir under a hydrogen atmosphere in a Parr system (250 psi, 70° C.) for 16 hours. Filter over Celite® and wash with ethanol. Concentrate the filtrate in vacuo to give tert-butyl 4-[1-(2-pyrrolidin-1-ylethyl)-4-tetrahydropyran-4-yl-imidazol-2-yl]piperidine-1-carboxylate as a brown oil (29.5 g, 98%). MS (ES) m/z=433 [M]+.

Provenance & Evidence