2-(2-Bromoethoxy)tetrahydro-2H-pyran → tert-Butyl 4-(4-bromo-1-(2-hydroxyethyl)-1H-imidazol-2-yl)piperidine-1-carboxylate

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Reaction Steps

tert-butyl 4-formylpiperidine-1-carboxylate 4a was reacted with aqueous glyoxal in the presence of aqueous ammonium hydroxide in methanol to give tert-butyl 4-(1H-imidazol-2-yl)piperidine-1-carboxylate 4b, which was bromined to afford tert-butyl 4-(4-bromo-1H-imidazol-2-yl)piperidine-1-carboxylate 4c. 4c was alkylated with 2-(2-bromoethoxy)tetrahydro-2H-pyran, followed by removal of THP group under acidic condition to yield tert-butyl 4-(4-bromo-1-(2-hydroxyethyl)-1H-imidazol-2-yl)piperidine-1-carboxylate 4d. Suzuki coupling was performed with bromide intermediate 4d to afford 4e. 4e was reacted with methanesulfonyl chloride or 4-methylbenzenesulfonyl chloride, followed by quenching with amine afforded 4f, which was treated with hydrogen chloride in methanol or trifloruoacetic acid in DCM to provide the amine intermediates 4g.

Provenance & Evidence