tert-Butyl 4-oxopiperidine-1-carboxylate → 1,1-Dimethylethyl 4-{[4-(benzyloxy)-2-(methoxycarbonyl)phenyl]amino}piperidine-1-carboxylate

Participants

Reaction Steps

A mixture of 2 g of methyl 2-amino-5-(benzyloxy)benzoate, 3.1 g of 1,1-dimethylethyl 4-oxopiperidine-1-carboxylate and 3.29 g of NaBH(OAc)3 in 10 ml of AcOH is irradiated under a microwave field (Biotage Initiator Sixty) at 110° C. for 20 min. The same reaction is repeated with two other lots of 2 g of methyl 2-amino-5-(benzyloxy)benzoate. The three reaction media are combined. The combined product is taken up in AcOEt. The organic phase is washed with water, with a saturated NH4Cl solution and with a saturated NaHCO3 solution, dried over Na2SO4 and filtered, and the solvent is evaporated under reduced pressure. The residue is chromatographed on silica gel, elution being carried out with an AcOEt/heptane mixture, (5/95, v/v) as far as (30/70, v/v), to give 10.2 g of the expected product.

Provenance & Evidence