Potassium Carbonate → Methyl cis(+/-)-5-(4-{[(benzyloxy)carbonyl]amino}-3-methoxypiperidin-1-yl)-2-nitrobenzoate

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Reaction Steps

Methanol (15 ml) and a 4 N hydrochloric acid/ethyl acetate solution (30 mL) were added to tert-butyl cis(±)-4-{[(benzyloxy)carbonyl]amino}-3-methoxypiperidine-1-carboxylate obtained in Example (40a) (1.5 g, 4.12 mmol), and the mixture was stirred at room temperature for two hours. The reaction solution was concentrated under reduced pressure, azeotropically dehydrated by adding toluene, and dissolved in DMF (10 ml). Methyl 5-chloro-2-nitrobenzoate (900 mg, 4.17 mmol) and potassium carbonate (2.1 g, 15.2 mmol) were added, and the mixture was stirred at 175° C. for 24 hours. The reaction solution was diluted with ethyl acetate, washed with water, and concentrated under reduced pressure. Thereafter, the residue was purified by silica gel column chromatography (elution solvent: ethyl acetate/hexane) to obtain the title compound. The total resulting compound was used for the next reaction.

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