tert-Butanol → tert-Butyl {1-(1,4-dioxa-8-azaspiro[4.5]dec-8-ylcarbonyl)-5-[4-(trifluoromethyl)phenyl]piperidin-3-yl}carbamate

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Reaction Steps

Activated molecular sieves 4 Å (about 8.4 g), 1.74 ml of triethylamine (12.5 mmol) and 3.15 g (11.4 mmol) of diphenyl phosphorazidate were added to the carboxylic acid from Example 60A (5.00 g, 10.4 mmol) in tert-butanol (189 ml), and the mixture was stirred under reflux overnight. The reaction solution was cooled, and the molecular sieves was then filtered off and thoroughly washed with ethyl acetate. The solvent was removed under reduced pressure and the residue was taken up in ethyl acetate. After washing with 2 N aqueous hydrogen chloride solution, saturated aqueous sodium bicarbonate solution and water, the organic phase was dried over magnesium sulphate, filtered and concentrated under reduced pressure. The crude product was used for the next step without further purification. Yield: 5.32 g (70% of theory, purity 71%)

Provenance & Evidence