Potassium Carbonate → Rac-4-[3-(2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-5-methoxy-benzoylamino]-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

1.60 g (4.6 mmol) of 4-(3-hydroxy-5-methoxy-benzoylamino)-piperidine-1-carboxylic acid tert-butyl ester (example 168a) was dissolved in 50 ml of MeCN at rt; 1.29 g (9.4 mmol) of anhydrous potassium carbonate was added, followed by 1.495 g (4.8 mmol) of rac-2,2-dimethyl-1,3-dioxolan-4-yl-methyl p-toluenesulfonate. The reaction mixture was stirred at reflux for 22 hours. It was then cooled down to ambient temperature and poured into crashed ice and extracted twice with EtOAc. The organic phases were washed with water and brine, dried over MgSO4, filtered and evaporated i.V. and the residue (2.11 g) was purified by chromatography (SiO2, MeCl2/MeOH) to yield 1.52 g of the title compound as a colorless amorphous solid. MS: 465.2 (MH+).

Provenance & Evidence