Acetic Acid → [4-(7-Chloro-1-oxo-1,2-dihydro-isoquinolin-6-yloxy)-piperidin-1-yl]-acetic acid ethyl ester

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Reaction Steps

1.5 g (5.38 mmol) of 7-Chloro-6-(piperidin-4-yloxy)-2H-isoquinolin-1-one (7, free base) were dissolved in 100 mL of methanol. At room temperature, 1.09 g (10.8 mmol) of triethylamine, 3.23 g (53.8 mmol) of acetic acid, 7.63 g (33.6 mmol) of glyoxylic acid ethyl ester and molecular sieves (4 A) were added, followed by 253.6 mg (4.04 mmol) of sodium cyanoborohydride. After stirring for 2 h at room temperature, the reaction mixture was filtered and the filtrate was evaporated i. vac. The residue was dissolved in dichloromethane and washed with 1 N NaOH and sat. NaCl-solution. The organic layer was dried with MgSO4 and evaporated. The obtained crude product was used without further purification.

Provenance & Evidence