Water → Ethyl 2-[(1R,5R)-2,6-diazabicyclo[3.2.0]hept-6-yl]-4-methyl-1,3-thiazole-5-carboxylate

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Reaction Steps

85% phosphoric acid (0.44 mL, 3.78 mmol) was added to a solution of tert-butyl (1R,5R)-6-[5-(ethoxycarbonyl)-4-methyl-1,3-thiazol-2-yl]-2,6-diazabicyclo[3.2.0]heptane-2-carboxylate obtained in Example (236b) (278 mg, 0.76 mmol) in dichloromethane (1 mL) at room temperature, followed by stirring for two hours. Water was added to the reaction solution, and the mixture was washed with ethyl acetate. Then, a 1 N aqueous sodium hydroxide solution was added to the aqueous layer, followed by extraction with an ethyl acetate/methanol mixed solvent. The combined organic layers were dried over anhydrous magnesium sulfate and filtered. Thereafter, the solvent was evaporated under reduced pressure to obtain 175 mg of the title compound as a pale yellow oily substance (87%).

Provenance & Evidence