1-tert-butoxycarbonylamide cyclohexanecarboxylic acid was prepared as follows: sodium hydroxide solution (43 mL, 4 mol/L), THF (40 mL) and 1-aminocyclohexanecarboxylic acid (5.0 g, 34.96 mmol) were added to a round-bottomed flask, and di-tert-butyl dicarbonate (9.13 g, 41.96 mmol) was added to the reaction flask at 0 C. After dropwise addition was complete, the reaction system was After the dropwise addition, the reaction system was stirred at room temperature overnight. Water (100 mL) was added to the reaction system, acidified with hydrochloric acid (50 mL, 1 mol/L), then extracted with ethyl acetate (50 mL2), the organic phases were combined, and the organic phases were washed with saturated brine (100 mL2) and dried with anhydrous sodium sulfate. Filtered, evaporated the solvent under reduced pressure, the crude product was purified by silica gel column chromatography (petroleum ether/ethyl acetate (V/V) = 4/1) to give the white solid title compound 1-tert-butoxycarbonylamide cyclohexanecarboxylic acid (7.3 g, 86%).
