GENERAL STEPS: To a solution of 4-aminophenol (2.93 g, 26.9 mmol) and 1-(4-fluorophenylcarbamoyl)cyclopropanecarboxylic acid (5.00 g, 22.4 mmol) in N,N-dimethylacetamide (DMA, 30 mL) was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI, 5.15 g, 26.9 mmol). The reaction mixture was stirred vigorously at room temperature until the reaction was complete (monitored by TLC, about 3 hours). Upon completion of the reaction, the reaction mixture was slowly poured into a flask containing saturated sodium bicarbonate (NaHCO3, 200 mL) aqueous solution under vigorous stirring. After continued stirring for 1 h, the resulting suspension was filtered. The solid product was collected, washed sequentially with water (50 mL) and chloroform (50 mL), and then dried under vacuum to afford N-(4-fluorophenyl)-N-(4-hydroxyphenyl)cyclopropane-1,1-dicarboxamide (6.22 g, 88% yield) as a white powder (HPLC purity >95%, and structure confirmed by 1H NMR).
