The general procedure for the synthesis of 2-chloro-4-(cyclopropylamino)pyrimidine-5-carboxylic acid using the compound (CAS:1192711-36-6) as a starting material was as follows: first, ethyl ester 1.5 (6.02 g, 24 mmol) was dissolved in 1,4-dioxane (26 mL), followed by the addition of an aqueous lithium hydroxide solution (1.0 M, 26 mL, 26 mmol). The reaction mixture was stirred at room temperature until all starting materials were completely converted to carboxylic acids. Next, the reaction mixture was diluted with water to a total volume of 100 mL and acidified with 6 M hydrochloric acid to pH=2. After acidification, the solids in the resulting suspension were collected by filtration and dried by suction drying to give 3.51 g of the carboxylic acid product in 64% yield. The structure of the product was confirmed by 1H NMR (DMSO-d6, 400 MHz) with chemical shifts of δ 8.64 (d, 1H), 8.74 (s, 1H), 4.50 (m, 1H), 2.31 (m, 2H), 2.03 (m, 2H), 1.72 (m, 2H), respectively.
