METHYL 2-CHLOROPYRIMIDINE-5-CARBOXYLATE

308348-93-8

287714-35-6

Step 3a. Synthesis of methyl 2-chloropyrimidine-5-carboxylate (Compound 1001-7): 2-Aminopyrimidine-5-carboxylic acid methyl ester (7 g, 0.046 mol) was added to a mixed solution of concentrated hydrochloric acid (15.2 mL) and dichloromethane (60 mL). After the reaction system was cooled, zinc chloride (18.6 g, 0.138 mol) was slowly added at 15-20 °C. The temperature was maintained at 15-20 °C and the reaction mixture was stirred for 0.5 h, followed by cooling to 5-10 °C. At this temperature, sodium nitrite (9.5 g, 0.138 mol) was added in batches to ensure that the internal temperature was maintained in the range of 5-10 °C. The reaction was continued for 2 hours. Upon completion, the reaction mixture was quenched by slowly pouring it into ice water (50 mL). The organic layer was separated and the aqueous phase was extracted twice with dichloromethane (30 mL x 2). The organic extracts were combined and concentrated to give the crude product (4.2 g). The crude product was suspended in hexane (20 mL), heated at 60°C for 30 min and filtered. Concentration of the filtrate gave the target compound methyl 2-chloropyrimidine-5-carboxylate (compound 1001-7, 3.5 g, 44.4% yield) as an off-white solid.LC-MS: m/z 214.1 [M+42]+.1H NMR (400 MHz, CDCl3): δ 4.00 (s, 3H), 9.15 (s, 2H).