N-(5-Chloropyridin-2-yl)oxalaMic acid ethyl ester synthesis

Yield:349125-08-2 92.2%

Reaction Conditions:

with anhydrous Sodium acetate in dichloromethane at 5 - 10; for 14 h;Reagent/catalyst;

Steps:

5-11 Example 7

Dichloromethane (120 mL),2-amino-5-chloropyridine (20.0 g, 0.156 mol, 1.00 eq.),Sodium acetate (25.5g, 0.311mol, 2.00eq.) was sequentially added to the 250mL reaction flask,Stir until homogeneous and the solid does not dissolve,The internal temperature of the reaction solution was lowered to -5°C.To the reaction solution was added dropwise ethyl chlorooxoacetate (42.2g, 0.311mol, 2.00eq.),The exotherm was intense, and the reaction solution turned brown-red.The temperature should not be higher than 5,The dropwise addition was completed in 15min. After dripping, the temperature was raised to 5-10 °C for 14 h. Add 40 mL of water, adjust the pH to 7-8 with sodium bicarbonate, and separate the liquids.The organic layer was washed once with 40 mL of water, and the layers were separated;The organic layer was evaporated under reduced pressure at 35°C until one third of the residue remained,Add n-heptane 120mL,Continue to evaporate under reduced pressure until there is no fraction;suction filtration,The filter cake was rinsed with n-heptane,Dry to obtain 32.8 g of yellow solid, yield: 92.2%, purity: 99.55%.

References:

CN113968813,2022,A Location in patent:Paragraph 0050-0070