反应详情

To a solution of 2-(3-ethoxycarbonyl-pyridin-2-yl)-piperazine-1,4-dicarboxylic acid di-tert-butyl ester (may be prepared as described in Intermediate 6; 1.55 g) in DCM (100 mL), TFA (5.0 mL) was added at 0° C. and then reaction mixture was allowed to warm to room temperature. TLC showed disappearance of starting material in 4 h. Reaction mixture was fully evaporated under vacuum to give 1.70 g of crude intermediate. Crude intermediate was dissolved in methanol (100 mL), and then potassium carbonate (4.0 eq) was added. Reaction mixture was stirred at room temperature. TLC showed disappearance of intermediate in 5 h. The reaction mixture was filtered through celite, and the filtrate was concentrated under vacuum to get 800 mg of the crude product. The crude product was purified by column chromatography over 100-200 mesh silica gel by using 0%-10% methanol in chloroform as solvent, which gave the title compound (280 mg).

1. customreaction mixture
2. customin 4 h
3. customReaction mixture
4. customwas fully evaporated under vacuum
5. customto give 1.70 g of crude intermediate
6. customReaction mixture
7. customin 5 h
8. filtrationThe reaction mixture was filtered through celite
9. concentrationthe filtrate was concentrated under vacuum
10. customto get 800 mg of the crude product
11. customThe crude product was purified by column chromatography over 100-200 mesh silica gel