783350-37-8

77873-76-8

24424-99-5

783350-37-8

The general procedure for the synthesis of (3S)-4-tert-butyl 3,4-morpholine dicarboxylate from 3-morpholinecarboxylic acid and di-tert-butyl dicarbonate was as follows: to a solution of dichloromethane (DCM, 100 mL) containing morpholine-3-carboxylic acid (3 g, 22.9 mmol, 1.0 eq.) was added sequentially triethylamine (TEA, 6.9 g, 68.7 mmol, 3.0 eq.) and di Di-tert-butyl carbonate (Boc2O, 15 g, 68.7 mmol, 3.0 eq.). The reaction mixture was stirred at room temperature for 3 hours. After completion of the reaction, the mixture was concentrated and the resulting residue was purified by silica gel column chromatography (eluent ratio petroleum ether/ethyl acetate = 5/1) to afford the target product (S)-4-(tert-butoxycarbonyl)morpholine-3-carboxylic acid (700 mg, 14% yield) as a colorless liquid.