Reaction #1178431

Reaction equation

formaldehyde

D-serine

4-chlorophenyl isocyanate

→

(R)-3-(4-chlorophenylcarbamoyl)oxazolidine-4-carboxylic acid

Solvents

sodium hydroxide

Conditions

Workup

1. 1
   Temperatureto cool
2. 2
   Otherthe precipitate formed
3. 3
   Filtrationis filtered off
4. 4
   Otherthe precipitate formed
5. 5
   Filtrationis filtered off
6. 6
   Otherdried

Procedure

2.1 1.49 ml (20.0 mmol) of 37% aqueous formaldehyde solution are added to a solution of 2.10 g (20.0 mmol) of D-serine in 10 ml of 1N aqueous sodium hydroxide solution. The resultant solution is left at 5° C. for 18 hours. The solution is heated to 80° C., 6.14 g (40 mmol) of 4-chlorophenyl isocyanate are added, and the mixture is stirred at this temperature for one hour. The mixture is allowed to cool, and the precipitate formed is filtered off. The filtrate is acidified using 1N HCl, and the precipitate formed is filtered off and dried, giving (R)-3-(4-chlorophenylcarbamoyl)oxazolidine-4-carboxylic acid as a colourless solid; ESI 271. 2.2 498 mg (2.60 mmol) of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (DAPECI) are added to a solution of 541 mg (2.00 mmol) of (R)-3-(4-chlorophenylcarbamoyl)oxazolidine-4-carboxylic acid and 384 mg (2.00 mmol) of 4-(4-aminophenyl)morpholin-3-one in 4 ml of dimethylformamide (DMF), and the mixture is stirred at room temperature for 18 hours. The reaction mixture is added to saturated sodium hydrogencarbonate solution, and the precipitate formed is filtered off, giving 3-N-[(4-chlorophenyl)]-4-N-{[4-(3-oxomorpholin-4-yl)phenyl]}-(R)-oxazolidine-3,4-dicarboxamide (“A2”) as a colourless solid; ESI 461.

Source