Dichloromethane → HCID 70593312, compound

Participants

Reaction Steps

16.5 g of L-proline methyl ester and 27.2 g of N,N'-dicyclohexylcarbodiimide were successively added to an ice-cooled and constantly stirred solution of 25.2 g of 3-hydroxy-2-nitro-p-toluic acid dissolved in a mixture consisting of 480 ml of dichloromethane and 43 ml of N,N'-dimethylformamide. The whole mixture was stirred at ice-cooled temperature for 1 hour and then at room temperature for 1 hour. After the reaction, the separated crystalline precipitate was filtered off, and the filtrate was washed with 10% aqueous hydrochloric acid, 5% aqueous solution of sodium hydrogen carbonate and 5% aqueous solution of sodium carbonate. The layer of 5% aqueous solution of sodium carbonate was acidified with hydrochloric acid and extracted with chloroform. The chloroform layer was dehydrated and concentrated. The residue was recrystallized from 50% ethanol, and there was obtained 32.7 g of 1-(3-hydroxy-2-nitro-p-toluyl)-L-proline methyl ester as yellow-colored prismatic crystal having a melting point of 111° to 113.5° C.

Provenance & Evidence