Reaction #1178441

Reaction equation

hydrochloric acid

tert-butyl (2R,4R)-4-hydroxy-2-[4-(3-oxomorpholin-4-yl)phenylcarbamoyl]pyrrolidine-1-carboxylate

→

N-[4-(3-oxomorpholin-4-yl)phenyl]-(2R,4R)-4-hydroxypyrrolidine-2-carboxamide hydrochloride

Yield 100.0%

Solvents

dioxane

dioxane

Conditions

Workup

1. 1
   FiltrationThe precipitate is subsequently filtered off
2. 2
   Washwashed with 50 ml of dioxane and 50 ml of diethyl ether
3. 3
   Otherdried in a desiccator

Procedure

7.1 16 g (12.86 mmol) of ethyl 2-ethoxy-1,2-dihydroquinoline-1-carboxylate (EEDQ) are added to a suspension of 15 g (64.86 mmol) of cis-N′-BOC-4-hydroxy-D-proline and 12.47 g (64.86 mmol of 1-(4-amino-phenyl)-1H-pyridin-2-one in 250 ml of toluene, and the mixture is stirred at room temperature for 18 hours. The precipitated product is subsequently filtered off, washed successively with 50 ml of toluene and 50 ml of diethyl ether and dried in a desiccator, giving 24.5 g (93.2%) of tert-butyl (2R,4R)-4-hydroxy-2-[4-(3-oxomorpholin-4-yl)phenylcarbamoyl]pyrrolidine-1-carboxylate as a grey-white powder. ESI 406. 7.2 300 ml of 4N hydrochloric acid in dioxane are added to a solution of 15 g (37 mmol) of tert-butyl (2R,4R)-4-hydroxy-2-[4-(3-oxomorpholin-4-yl)phenylcarbamoyl]pyrrolidine-1-carboxylate in 200 ml of dioxane, and the mixture is stirred at room temperature for 12 hours. The precipitate is subsequently filtered off, washed with 50 ml of dioxane and 50 ml of diethyl ether and dried in a desiccator, giving 12.64 g (100%) of N-[4-(3-oxomorpholin-4-yl)phenyl]-(2R,4R)-4-hydroxypyrrolidine-2-carboxamide hydrochloride as a white powder. ESI 306. 7.3 12.64 g (36.98 mmol) of N-[4-(3-oxomorpholin-4-yl)phenyl]-(2R,4R)-4-hydroxypyrrolidine-2-carboxamide hydrochloride are suspended in 1200 ml of dichloromethane, and 5.4 ml of triethylamine are added with cooling in an ice bath. The solution of 5.96 g (38.83 mmol) of 4-chloro-phenyl isocyanate in 100 ml of dichloroethane is subsequently added dropwise to the mixture at 2° C. over the course of 1.5 hours, and the reaction solution is then left to stir for a further 30 minutes with ice cooling. The dichloromethane solution, is then washed successively with 100 ml of 1N hydrochloric acid and 100 ml of water and dried over sodium sulfate. After the drying agent has been filtered off and the methylene chloride solution has been evaporated to ⅓ of the original volume in a rotary evaporator, the precipitated product is filtered off, washed with 50 ml of petroleum ether and dried in a desiccator, giving 14.6 g (86%) of 1-N-[(4-chlorophenyl)]-2-N-{[4-(3-oxomorpholin-4-yl)phenyl]}-(2R,4R)-4-hydroxy-pyrrolidine-1,2-dicarboxamide (“A8”) as a white powder, ESI 459; m.p. 216°.

Source