Reaction #1288

Reaction equation

glycine, ethyl ester, hydrochloride salt

4-methyl morpholine

(S)-2-phthalimido-6-hydroxyhexanoic acid

hydroxybenzotriazole

→

title product

(S)-N-(2-Phthalimido-1-oxohexyl)glycine, ethyl ester

Solvents

dimethylformamide

Conditions

Workup

1. 1
   Temperaturecooled to 0° C.
2. 2
   workup.STIRRINGAfter stirring at 0° C. for 1 hour and at room temperature for 2 hours
3. 3
   Otherthe mixture was partitioned between ethyl acetate and 0.5N hydrochloric acid
4. 4
   Extractionsubsequently extracted three times with ethyl acetate
5. 5
   WashThe pooled ethyl acetate extracts were washed in succession with water, saturated sodium bicarbonate, and brine
6. 6
   Dryingdried (sodium sulfate)
7. 7
   Filtrationfiltered
8. 8
   Otherto give 5.77 g

Procedure

A slurry of glycine, ethyl ester, hydrochloride salt (2.718 g, 19.5 mmol.) in dimethylformamide (36 ml.) was treated with 4-methyl morpholine (2.60 ml., 2.39 g., 23.6 mmol.) and stirred at room temperature for 5 minutes. The mixture was then treated with (S)-2-phthalimido-6-hydroxyhexanoic acid (4.50 g., 16.2 mmol.) and hydroxybenzotriazole (2.225 g., 16.5 mmol.), cooled to 0° C., and then treated with ethyl-3-(3-dimethylamino)propyl carbodiimide, hydrochloride salt (3.438 g., 17.9 mmol.). After stirring at 0° C. for 1 hour and at room temperature for 2 hours, the mixture was partitioned between ethyl acetate and 0.5N hydrochloric acid and subsequently extracted three times with ethyl acetate. The pooled ethyl acetate extracts were washed in succession with water, saturated sodium bicarbonate, and brine, then dried (sodium sulfate), filtered and stripped to give 5.77 g. of title product as a colorless oil. TLC (ethyl acetate) Rf =0.34.

Source