Reaction #93190

Reaction equation

hydrochloric acid

O-(3-acetylthiopropanoyl)glycolic acid

O-(3-Acetylthiopropanoyl)glycolic Acid

ammonium hydroxide

→

O-(3-Mercaptopropanoyl)glycolic Acid

Solvents

water

Conditions

Workup

1. 1
   TemperatureThis is chilled
2. 2
   Extractionextracted into ethyl acetate, yield: 1.2 g
3. 3
   OtherThis product O-(3-mercaptopropanoyl)glycolic acid is chromatographed on DEAE Sephadex A25 (Polidextrane anion exchange resin) with a linear gradient of ammonium bicarbonate
4. 4
   Concentrationconcentrated
5. 5
   workup.DISSOLUTIONby dissolving in ether
6. 6
   Otherprecipitating by the addition of dicyclohexylamine, m.p. 143°-144°

Procedure

O-(3-acetylthiopropanoyl)glycolic acid from Example 1 (1.3 g), under a blanket of argon is treated for fifteen minutes with a cold solution of 7 ml of water and 7 ml of concentrated ammonium hydroxide. This is chilled, acidified with concentrated hydrochloric acid and extracted into ethyl acetate, yield: 1.2 g. This product O-(3-mercaptopropanoyl)glycolic acid is chromatographed on DEAE Sephadex A25 (Polidextrane anion exchange resin) with a linear gradient of ammonium bicarbonate. The desired fractions (45-70; U.V. peak at 254 nm.) are pooled, concentrated and lyophilized. This ammonium salt of O-(3-mercaptopropanoyl)glycolic acid is converted to the free acid by treatment with Dowex 50WX2 cation exchange resin, yield 320 mg. The O-(3-mercaptopropanoyl)glycolic acid is converted to the dicyclohexylamine salt by dissolving in ether and precipitating by the addition of dicyclohexylamine, m.p. 143°-144°.

Source