Reaktion #3853

Reaktionsgleichung

Sodium hydroxide

( b )

(±)-5-[[2-[(Acetylthio)methyl]-1-oxo-3-phenylpropyl]amino]pentanoic acid, methyl ester

→

(±)-5-[[2-(mercaptomethyl)-1-oxo-3-phenylpropyl]amino] pentanoic acid

Lösungsmittel

ethyl acetate

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirred for 3 hours
2. 2
   EinengenThe mixture is concentrated to half volume in vacuo
3. 3
   workup.ADDITIONThe residue is diluted with water (40 ml.)
4. 4
   Waschenwashed with chloroform (2×20 ml.)
5. 5
   ExtraktionThe resulting white suspension is extracted with ethyl acetate (3×15 ml.)
6. 6
   Waschenwashed with water and brine (20 ml
7. 7
   Trockneneach), dried (Na2SO4)
8. 8
   Einengenconcentrated
9. 9
   Sonstigeto yield a white waxy solid (0.82 g.)
10. 10
    Filtrationfiltered
11. 11
    Einengenconcentrated
12. 12
    Sonstigethe residue triturated with ether

Vorschrift

1N Sodium hydroxide (12.9 ml., 3.8 equiv.) is added dropwise over 10 minutes to a chilled solution (ice bath) of the product from part (b) (1.20 g., 3.41 mmole) dissolved in methanol (13 ml.) under a nitrogen atmosphere. The mixture is stirred at 0° for 10 minutes and then allowed to warm to room temperature and stirred for 3 hours. The mixture is concentrated to half volume in vacuo. The residue is diluted with water (40 ml.) washed with chloroform (2×20 ml.), and acidified to a pH of about 1.5 with concentrated hydrochloric acid. The resulting white suspension is extracted with ethyl acetate (3×15 ml.). These organic extracts are combined, washed with water and brine (20 ml. each), dried (Na2SO4) and concentrated to yield a white waxy solid (0.82 g.). This solid is dissolved in ethyl acetate, filtered, concentrated and the residue triturated with ether to give (±)-5-[[2-(mercaptomethyl)-1-oxo-3-phenylpropyl]amino] pentanoic acid as white solids; m.p. 78°-79°. TLC (silica gel, 4:1 benzene/acetic acid) Rf =0.30 (slight tailing).

Quelle