Reaktion #2122492

Reaktionsgleichung

3-[1-Methoxy-4-(4-methoxy-benzylsulfanyl)-piperidin-4-yl]-3-oxo-2-(2,4,6-trimethylphenyl)-propionic acid methyl ester

3-[1-methoxy-4-(4-methoxy-benzylsulfanyl)-piperidin-4-yl]-3-oxo-2-(2,4,6-trimethylphenyl)-propionic acid methyl ester

sodium hydroxide

→

4-hydroxy-8-methoxy-3-(2,4,6-trimethyl-phenyl)-1-thia-8-aza-spiro[4.5]dec-3-en-2-one

Ausbeute 48.3%

Lösungsmittel

water

trifluoroacetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturheated
2. 2
   Temperaturon reflux for 18 hours
3. 3
   Extraktionextracted with t-butylmethyl ether
4. 4
   TrocknenThe organic layer was dried over anhydrous sodium sulfate
5. 5
   Sonstigethe solvent evaporated
6. 6
   SonstigeThe residue was chromatographed on silica gel with ethyl acetate/cyclohexane (1:1

Vorschrift

470 mg 3-[1-Methoxy-4-(4-methoxy-benzylsulfanyl)-piperidin-4-yl]-3-oxo-2-(2,4,6-trimethylphenyl)-propionic acid methyl ester (from Step 6) was dissolved in 15 ml trifluoroacetic acid and heated on reflux for 18 hours. The mixture was cooled to room temperature, diluted with water, the pH adjusted to 4.2 by the addition of aqueous sodium hydroxide, then extracted with t-butylmethyl ether. The organic layer was dried over anhydrous sodium sulfate, and the solvent evaporated. The residue was chromatographed on silica gel with ethyl acetate/cyclohexane (1:1, then 2:1) as a solvent, to yield 156 mg 4-hydroxy-8-methoxy-3-(2,4,6-trimethyl-phenyl)-1-thia-8-aza-spiro[4.5]dec-3-en-2-one (compound P2.4) as a solid, mp 67-71° C.

Quelle