反应详情

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.

1. temperatureheated
2. temperatureon reflux for 18 hours
3. extractionextracted with t-butylmethyl ether
4. dry with materialThe organic layer was dried over anhydrous sodium sulfate
5. customthe solvent evaporated
6. customThe residue was chromatographed on silica gel with ethyl acetate/cyclohexane (1:1