[C:1]12(OCC[O:12]1)[C:9]1[C:4](=[CH:5][C:6]([CH2:10][OH:11])=[CH:7][CH:8]=1)[CH2:3][CH2:2]2.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(=O)([O-])[O-].[K+].[K+].N>O.CC(C)=O>[OH:11][CH2:10][C:6]1[CH:5]=[C:4]2[C:9](=[CH:8][CH:7]=1)[C:1](=[O:12])[CH2:2][CH2:3]2A solution of Example 332B (8.0 g, 38.7 mmol) and p-toluenesulfonic acid (7.4 g, 38.7 mmol) in a mixture of water (20 mL) and acetone (85 mL) was refluxed for about 1 hour. The mixture was concentrated in vacuum, diluted with water and was neutralized by careful addition of potassium carbonate (2.7 g, 19.4 mmol). The precipitate was filtered off, washed with a minimum of water and diethyl ether and was dried in vacuum to give the above intermediate. MS (DCI/NH3): m/z 180 (M+NH4)+.
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