反应详情

温度

40 °C

To a solution of (3S,4S)-4-carboxy-3-(1-(R)-hydroxyethyl)-1-di(p-anisyl)methyl-2-azetidinone (34 g) in methanol (310 ml), there was added 98% sulfuric acid (2.9 g). The resultant mixture was heated at 65° C. for 3 hours, cooled down to 40° C., neutralized with 8% aqueous sodium hydroxide solution (15 ml) and concentrated to make a one third volume. The concentrate was diluted with 1,2-di-chloroethane (105 ml) and washed with water. The aqueous layer was separated from the organic layer and extracted with 1,2-dichloroethane (105 ml). The extract was combined with the organic layer, washed with water and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated in vacuo to give (3S,4S)-4-methoxycarbonyl-3-(1-(R)-hydroxyethyl)-1-di(p-anisyl)methyl-2-azetidinone. m.p., 102°-104° C.

1. concentrationconcentrated
2. additionThe concentrate was diluted with 1,2-di-chloroethane (105 ml)
3. washwashed with water
4. customThe aqueous layer was separated from the organic layer
5. extractionextracted with 1,2-dichloroethane (105 ml)
6. washwashed with water
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationAfter filtration
9. concentrationthe filtrate was concentrated in vacuo