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) was added 98% sulfuric acid (2.9 g), and the resultant mixture was heated at 65° C. for 3 hours, cooled down to 40° C., neutralized with 8% sodium hydroxide (15 ml) and concentrated to make a one third volume. The concentrate was diluted with 1,2-dichloroethane (105 ml) and washed with water. The aqueous layer was separated from the organic layer and extracted with 1,2-dichloroethane (105 ml). The extracts and the organic layer were combined together, washed with water and dried over anhydrous sodium sulfate. Filtration and concentration of the filtrate in vacuo gave (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-dichloroethane (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. filtrationFiltration and concentration of the filtrate in vacuo