反应详情

10 g of 7-amino-3-formyl-3-cephem-4-carboxylic acid in 200 ml of acetonitrile: methylenchloride (1:1) are treated with 37.4 ml of N,O-bis(trimethylsilyl)acetamide at room temperature within ca. 5 minutes. After ca. 30 minutes the reaction mixture is cooled to −10° and 21 g of 2-(2-tritylaminothiazol-4-yl)-(Z)-2-methoxyiminoacetic acid chloride are added in 3 portions. The temperature raises to −5°. After ca. 45 minutes the reaction mixture is treated with 4 ml of water. The temperature raises to 20°. The reaction mixture is stirred for ca. 10 minutes and filtered. 15 g of active charcoal are added to this filtrate and stirring is continued for ca. 10 minutes. After filtration the solvent of the filtrate obtained is evaporated. The evaporation residue is treated with tert.butyl-methyl ether. A crystalline, almost colourless precipitate is obtained, filtered off and dried. Crystalline N-(1,4,5a,6-Tetrahydro-3-hydroxy-1,7-dioxo-3H,7H-azeto[2,1-b]furo[3,4-d][1,3]thiazin-6-yl)-2-(2-tritylaminothiazol-4-yl)-2-methoxyiminoacetic acid amide is obtained in form of a diastereomeric mixture in the ratio of ca. 1:1.

1. temperatureAfter ca. 30 minutes the reaction mixture is cooled to −10°
2. temperatureThe temperature raises to −5°
3. temperatureThe temperature raises to 20°
4. filtrationfiltered
5. addition15 g of active charcoal are added to this filtrate
6. stirringstirring
7. waitis continued for ca. 10 minutes
8. filtrationAfter filtration the solvent of the filtrate
9. customobtained
10. customis evaporated
11. additionThe evaporation residue is treated with tert.butyl-methyl ether
12. customA crystalline, almost colourless precipitate is obtained
13. filtrationfiltered off
14. customdried