反应详情

A mixture of 1.2 g of the product of Step A, 2 ml of methanolic 1N potassium hydroxide solution and 4 ml of methanol was refluxed for 2 hours and was then cooled during which 390 mg of the starting material crystallized which meant 810 mg of the starting product was saponified. The mixture was filtered and the filtrate was evaporated to dryness. The residue was taken up in 1 ml of dimethylformamide and 2 ml of N hydrochloric acid solution (pH=2). The mixture was stirred and 10 ml of water were added thereto. The mixture was extracted with methylene chloride and the organic phase was washed with water. The wash waters were extracted with methylene chloride and the combined organic phases were dried and vacuum filtered. The filtrate was evaporated and the oil residue was taken up in 4 ml of chloroform. The solution was diluted with 30 ml of ether and crystallization was effected. After 30 minutes with stirring, the mixture was vacuum filtered and the product was rinsed with ether and dried to obtain 472 mg of the syn isomer of 2-(2-tritylamino-4-thiazolyl)-2-(1-tert.-butoxycarbonyl-1-methylethyloxyimino)-acetic acid melting at 190° C.

1. temperaturewas refluxed for 2 hours
2. customcrystallized which
3. filtrationThe mixture was filtered
4. customthe filtrate was evaporated to dryness
5. addition10 ml of water were added
6. extractionThe mixture was extracted with methylene chloride
7. washthe organic phase was washed with water
8. extractionThe wash waters were extracted with methylene chloride
9. customthe combined organic phases were dried
10. filtrationvacuum filtered
11. customThe filtrate was evaporated
12. additionThe solution was diluted with 30 ml of ether and crystallization
13. stirringAfter 30 minutes with stirring
14. filtrationfiltered
15. washthe product was rinsed with ether
16. customdried