反应详情

温度

-10 °C

A mixture of 9.88 g of the hydrochloride of ethyl 2-(2-tritylamino-4-thiazolyl)-2-hydroxyimino-acetate and 8.28 g of potassium carbonate in 25 ml of dry dimethylformamide was cooled in a bath at -10° C. for 10 minutes and 19 ml of raw tert.-butyl 2-bromo-2-methyl-propionate were added thereto over 3 minutes. The mixture was stirred for 16 hours during which it solidifed into a mass which was poured into a mixture of 400 ml of distilled water and 200 ml of ethyl acetate. The mixture was stirred and decanted and the organic phase was washed with water. The aqueous phase was extracted twice with 100 ml of ethyl acetate and the combined organic phases were dried and vacuum filtered. The filtrate was evaporated to dryness to obtain an oil residue which was added to 240 ml of petroleum ether. The mixture was cooled and crystallization was effected. The mixture was vacuum filtered after 30 minutes to obtain 10.8 g of the syn isomer of ethyl 2-(2-tritylamino-4-thiazolyl)-2-(1-tert.-butoxycarbonyl-1-methylethyl oxyimino)-acetate melting at 134° C.

1. stirringThe mixture was stirred
2. customdecanted
3. washthe organic phase was washed with water
4. extractionThe aqueous phase was extracted twice with 100 ml of ethyl acetate
5. customthe combined organic phases were dried
6. filtrationvacuum filtered
7. customThe filtrate was evaporated to dryness
8. customto obtain an oil residue which
9. temperatureThe mixture was cooled
10. customcrystallization
11. filtrationfiltered after 30 minutes