反应详情

温度

20 °C

4.14 g of potassium carbonate were added at room temperature over 3 minutes under an argon atmosphere to a mixture of 4.94 g of the syn isomer of ethyl 2-hydroxyimino-2-(2-tritylamino-4-thiazolyl)-acetate in 10 ml of dimethylformamide and after stirring the mixture at 20° C. for 20 minutes, 8.65 ml of 1,2-dibromoethane were added thereto. The mixture was stirred for 30 hours and was then poured into a mixture of 100 ml of distilled water and 20 ml of methylene chloride. The decanted aqueous phase was extracted with methylene chloride and the combined organic phases were washed with water, dried and evaporated to dryness. The residue was chromatographed over silica gel and was eluted with benzene containing 5% of ether to obtain a first fraction which was dissolved at 50° to 60° C. in methanol and crystallized at 0° C. to 5° C. The mixture was vacuum filtered to obtain 1.16 g of syn isomer of ethyl 2-(2-bromoethoxyimino)-2-(2-tritylamino-4-thiazolyl)-acetate in the form of a cream white product melting at 117° C. There was obtained a homogenous fraction of 1.258 g.

1. stirringThe mixture was stirred for 30 hours
2. extractionThe decanted aqueous phase was extracted with methylene chloride
3. washthe combined organic phases were washed with water
4. customdried
5. customevaporated to dryness
6. customThe residue was chromatographed over silica gel
7. washwas eluted with benzene containing 5% of ether
8. customto obtain a first fraction which
9. customcrystallized at 0° C. to 5° C
10. filtrationfiltered