反应详情

温度

20 °C

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

1. stirringwas then stirred for 30 hours
2. customThe mixture was decanted
3. washThe combined organic phases were washed with distilled water
4. customdried
5. filtrationvacuum filtered
6. washThe filter was rinsed
7. customthe filtrate was evaporated to dryness
8. customThe raw residue was chromatographed over silica gel
9. washwas eluted with benzene containing 5% ether
10. dissolutionThe first fraction was dissolved at 50° to 60° C. in methanol
11. temperaturethe mixture was cooled to 0° to 5° C.
12. filtrationfiltered