反应详情

Ethyl (Z)-2-hydroxyimino-2-(2-triphenylmethylaminothiazol-4-yl)acetate, hydrochloride salt (8.7 g) was stirred with potassium carbonate (15.35 g) in dimethyl sulphoxide (30 ml) under nitrogen at 21° . Bromofluoromethane (ca 3 g) was added. The nitrogen flow was stopped and the stirring continued for two hours. The mixture was poured into an ice-water mixture with stirring and the solid was collected by filtration and washed with water. The solid was dissolved in methylene chloride and the organic layer was separated and dried with magnesium sulphate. Evaporation gave a foam. This was dissolved in methylene chloride and pre-absorbed onto Kieselgel 60 (50 g). This was added to the top of a column of similar silica (125 g) set up in 10% ethyl acetate in cyclohexane. The column was eluted successively with 10%, 20% and 33% ethyl acetate in cyclohexane. After combination of appropriate fractions, evaporation gave the title compound (8.06 g) as a foam; λmax (EtOH) 302 nm (E1 cm1% 92), λinfl include 227.5 nm (E1 cm1% 546) and 259 nm (E1 cm1% 221), νmax (CHBr3) 3400 (NH), 1739 (ester) and 1533 cm-1 (C=N).

1. filtrationthe solid was collected by filtration
2. washwashed with water
3. dissolutionThe solid was dissolved in methylene chloride
4. customthe organic layer was separated
5. dry with materialdried with magnesium sulphate
6. customEvaporation
7. customgave a foam
8. custompre-absorbed onto Kieselgel 60 (50 g)
9. additionThis was added to the top of a column of similar silica (125 g)
10. washThe column was eluted successively with 10%, 20% and 33% ethyl acetate in cyclohexane
11. customAfter combination of appropriate fractions, evaporation