反应详情

3.46 g (14.8 mmol) of the compound from Example 40A are initially introduced into 50 ml anhydrous toluene under argon, 712 mg (17.8 mmol) sodium hydride suspension (60% strength in paraffin oil) are added in portions and the mixture is stirred at RT for 1 h and then at 80° C. for 20 min. After cooling, 392 mg (1.48 mmol) 18-crown-6 and then, while cooling with ice, 2.20 g (29.7 mol) formic acid ethyl ester are added dropwise. The mixture is stirred first at 0° C. for 1 h and then at RT for 1 h. A mixture of 100 ml ethyl acetate and 150 ml 0.1 M hydrochloric acid is added, the phases are separated, the aqueous phase is extracted several times with ethyl acetate and the combined organic phases are dried over sodium sulfate, filtered and concentrated. The residue is purified by means of flash chromatography on silica gel (mobile phase: cyclohexane/ethyl acetate gradient).

1. waitat 80° C. for 20 min
2. temperatureAfter cooling
3. additionare added dropwise
4. stirringThe mixture is stirred first at 0° C. for 1 h
5. waitat RT for 1 h
6. additionis added
7. customthe phases are separated
8. extractionthe aqueous phase is extracted several times with ethyl acetate
9. dry with materialthe combined organic phases are dried over sodium sulfate
10. filtrationfiltered
11. concentrationconcentrated
12. customThe residue is purified by means of flash chromatography on silica gel (mobile phase: cyclohexane/ethyl acetate gradient)