反应详情

The compound of Example 2 (988 mg, 5.0 mmol) was dissolved in 30 ml of anhydrous pyridine. After addition of 0.6 ml (5.5 mmol) of isopropenyl chloroformate, the mixture was stirred at room temperature for 4 h and subsequently concentrated. The residue was dissolved in ethyl acetate and washed three times with water, dried (sodium sulfate) and concentrated. After chromatography on silica gel (ethyl acetate/heptane=1:2), the desired compound was isolated and crystallized from diethyl ether/pentane; yield 380 mg (27%) of melting point 86°-87° C.

1. concentrationsubsequently concentrated
2. dissolutionThe residue was dissolved in ethyl acetate
3. washwashed three times with water
4. dry with materialdried (sodium sulfate)
5. concentrationconcentrated