反应详情

18 g of molecular sieves 4 Å, 3.2 ml (2.3 g, 23 mmol) of triethylamine and 4.6 ml (5.8 g, 21 mmol) of diphenyl phosphorazidate were added to a solution of 7.90 g (19.3 mmol) of the carboxylic acid from Example 67A in 350 ml of tert-butanol, and the mixture was stirred under reflux overnight. The molecular sieves were then filtered off and washed repeatedly with ethyl acetate, and the filtrate was concentrated under reduced pressure. The residue was taken up in ethyl acetate and then washed with 2N hydrochloric acid, saturated aqueous sodium bicarbonate solution and water. The organic phase was dried over magnesium sulphate, filtered and concentrated under reduced pressure. Yield: 8.34 g with a purity of 91% (82% of theory)

1. temperatureunder reflux overnight
2. filtrationThe molecular sieves were then filtered off
3. washwashed repeatedly with ethyl acetate
4. concentrationthe filtrate was concentrated under reduced pressure
5. washwashed with 2N hydrochloric acid, saturated aqueous sodium bicarbonate solution and water
6. dry with materialThe organic phase was dried over magnesium sulphate
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure