反应详情

Diethylazodicarboxylate (3.60 mL, 22.9 mmol) was added dropwise over 30 min to a solution comprised of O-[2-(2,2,2-trifluoro-ethylamino)-ethyl]-hydroxylamine (3.19 g, 22.3 mmol, prepared as in J. Am. Chem. Soc. 1979, 101, 4300), triphenylphosphine (6.05 g, 23.1 mmol), and N-hydroxyphthalimide (3.65 g, 22.4 mmol). The resultant reaction mixture was stirred at ambient temperature. After 20 h, the reaction mixture was concentrated and the residue was dissolved in 60 mL of warm chloroform. Upon cooling, crystallization of diethyl 1,2-hydrazaine dicarboxylate ensued. The precipitate was filtered and the filtrate was concentrated and further diluted with ether. A single crystal of triphenylphosphine oxide was added, initiating copious precipitation. The resultant precipitate was removed by filtration and the filtrate was concentrated in vacuo and chromatographed on silica gel. Elution with hexanes-ethyl acetate (2:1) afforded 2-[2-(2,2,2-trifluoro-ethylamino)-ethoxy]-isoindole-1,3-dione (4.05 g, 63% yield) as a colorless oil: 1H NMR (400 Mz, CDCl3) δ 7.84-7.73 (m, 4H), 4.30 (t, J=4.8 Hz, 2H), 3.26 (q, J=9.5 Hz, 2H), 3.00 (t, J=4.9 Hz, 2H), 2.33 (br s, 1H); MS (APCI+)=289.0.

1. customThe resultant reaction mixture
2. concentrationthe reaction mixture was concentrated
3. dissolutionthe residue was dissolved in 60 mL of warm chloroform
4. temperatureUpon cooling
5. customcrystallization of diethyl 1,2-hydrazaine dicarboxylate
6. filtrationThe precipitate was filtered
7. concentrationthe filtrate was concentrated
8. additionfurther diluted with ether
9. additionA single crystal of triphenylphosphine oxide was added
10. customprecipitation
11. customThe resultant precipitate was removed by filtration
12. concentrationthe filtrate was concentrated in vacuo
13. customchromatographed on silica gel
14. washElution with hexanes-ethyl acetate (2:1)