Triphenylphosphine → 1-Azido-2-(benyloxycarbonylamino)-2-methylbutane

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

2-(Benyloxycarbonylamino)-2-methyl-1-butanol (1.358 g, 5.722 mmol) and triphenylphosphine (1.800 g, 6.86 mmol) were dissolved in 10 mL CH2Cl2, and the resulting solution was cooled to 0° C. A solution of hydrazoic acid (prepared from sodium azide (1.30 g, 20.0 mmol), 0.533 mL concentrated sulfuric acid and 1.3 mL water) in 20 mL CH2Cl2 was passed through a plug of MgSO4, the filtrate was added to the above alcohol solution, then diisopropyl azodicarboxylate (1.35 mL, 1.40 g, 6.91 mmol) was added dropwise over 3 min. The reaction mixture was stirred at 0° C. for 1 h, then at room temperature for 5 h. The mixture was concentrated in vacuo, and the residue was applied to 300 g of silica gel in a fritted disc funnel and eluted with 3×500 mL of 10% EtOAc-hexane. The second fraction contained pure desired azide (0.822 g, 3.13 mmol, 55%) as a colorless oil: Rf 0.17 (10% EtOAc-hexane); 1H NMR (CDCl3) δ 1.33 (s, 6 H), 2.02 (bt, J=7.5 Hz, 2 H), 3.32 (bt, J=7.5 Hz, 2 H), 4.74 (br s, 1 H), 5.05 (s, 2 H), 7.3-7.4 (m, 5 H); MS m/e 263 ((M+H)+), 280 (M+NH4)+).

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