反应详情

A solution of tert-butyl 4-oxooct-7-enylcarbamate (300 mg; 1.24 mmol), methylammonium acetate (680 mg, 7.46 mmol) in 2,2,2-trifluoroethanol (2 mL) was treated with tert-butyl isocyanide (0.56 mL, 5.0 mmol) and stirred at room temperature for 5 days. Ethyl acetate (5 mL) and 2 M aq HCl (2 mL) were added and the solution was vigorously stirred for 3 additional hrs. The phases were separated and the organic phase was washed successively with water and sat'd aq sodium chloride, dried over MgSO4, filtered and concentrated. The crude viscous yellow oil residue was purified by flash column chromatography (2% methanol in dichloromethane) to give tert-butyl 4-(tert-butylcarbamoyl)-4-(N-methylacetamido)oct-7-enylcarbamate (130 mg, 26%). 1H NMR (CDCl3, 500 MHz) δ 5.81-5.73 (m, 1H), 5.40 (s, 1H), 5.05-4.96 (m, 2H), 4.62 (bs, 1H), 3.15-3.09 (m, 2H), 3.01 (s, 3H) 2.17-2.12 (m, 2H), 2.10 (s, 3H) 2.04-1.94 (m, 2H), 1.77-1.71 (m, 2H), 1.43 (s, 9H), 1.38-1.34 (m, 2H), 1.32 (s, 9H). ESI MS found for C21H39N3O4 m/z [420.5 (M+Na+), 442.4 (M+HCOO−), 396.6 (M−1)].

1. stirringthe solution was vigorously stirred for 3 additional hrs
2. customThe phases were separated
3. washthe organic phase was washed successively with water
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated
7. customThe crude viscous yellow oil residue was purified by flash column chromatography (2% methanol in dichloromethane)