反应详情

N-(6-Bromochroman-4-ylidene)-2-methylpropane-2-sulfinamide (2.0 g, 6.0 mmol, Intermediate 1) was dissolved in dry dioxane (2 mL), and 4M HCl in dioxane (15 mL, 60.00 mmol) was added. A white precipitate started to form. The mixture was stirred at r.t. for 12 h. The mixture was diluted with dry Et2O (50 mL) and vacuum filtered. The filter cake was washed with dry Et2O (50 mL), then immediately dissolved by shaking in NaHCO3 (aq) and CH2Cl2. The organic phase was dried (K2CO3) and evaporated to give 6-bromochroman-4-imine (1.3 g, 5.7 mmol). The solid was dissolved together with 2-oxopropanethioamide (Intermediate 2, 1.7 g, 17 mmol, Intermediate 2) in dry methanol (5 mL) and the resulting solution was heated at 60° C. for 12 h. Evaporation onto silica and purification by flash chromatography (EtOAc in heptane) gave the title compound (0.39 g, 21% yield). 1H NMR (400 MHz, CDCl3) δ ppm 2.18 (m, 1H), 2.35 (m, 1H), 2.42 (s, 3H), 4.35-4.40 (m, 1H), 4.60 (m, 1H), 6.81 (d, 1H), 6.88 (d, 1H), 7.33 (dd, 1H); MS (ES+) m/z 311 [M+H]+.

1. customto form
2. filtrationfiltered
3. washThe filter cake was washed with dry Et2O (50 mL)
4. dissolutionimmediately dissolved
5. stirringby shaking in NaHCO3 (aq)
6. dry with materialThe organic phase was dried (K2CO3)
7. customevaporated