反应详情

A solution of t.BuOK (2.42 g, 21 mmol) in anhydrous t.BuOH (40 mL) was heated to reflux. Compound 70 (1.8 g, 5.4 mmol) was added portion-wise over a 5 min period, and the dark red solution formed was stirred at reflux for an additional 20 min. The mixture was cooled to rt, and HCl (4 M in dioxane, 8.0 mL, 32 mmol) was added, after which the reaction mixture was concentrated under vacuum. In order to assure that all of the HCl and dioxane were removed, the crude product was re-dissolved in CH2Cl2 twice and thoroughly evaporated to obtain the slightly impure HCl salt of compound 71 (1.62 g) as a brown solid. The product was dissolved in CH2Cl2 and washed with saturated NaHCO3, after which the aqueous phase was extracted several times with CH2Cl2. The combined organic phases were dried (MgSO4) and evaporated to give compound 71 (1.38 g, 81%) as a light brown solid (>95% pure according to HPLC tests). 1H-NMR (MeOH-d4, 400 MHz): δ 1.30 (d, J=6.0 Hz, 6H), 3.93 (s, 3H), 3.95-4.07 (m, 1H), 6.73 (s, 1H), 6.99 (dd, J=2.4, 9.2 Hz, 1H), 7.26 (d, J=2.4 Hz, 1H), 7.37 (s, 1H), 8.10 (d, J=9.2 Hz, 1H).

1. customthe dark red solution formed
2. temperatureat reflux for an additional 20 min
3. concentrationafter which the reaction mixture was concentrated under vacuum
4. customwere removed
5. dissolutionthe crude product was re-dissolved in CH2Cl2 twice
6. customthoroughly evaporated