反应详情

Intermediate #63 (400 mg, 0.989 mmol, 1 eq.) was treated with a 4 M solution of hydrochloric acid in dioxane (10 mL, 40 mmol, 40 eq.). After 1 hour, the reaction mixture was concentrated in vacuo and the residue was taken up in dichloromethane and washed with 1 M sodium hydroxide solution. The aqueous layer was back-extracted with dichloromethane and the combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to provide #64 (301 mg, quantitative) as a brown oil, which slowly began to solidify upon standing. LC-MS: m/z 305.3 [M+H+], retention time=0.54 minutes; HPLC (Protocol G): retention time=4.848 minutes; 1H NMR (400 MHz, CDCl3), characteristic signals: δ 6.64-6.67 (m, 2H), 6.16-6.22 (m, 2H), 6.08-6.14 (br m, 1H), 5.16-5.22 (m, 2H), 3.44 (s, 3H), 3.31 (dd, J=6.3, 4.5 Hz, 1H), 2.98-3.04 (m, 1H), 2.94 (ddd, J=10.5, 7.2, 5.6 Hz, 1H), 2.81 (ddd, J=10.5, 7.7, 6.7 Hz, 1H), 2.57 (qd, J=7.1, 4.5 Hz, 1H), 1.90-1.97 (m, 2H), 1.49-1.55 (m, 1H), 1.18 (d, J=7.1 Hz, 3H).

1. concentrationthe reaction mixture was concentrated in vacuo
2. washwashed with 1 M sodium hydroxide solution
3. extractionThe aqueous layer was back-extracted with dichloromethane
4. dry with materialthe combined organic layers were dried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto provide #64 (301 mg, quantitative) as a brown oil, which