反应详情

A solution of 1.16 grams (3.72 mmol, 1.0 eq) of oxazole 11a in 19 mL of MeOH was stirred in a 50 mL round bottom flask at room temperature under argon. To this solution was added 1.54 grams (11.16 mmol, 3.0 eq) of K2CO3 forming a heterogenous mixture. This suspension was vigorously stirred at room temperature until the reaction was complete by TLC (1:1 hexane:EtOAc, Rf=0.50). Upon completion (˜1 hour), the mixture was diluted with EtOAc and washed with 1.0 M HCl. The aqueous layer was then extracted twice more with EtOAc and the combined organic fractions were washed with brine and dried over MgSO4. Concentration yielded 860 mg (97%) of 11b as a light brown oil. This material could be purified via silica gel chromatography (hexane/EtOAc), though often the material was used directly for subsequent transformations. 1H-NMR (500 MHz, CDCl3): 7.91 (s, 1H), 7.78 (1H, d, J=7.8 Hz), 7.54 (1H, t, J=7.6 Hz), 7.40 (1H, d, J=7.6 Hz), 7.35 (1H, t, J=7.6 Hz), 4.12 (1H, dq, J=7.0 Hz, 2.5 Hz), 2.38 (3H, s), 2.18 (1H, d, J=2.4 Hz), 1.51 (3H, d, J=6.8 Hz). 13C-NMR (500 MHz, CDCl3): 185.43, 152.17, 147.06, 145.38, 142.10, 136.17, 131.80, 128.50, 128.32, 126.68, 87.10, 70.17, 28.31, 24.65, 14.16. IR (cm−1): 3293 (w), 1653 (vs), 1579 (s), 1485 (m), 1443 (w), 1384 (m), 1356 (s), 907 (s). HRMS (EI) calcd. for C15H13NO2: 239.0946. found: 239.0936.

1. washwashed with 1.0 M HCl
2. extractionThe aqueous layer was then extracted twice more with EtOAc
3. washthe combined organic fractions were washed with brine
4. dry with materialdried over MgSO4
5. concentrationConcentration