反应详情

A solution of the product of Example 287B (0.406 g, 1.15 mmol) in saturated LiOH-methanol (6 mL) was heated to reflux for 15 hours. The reaction mixture was cooled to ambient temperature and treated with H2O. The mixture was extracted with ether (3×). The ether extracts were discarded and the aqueous phase was made acidic with 3 M HCl. The mixture was extracted with ether (4×), and the organic extracts were dried (Na2SO4) and concentrated under reduced pressure. The resulting amber oil was dissolved in DMF (12 mL) and the solution was treated with L-methionine, methyl ester hydrochloride (0.459 g, 2.30 mmol), 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (0.957 g, 5.75 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (1.12 g, 5.75 mmol), and finally N-methylmorpholine (0.822 g, 8.05 mmol). The reaction mixture was stirred at ambient temperature for 60 hours, diluted with ethyl acetate (36 mL), and extracted with 2 N HCl (3×), followed by saturated aqueous NaHCO3 (3×) and brine. The organic phase was dried (MgSO4) and concentrated to provide a gold oil. Flash column chromatography (30% ethyl acetate-hexane) afforded the desired compound (0.172 g, 29%).

1. temperatureto reflux for 15 hours
2. extractionThe mixture was extracted with ether (3×)
3. extractionThe mixture was extracted with ether (4×)
4. dry with materialthe organic extracts were dried (Na2SO4)
5. concentrationconcentrated under reduced pressure
6. dissolutionThe resulting amber oil was dissolved in DMF (12 mL)
7. extractionextracted with 2 N HCl (3×)
8. dry with materialThe organic phase was dried (MgSO4)
9. concentrationconcentrated
10. customto provide a gold oil