反应详情

温度

80 °C

Methyl 3-methyl-2-(5-(4-nitrophenyl)oxazole-2-carboxamido)butanoate (step E product, 700 mg) was dissolved in a solvent mixture of EtOH (7 ml), THF (2.8 ml), and water (2.8 ml). Ammonium chloride (323 mg) and iron (264 mg) were then added and the reaction mixture was refluxed at 80° C. for 3 hours. It was then cooled, filtered through celite and the solvent was removed under reduced pressure to get dark brown residue. The residue was dissolved in water and extracted with EtOAc. Organic layer was separated, dried over Na2SO4 and concentrated to get dark brown residue which was purified by silica gel column chromatography in 2.5:7.5 EtOAc:CHCl3 to get yellow solid which was crystallized in DCM/Pet ether to yield 550 mg (86%) yellow solid. 1HNMR (DMSO-d6, 300 MHz): δ 8.83 (d, 1H), 7.55 (s, 1H), 7.48 (d, 2H), 6.66 (d, 2H), 5.63 (bs, 2H), 4.28 (m, 1H), 3.67 (s, 3H), 1.98 (m, 1H), 0.96 (d, 6H).

1. temperatureIt was then cooled
2. filtrationfiltered through celite
3. customthe solvent was removed under reduced pressure
4. customto get dark brown residue
5. extractionextracted with EtOAc
6. customOrganic layer was separated
7. dry with materialdried over Na2SO4
8. concentrationconcentrated
9. customto get dark brown residue which
10. customwas purified by silica gel column chromatography in 2.5:7.5 EtOAc
11. customCHCl3 to get yellow solid which
12. customwas crystallized in DCM/Pet ether