反应详情

To a mixture of 4-hydroxy-2-nitroaniline (25.0 g), 2-methoxyethanol (21.0 g), tributylphosphine (49.2 g) and tetrahydrofuran (700 mL) was added 1,1′-(azodicarbonyl)dipiperidine (61.3 g) at room temperature, and the mixture was stirred at room temperature for 2.5 days. The precipitate was filtered off, and the filtrate was concentrated. Diisopropyl ether was added to the residue, and the insoluble substance was filtered off. The filtrate was concentrated, and the residue was subjected to basic silica gel column chromatography, and eluted with hexane-ethyl acetate (2:1, volume ratio). The obtained crude product was further subjected to silica gel column chromatography, and eluted with hexane-ethyl acetate (4:1-2:1, volume ratio) to give the title compound (30.9 g, yield 90%) as orange crystals. The crystals were recrystallized from hexane-ethyl acetate to give orange prism crystals. melting point 89-90° C.

1. filtrationThe precipitate was filtered off
2. concentrationthe filtrate was concentrated
3. additionDiisopropyl ether was added to the residue
4. filtrationthe insoluble substance was filtered off
5. concentrationThe filtrate was concentrated
6. washeluted with hexane-ethyl acetate (2:1, volume ratio)
7. customThe obtained crude product
8. washeluted with hexane-ethyl acetate (4:1-2:1, volume ratio)