反应详情

A mixture of 1-(5-amino-4-fluoro-2-hydroxyphenyl)-4-methyl-1H-tetrazol-5(4H)-one (5.00 g, 22.2 mmol, 1.00 equiv), ethyl 2-bromo-2-methylpropanoate (6.50 g, 4.94 mL, 33.3 mmol, 1.50 equiv), K2CO3 (6.15 g, 44.4 mmol, 2.00 equiv), and tetra-n-butylammonium bromide (716 mg, 2.22 mmol, 0.10 equiv) in acetone (220 mL) was heated at reflux overnight. After cooling to RT, the reaction mixture was concentrated to dryness. The crude product was taken in excess water and EtOAc. The layers were separated, and the aqueous layer was extracted with EtOAc 2×. The organic layer was dried over Na2SO4, filtered, and concentrated to dryness. The crude product was absorbed onto silica gel and purified by flash chromatography and eluted with DCM:MeOH=100:0 to 98% MeOH using 1% MeOH increments to provide ethyl 2-(4-amino-5-fluoro-2-(4-methyl-5-oxo-4,5-dihydro-1H-tetrazol-1-yl)phenoxy)-2-methylpropanoate (5.60 g, 74%) as a clear brown oil.

1. temperaturewas heated
2. temperatureat reflux overnight
3. concentrationthe reaction mixture was concentrated to dryness
4. customThe layers were separated
5. extractionthe aqueous layer was extracted with EtOAc 2×
6. dry with materialThe organic layer was dried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated to dryness
9. customThe crude product was absorbed onto silica gel
10. custompurified by flash chromatography
11. washeluted with DCM