反应详情

温度

-78 °C

Dissolve (1,3,5-trimethyl-1H-pyrazol-4-yl)-acetic acid ethyl ester (2.8 g, 14.3 mmol) in tetrahydrofuran (200 mL) and cool to −78° C. Add diisobutylaluminum hydride (42.8 mL, 42.8 mmol, 1 M in toluene) dropwise over 30 min. Stir an additional 2 hr. at −78° C. Partition between saturated aqueous potassium sodium tartrate solution (150 mL) and ethyl acetate (500 mL) and stir for 16 hr. at room temperature. Separate organic layer, dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 1:1 hexanes:ethyl acetate), to give the title preparation (0.26 g, 12%). 1H NMR (CDCl3) δ 9.54 (t, 1H), 3.71 (s, 3H), 3.38 (d, 2H), 2.15 (s, 3H), 2.14 (s, 3H).

1. customat −78° C
2. customPartition between saturated aqueous potassium sodium tartrate solution (150 mL) and ethyl acetate (500 mL)
3. stirringstir for 16 hr
4. customat room temperature
5. dry with materialSeparate organic layer, dry (sodium sulfate)
6. filtrationfilter
7. concentrationconcentrate
8. custompurify
9. wash(silica gel chromatography, eluting with 1:1 hexanes:ethyl acetate)
10. customto give the title
11. custompreparation (0.26 g, 12%)