反应详情

A solution of 1-Isopropyl-1H-pyrazole-3-carboxylic acid ethyl ester (41.1 g, 226 mmol) in THF (678 mL) was cooled to 0° C. under N2. LiAlH4 (1M in THF, 226 mL, 226 mmol) was added dropwise to this solution over 20 min. The reaction was stirred for 1 h, at which point the ester starting material was not detectable by LCMS. H2O (8.58 mL) was added to the reaction dropwise, followed by dropwise addition of 15% NaOH (8.58 mL), followed by H2O (8.57 mL). Celite was then added to the solution and this was allowed to stir overnight. The mixture was then filtered through celite, washing the filter cake to remove all the product (1× with EtOAc, then 2× with 90:10 CH2Cl2:MeOH, then 2× with 1:1 CH2Cl2:MeOH, then 1× with MeOH.) The solvent was then concentrated to give a mixture of solid and oil. The oil was dissolved in EtOAc and filtered through celite, then concentrated. The resulting oil was a mixture of ˜1:1 product with aluminum complexed product. The oil was dissolved in THF (400 mL), 15% NaOH (300 mL) was added and this solution was stirred vigorously for 3 h. The layers were separated, and the aqueous was extracted with EtOAc (6×200 mL) then 2:1 CHCl3:iPrOH (2×300 mL). The combined organic was dried over MgSO4, filtered, and concentrated. The resulting oil was carried on without further purification.

1. additionCelite was then added to the solution
2. filtrationThe mixture was then filtered through celite
3. washwashing the filter cake
4. customto remove all the product (1× with EtOAc
5. concentration) The solvent was then concentrated
6. customto give
7. additiona mixture of solid and oil
8. filtrationfiltered through celite
9. concentrationconcentrated
10. additiona mixture of ˜1:1 product with aluminum complexed product
11. dissolutionThe oil was dissolved in THF (400 mL)
12. addition15% NaOH (300 mL) was added
13. stirringthis solution was stirred vigorously for 3 h
14. customThe layers were separated
15. extractionthe aqueous was extracted with EtOAc (6×200 mL)
16. dry with materialThe combined organic was dried over MgSO4
17. filtrationfiltered
18. concentrationconcentrated
19. customThe resulting oil was carried on without further purification