Carbon Dioxide → 1-tert-Butyl-1H-pyrazole-4-carboxylic acid

HRID 1930361

반응식

HRID 1930361 반응식
Br[C:2]1[CH:3]=[N:4][N:5]([C:7]([CH3:10])([CH3:9])[CH3:8])[CH:6]=1.[Li]CCCC.[C:16](=[O:18])=[O:17]>C1COCC1>[C:7]([N:5]1[CH:6]=[C:2]([C:16]([OH:18])=[O:17])[CH:3]=[N:4]1)([CH3:10])([CH3:9])[CH3:8]

참가 물질

5

반응물 3

HCID 280Carbon DioxideHCID 532168984-Bromo-1-(1,1-dimethylethyl)-1H-pyrazoleHCID 178418339Butyllithium

생성물 1

HCID 246962911-tert-Butyl-1H-pyrazole-4-carboxylic acid수율 67%

시약·촉매·용매 1

HCID 8028Tetrahydrofuran용매

반응 조건

온도
-78 °C

실험 절차

To a −78° C. solution of 4-bromo-1-t-butyl-1H-pyrazole (15 g, 74.3 mmol) in anhydrous THF (100 mL) was added n-BuLi (2.5 M in hexane, 53 mL, 132 mmol) under N2, and the resulting mixture was stirred at −78° C. for 30 min. Excess dry ice was added at −78° C., and the mixture was warmed slowly to RT and stirred overnight. The reaction was concentrated in vacuo, water was added and the pH was adjusted to pH 3 by the addition of 2N aq HCl. The aqueous solution was extracted with EtOAc. The extracts were washed with brine, dried (MgSO4) and concentrated in vacuo. The residue was recrystallized (EtOAc-pet. ether) to give 1-t-butyl-1H-pyrazole-4-carboxylic acid (8.0 g, 67% yield). 1H NMR (300 MHz, CDCl3): δ 8.10 (s, 1 H), 8.03 (s, 1 H), 1.64 (s, 9 H); MS (ESI) m/z: 168.9 [M+H]+.

후처리

  1. temperaturethe mixture was warmed slowly to RT
  2. stirringstirred overnight
  3. concentrationThe reaction was concentrated in vacuo, water
  4. additionwas added
  5. additionthe pH was adjusted to pH 3 by the addition of 2N aq HCl
  6. extractionThe aqueous solution was extracted with EtOAc
  7. washThe extracts were washed with brine
  8. dry with materialdried (MgSO4)
  9. concentrationconcentrated in vacuo
  10. customThe residue was recrystallized (EtOAc-pet. ether)

출처 및 근거

ORD 기록
ord-2e5d6ab72fb946d08de5af6548adf38c
출처 데이터셋
uspto-grants-2012_05
특허 번호
US08188113B2

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