Carbon Dioxide → 1-cyclopentyl-1H-pyrazole-4-carboxylic acid

HRID 1098567노트

반응식

HRID 1098567 반응식
Br[C:2]1[CH:3]=[N:4][N:5]([CH:7]2[CH2:11][CH2:10][CH2:9][CH2:8]2)[CH:6]=1.[Li]CCCC.[C:17](=[O:19])=[O:18]>C1COCC1>[CH:7]1([N:5]2[CH:6]=[C:2]([C:17]([OH:19])=[O:18])[CH:3]=[N:4]2)[CH2:11][CH2:10][CH2:9][CH2:8]1

참가 물질

5

반응물 3

HCID 280Carbon DioxideHCID 518921224-bromo-1-cyclopentyl-1H-pyrazoleHCID 178418339Butyllithium

생성물 1

HCID 196200201-cyclopentyl-1H-pyrazole-4-carboxylic acid수율 47%

시약·촉매·용매 1

HCID 8028Tetrahydrofuran용매

반응 조건

온도
-78 °C

실험 절차

To a solution of 4-bromo-1-cyclopentyl-1H-pyrazole (9.0 g, 42 mmol) in THF (100 mL) at −78° C. under nitrogen was added a solution of n-BuLi in hexanes (2.5 M, 18.5 mL, 46.2 mmol). The resulting mixture was stirred at −78° C. for 30 min. Dry-ice (solid CO2) was added at −78° C. and the reaction mixture was allowed to slowly warn to RT overnight. The solvent was removed under reduced pressure. Water was added, and the mixture was acidified (pH 3) by the addition of aq. HCl. The aqueous layer was extracted with EtOAc, and the extracts were washed with brine, dried over MgSO4, and concentrated in vacuo. The residue was recrystallized (EtOAc-petroleum ether) to provide 1-cyclopentyl-1H-pyrazole-4-carboxylic acid (3.5 g, 47% yield). 1H NMR (400 MHz, DMSO-d6): δ 12.50 (br s, 1 H), 8.31 (s, 1 H), 7.85 (s, 1 H), 4.78 (m, 1 H), 2.16-1.68 (m, 8 H); MS (ESI) m/z: 181.0 [M+H]+.

후처리

  1. waitto slowly warn to RT overnight
  2. customThe solvent was removed under reduced pressure
  3. additionWater was added
  4. additionby the addition of aq. HCl
  5. extractionThe aqueous layer was extracted with EtOAc
  6. washthe extracts were washed with brine
  7. dry with materialdried over MgSO4
  8. concentrationconcentrated in vacuo
  9. customThe residue was recrystallized (EtOAc-petroleum ether)

출처 및 근거

ORD 기록
ord-4aa6626c1f3443eb893075463808c4b5
출처 데이터셋
uspto-grants-2012_03
특허 번호
US08143293B2

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