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

HRID 1098567ノート

反応式

HRID 1098567 の反応式
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

参加物

5

反応物 3

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

生成物 1

HCID 196200201-cyclopentyl-1H-pyrazole-4-carboxylic acid収率 47%

試薬・触媒・溶媒 1

HCID 8028Tetrahydrofuran溶媒

反応条件

温度
-78 °C

実験手順

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]+.

後処理

  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)

出典と根拠

ORDレコード
ord-4aa6626c1f3443eb893075463808c4b5
出典データセット
uspto-grants-2012_03
特許番号
US08143293B2

反応ノート

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