Chlorotrimethylsilane → 1-(1,5-dimethyl-1H-pyrazol-3-yl)ethanone

HRID 1825332

反応式

HRID 1825332 の反応式
[CH3:1][N:2]1[C:6]([CH3:7])=[CH:5][C:4]([C:8]([O:10]CC)=O)=[N:3]1.[CH3:13][Si](Cl)(C)C.C[Li]>O1CCCC1>[C:8]([C:4]1[CH:5]=[C:6]([CH3:7])[N:2]([CH3:1])[N:3]=1)(=[O:10])[CH3:13]

参加物

5

反応物 3

HCID 6397ChlorotrimethylsilaneHCID 1385771,5-Dimethyl-3-ethoxycarbonylpyrazoleHCID 178418348HCID 178418348、化合物

生成物 1

HCID 131074871-(1,5-dimethyl-1H-pyrazol-3-yl)ethanone

試薬・触媒・溶媒 1

HCID 8028Tetrahydrofuran溶媒

反応条件

温度
-100 °C

実験手順

Ethyl 1,5-dimethylpyrazole-3-carboxylate (3.59 g, 21.4 mM) was dissolved in dry tetrahydrofuran (70 ml) and cooled to −100° C. whilst under an atmosphere of argon. Trimethylsilylchloride (13.5 ml, 107 mM) was added by rapid dropwise addition. Immediately after methyllithium (77.7 ml of 1.1M solution in diethylether, 85.5 mM) was added dropwise in such a way that the internal temperature never exceeded −85° C. After complete addition the heterogeneous reaction was allowed to warm to room temperature. Most of the solvent was removed by evaporation in vacuo before treating with ethanol (6 ml) followed by water (6 ml). After vigorously stirring for 5 minutes the mixture was diluted with ethyl acetate and water. The pH was adjusted to 7 by treating with saturated sodium bicarbonate solution. The organic phase was separated and washed with brine before drying (MgSO4). Purification was accomplished by chromatography on silica gel (12×4.25 cm) loading in dichloromethane and eluting with 40% ethylacetate in hexane followed by 60% ethyl acetate in hexane. Removal of the solvents gave the title compound as a coloured oil which solidified on standing at room temperature (1.42 g): υmax (CH2Cl2) 1679, 1551, 1448, and 1373 cm−1; δH (CDCl3) 2.30 (3H, s), 2.54 (3H, s), 3.84 (3H, s), 6.53 (1H, d, J 0.55 Hz); E.I. m/e 138 (95%), NH3DCI m/e 139 (100%).

後処理

  1. additionAfter complete addition
  2. customthe heterogeneous reaction
  3. temperatureto warm to room temperature
  4. customMost of the solvent was removed by evaporation in vacuo
  5. additionbefore treating with ethanol (6 ml)
  6. additionwas diluted with ethyl acetate and water
  7. additionby treating with saturated sodium bicarbonate solution
  8. customThe organic phase was separated
  9. washwashed with brine
  10. dry with materialbefore drying (MgSO4)
  11. customPurification
  12. washeluting with 40% ethylacetate in hexane
  13. customRemoval of the solvents

出典と根拠

ORDレコード
ord-1bc518db245f44e29d73d14b4c085b69
出典データセット
uspto-grants-2006_05
特許番号
US07045619B2

関連ノート

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