Ethanol → (S)-4-bromo-3-methyl-butyric acid ethyl ester

HRID 655499ノート

反応式

HRID 655499 の反応式
[C:1]([Br:4])(=O)[CH3:2].C[C@@H:6]1[CH2:10][O:9][C:8](=[O:11])[CH2:7]1.[CH2:12](O)C>>[CH2:10]([O:9][C:8](=[O:11])[CH2:7][C@H:2]([CH3:12])[CH2:1][Br:4])[CH3:6]

参加物

4

反応物 3

HCID 702Ethanol2 回HCID 10482Acetyl bromideHCID 11115993(4S)-Dihydro-4-methyl-2(3H)-furanone

生成物 1

HCID 11085055(S)-4-bromo-3-methyl-butyric acid ethyl ester

実験手順

To ethanol (55 ml) cooled to 0° C. was added acetyl bromide (41 ml, 0.6 mol) dropwise, followed by a solution of (S)-4-methyl-dihydro-furan-2-one (Tetrahedron 1983, 39, 3107; 18.6 g, 0.2 mol) in ethanol (20 ml). The ice bath was removed and the reaction allowed to reach room temperature. After 2 h of stirring the reaction was concentrated, the residue redissolved in dichloromethane, washed with sat. aq. sodium hydrogencarbonate solution, dried (Na2SO4) and concentrated affording (S)-4-bromo-3-methyl-butyric acid ethyl ester (33.6 g, quantitative). This was redissolved in ethanol (100 ml), cooled to 0° C. and N-benzylglycine ethyl ester (28.2 g, 0.14 mol) and triethylamine (22.4 ml, 0.16 mmol) were added. The reaction was then warmed to 75° C. for 4 d after which time the reaction was concentrated, the residue redissolved in dichloromethane, washed with sat. aq. sodium hydrogencarbonate solution, dried (Na2SO4) and concentrated. Purification by flash column chromatography (ethyl acetate/heptane 5:95) afforded the titled product as a light gold oil (20.3 g, 43%). MS (ISP)=322.2 (M+H)+.

後処理

  1. customThe ice bath was removed
  2. customto reach room temperature
  3. concentrationwas concentrated
  4. dissolutionthe residue redissolved in dichloromethane
  5. washwashed with sat. aq. sodium hydrogencarbonate solution
  6. dry with materialdried (Na2SO4)
  7. concentrationconcentrated

出典と根拠

ORDレコード
ord-64d5feec5307422fa9224f7dca2bfd04
出典データセット
uspto-grants-2011_12
特許番号
US08071586B2

反応ノート

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