Ethylbenzene → 1-[3-(2-Hydroxy-3,3-dimethylpentyl)-5-methoxy-1-benzofuran-2-yl]-2,2-dimethylpropan-1-one

HRID 2103776Notes

Reaction equation

HRID 2103776 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[O:10][C:9]([C:11](=[O:16])[C:12]([CH3:15])([CH3:14])[CH3:13])=[C:8]([CH3:17])[C:7]=2[CH:18]=1.[Li+].CC([N-]C(C)C)C.C(C1C=CC=CC=1)C.[CH3:35][C:36]([CH3:41])([CH2:39][CH3:40])[CH:37]=[O:38]>C1COCC1.CCCCCCC>[OH:38][CH:37]([C:36]([CH3:41])([CH3:35])[CH2:39][CH3:40])[CH2:17][C:8]1[C:7]2[CH:18]=[C:3]([O:2][CH3:1])[CH:4]=[CH:5][C:6]=2[O:10][C:9]=1[C:11](=[O:16])[C:12]([CH3:13])([CH3:14])[CH3:15]

Participants

7

Reactant 4

HCID 7500EthylbenzeneHCID 137426Butanal, 2,2-dimethyl-HCID 2724682Lithium diisopropylamideHCID 288262421-(5-Methoxy-3-methyl-1-benzofuran-2-yl)-2,2-dimethylpropan-1-one

Product 1

HCID 689512471-[3-(2-Hydroxy-3,3-dimethylpentyl)-5-methoxy-1-benzofuran-2-yl]-2,2-dimethylpropan-1-one

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8900HeptaneSolvent

Procedure

To a solution of 0.493 g 1-(5-methoxy-3-methyl-1-benzofuran-2-yl)-2,2-dimethylpropan-1-one from Step A Example 1 in 20 mL anhydrous THF at −78° C. under nitrogen was added 2.0 mL 2 M LDA in heptane, THF, and ethylbenzene. After 50 minutes, 0.40 g 2,2-dimethylbutanal was added. Remove the cooling bath and let the reaction mixture warm up to room temperature. After 70 minutes, the reaction was quenched by adding 2 mL saturated ammonium chloride and the reaction mixture was evaporated under reduced pressure to remove solvents. Dilute the residue with ether, wash with 1 M HCl (2×) and saturated brine, dry over anhydrous Na2SO4, and evaporate to give a crude product. It was purified on RP-HPLC using 65˜100% MeCN in water without TFA to give the title compound as colorless solid after lyophilization. 1H NMR (CDCl3, 500 MHz) 7.44 (d, 9.1 Hz, 1H), 7.20 (d, 2.0 Hz, 1H), 7.10 (dd, 2.5 & 9.1 Hz, 1H), 3.86 (s, 3H), 3.58 (dd, 1.6 & 10.6 Hz, 1H), 3.29˜3.34 (m, 1H), 2.90˜2.95 (m, 1H), 1.51˜1.59 (m, 1H), 1.39˜1.46 (m, 1H), 1.40 (s, 9H), 1.02 (s, 3H), 1.01 (s, 3H), 0.92 (t, 7.6 Hz, 3H). LC-MS: 4.47 min. (m/Z=329.3, 369.2, 347). A faster-eluting isomeric side-product was also isolated during purification and was identified as 1-[2-(1-hydroxy-2,2-dimethylpropyl)-5-methoxy-1-benzofuran-3-yl]-3,3-dimethylpentan-2-one. 1H NMR (CDCl3, 500 MHz) 7.30 (d, 9.0 Hz, 1H), 6.84 (dd, 2.5 & 8.9 Hz, 1H), 6.75 (d, 2.5 Hz, 1H), 4.44 (s, 1H), 4.07 (AB d, 18.5 Hz, 1H), 4.04 (AB d, 18.5 Hz, 1H), 3.78 (s, 3H). 1.74 (q, 7.6 Hz, 2H), 1.263 (s, 3H), 1.260 (s, 3H), 0.99 (s, 9H), 0.91 (t, 7.4 Hz, 3H). LC-MS: 3.95 min. (m/Z=369.3=M+Na, 329.3,).

Workup

  1. customRemove the cooling bath
  2. waitAfter 70 minutes
  3. customthe reaction was quenched
  4. additionby adding 2 mL saturated ammonium chloride
  5. customthe reaction mixture was evaporated under reduced pressure
  6. customto remove solvents
  7. additionDilute the residue with ether
  8. washwash with 1 M HCl (2×) and saturated brine
  9. dry with materialdry over anhydrous Na2SO4
  10. customevaporate
  11. customto give a crude product
  12. customIt was purified on RP-HPLC

Sources & evidence

ORD record
ord-0374708865424ef1a1aa218ca761f62c
Source dataset
uspto-grants-2009_08
Patent number
US07576122B2

Reaction notes

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