Cyclopentanone → Ethyl 6-amino-5-bromo-2-(1-hydroxycyclopentyl)benzofuran-3-carboxylate

HRID 595579Notes

Reaction equation

HRID 595579 reaction equation
[Li+].CC([N-]C(C)C)C.[NH2:9][C:10]1[C:23]([Br:24])=[CH:22][C:13]2[C:14]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:15][O:16][C:12]=2[CH:11]=1.[C:25]1(=[O:30])[CH2:29][CH2:28][CH2:27][CH2:26]1.[NH4+].[Cl-]>C1COCC1>[NH2:9][C:10]1[C:23]([Br:24])=[CH:22][C:13]2[C:14]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[C:15]([C:25]3([OH:30])[CH2:29][CH2:28][CH2:27][CH2:26]3)[O:16][C:12]=2[CH:11]=1

Participants

6

Reactant 4

HCID 8452CyclopentanoneHCID 25517Ammonium ChlorideHCID 2724682Lithium diisopropylamideHCID 89428742Ethyl 6-amino-5-bromobenzofuran-3-carboxylate

Product 1

HCID 90332481Ethyl 6-amino-5-bromo-2-(1-hydroxycyclopentyl)benzofuran-3-carboxylateYield 44.7%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of LDA (6.32 g, 59.0 mmol) in THF (60 mL) was added dropwise ethyl 6-amino-5-bromobenzofuran-3-carboxylate (5 g, 17.6 mmol) at −78° C. under N2. After the mixture was stirred for 1 hour, cyclopentanone (4.44 g, 52.8 mmol) in THF (40 mL) was added dropwise at −78° C. After the mixture was stirred for 1 h, NH4Cl (a.q.) was added, then the mixture was extracted with EtOAc (100 mL*3) and dried over Na2SO4 After concentration, the residue was purified by column chromatography (PE:EtOAc=10:1) to give the product of ethyl 6-amino-5-bromo-2-(1-hydroxycyclopentyl)benzofuran-3-carboxylate (2.9 g, yield: 44%). 1H-NMR (CDCl3, 400 MHz) δ 7.94 (s, 1H), 6.86 (s, 1H), 6.07 (s, 1H), 4.46 (q, J=7.2 Hz, 2H), 4.20 (s, 1H), 2.12˜2.17 (m, 4H), 1.99 (t, J=5.6 Hz, 2H), 1.79 (t, J=3.2 Hz, 2H), 1.50 (t, J=7.2 Hz, 3H). MS (M+H)+: 368/370.

Workup

  1. stirringAfter the mixture was stirred for 1 h
  2. extractionthe mixture was extracted with EtOAc (100 mL*3)
  3. dry with materialdried over Na2SO4
  4. concentrationAfter concentration
  5. customthe residue was purified by column chromatography (PE:EtOAc=10:1)

Sources & evidence

ORD record
ord-9aedccbd4a9f4ddab2b9dcfa5999ac77
Source dataset
uspto-grants-2016_01
Patent number
US09242998B2

Reaction notes

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