Boron trifluoride etherate → Ethyl 5-bromo-1,3,4,9-tetrahydro-8-methyl-1-propylpyrano[3,4-b]indole-1-acetate

HRID 1351718Notes

Reaction equation

HRID 1351718 reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[C:4]2[C:9]([CH2:12][CH:13](N)CO)=[CH:10][NH:11][C:3]=12.[C:17]([CH2:22][C:23]([O:25][CH2:26][CH3:27])=[O:24])(=[O:21])[CH2:18][CH2:19][CH3:20].B(F)(F)F.CCOCC>C(Cl)Cl>[CH2:26]([O:25][C:23](=[O:24])[CH2:22][C:17]1([CH2:18][CH2:19][CH3:20])[C:10]2[NH:11][C:3]3[C:4]([C:9]=2[CH2:12][CH2:13][O:21]1)=[C:5]([Br:8])[CH:6]=[CH:7][C:2]=3[CH3:1])[CH3:27]

Participants

5

Reactant 3

HCID 8000Boron trifluoride etherateHCID 238498Ethyl 3-oxohexanoateHCID 90471058HCID 90471058, compound

Product 1

HCID 11452194Ethyl 5-bromo-1,3,4,9-tetrahydro-8-methyl-1-propylpyrano[3,4-b]indole-1-acetateYield 93.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 4-bromo-7-methyl tryptophol (1.12 g, 4.41 mmol) and ethyl butyrylacetate (0.71 mL, 4.41 mmol) in CH2Cl2 (20 mL) was added BF3.OEt2 (0.56 mL, 4.41 mmol) dropwise at room temperature. The solution was stirred for 2 hours and then washed with saturated aqueous NaHCO3 (15 mL) and brine (15 mL). The organic phase was dried (Na2SO4) and filtered through a pad of silica gel. The filter cake was washed with additional CH2Cl2 and the combined organic layer was evaporated to provide 1.62 g (93%) of title compound as a white solid. 1H NMR (CDCl3): 300 MHz δ 9.33 (bs, 1H), 7.11 (d, J=7.65 Hz, 1H), 6.76 (d, J=7.65 Hz, 1H), 4.19 (m, 2H), 4.03 (m, 1H), 3.90 (m, 1H), 3.15 (m, 2H), 3.03 (d, J=16.6 Hz, 1H), 2.89 (d, J=16.6 Hz, 1H), 2.43 (s, 3H), 2.08 (m, 1H), 1.96 (m, 1H), 1.38 (m, 1H), 1.27 (t, J=7.14 Hz, 3H), 1.18 (m, 1H), 0.87 (t, J=7.29 Hz, 3H).

Workup

  1. washwashed with saturated aqueous NaHCO3 (15 mL) and brine (15 mL)
  2. dry with materialThe organic phase was dried (Na2SO4)
  3. filtrationfiltered through a pad of silica gel
  4. washThe filter cake was washed with additional CH2Cl2
  5. customthe combined organic layer was evaporated

Sources & evidence

ORD record
ord-ec93c91a68024151967ca013226234ed
Source dataset
uspto-grants-2007_05
Patent number
US07217730B2

Reaction notes

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