Lithium borohydride → 2-(6-Bromo-1,8-diethyl-4,9-dihydro-3H-pyrano[3,4-b]indol-1-yl)ethanol

HRID 2249532Notes

Reaction equation

HRID 2249532 reaction equation
C([O:3][C:4](=O)[CH2:5][C:6]1([CH2:22][CH3:23])[C:11]2[NH:12][C:13]3[C:18]([C:10]=2[CH2:9][CH2:8][O:7]1)=[CH:17][C:16]([Br:19])=[CH:15][C:14]=3[CH2:20][CH3:21])C.[BH4-].[Li+]>O1CCCC1>[Br:19][C:16]1[CH:17]=[C:18]2[C:13](=[C:14]([CH2:20][CH3:21])[CH:15]=1)[NH:12][C:11]1[C:6]([CH2:5][CH2:4][OH:3])([CH2:22][CH3:23])[O:7][CH2:8][CH2:9][C:10]2=1

Participants

4

Reactant 2

HCID 4148881Lithium borohydrideHCID 69195683HCID 69195683, compound

Product 1

HCID 113370992-(6-Bromo-1,8-diethyl-4,9-dihydro-3H-pyrano[3,4-b]indol-1-yl)ethanolYield 82%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
90 °C

Procedure

To a solution of (6-bromo-1,8-diethyl-1,3,4,9-tetrahydro-pyrano[3,4-b]indol-1-yl)-acetic acid ethyl ester (5.2 g, 13.2 mmol) in tetrhydrofuran at room temperature under nitrogen was dropped a 2.0 M solution of lithium borohydride in tetrahydrofuran. The reaction mixture was heated at 90° C. (oil bath) for 5 hours. After cooling to room temperature, it was quenched with 5% hydrochloric acid solution until the excess lithium borohydride was destroyed. Water was added and the mixture extracted with ethyl acetate. Extracts were dried over magnesium sulfate and concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel, 50% ethyl acetate/hexane) to give the title compound (3.80 g, 82% yield). 1H NMR (CDCl3) δ8.07 (s, 1H), 7.64 (d, 1H), 7.26 (d, 1H), 4.17 (m, 2H), 3.86 (m, 2H), 2.94 (m, 3H), 2.87 (dt, 1H), 2.76 (t, br, 1H), 2.36 (m, 1H), 2.24 (m, 1H), 2.13 (m, 2H), 1.49 (t, 3H), 1.08 (t, 3H). ES-MS (m/z) 352 [M+1]+, 350 [M−1]−.

Workup

  1. temperatureAfter cooling to room temperature
  2. customit was quenched with 5% hydrochloric acid solution until the excess lithium borohydride
  3. customwas destroyed
  4. additionWater was added
  5. extractionthe mixture extracted with ethyl acetate
  6. dry with materialExtracts were dried over magnesium sulfate
  7. concentrationconcentrated under reduced pressure
  8. customThe crude product was purified by column chromatography (silica gel, 50% ethyl acetate/hexane)

Sources & evidence

ORD record
ord-23e928db4eb6490dbda90f88d1c37aa1
Source dataset
uspto-grants-2008_01
Patent number
US07314886B2

Reaction notes

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