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

HRID 268653
Notes
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Reaction equation

HRID 268653 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
ParticipantsConditionsProcedureWorkupSources & evidenceReaction notes

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 8028TetrahydrofuranSolvent2×

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 tetrahydrofuran 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) δ 8.07 (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-b335506f74a045d7a673bd1811c381bd
Source dataset
uspto-grants-2008_11
DOI
10.6084/m9.figshare.5104873.v1
Patent number
US07446122B2

Reaction notes

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On this pageParticipantsConditionsProcedureWorkupSources & evidenceReaction notes