1,2,3,4-Tetrahydrocarbazole → 6-(1,2,3,4-Tetrahydrocarbazol-9-yl)hexanoic acid ethyl ester

HRID 403627

Reaction equation

HRID 403627 reaction equation
[CH2:1]1[C:13]2[NH:12][C:11]3[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=3)[C:5]=2[CH2:4][CH2:3][CH2:2]1.CC(C)([O-])C.[K+].Br[CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][C:26]([O:28][CH2:29][CH3:30])=[O:27]>CS(C)=O>[CH2:29]([O:28][C:26](=[O:27])[CH2:25][CH2:24][CH2:23][CH2:22][CH2:21][N:12]1[C:13]2[CH2:1][CH2:2][CH2:3][CH2:4][C:5]=2[C:6]2[C:11]1=[CH:10][CH:9]=[CH:8][CH:7]=2)[CH3:30]

Participants

5

Reactant 3

HCID 136641,2,3,4-TetrahydrocarbazoleHCID 117544Ethyl 6-bromohexanoateHCID 23665647Potassium tert-butoxide

Product 1

HCID 683805226-(1,2,3,4-Tetrahydrocarbazol-9-yl)hexanoic acid ethyl esterYield 32.2%

Reagents, catalysts & solvents 1

HCID 679Dimethyl SulfoxideSolvent

Conditions

Temperature
110 °C

Procedure

A RB flask fitted with reflux condenser containing tetrahydrocarbazole (1.71 g, 10.0 mol) was dissolved in DMSO (30 mL), treated with potassium tert-butoxide (1M solution in THF, 12 mL) and stirred at 110° C. for 20 min. Ethyl 6-bromohexanoate (1.67 mL, 10.0 mmol) was added and the mixture stirred at 110° C. for 60 min. The reaction was quenched with a 1:1 brine:water solution (120 mL) and extracted with ethyl acetate. The combined organic extracts were washed with brine, dried (Na2SO4) and concentrated. Purification by column chromatography (25% ethyl acetate in hexane) afforded the title compound (1.01 g, 32%). 1H NMR (400 MHz, CDCl3): δ 7.52 (m, 1H), 7.27 (m, 1H), 7.19 (m, 1H), 7.12 (m, 1H), 4.18 (q, 2H, J=7.1 Hz), 4.04 (t, 2H, J=7.4 Hz), 2.78-2.73 (m, 4H), 2.33 (t, 2H, J=7.5 Hz), 2.00-1.92 (m, 4H), 1.80-1.75 (m, 2H), 1.72-1.66 (m, 2H), 1.42 (m, 2H), 1.30 (t, 3H, J=6.9 Hz). ESI-HRMS (m/z): [M+H]+ calcd. for C20H27NO2, 314.2115. found, 314.2103.

Workup

  1. customA RB flask fitted
  2. temperaturewith reflux condenser
  3. stirringthe mixture stirred at 110° C. for 60 min
  4. customThe reaction was quenched with a 1:1 brine
  5. extractionwater solution (120 mL) and extracted with ethyl acetate
  6. washThe combined organic extracts were washed with brine
  7. dry with materialdried (Na2SO4)
  8. concentrationconcentrated
  9. customPurification by column chromatography (25% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-c154693568274938b9529162e27787ba
Source dataset
uspto-grants-2014_06
Patent number
US08748451B2

Linked notes

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