Sodium Hydroxide → 9-(2-Benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid

HRID 1753934Notes

Reaction equation

HRID 1753934 reaction equation
C([O:3][C:4]([CH:6]1[C:18]2[C:17]3[C:12](=[CH:13][CH:14]=[CH:15][CH:16]=3)[N:11]([CH2:19][CH2:20][O:21][CH2:22][C:23]3[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=3)[C:10]=2[CH2:9][CH2:8][CH2:7]1)=[O:5])C.[OH-].[Na+]>C(O)C.O>[CH2:22]([O:21][CH2:20][CH2:19][N:11]1[C:10]2[CH2:9][CH2:8][CH2:7][CH:6]([C:4]([OH:5])=[O:3])[C:18]=2[C:17]2[C:12]1=[CH:13][CH:14]=[CH:15][CH:16]=2)[C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1

Participants

5

Reactant 2

HCID 14798Sodium HydroxideHCID 666793589-(2-Benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid ethyl ester

Product 1

HCID 666795949-(2-Benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acidYield 92%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent

Procedure

9-(2-Benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid ethyl ester (25) (35 g, 9.3 mmol) was dissolved in ethanol (9 mL) and then NaOH (1.56 g) in water (15 mL) was added. The reaction was heated at reflux for 2 h. The reaction was concentrated in vacuo and the residue diluted with water and washed with dichloromethane (2×150 mL). The aqueous layer was added drop wise to 2 N HCl (150 mL) and then extracted into dichloromethane (3×150 mL). The organics were dried and concentrated in vacuo to afford 2.48 g (92%) of 9-(2-benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid (26) as a yellow solid which was used in the next step without purification. The structure was confirmed by 13C NMR (75 MHz, CDCl3) δC 20.4, 21.8, 26.4, 38.3, 42.9, 68.7, 73.3, 105.7, 108.8, 118.7, 119.3, 102.9, 127.4, 127.6, 128.3, 136.2, 137.1, 137.8, 108.9.

Workup

  1. temperatureThe reaction was heated
  2. temperatureat reflux for 2 h
  3. concentrationThe reaction was concentrated in vacuo
  4. additionthe residue diluted with water
  5. washwashed with dichloromethane (2×150 mL)
  6. additionThe aqueous layer was added drop wise to 2 N HCl (150 mL)
  7. extractionextracted into dichloromethane (3×150 mL)
  8. customThe organics were dried
  9. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-c40c30caafcf4e998ef451de9cfe6eb2
Source dataset
uspto-grants-2015_10
Patent number
US09168317B2

Reaction notes

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