Hydrochloric Acid → 9H-Carbazole-9-carboxylic acid, ethyl ester

HRID 1970827Notes

Reaction equation

HRID 1970827 reaction equation
[CH:1]1[C:13]2[NH:12][C:11]3[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=3)[C:5]=2[CH:4]=[CH:3][CH:2]=1.ClCCl.Cl[C:18]([O:20][CH2:21][CH3:22])=[O:19].Cl>C(N(CC)CC)C>[CH2:21]([O:20][C:18]([N:12]1[C:11]2[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=2[C:5]2[C:13]1=[CH:1][CH:2]=[CH:3][CH:4]=2)=[O:19])[CH3:22]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 6344DichloromethaneHCID 6854CarbazoleHCID 10928Ethyl chloroformate

Product 1

HCID 37460099H-Carbazole-9-carboxylic acid, ethyl esterYield 23.6%

Reagents, catalysts & solvents 1

HCID 8471TriethylamineSolvent

Procedure

An argon filled RB flask containing carbazole (0.500 g, 2.99 mmol) at 0° C. was treated with dichloromethane (12.5 mL) and triethylamine (2.5 mL), followed by slow addition of ethyl chloroformate (0.59 mL, 5.98 mmol). The mixture was stirred at ambient temperature for 16 h, poured into 25 mL of 2N HCl, and extracted with chloroform. The organic portion was washed with saturated aqueous NaHCO3 and brine, dried (Na2SO4) and concentrated. The crude product was treated with methanol (4 mL) and filtered. The filtrate was concentrated to give carbazole-9-carboxylic acid ethyl ester (169 mg). Carbazole-9-carboxylic acid ethyl ester (95 mg, 0.39 mmol) was converted to hydroxamic acid by procedure A. Purification by HPLC gave the title compound (19 mg). 1H NMR (400 MHz, CD3CN): δ 9.43 (br, 1H), 8.08 (d, 2H, J=7.7 Hz), 7.50 (d, 2H, J=8.1 Hz), 7.43 (t, 2H, J=7.1 Hz), 7.22 (t, 2H, J=7.1 Hz). 13C NMR APT (100 MHz, CD3OD): δ 125.8 (down), 120.3 (down), 119.4 (down), 110.6 (down). ESI-MS (m/z): [M+Na]+ 249.6. Analytical HPLC: Purity=99%, tR=8.51 min, Method A.

Workup

  1. extractionextracted with chloroform
  2. washThe organic portion was washed with saturated aqueous NaHCO3 and brine
  3. dry with materialdried (Na2SO4)
  4. concentrationconcentrated
  5. additionThe crude product was treated with methanol (4 mL)
  6. filtrationfiltered
  7. concentrationThe filtrate was concentrated

Sources & evidence

ORD record
ord-3327db1db89746d09409e0725ff1d0fc
Source dataset
uspto-grants-2013_04
Patent number
US08431538B2

Reaction notes

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