Ammonium Chloride → Ethyl 5-methoxy-1H-pyrrolo[3,2-b]pyridine-2-carboxylate

HRID 751629Notes

Reaction equation

HRID 751629 reaction equation
[CH2:1]([O:3][C:4](=[O:19])[C:5](=O)[CH2:6][C:7]1[C:12]([N+:13]([O-])=O)=[CH:11][CH:10]=[C:9]([O:16][CH3:17])[N:8]=1)[CH3:2].[Cl-].[NH4+]>C1COCC1.C(O)C.[Fe]>[CH2:1]([O:3][C:4]([C:5]1[NH:13][C:12]2[C:7](=[N:8][C:9]([O:16][CH3:17])=[CH:10][CH:11]=2)[CH:6]=1)=[O:19])[CH3:2]

Participants

6

Reactant 2

HCID 25517Ammonium ChlorideHCID 59753655Ethyl 3-(6-methoxy-3-nitropyridin-2-yl)-2-oxopropanoate

Product 1

HCID 15275362Ethyl 5-methoxy-1H-pyrrolo[3,2-b]pyridine-2-carboxylate

Reagents, catalysts & solvents 3

HCID 23925IronCatalystHCID 702EthanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a suspension of 3-(6-methoxy-3-nitropyridin-2-yl)-2-oxopropionic acid ethyl ester (Preparation 34, 276 mg, 1.03 mmol) in THF (12 mL) and ethanol (5 mL) was added saturated aqueous ammonium chloride solution (5 mL) and iron powder (346 mg, 6.18 mmol) in one portion. The reaction mixture was heated under reflux for 1 h then filtered whilst still hot through a celite plug, washing with hot ethyl acetate. The filtrate was cooled and washed with brine (20 mL), dried (MgSO4), filtered and adsorbed onto silica gel in vacuo. Purification via flash column chromatography (SiO2, ethyl acetate/hexanes, 1:9) gave the title compound as a beige solid. δH (CDCl3): 1.40 (3H, t), 3.99 (3H, s), 4.41 (2H, q), 6.74 (1H, d), 7.20 (1H, m), 7.62 (1H, d), 9.27 (1H, s).

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureunder reflux for 1 h
  3. filtrationthen filtered whilst still hot through a celite plug
  4. washwashing with hot ethyl acetate
  5. temperatureThe filtrate was cooled
  6. washwashed with brine (20 mL)
  7. dry with materialdried (MgSO4)
  8. filtrationfiltered
  9. customPurification via flash column chromatography (SiO2, ethyl acetate/hexanes, 1:9)

Sources & evidence

ORD record
ord-05e40e98b6164942a5609e37792773c5
Source dataset
uspto-grants-2008_07
Patent number
US07405210B2

Reaction notes

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