Water → 5-Chloro-4-methoxypicolinic acid

HRID 1908815Notes

Reaction equation

HRID 1908815 reaction equation
[Cl:1][C:2]1[C:3]([O:10][CH3:11])=[CH:4][C:5]([CH:8]=C)=[N:6][CH:7]=1.[O-:12][Mn](=O)(=O)=O.[K+].[OH2:18]>CC(C)=O>[Cl:1][C:2]1[C:3]([O:10][CH3:11])=[CH:4][C:5]([C:8]([OH:12])=[O:18])=[N:6][CH:7]=1

Participants

5

Reactant 3

HCID 962WaterHCID 516875Potassium PermanganateHCID 670268745-Chloro-4-methoxy-2-vinyl-pyridine

Product 1

HCID 670269695-Chloro-4-methoxypicolinic acid

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

To a solution of 5-chloro-4-methoxy-2-vinyl-pyridine (435 mg, 2.57 mmol) in acetone (20 mL) and water (20 mL), KMnO4 (2.03 g, 12.8 mmol) is added. The mixture is stirred at rt for 15 h before it is filtered through a glass-filter pad. The filtrate is evaporated and dried to give 5-chloro-4-methoxy-pyridine-2-carboxylic acid (987 mg) as potassium salt containing water in the form of a white solid; LC-MS: tR=0.45 min, [M+1]+=187.91. This material is dissolved in ethanol (20 mL) and H2SO4 (4 mL) is added. The mixture is stirred at 80° C. for 18 h. The solvent is evaporated and the residue is dissolved in EA (150 mL) and washed with sat. aq. NaHCO3 solution and water. The org. extract is dried over MgSO4, filtered and concentrated. The crude product is purified on prep. TLC plates using heptane:EA 1:1 to give 5-chloro-4-methoxy-pyridine-2-carboxylic acid ethyl ester (350 mg) as a pale yellow oil; LC-MS: tR=0.81 min, [M+1]+=215.92; 1H NMR (D6-DMSO): δ 1.34 (t, J=7.3 Hz, 3H), 4.05 (s, 3H), 4.37 (q, J=7.0 Hz, 2H), 7.75 (s, 1H), 8.61 (m, 1H).

Workup

  1. filtrationis filtered through a glass-filter pad
  2. customThe filtrate is evaporated
  3. customdried

Sources & evidence

ORD record
ord-8ee268d611c645c3a7862ef057f45db9
Source dataset
uspto-grants-2013_12
Patent number
US08598208B2

Reaction notes

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