Isopropanol → 2-Chloro-6-methyl-isonicotinic acid isopropyl ester

HRID 1908725Notes

Reaction equation

HRID 1908725 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([CH3:11])[N:10]=1)[C:5]([OH:7])=[O:6].[CH:12](O)([CH3:14])[CH3:13]>OS(O)(=O)=O>[CH:12]([O:6][C:5](=[O:7])[C:4]1[CH:8]=[C:9]([CH3:11])[N:10]=[C:2]([Cl:1])[CH:3]=1)([CH3:14])[CH3:13]

Participants

4

Reactant 2

HCID 3776IsopropanolHCID 1412092-Chloro-6-methylpyridine-4-carboxylic acid

Product 1

HCID 866398782-Chloro-6-methyl-isonicotinic acid isopropyl ester

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
40 °C

Procedure

To a suspension of 2-chloro-6-methyl-isonicotinic acid (20.0 g, 117 mmol) in isopropanol (80 mL), H2SO4 (5 mL) is added dropwise. The mixture becomes warm (40° C.). The mixture is stirred for 24 h at rt, then at 90° C. for 28 h before the solvent is removed in vacuo. The residue is dissolved in diethyl ether (200 mL), washed with sat. aq. NaHCO3-solution (3×50 mL) followed by brine (3×50 mL), dried over Na2SO4, filtered and concentrated to give 2-chloro-6-methyl-isonicotinic acid isopropyl ester (21.0 g) as a colourless oil which slowly crystallises; LC-MS: tR=0.97 min, [M+1]+=214.05.

Workup

  1. additionis added dropwise
  2. customat 90° C. for 28 h before the solvent is removed in vacuo
  3. dissolutionThe residue is dissolved in diethyl ether (200 mL)
  4. washwashed with sat. aq. NaHCO3-solution (3×50 mL)
  5. dry with materialdried over Na2SO4
  6. filtrationfiltered
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-6d6b61d51bec408e9416c2086901fd0a
Source dataset
uspto-grants-2013_12
Patent number
US08598208B2

Reaction notes

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