p-Toluenesulfonic acid → Methyl 6-iodopyridine-3-carboxylate

HRID 963395Notes

Reaction equation

HRID 963395 reaction equation
[I:1][C:2]1[N:7]=[CH:6][C:5]([C:8]([OH:10])=[O:9])=[CH:4][CH:3]=1.[C:11]1(C)C=CC(S(O)(=O)=O)=CC=1>CO>[I:1][C:2]1[N:7]=[CH:6][C:5]([C:8]([O:10][CH3:11])=[O:9])=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 8190626-Iodopyridine-3-carboxylic acid

Product 1

HCID 14784670Methyl 6-iodopyridine-3-carboxylateYield 43%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A solution of 6-iodo-pyridine-3-carboxylic acid (J. Am. Chem. Soc. 72, 1032, (1950)), 1.2 g of trimethyl o-formate and 0.2 g of p-toluenesulphonic acid in 75 ml of methanol is held at reflux for 2 hrs. The reaction mixture is concentrated and the residue is taken up in 50 ml of diethyl ether. The ether phase is washed twice with 50 ml of 2N aqueous sodium hydroxide solution each time and twice with 50 ml of saturated, aqueous sodium chloride solution each time, dried over magnesium sulphate and concentrated. The residue is recrystallized from 30 ml of hot methanol. 1.15 g (43%) of methyl 6-iodo-pyridine-3-carboxylate are isolated as a colourless solid. M.p. 134°-135°.

Workup

  1. temperatureat reflux for 2 hrs
  2. concentrationThe reaction mixture is concentrated
  3. washThe ether phase is washed twice with 50 ml of 2N aqueous sodium hydroxide solution each time
  4. dry with materialtwice with 50 ml of saturated, aqueous sodium chloride solution each time, dried over magnesium sulphate
  5. concentrationconcentrated
  6. customThe residue is recrystallized from 30 ml of hot methanol

Sources & evidence

ORD record
ord-60ea1fc469f34d33bd976306af2d7aa7
Source dataset
uspto-grants-1998_06
Patent number
US05763450

Reaction notes

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