Benzene → Methyl 2-oxo-1,2-dihydropyridine-3-carboxylate

HRID 1199804Notes

Reaction equation

HRID 1199804 reaction equation
[O:1]=[C:2]1[C:7]([C:8]([OH:10])=[O:9])=[CH:6][CH:5]=[CH:4][NH:3]1.S(=O)(=O)(O)O.[CH:16]1C=CC=CC=1>CO>[O:1]=[C:2]1[C:7]([C:8]([O:10][CH3:16])=[O:9])=[CH:6][CH:5]=[CH:4][NH:3]1

Participants

5

Reactant 3

HCID 241BenzeneHCID 1118Sulfuric AcidHCID 691142-Hydroxynicotinic acid

Product 1

HCID 579028Methyl 2-oxo-1,2-dihydropyridine-3-carboxylate

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A mixture containing 27.8 g of 1,2-dihydro-2-oxo-3-pyridinecarboxylic acid, 3.0 ml of concentrated sulfuric acid in 500 ml of methanol, and 300 ml of benzene are heated under reflux for 2.5 hours. A Dean-Stark trap is then attached, and the azeotrope collected is removed periodically in 25 ml fractions over a period of 28 hours. The remaining solvent is removed by evaporation under reduced pressure and the solid residue suspended in 500 ml of cold water. The suspension is filtered (from which unreacted starting material can be recovered) and the filtrate continuously extracted with methylene chloride. The extracts are concentrated under reduced pressure to yield the title compound as a white solid which, upon recrystallization from 1.4 L of benzene, yields 19.48 g (64%) of methyl 2-oxo-1,2-dihydro-3-pyridinecarboxylate: m.p. 148°-151° C.; NMR (DMSO-d6, 80 MHz) delta 3.72 (s, 3H), 6.25 (dd, 1H, J=7.1 Hz, J=6.3 Hz), 7.64 (dd, 1H, J=6.3 Hz, J=2.2 Hz), 8.03 (dd, 1H, J=7.1 Hz, J=2.2 Hz).

Workup

  1. temperatureare heated
  2. temperatureunder reflux for 2.5 hours
  3. customthe azeotrope collected
  4. customis removed periodically in 25 ml fractions over a period of 28 hours
  5. customThe remaining solvent is removed by evaporation under reduced pressure
  6. filtrationThe suspension is filtered
  7. custom(from which unreacted starting material can be recovered)
  8. extractionthe filtrate continuously extracted with methylene chloride
  9. concentrationThe extracts are concentrated under reduced pressure

Sources & evidence

ORD record
ord-3b17fcc9b14f4e2a93158df4493e57f2
Source dataset
uspto-grants-1990_02
Patent number
US04902796

Reaction notes

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