Hydrochloric Acid → 8-Methoxy-1-oxo-1H-2-benzopyran-3-carboxylic acid

HRID 1288253Notes

Reaction equation

HRID 1288253 reaction equation
[C:1]([C:4]1[C:22]([O:23][CH3:24])=[CH:21][CH:20]=[CH:19][C:5]=1[CH:6]=[C:7]1[C:11](=[O:12])[O:10]C(C2C=CC=CC=2)=N1)([OH:3])=[O:2].O1C=CNC1=O.[OH-].[Na+].Cl>O>[CH3:24][O:23][C:22]1[C:4]2[C:1](=[O:3])[O:2][C:7]([C:11]([OH:10])=[O:12])=[CH:6][C:5]=2[CH:19]=[CH:20][CH:21]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 68143331oxazolone 4-(2-carboxy-3-methoxybenzylidene)-2-phenyl-5(4H)-oxazolone

Product 1

HCID 215047378-Methoxy-1-oxo-1H-2-benzopyran-3-carboxylic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A solution of the oxazolone of Example 4 (1.80 g., 5.57 mM) and 3.06 g. of sodium hydroxide in 15.2 ml. of water is refluxed under nitrogen for two hours. The resulting solution is cooled, acidified with concentrated hydrochloric acid, and refluxed for 0.5 hour. The solution is cooled and filtered to separate the precipitated solids. The dried solid is triturated with 2 ml. of cold methanol (to remove benzoic acid) and filtered to separate the product, m.p. 251°-253°. Recrystallization from 12 ml. of methanol (charcoal) gives 8-methoxy-1-oxo-1H-2-benzopyran-3-carboxylic acid as a white solid, m.p. 255°-256°.

Workup

  1. temperatureThe resulting solution is cooled
  2. temperaturerefluxed for 0.5 hour
  3. temperatureThe solution is cooled
  4. filtrationfiltered
  5. customto separate the precipitated solids
  6. customThe dried solid is triturated with 2 ml
  7. filtrationof cold methanol (to remove benzoic acid) and filtered
  8. customto separate the product, m.p. 251°-253°
  9. customRecrystallization from 12 ml

Sources & evidence

ORD record
ord-e556ece14cde4f71980d829a28c4c145
Source dataset
uspto-grants-1976_10
Patent number
US03987185

Reaction notes

Loading…