Isopropanol → 5,6-Dimethoxyquinazoline-2,4(1H,3H)-dione

HRID 980879Notes

Reaction equation

HRID 980879 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[C:7]([O:13][CH3:14])[C:3]=1[C:4]([OH:6])=O.[O-:15][C:16]#[N:17].[K+].[OH-].[Na+].C(O)(C)C>C(O)(=O)C.O>[CH3:14][O:13][C:7]1[C:8]([O:11][CH3:12])=[CH:9][CH:10]=[C:2]2[C:3]=1[C:4](=[O:6])[NH:17][C:16](=[O:15])[NH:1]2

Participants

7

Reactant 4

HCID 3776IsopropanolHCID 14798Sodium HydroxideHCID 11378442Potassium cyanateHCID 117455906-Amino-2,3-dimethoxybenzoic acid

Product 1

HCID 137720085,6-Dimethoxyquinazoline-2,4(1H,3H)-dioneYield 60.8%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Conditions

Temperature
60 °C

Procedure

2-Amino-5,6-dimethoxybenzoic acid (10.5 g, 53.2 mM) was dissolved in glacial acetic acid (100 ml) and potassium cyanate (10.8 g, 133.0 mM) in 120 ml H2O was added gradually and stirred for 2 hours at 60° C. After cooling the reaction mixture to 20° C., sodium hydroxide pellets (78.2 g, 196 mole) were added while maintaining the temperature below 60° C. The reaction mixture was then heated at 90° C. for 45 minutes. Upon cooling in an ice bath, the sodium salt of the product precipitated, was filtered resuspended in H2O (120 ml), acidified (pH 3) with concentrated HCl, cooled, and filtered to give the crude product. Trituration with warm isopropanol afforded (60.8%) of a white solid, mp 266°-268° C.

Workup

  1. temperatureAfter cooling the reaction mixture to 20° C.
  2. temperaturewhile maintaining the temperature below 60° C
  3. temperatureThe reaction mixture was then heated at 90° C. for 45 minutes
  4. temperatureUpon cooling in an ice bath
  5. customthe sodium salt of the product precipitated
  6. filtrationwas filtered
  7. temperaturecooled
  8. filtrationfiltered
  9. customto give the crude product

Sources & evidence

ORD record
ord-42a79d7e013e497183e1a0c228022ddd
Source dataset
uspto-grants-1987_01
Patent number
US04639518

Reaction notes

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