Toluene → 5-Methyl-2h-thieno[2,3-d][1,3]oxazine-2,4(1h)-dione

HRID 2374744Notes

Reaction equation

HRID 2374744 reaction equation
[NH2:1][C:2]1[S:3][CH:4]=[C:5]([CH3:12])[C:6]=1[C:7]([O:9][CH2:10]C)=[O:8].[OH-].[Na+].C(Cl)(Cl)=[O:16].C1(C)C=CC=CC=1>CO>[CH3:12][C:5]1[C:6]2[C:7](=[O:8])[O:9][C:10](=[O:16])[NH:1][C:2]=2[S:3][CH:4]=1

Participants

6

Reactant 4

HCID 1140TolueneHCID 6371PhosgeneHCID 14798Sodium HydroxideHCID 521132Ethyl 2-amino-4-methylthiophene-3-carboxylate

Product 1

HCID 587883805-Methyl-2h-thieno[2,3-d][1,3]oxazine-2,4(1h)-dioneYield 59%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A mixture of ethyl 2-amino-4-methylthiophene-3-carboxylate (5 g, 0.03 mol) in methanol (25 ml) and aq. 2M sodium hydroxide (20.24 ml, 0.04 mol) was heated under reflux for 4 h. After cooling the solvents were evaporated, the residue dissolved in water (30 ml) and a 20% solution of phosgene in toluene (24 ml, 0.05 mol) added dropwise with ice cooling. After a further 30 min the solid which had precipitated was filtered, washed with water then ether, and dried to give the title compound 2.93 g (59%). 1H NMR (d6-DMSO) δ 2.31 (3H, s), 6.78 (1H, s), 12.50 (1H, br. s).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 4 h
  3. temperatureAfter cooling the solvents
  4. customwere evaporated
  5. dissolutionthe residue dissolved in water (30 ml)
  6. customAfter a further 30 min the solid which had precipitated
  7. filtrationwas filtered
  8. washwashed with water
  9. dry with materialether, and dried

Sources & evidence

ORD record
ord-c34ea20af2ba4381adfc8cc40c273ae1
Source dataset
uspto-grants-2008_12
Patent number
US07462620B2

Reaction notes

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