Hexamethylenetetramine → 3-Methyl-2-oxo-2,3-dihydro-1,3-benzoxazole-6-carbaldehyde

HRID 723505Notes

Reaction equation

HRID 723505 reaction equation
[CH3:1][N:2]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[O:4][C:3]1=[O:11].C1N2CN3CN(C2)CN1C3.FC(F)(F)[C:24](O)=[O:25]>>[CH3:1][N:2]1[C:6]2[CH:7]=[CH:8][C:9]([CH:24]=[O:25])=[CH:10][C:5]=2[O:4][C:3]1=[O:11]

Participants

4

Reactant 3

HCID 4101HexamethylenetetramineHCID 6422Trifluoroacetic acidHCID 308462-Benzoxazolinone, 3-methyl-

Product 1

HCID 30429773-Methyl-2-oxo-2,3-dihydro-1,3-benzoxazole-6-carbaldehydeYield 45%

Procedure

3-Methyl-3H-benzooxazol-2-one (2.00 g, 13.42 mmol) and hexamethylenetetramine (3.76 g, 26.84 mmol) were dissolved in trifluoroacetic acid (20 mL) and heated at reflux for 20 hours. The volatiles were removed in vacuo and the residue was treated with ice water (60 mL). The resultant mixture was stirred for 30 minutes and then made basic with sodium carbonate. The solid was isolated by filtration and washed with water then dried under vacuum. The solid was purified by column chromatography on silica gel eluting with an ethyl acetate and hexane solvent gradient. This provided the desired product as a white solid (1.07 g, 45%).

Workup

  1. temperatureheated
  2. temperatureat reflux for 20 hours
  3. customThe volatiles were removed in vacuo
  4. additionthe residue was treated with ice water (60 mL)
  5. customThe solid was isolated by filtration
  6. washwashed with water
  7. customthen dried under vacuum
  8. customThe solid was purified by column chromatography on silica gel eluting with an ethyl acetate and hexane solvent gradient

Sources & evidence

ORD record
ord-4cc041da96e54f1f813e23eb7f052c26
Source dataset
uspto-grants-2006_11
Patent number
US07141564B2

Reaction notes

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