3-Bromobenzaldehyde → 2-(3-Bromophenyl)-4,5-dimethyloxazole-3-oxide

HRID 398107Notes

Reaction equation

HRID 398107 reaction equation
[CH3:1][C:2](=[N:6][OH:7])[C:3](=[O:5])[CH3:4].[Br:8][C:9]1[CH:10]=[C:11]([CH:14]=[CH:15][CH:16]=1)[CH:12]=O>C(O)(=O)C>[Br:8][C:9]1[CH:10]=[C:11]([C:12]2[O:5][C:3]([CH3:4])=[C:2]([CH3:1])[N+:6]=2[O-:7])[CH:14]=[CH:15][CH:16]=1

Participants

4

Reactant 2

HCID 765833-BromobenzaldehydeHCID 63989692-Oxime 2,3-butanedione

Product 1

HCID 40877752-(3-Bromophenyl)-4,5-dimethyloxazole-3-oxideYield 74.1%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of 2,3-butanedione monooxime (50 g, 0.49 mol) and 3-bromobenzaldehyde (101 g, 0.54 mol) in acetic acid (500 mL) was cooled to 0° C. and then gaseous HCl was bubbled through the solution for 35 min while the reaction was stirred in an ice bath. Diethyl ether (500 mL) was then added to the reaction to precipitate the product and the resultant slurry stirred 45 min at 0° C. before being filtered. The solids were rinsed with Et2O (50 mL), taken up in water (1 L) and concentrated NH4OH (60 mL) added to the slurry. This mixture was extracted with CHCl3, the organic layer was dried (MgSO4), and the solvent removed in vacuo to give 97.4 g (74%) of 2-(3-bromophenyl)-4,5-dimethyloxazole-3-oxide as a white solid. The compound should be used directly with 24-48 h. 1H NMR (300 MHz, CDCl3) δ8.60 (s, 1H), 8.40 (d, J=8.0 Hz, 1H), 7.55 (d, J=8.0 Hz, 1H), 7.38 (d, J =8.0 Hz, 1H), 2.39 (s, 3H), 2.20 (s, 3H).

Workup

  1. customgaseous HCl was bubbled through the solution for 35 min while the reaction
  2. additionDiethyl ether (500 mL) was then added to the reaction
  3. customto precipitate the product
  4. stirringthe resultant slurry stirred 45 min at 0° C.
  5. filtrationbefore being filtered
  6. washThe solids were rinsed with Et2O (50 mL)
  7. additionconcentrated NH4OH (60 mL) added to the slurry
  8. extractionThis mixture was extracted with CHCl3
  9. dry with materialthe organic layer was dried (MgSO4)
  10. customthe solvent removed in vacuo

Sources & evidence

ORD record
ord-1b3dc9fc2ab64e14a2f071aeeb42f541
Source dataset
uspto-grants-2003_08
Patent number
US06610696B2

Reaction notes

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