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

HRID 398098Notes

Reaction equation

HRID 398098 reaction equation
[CH3:1][C:2](=[N:6][OH:7])[C:3](=[O:5])[CH3:4].[Br:8][C:9]1[CH:16]=[CH:15][C:12]([CH:13]=O)=[CH:11][CH:10]=1>C(O)(=O)C>[CH3:1][C:2]1[N+:6]([O-:7])=[C:13]([C:12]2[CH:15]=[CH:16][C:9]([Br:8])=[CH:10][CH:11]=2)[O:5][C:3]=1[CH3:4]

Participants

4

Reactant 2

HCID 707414-BromobenzaldehydeHCID 63989692-Oxime 2,3-butanedione

Product 1

HCID 109015972-(4-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 4-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 conc. 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 4,5-dimethyl-2-(4-bromophenyl)-oxazole oxide as a white solid. The compound should be used directly within 24-48 h: 1H NMR (500 MHz, CDCl3) 8.34 (d, J=9.0 Hz, 2H), 7.61 (d, J=9.0 Hz, 2H), 2.35 (s, 3H), 2.20 (s, 3H); 13C (125 MHz, CDCl3) 142.1, 131.9, 129.5, 126.3, 124.1, 122.2, 11.1, 6.2; IR (KBr) 1685, 1529, 1418, 1377, 1233, 1165 cm−1; UV (EtOH) max307 nm (24371); HRMS (TOF) m/z calculated for C11H1179BrNO2: 267.997, found 267.9951.

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. additionconc. 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-729042dd78634d179e3b1eb1fda4d858
Source dataset
uspto-grants-2003_08
Patent number
US06610696B2

Reaction notes

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