Phosphorus oxychloride → 2-(3-Bromophenyl)-4-(chloromethyl)-5-methyl-1,3-oxazole

HRID 348272Notes

Reaction equation

HRID 348272 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([C:8]2[O:9][C:10]([CH3:15])=[C:11]([CH3:14])[N+:12]=2[O-])[CH:5]=[CH:6][CH:7]=1.P(Cl)(Cl)([Cl:18])=O>C(Cl)(Cl)Cl>[Br:1][C:2]1[CH:3]=[C:4]([C:8]2[O:9][C:10]([CH3:15])=[C:11]([CH2:14][Cl:18])[N:12]=2)[CH:5]=[CH:6][CH:7]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 40877752-(3-Bromophenyl)-4,5-dimethyloxazole-3-oxide

Product 1

HCID 40879032-(3-Bromophenyl)-4-(chloromethyl)-5-methyl-1,3-oxazoleYield 72%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

A solution of 2-(3-bromophenyl)-4,5-dimethyloxazole-3-oxide (96.6 g, 0.36 mol) in CHCl3 (0.90 L) was treated dropwise with phosphorous oxychloride (61.1 g, 0.40 mol) allowing the reaction to exotherm and then stirred at reflux for 30 min. The reaction was then cooled to room temperature and washed with water (2×1 L). The combined aqueous washes were back extracted with CH2Cl2 (2×400 mL). The organic layers were dried (MgSO4), and the solvent removed in vacuo to give crude product that was recrystallized from hot hexanes (300 mL), decanting the hot supernate away from a dark oily material. The remaining dark oil was agitated in additional hot hexanes (200 mL) and the combined supernates were cooled to 0° C. to crystallize the product which was isolated by filtration to give 74.2 g (72%) of 2-(3-bromophenyl)-4-(chloromethyl)-5-methyloxazole as a lime-green powder.

Workup

  1. customthe reaction
  2. temperatureat reflux for 30 min
  3. washwashed with water (2×1 L)
  4. extractionThe combined aqueous washes were back extracted with CH2Cl2 (2×400 mL)
  5. dry with materialThe organic layers were dried (MgSO4)
  6. customthe solvent removed in vacuo
  7. customto give crude product that
  8. customwas recrystallized from hot hexanes (300 mL)
  9. customdecanting the hot supernate away from a dark oily material
  10. stirringThe remaining dark oil was agitated in additional hot hexanes (200 mL)
  11. temperaturethe combined supernates were cooled to 0° C.
  12. customto crystallize the product which
  13. customwas isolated by filtration

Sources & evidence

ORD record
ord-6edf0e42f05b4d04a6bc5212d9706a85
Source dataset
uspto-grants-2007_02
Patent number
US07176224B2

Reaction notes

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