2-Methylbenzenesulfonic acid hydrate → 2-(3-Nitro-4-methoxyphenyl)-5-bromobenzoxazole

HRID 722493Notes

Reaction equation

HRID 722493 reaction equation
O[C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][C:3]=1[NH:9][C:10](=[O:22])[C:11]1[CH:16]=[CH:15][C:14]([O:17][CH3:18])=[C:13]([N+:19]([O-:21])=[O:20])[CH:12]=1.O.C1(C)C(S(O)(=O)=O)=CC=CC=1>C1(C)C=CC=CC=1>[N+:19]([C:13]1[CH:12]=[C:11]([C:10]2[O:22][C:2]3[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][C:3]=3[N:9]=2)[CH:16]=[CH:15][C:14]=1[O:17][CH3:18])([O-:21])=[O:20]

Participants

4

Reactant 2

HCID 124969952-Methylbenzenesulfonic acid hydrateHCID 21884460HCID 21884460, compound

Product 1

HCID 218843422-(3-Nitro-4-methoxyphenyl)-5-bromobenzoxazoleYield 93%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A suspension of N-(2-hydroxy-5-bromophenyl)-3-nitro-4-methoxybenzamide (5.24 g, 14.2 mmol) and toluenesulfonic acid monohydrate (5.36 g, 31.2 mmol) in toluene (100 ml) was heated to reflux overnight. The cooled reaction mixture was washed with saturated sodium hydrogen carbonate solution (care foaming) and the organic layer separated. The aqueous layer was extracted with ethyl acetate (2×50 ml) and the combined organic layers dried over sodium sulfate and the solvent removed under reduced pressure. The residue was triturated with ether, filtered and dried under vacuum to give the subtitle compound as a pale pink solid (4.51 g, 93%). 1H NMR (DMSO) δ 8.61(d, 1H), 8.42(dd, 1H), 8.05(d, 1H), 7.79(d, 1H), 7.61(m, 2H), 4.05(s, 3H). MS m/z 349.0 (M+H)+.

Workup

  1. temperaturewas heated
  2. temperatureto reflux overnight
  3. customThe cooled reaction mixture
  4. washwas washed with saturated sodium hydrogen carbonate solution (care foaming)
  5. customthe organic layer separated
  6. extractionThe aqueous layer was extracted with ethyl acetate (2×50 ml)
  7. dry with materialthe combined organic layers dried over sodium sulfate
  8. customthe solvent removed under reduced pressure
  9. customThe residue was triturated with ether
  10. filtrationfiltered
  11. customdried under vacuum

Sources & evidence

ORD record
ord-378a89e407b545b398f7b06dbc222db3
Source dataset
uspto-grants-2006_11
Patent number
US07138425B2

Reaction notes

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