Sulfuric Acid → (E)-3-(4-bromo-2-fluoro-6-nitrophenyl)acrylaldehyde

Reaction equation

C([O:3][CH:4](OCC)/[CH:5]=[CH:6]/[C:7]1[C:12]([N+:13]([O-:15])=[O:14])=[CH:11][CH:10]=[CH:9][C:8]=1[F:16])C.[Br:20]N1C(C)(C)C(=O)N(Br)C1=O.S(=O)(=O)(O)O>>[Br:20][C:10]1[CH:11]=[C:12]([N+:13]([O-:15])=[O:14])[C:7](/[CH:6]=[CH:5]/[CH:4]=[O:3])=[C:8]([F:16])[CH:9]=1

Participants

Reactant 3

HCID 1118Sulfuric Acid

HCID 64791,3-Dibromo-5,5-dimethylhydantoin

HCID 68514002(E)-2-(3,3-diethoxyprop-1-enyl)-1-fluoro-3-nitrobenzene

Product 1

HCID 86647069(E)-3-(4-bromo-2-fluoro-6-nitrophenyl)acrylaldehydeYield 76.4%

Procedure

A mixture of (E)-2-(3,3-diethoxyprop-1-enyl)-1-fluoro-3-nitrobenzene (63.5 mg, 0.22 mmol), 1,3-dibromo-5,5-dimethylhydantoin (63.5 mg, 0.222 mmol, Aldrich) and sulfuric acid, 95% (0.5 mL, 7.14 mmol) was stirred at room temperature for 4 h. Ice (5 g) was added and the mixture was extracted with EtOAc (2×20 mL). The combined organic extracts were washed with saturated NaCl (6 mL) and dried over Na2SO4. The solution was filtered and concentrated in vacuo to give the crude material as a yellow oil. The crude product was purified by silica gel chromatography eluting with 20% EtOAc/hexanes to give (E)-3-(4-bromo-2-fluoro-6-nitrophenyl)acrylaldehyde (46 mg, 0.168 mmol, 39.3% yield). 1H NMR (300 MHz, CDCl3) δ 7.47-7.58 (m, 1H) 7.58-7.71 (m, 1H) 8.10 (d, J=8.33 Hz, 1H) 8.15 (s, 1H) 9.50 (s, 1H). m/z (ESI, +ve ion) 273 (M+H)+.