反应详情

A mixture of 8 mL of concentrated H2SO4, 12 mL of water, 3-iodo-4-methylaniline (5.00 g, 21.5 mmol) and 20 g of ice was stirred under ice-bath cooling until a paste resulted. To this paste was added slowly an ice-cold solution of NaNO2 (1.55 g, 22.4 mmol) in 3.5 mL of water and the resulting mixture stirred for 20 minutes while maintaining the temperature at <5° C. The resulting suspension was slowly added to a mixture of 26 mL of concentrated H2SO4 and 24 mL of water preheated to 80° C. This mixture was stirred at 80° C. for 15 min, then chilled in an ice-bath and poured onto 200 g of ice. The resulting mixture was extracted with 100 mL of EtOAc, and the organic extract washed with water, brine, dried (MgSO4) and evaporated to give a residue. The residue was adsorbed onto 15 g of SiO2 from CH2Cl2, loaded into a precolumn and subjected to MPLC through a 120 g column of SiO2 eluting with 5% EtOAc in hexanes (10 min) and then 10% EtOAc (20 min) to provide 3-iodo-4-methylphenol 1-1 as an oil. 1H NMR (300 MHz, DMSO-d6): δ 2.25 (s, 3H), 6.71 (dd, 1H, J=8, 2 Hz), 7.11 (d, 1H, J=8 Hz), 7.23 (d, 1H, J=2 Hz), 9.51 (s, 1H); LC-MS: calculated for C7H7IO 234.0, observed m/e 234.6 (M+H)+.

1. temperaturecooling until a paste
2. customresulted
3. stirringthe resulting mixture stirred for 20 minutes
4. temperaturewhile maintaining the temperature at <5° C
5. custompreheated to 80° C
6. stirringThis mixture was stirred at 80° C. for 15 min
7. temperaturechilled in an ice-bath
8. extractionThe resulting mixture was extracted with 100 mL of EtOAc
9. extractionthe organic extract
10. washwashed with water, brine
11. dry with materialdried (MgSO4)
12. customevaporated
13. customto give a residue