反应详情

To ice cold sulphuric acid (360 mL) was added fuming nitric acid (180 mL). 5-bromo-2-nitrobenzaldehyde (60 g, 0.26 mol) was added to the solution within 15 min. The reaction mixture was stirred for 10 minutes at the same temperature then at RT for 30 min, at 45° C. for 2 h and finally at 50° C. for 3 h, at which time TLC showed complete reaction. The reaction mixture was poured into ice water and extracted with chloroform to give a mixture of products which was separated by flash column chromatography eluting with PE/EtOAc (20/1 to 3/1). The desired 5-bromo-2,4-dinitrobenzaldehyde was isolated as white solid (6.5 g, 9%). 1H-NMR (CDCl3, 400 MHz) δ 10.48 (s, 1H), 8.61 (s, 1H), 8.30 (s, 1H). MS (M+H)+: 275/277.

1. waitat RT for 30 min
2. waitat 45° C. for 2 h
3. waitfinally at 50° C. for 3 h
4. customreaction
5. extractionextracted with chloroform
6. customto give
7. additiona mixture of products which
8. customwas separated by flash column chromatography
9. washeluting with PE/EtOAc (20/1 to 3/1)