Preparation method of 1-aryl-1,2-dibromoethane
A technology of dibromoethane and aryl alkanes, which is applied in the field of organic chemical synthesis, can solve problems such as inability to recycle, increase synthesis steps, and limit the adaptability of reaction substrates, and achieve less environmental pollution, simplify synthesis processes, and reduce substrates. Effects with a wide range of applicability
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Embodiment 1
[0020] Example 1 The preparation of 1-phenyl-1,2-dibromoethane 3a, its synthetic route is as follows:
[0021]
[0022] Under nitrogen protection, ethylbenzene 1a (0.5 mmol), NBS (1.25 mmol) and DCE (2 mL) were added to the reaction tube. Stir at 100°C for 12 hours. After stopping the reaction, cool to room temperature, evaporate the solvent, and separate by column chromatography. The volume ratio (mL / mL) of the eluent used is ethyl acetate:petroleum ether=0:100~1:200 to obtain 1-phenyl- 1,2-Dibromoethane 3a, 73% yield.
[0023] 1-Phenyl-1,2-dibromoethane 3a: 1 H NMR (400 MHz, CDCl 3 ) δ 7.41-7.32 (m, 5H), 5.13 (dd, J = 10.6 Hz, 5.4Hz, 1H), 4.07 (dd, J = 10.3 Hz, 5.5Hz, 1H), 4.01(t, J = 10.5 Hz, 1H). 13 C NMR (100 MHz, CDCl 3 ) δ 138.7, 129.2, 128.9, 127.7, 50.9, 35.1.
Embodiment 2
[0024] Example 2 Preparation of 1-(4-chloro)phenyl-1,2-dibromoethane 3b, the synthetic route is as follows:
[0025]
[0026] Under nitrogen protection, 1-chloro-4-ethylbenzene 1b (0.5 mmol), NBS (1.0 mmol) and DCE (2 mL) were added to the reaction tube. Stir at 100°C for 12 hours. After stopping the reaction, cool to room temperature, evaporate the solvent to dryness, and separate by column chromatography. The volume ratio (mL / mL) of the eluent used is ethyl acetate:petroleum ether=0:100~1:200 to obtain 1-(4- Chloro)phenyl-1,2-dibromoethane 3b, the yield was 85%.
[0027] 1-(4-Chloro)phenyl-1,2-dibromoethane 3b: 1 H NMR (400 MHz, CDCl 3 ) δ 7.36-7.31 (m,4H), 5.09 (dd, J = 11.0Hz, 5.1Hz, 1H), 4.04 (dd, J = 10.3 Hz, 5.1Hz, 4H),3.95 (t, J = 5.44 Hz, 4H), 2.32 (s, 6H). 13 C NMR (100 MHz, CDCl 3 ) δ 137.2, 135.0, 129.2, 129.1, 49.6, 34.8.
Embodiment 3
[0028] Example 3 Preparation of 1-(4-bromo)phenyl-1,2-dibromoethane 3c, the synthesis route is as follows:
[0029]
[0030] Under nitrogen protection, 1-bromo-4-ethylbenzene 1c (0.5 mmol), NBS (1.25 mmol) and DCE (2 mL) were added to the reaction tube. Stir at 80°C for 48 hours. After stopping the reaction, cool to room temperature, evaporate the solvent to dryness, and separate by column chromatography. The volume ratio (mL / mL) of the eluent used is ethyl acetate:petroleum ether=0:100 ~ 1:200 to obtain 1-(4- Bromo)phenyl-1,2-dibromoethane 3c, 74% yield.
[0031] 1-(4-bromo)phenyl-1,2-dibromoethane 3c: 1 H NMR (400 MHz, CDCl 3 ) δ 7.52-7.49 (m,2H), 7.28-7.25 (m, 2H), 5.08 (dd, J = 11.0 Hz, 5.1Hz, 1H), 4.05 (dd, J =10.3, 5.1 Hz, 1H), 3.95 (t , J = 10.8 Hz, 4H). 13 C NMR (100 MHz, CDCl 3 ) δ 137.7, 132.1, 129.4, 123.2, 49.7, 34.7.
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