تفاعل #1772829

معادلة التفاعل

3-benzoyloxy-4-fluorotoluene

NBS

→

3-benzoyloxy-4-fluorobenzyl bromide

المردود 58.2%

المذيبات

Et2O

water

carbon tetrachloride

ظروف التفاعل

المعالجة

1. 1
   أخرىCommercial N-bromosuccinimide (NBS) was recrystallised from water
2. 2
   أخرىthoroughly dried in vacuo (24 h)
3. 3
   أخرى(mp. 180-182° C., lit. 180-183° C.)
4. 4
   درجة الحرارةThe mixture heated
5. 5
   درجة الحرارةat reflux for 2 h
6. 6
   درجة الحرارةcooled
7. 7
   غسيلThe ethereal layer was washed with brine (20 mL)
8. 8
   تجفيفdried (Na2SO4)
9. 9
   أخرىConcetration in vacuo and subsequent purification by flash column chromatography [SiO2, EtOAc/n-hexane (1:25)]

الإجراء التجريبي

Commercial N-bromosuccinimide (NBS) was recrystallised from water and thoroughly dried in vacuo (24 h) prior to use (mp. 180-182° C., lit. 180-183° C.). To a solution of 3-benzoyloxy-4-fluorotoluene (2.47 g, 10 mmol) in anhydrous carbon tetrachloride (25 mL) was added finely powdered NBS (1.96 g, 11 mmol) and benzoylperoxide (0.01 g). The mixture heated at reflux for 2 h, cooled and diluted with Et2O (100 mL) and water (50 mL). The ethereal layer was washed with brine (20 mL) and dried (Na2SO4). Concetration in vacuo and subsequent purification by flash column chromatography [SiO2, EtOAc/n-hexane (1:25)] gave 3-benzoyloxy-4-fluorobenzyl bromide as a white solid (1.80 g, 58%); δH (400 MHz, CDCl3) 4.48 (s, 2H), 7.18 (dd, J=9.8, 8.6, 1H), 7.28 (ddd, J=8.6, 4.3, 2.3, 1H), 7.34 (dd, J=7.0, 2.3, 1H), 7.50-7.55 (m, 2H), 7.64-7.69 (m, 1H), 8.18-8.23 (m, 2H); LRMS (FAB+) m/z (rel. intensity) 229.1 (95), 309.0 (100, [M+H]+). Found: C, 54.1, H, 3.22; C14H10BrFO2 requires C, 54.39, H, 3.26%.

المصدر