反应详情

Wash 60% mineral oil suspended sodium hydride (1.2 equiv; 1.1 g, 27.52 mmoles) with a small amount of iso-hexane (×2). Suspend in N,N-dimethylacetamide (15 mL) and chill in an ice-bath. Add ethyl 4-bromo-1H-pyrrole-2-carboxylate (5.0 g, 22.93 mmoles) portionwise over 15 minutes allowing gas evolution to subside between additions. Stir at room temperature for 15 minutes to give a brown solution. Add 2-(bromomethyl)-4-chloro-1-nitro-benzene (1.15 equiv; 6.61 g, 26.37 mmoles) in portions over 15 minutes and stir the resulting purple solution at room temperature for 2.5 h. Cool in an ice-bath and quench with water (10 mL). Partition between 1M hydrochloric acid (100 mL) and EtOAc (300 mL). Wash the organic layer with water (2×100 mL) then brine. Dry over Na2SO4 and decolorize with activated charcoal. Filter through celite and evaporate to give ethyl 4-bromo-1-(5-chloro-2-nitrobenzyl)-1H-pyrrole-2-carboxylate as a an orange oil (9.1 g, quantitative). 1H-NMR (CDCl3) δ: 8.12 (1H, d), 7.40 (1H, dd), 7.07 (1H, d), 6.92 (1H, d), 6.53 (1H, d), 5.87 (2H, s), 4.17 (2H, q), 1.25 (3H, t).

1. washWash 60% mineral oil
2. temperaturechill in an ice-bath
3. customto give a brown solution
4. stirringstir the resulting purple solution at room temperature for 2.5 h
5. temperatureCool in an ice-bath
6. customquench with water (10 mL)
7. customPartition between 1M hydrochloric acid (100 mL) and EtOAc (300 mL)
8. washWash the organic layer with water (2×100 mL)
9. dry with materialDry over Na2SO4
10. filtrationFilter through celite
11. customevaporate