反应详情

A mixture of 400 ml absolute ethanol and 60 ml toluene was heated to reflux and 20 ml of azeotrope was removed via a Dean Stark trap. To the ethanol-toluene solution was added 33.0 g (0.2 mol) of 3-bromo-4-hydroxy-3-buten-2-one and reflux was continued for 2 hours during which period three aliquots of 20 ml of ethanol-toluene were removed via the trap. The solution was concentrated in vacuo to give 38.6 g (100%) of 3-bromo-4-ethoxy-3-buten-2-one as a mobile oil. nmr (DMSO-6) (δ): 8.21 (s, 1H); 4.23 (q, 2H); 2.33 (s, 3H); 1.31 (s, 3H).

1. temperaturewas heated
2. temperatureto reflux
3. custom20 ml of azeotrope was removed via a Dean Stark trap
4. temperaturereflux
5. customwere removed via the trap
6. concentrationThe solution was concentrated in vacuo