6-bromo-8-chloro-2,3-dihydrochromen-4-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To the amalgam of zinc--prepared from 1280 g (19.7 gram-atoms) of zinc, 128 g (5.4×10-1M) of mercurous chloride, 64 cm3 of concentrated hydrochloric acid and 1900 cm3 of water--are added, in order, 1000 cm3 water, 1500 cm3 of concentrated hydrochloric acid, 3500 cm3 of toluene and 640 g (2.45M) of 6-bromo-8-chloro-4-chromanone (III2). The mixture is refluxed for 1 hour and, after cooling and decantation, it is extracted with ether and washed in water up to neutrality. 305 g (yield=50%) of expected product are thus isolated. The mixture is refluxed for 1 hour after cooling decantation, it is extracted with ether washed in water up to neutrality

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To the amalgam of zinc--prepared from 1280 g (19.7 gram-atoms) of zinc, 128 g (5.4×10-1M) of mercurous chloride, 64 cm3 of concentrated hydrochloric acid and 1900 cm3 of water--are added, in order, 1000 cm3 water, 1500 cm3 of concentrated hydrochloric acid, 3500 cm3 of toluene and 640 g (2.45 M) of 6-bromo-8-chloro-4-chromanone (III2). The mixture is refluxed for 1 hour and, after cooling and decantation, it is extracted with ether and washed in water up to neutrality. 305 g (yield=50%) of expected product are thus isolated. B.p.0.01 =128° C. The mixture is refluxed for 1 hour after cooling decantation, it is extracted with ether washed in water up to neutrality