Water → 6-(Benzyloxy)-8-(bromoacetyl)-2H-1,4-benzoxazin-3(4H)-one

Participants

Reaction Conditions

Reaction Steps

12.00 kg (40.36 mol) 8-acetyl-6-(phenylmethoxy)-2H-1,4-benzoxazin-3(4H)-one 3a are dissolved in 108 l 1,4-dioxane. Then a solution of 24.33 kg (50.45 mol) tetrabutylammonium tribromide in 48 l of 1,4-dioxane and 12 l methanol is metered into the suspension at 20° C. The reactor contents are stirred for 2 hours at 20° C. Then 72 l water are added at 20° C. within 15 minutes. After cooling to 3° C. the mixture is stirred for 1 hour, centrifuged and washed with a mixture of 9 l of 1,4-dioxane and 4.5 l water. Then it is washed with 60 l water and dried in vacuo at 50° C.

Provenance & Evidence