Methane → 1'-[4-Bromo-2-fluorobenzyl]-7'-chloro-spiro[imidazolidine-4,3'-indoline]-2,2',5-trione

Participants

Reaction Steps

A stirred suspension of 1-(4-bromo-2-fluorobenzyl)-7-chloro-indoline-2,3-dione (96 g.) in ethanol (1500 ml.) was treated with a solution of potassium cyanide (21.0 g.) and ammonium carbonate (300 g.) in water (1500 ml.). The mixture was stirred at 45°-50° C. for 4 hours. Activated charcoal (50 g.) was added and the mixture was stirred for a further hour at 45°-50° C. The hot mixture was filtered through diatomaceous earth and the filter cake was washed with aqueous ethanol (2×200 ml.; 1:1 v/v) at 60° C. The cooled filtrate was made acid to pH 4 at 0°-5° C. with 10M hydrochloric acid and the precipitated solid was collected by filtration, washed with water and dried. Recrystallisation twice from 1:1 v/v ethyl acetate/petroleum ether, b.p. 60°-80° C. gave (±)-1'-(4-bromo-2-fluoro-benzyl)-7'-chloro-spiro-(imidazolidine-4,3'-indoline)2,2',5-trione (60 g.) m.p. 240°-242° C.

Provenance & Evidence