Fig. 4
Likely origin of the two different 543.7 MW (nominal MW 541) bromethalin breakdown products as dehydrofluorodesmethylbromethalin structures of formula C13H4N3O4F2Br3. The compounds have been given common names of dehydrofluorodesmethylbromethalin-I and –II, which would be 6-(difluoromethylene)-2,4-dinitro-N-(2,4,6-tribromophenyl)cyclohexa-2,4-dien-1-imine and 8,8-difluoro-3,5-dinitro-(2,4,6-tribromophenyl)-7-azabicyclo[4.2.0]octa-1,3,5-triene, respectively. Dehydrofluorobromethalin (3,3-difluoro-5,7-dinitro-1-(2,4,6-tribromophenyl)indoline) was not seen and its absence is significant in light of the apparent lack of formation of a five member ring in deference to a more constrained four member ring