label: (3R,4S,5S,6R)-pentachlorocyclohexene = (3R,6R)-1,3,4,6-tetrachlorocyclohexa-1,4-diene + chloride + H(+)
label_lc: (3r,4s,5s,6r)-pentachlorocyclohexene = (3r,6r)-1,3,4,6-tetrachlorocyclohexa-1,4-diene + chloride + h(+)