Narcotine, another of the opium alkaloids, when heated with manganese dioxide and sulphuric acid, is oxidized and splits apart into opianic acid, C{10}H{10}O{5}, and cotarnine, C{12}H{13}NO{3}.

In this case, instead of opianic acid, its reduction product meconine, C{10}H{10}O{4}, is produced.