Stedman's" meta" compound (11) was as unstable as physostigmine (I) in aqueous solution. This led Aeschlimann and Reinert3 to produce a more stable derivative, such as I11 which, though somewhat less toxic than 11, retained a high order of activity. Later, Stevens and Beute14 showed that the introduction of nuclear alkyl groups considerably increased the toxicity in mice of the comparatively inactive 4-dimethylaminophenol derivatives higher ...