Hinsberg and Treupel have studied the physiological effect of substituting various alkyls for the hydrogen of the hydroxyl group in para-acetamido-phenol.
Para-aceto-amido-phenol when given to dogs in doses of 0.5 grm. for every kilogr. of body weight causes slight narcotic symptoms, with slight paralysis; there is cyanosis and in the blood much methæmoglobin.
In men doses of half a gramme (7·7 grains) act as an antipyretic, relieve neuralgia and have weak narcotic effects.
The following is the result of substituting certain alkyls for H in the HO group.
(1) Methyl.—The narcotic action is strengthened and the antipyretic action unaffected. The methæmoglobin in the blood is somewhat less.
(2) Ethyl.—Action very similar, but much less methæmoglobin is produced.
(3) Propyl.—Antipyretic action a little weaker. Methæmoglobin in the blood smaller than in para-acetamido-phenol, but more than when the methyl or ethyl compound is administered.
(4) Amyl.—Antipyretic action decreased.
The smallest amount of toxicity is in the ethyl substitution; while the maximum antipyretic and antineuralgic action belongs to the methyl substitution.