Next substitution was tried in the Imid group. It was found that substituting ethyl for H in the imid group annihilated the narcotic and antipyretic properties. No methæmoglobin could be recognised in the blood.
Lastly, simultaneous substitution of the H of the HO group by ethyl and the substitution of an alkyl for the H in the NH group gave the following results:—
Methyl.—In dogs the narcotic action was strengthened, the methæmoglobin in the blood diminished. In men the narcotic action was also more marked as well as the anti-neural action. The stomach and kidneys were also stimulated.
Ethyl.—In dogs the narcotic action was much strengthened, while the methæmoglobin was diminished. In men the antipyretic and anti-neural actions were unaffected.
Propyl.—In dogs the narcotic action was feebler than with methyl or ethyl, and in men there was diminished antipyretic action.
Amyl.—In dogs the narcotic action was much smaller.
From this latter series the conclusion is drawn that the maximum of narcotic action is obtained by the introduction of methyl and the maximum antipyretic action by the introduction of methyl or ethyl. The ethyl substitution is, as before, the less toxic.[36]
[36] Ueber die physiologische Wirkung des p-amido-phenol u. einiger Derivate desselben. O. Hinsberg u. G. Treupel, Archiv f. Exp. Pathol. u. Pharm., B. 33, S. 216.