CH CNH₂ /\ /\ / \C/ \ CH | | | CH | | | CH | | | CH \ /C\ / \/ \/ CH CH
CH CH /\ /\ / \C/ \ CH | | | CNH₂ | | | CH | | | CH \ /C\ / \/ \/ CH CH
CH CH₂ /\ /\ / \C/ \ CH | | | CNH₃ | | | CH | | | CH₂ \ /C\ / \/ \/ CH CH₂
CH₂ CH /\ /\ / \C/ \ CH₂ | | | CNH₂ | | | CH₂ | | | CH \ /C\ / \/ \/ CH₂ CH
The acylic β tetrahydro-naphthylamine, the β tetrahydroethylnaphthylamine, and the β tetrahydromethylnaphthylamine all cause dilatation of the pupil and produce symptoms of excitation of the cervical sympathetic nerve; the other members of the group are inactive.
§ 24. The result of replacing hydrogen by alkyls in aromatic bodies has been studied by Schmiedeberg and others; replacing the hydrogen of the amidogen by ethyl or methyl, usually results in a body having a more or less pronounced narcotic action. The rule is that methyl is stronger than ethyl, but it does not always hold good; ortho-amido-phenol is not in itself poisonous, but when two hydrogens of the amidogen group are replaced by two methyls thus--
the resulting body has a weak narcotic action.
It would naturally be inferred that the replacement of the H in the hydroxyl by a third methyl would increase this narcotic action, but this is not so: on the other hand, if there are three ethyl groups in the same situation a decidedly narcotic body is produced.
The influence of position of an alkyl in the aromatic bodies is well shown in ortho-, para- and meta-derivatives. Thus the author proved some years ago that with regard to disinfecting properties, ortho-cresol was more powerful than meta-; meta-cresol more powerful than para-; so again ortho-aceto-toluid is poisonous, causing acute nephritis; meta-aceto-toluid has but feeble toxic actions but is useful as an antipyretic; and para-aceto-toluid is inactive.
In the trioxybenzenes, in which there are three hydroxyls, the toxic action is greater when the hydroxyls are consecutive, as in pyrogallol, than when they are symmetrical, as in phloroglucin.
The introduction of methyl into the complicated molecule of an alkaloid often gives curious results: thus methyl strychnine and methyl brucine instead of producing tetanus have an action on voluntary muscle like curare.
Benzoyl-ecgonine has no local anæsthetic action, but the introduction of methyl into the molecule endows it with a power of deadening the sensation of the skin locally; on the other hand, cocethyl produces no effect of this kind.