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N-Methylconiine

N-Methylconiine is a poisonous alkaloid found in poison hemlock in small quantities.

Isolation and properties

The -(+)-stereoisomer of N-methylconiine is reported to occur in hemlock in small quantities, and methods for its isolation are described by Wolffenstein and by von Braun. It is a colourless, oily, coniine-like liquid, specific rotation [α]<sub>D</sub> +81.33° at 24.3&nbsp;°C. The salts are crystalline ("B" marks one molecule of the base): the hydrochloride, B•HCl, forms masses of needles, mp. 188&nbsp;°C; the platinichloride, B<sub>2</sub>•H<sub>2</sub>PtCl<sub>6</sub>, has mp. 158&nbsp;°C.

The -(−)-stereoisomer was obtained by Ahrens from residues left in the isolation of coniine as hydrobromide or by removing coniine as the nitroso-compound. It is a colourless, coniine-like liquid, bp. 175.6&nbsp;°C/767 mmHg, specific rotation [α]<sub>D</sub> −81.92° at 20&nbsp;°C. The monohydrochloride crystallises in leaflets, mp. 191–192&nbsp;°C; the monohydrobromide in leaflets, mp. 189–190&nbsp;°C; the platinichloride in orange crystals, mp. 153–154&nbsp;°C; the aurichloride in leaflets, mp. 77–78&nbsp;°C; and the picrate in long needles, mp. 121–122&nbsp;°C.

Synthesis

N-Methyl--coniine was prepared by the action of potassium methyl sulfate on coniine by Passon. Hess and Eichel have shown that -coniine with formaldehyde and formic acid yields an active N-methyl--coniine, and that methyl-isopelletierine hydrazone yields N-methyl--coniine when heated with sodium ethoxide at 150–170&nbsp;°C.

References