N-Methylconiine

N-Methylconiine
IUPAC name 1-Methyl-2-propylpiperidine
Properties
Molecular formula	C9H19N
Molar mass	141.25 g mol−1
Density	(D) 0.8318 g cm-3 at 24.3 °C (L) 0.8349 g cm-3 at 20 °C
Boiling point	173-174 °C, 446-447 K, 343-345 °F
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Infobox references

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

Isolation and properties

The D-(+)-stereoisomer of N-methylconiine is reported to occur in hemlock in small quantities,^[1] and methods for its isolation are described by Wolffenstein^[2] and by von Braun.^[3] It is a colourless, oily, coniine-like liquid, specific rotation [α]_D +81.33° at 24.3 °C. The salts are crystalline ("B" marks one molecule of the base): the hydrochloride, B•HCl, forms masses of needles, mp. 188 °C; the platinichloride, B₂•H₂PtCl₆, has mp. 158 °C.

The L-(-)-stereoisomer was obtained by Ahrens^[4] 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 °C/767 mmHg, specific rotation [α]_D -81.92° at 20 °C. The monohydrochloride crystallises in leaflets, mp. 191-2 °C; the monohydrobromide in leaflets, mp. 189-190 °C; the platinichloride in orange crystals, mp. 153-4 °C; the aurichloride in leaflets, mp. 77-8 °C; and the picrate in long needles, mp. 121-2 °C.

Synthesis

N-Methyl-D-coniine was prepared by the action of potassium methyl sulfate on coniine by Passon.^[5] Hess and Eichel^[6] have shown that D-coniine with formaldehyde and formic acid yields an active N-methyl-D-coniine, and that methyl-isopelletierine hydrazone yields N-methyl-DL-coniine when heated with sodium ethoxide at 150-70 °C.

References

1. ^ Planta and Kekulé, Annalen, 1854, 89, 150.
2. ^ Ber., 1894, 27, 2615; 1895, 28, 302
3. ^ Ber., 1905, 38, 3108; 1917, 50, 1477.
4. ^ Ber., 1902, 35, 1330; cf. Löffler and Friedrich, ibid., 1909, 42, 107.
5. ^ Ber., 1891, 24, 1678.
6. ^ Ber., 1917, 50, 1386; 1919, 52, 1622; 1920, 53, 129.