1. The alkaloidal content of the Australian drug,
Duboisia myoporoides, has been examined.
Despite the claims of most of the earlier
workers, no trace of hyoscyamine has been
isolable from any of a large number of samples.
In addition to hyoscine, four new alkaloids
have been found: tigloidine (0.1%), valeroidine
(0.1%), poroidine, and isoporoidine, the last
two being isolated as a difficultly- separable
mixture, Base Z (0.003 %), at first thought to be
a single substance.
2. Tigloidine, C₁₃H₂₁O₂N, a syrup, has been shown
to be tiglyl-ψ-tropëine, and has been
synthesised, as has its geometric isomer,
tiglyltropëine. Both these alkaloids are
remarkable in possessing hydrobromides which
are readily soluble in chloroform, and which
can be extracted from aqueous solution by this
solvent. Catalytic reduction of them has
yielded respectively dl-α-methylbutyryl-ψ-tropëine, and dl-α-methylbutyryltropëine.
The hydrobromides of acetyltropëine and
acetyl-ψ-tropëine have also been prepared;
they are shown to be useful in the identification of tropine and ψ-tropine respectively.
3. Valeroidine, C₁₃H₂₃O₃N, m.p. 85°, [α]²⁰°D -9.0°
has been shown to be the monoisovaleryl ester
of a dihydroxytropane previously isolated as
the dibenzoyl ester by Wolfes and Hromatka
(Merck's Jahresber, 1933, 47, 45) from
Peruvian coca leaves. The hydrobromide is
readily soluble in chloroform, but unlike that
of tigloidine, is not extracted from water by
this solvent. An attempt has been made to
determine the positions of substitution of
the hydroxyl groups in the tropane molecule.
In the course of this work it has been found
that under certain conditions thionyl chloride
possesses the remarkable property of demethylating the N-methyl group in valeroidine with
production of the secondary base, norvaleroidine,
C₁₃H₂₁O₃N. While very stable to oxidation,
valeroidine when treated with potassium
permanganate in acetone yielded a neutral
product, C₁₃H₂₁O₄N which on subsequent treatment with alcoholic hydrochloric acid also
gave norvaleroidine. It is hoped to pursue this
work.
4. Base Z, C₁₂H₂₁O₂N, a syrup, [α]²⁰°D +2.5° has been
shown to be a mixture of about ten parts of
poroidine (isovalerylnortropëine) with one part of
isoporoidine (d-α-methylbutyrylnortropëine),
and has been indirectly racemised. The former
constituent was separated by an indirect method,
and both have been synthesised; their mixture
in the above ratio was shown to be similar to
base Z. A probable derivation of these bases
from leucine and isoleucine respectively is
suggested. Tiglylnortropëine, C₁₂H₁₉O₂N,
has also been synthesised. The hydrobromides
of the above three alkaloids are readily
soluble in chloroform, which solvent also
extracts them from aqueous solution. The
p-phenylphenacyl esters of the butyric and
valeric acids are described. A method for
the recovery of acid and alcohol from such
esters is also given.
