Page 68 - Phytochemistry 2 (06-PG 605)
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Hyoscyamine
It has the same structure as atropine but differs in having an
optically active l-tropic acid moiety.
Occurrence
It occurs in Atropa belladona, Datura and Hyoscyamus species.
Properties
It is the most common tropane alkaloid. The major source is
Hyoscyamus muticus, (indigenous to Egypt). It is laevorotatory,
(due to the optically active tropic acid moiety). Hyoscyamine is
crystalline solid, occurs in silky needles, m.p. 108-111 oC; very
soluble in ethanol (1:3), chloroform (1:2), less soluble in ether and
benzene. Hyoscyamine is readily racemized by alcoholic potash to
give atropine. Racemization is brought about even when
hyoscyamine is heated under vacuum or boiled in chloroform.
Hyoscyamine is hydrolyzed by dil. alkali or dil. acids to yield tropic
acid and tropine base. Hyoscyamine sulphate crystallizes from
ethanol in needles. It is very soluble in water.
Uses
As atropine but more active.
Hyoscine (Scopolamine)
Me
N OH
O
H
H
O
O
l (-)- Hyoscine (Scopolamine)
- ٦۷ -
