By GUSTAVE MICHAUD.
_Achras Sapota, L._, is a large tree scattered through the forests of
Central America and the West Indies; its fruit is often seen upon the
Creole dinner table. This fruit is a berry, the size of an orange, the
taste of which suggests the flavor of melon, as well as that of
hydrocyanic acid. The fruit contains one or two seeds like large
chestnuts, which, if broken, let fall a white almond. This last
contains the glucoside which I call _sapotin_.
I obtained sapotin for the first time by heating dry raspings of the
almond with 90 per cent. alcohol. While cooling, the filtered liquid
deposited a good deal of the compound. Since that time I have
advantageously modified the process and increased the amount of
product. I prepare sapotin in the following way: The almonds are
rasped, dried at 100° C. and washed with benzene, which takes away an
enormous quantity of fatty matter. The benzene which remains in the
almond is driven put first by compression, afterward by heating. Then
the raspings are exhausted with boiling 90 per cent. alcohol. The
solution is filtered as rapidly as possible, in order to avoid its
cooling and depositing the sapotin in the filter. As soon as the
temperature of the filtered liquid begins to fall, a voluminous
precipitate is seen to form, which is the sapotin.
In order to purify it, the precipitate is collected in a filter and
expressed between sheets of filter paper. When dry it is washed with
ether, which takes away the last particles of fatty and resinous
matter. The purification is completed by two crystallizations from 90
per cent. alcohol. At last the substance is dried at 100°.
The sapotin separates from its alcohol solution in the form of
microscopic crystals. When dry, it is a white, inodorous powder. Its
taste is extremely acrid and burning. If the powder penetrate into the
nostrils or the eyes, it produces a persistent burning sensation which
brings about sneezing and flow of tears. It melts at 240° C., growing
brown at the same time.
It has a laevo-rotatory power of [a]_{j} = -32.11, which was
determined with an alcoholic solution, the aqueous solution not being
sufficiently transparent.
It is very soluble in water, easily soluble in boiling alcohol, much
less in cold alcohol, and insoluble in ether, chloroform and benzene.
Its alcoholic solution is precipitated by ether.
Tannin has no action on it, but basic acetate of lead produces a
gelatinous precipitate in its aqueous solution. Strange enough, this
precipitate is entirely soluble in a small excess of basic acetate of
lead. If thrown into concentrated sulphuric acid, sapotin colors it
with a garnet red tint. It does not reduce Fehling's solution. Its
analysis gave the following results:
Calculated for Found.
C_{29}H_{52}O_{20}. I. II.
C 48.33 48.69 48.31
H 7.23 7.33 7.45
When heated with water and a little sulphuric acid, sapotin is
decomposed and yields glucose and an insoluble matter which I call
_sapotiretin_. One hundred parts of sapotin produce 51.58 parts of
glucose and 49.67 of sapotiretin. The equation which represents this
reaction is: