1
64
C. Husson et al./Carbohydrate Research 307 (1998) 163±165
mixture of inositols was precipitated by ethanol
Much work has been done on equilibration of
ꢀ
1
diastereoisomers of sugars [11] or cyclitols [6,12] by
Raney nickel in water or deuterium oxide. The
mechanism of this equilibration is not yet com-
pletely understood but it is clear however that ther-
modynamically stable diastereoisomers are favored
in the resulting mixture provided that equilibrium
has been reached [13].
addition at 80 C. The H NMR spectrum
(Fig. 1(a)) of the crude product revealed 20±30%
(depending on experiment) of scyllo-inositol as well
as unreacted myo-inositol. The total recovered
crude material was 16 g.
In the second step the crude product obtained
was dissolved in anhydrous DMF (100 mL) and
stirred with triethylorthoacetate (60 mL) in the
presence of toluene-p-sulfonic acid as catalyst (2 g)
ꢀ
1
. Experimental
for 18 h at 100 C, then cooled to room tempera-
ture and neutralized by aqueous ammonia. After
concentration to dryness the residue was dissolved
in the minimum of hot water and left at room
temperature for crystallization. After about a
week the white crystalline mass (4 g) in the bottom
of the ¯ask was ®ltered o. It represents 80% of
the scyllo-inositol present in the crude product;
In the ®rst step myo-inositol (20 g, 111 mmol)
was dissolved in distilled water (250 mL) and
re¯uxed with Raney nickel (30 g) (Fluka 83440).
The solution was approximately at pH 10. After
4 h the reaction medium was ®ltered and the clear
ltrate was concentrated to 10% by volume. The
2
®
ꢀ
1
mp 352 C (litt [14]. 348.5±350); H NMR (Fig. 1b)
200 MHz, ꢀ ppm: 3.34 (s, 6H), 4.80 (s, HOD).
The myo-inositol derivative was separated by
column chromatography on silica gel [15] and re-
used for further syntheses.
Acknowledgement
We thank Professor S. J. Angyal for his interest
in our work.
References
[1] A.J. Kluyver and A.G.J. Boezaardt, Rec. Trav.
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[2] Th. Posternak, Helv. Chim. Acta, 24 (1941) 1045±
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058.
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[
3] D. Reymond, Helv. Chim. Acta, 40 (1957) 492±494.
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3
5] M. Nakajima, I. Tomida, N. Kuirihara, and S.
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682±3691 (1957).
[
[
[
7] K. Sasaki, K.B. Hicks, and G. Nagahashi, Carbo-
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1
[8] K. Sasaki and F.A. Lúuwus Plant Physiol., 66
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[9] M. Ghias-ud-din, A. E. Smith, and D.V. Phillips,
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10] O. Vogl, B.C. Anderson, and D.M. Simons, J. Org.
Fig. 1. (a) H NMR spectrum of the crude product resulting
from epimerization by Raney nickel. Protons are referred to
1
the usual nomenclature of the inositols; (b) H NMR spectrum
of crystalline scyllo-inositol showing only one signal due to the
presence of a C symmetry axis for the molecule. Small pics at
6
.8 and 3.77 ppm in the spectrum of the crude product are
respectively attributable to traces of quebractitols and other
inositols.
[
2
Chem., 34 (1969) 204±207.
[11] (a) H.J. Koch and R.S. Stuart, Carbohydr. Res., 59
Husson, Christian
