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Column-Chromatographic Separation of Neutral Sugars on a Dihydroxyboryl-Substituted Polymer.

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doublet with evident broadening due to long-range
45(31PCA~C1H)
and 43(’HCA~C1H)coupling. The IR
spectra contain characteristic bands of A u - C stretching
vibrations at 561/550 ( I ) or 549 cm-’ (2).
Like its copper and silver analogs[61,this dimeric gold(1)dimethylphosphonium bismethylide is soluble in organic
solvents such as CH2C12 and CHC13 and is volatile in
a vacuum. In the mass spectrum[71 the molecular ion
0
(CH3),P+AU-C1
i
H3C\ /CHZ-Au-CH,\
+ (CH3)3P=CH,
OP
‘cH,-A~-cH,
H,C’
O
[ (CH3)3P~Au-CHz-P(CH,)3] CIQ
0)
/CH3
/
0
PQ
\
(6)
CH,
appears with great intensity at m/e=572; vAuC occurs
as a strong IR band at 551 cm- (6) is remarkably insensitive to air and moisture. ‘H-NMR: GCH,P= -1.65ppm
(d, 3 H), J(HCP)= - 1 1.9 Hz; 6CH2P= -0.93 ppm (d, 2H),
J(H2CP)= - 12.3Hz. 31P-NMR: 6P= -32.2ppm (s, ‘H
decoupled)[* 1.
’.
Even the more weakly basic ylides mono- and bis(trimethylsilyl)methylenetrimethylphosphorane~41 form
one and two Au-C bonds, respectively, and yield the
aurated onium salts ( 3 ) , ( 4 ) , and (5).
Received: February 21, 1973 (2 806b IE]
German version: Angew. Chem. 85, 449 (1973)
Column-Chromatographic Separation
of Neutral Sugars on a
DihydroxyborylSubstituted Polymerp]
By Konrad Reske and Herbert Schott“]
The separation of ribo- and deoxyribo-nucleic acid units
on dihydroxyboryl-substituted polymers (“boric acid gels”)
was reported recently“]. Meanwhile we have been able
to separate mixtures of mono- and oligo-saccharides by
means of this gel (Figs. 1 and 2).
Introducing the large organosilicon ligands increases the
solubility of the substances in weakly polar solvents, so
that high concentrations can be achieved. The decomposition temperatures for (3) to ( 5 ) are at or above 150°C.
The 31P-NMR spectrum of ( 5 ) contains an AB system
with 6P’”= -2.82, 6Pv= -23.4, and 3J(31PA~C31P)=
17 Hz[’].
When an excess of the ylide reacts with (CH,),PAuCl, or
with ( I ) or (2), dehydrohalogenation and precipitation
of [(CH,),P]Cl occur, with formation of the novel eightmembered heterocycle (6), m. p. 216-218°C.
20
[ I ] B. Armrr and H . Schmidbaur, Angew. Chem. 82, 120 (1970): Angew.
Chem. internal. Edit. 9, 101 (1970).
[2] H . Schmidbaur and W Tronich, Chem. Ber. l o / , 595 (1968).
[3] H. Schmidbnur, W Buchner, and D. Scheutrow, Chem. Ber. 106,1251
(1973); H . Schmidbaur and W Donich, ibid. IQI, 3556 (1968); see also K .
Hifdenbrand and H . Dreeskamp, Z. Naturforsch, in press (personal communication).-We thank Dr. W Buchner and C. P. Kneis for the NMR
measurements.
[4] H . Schmidbaur and W Tronich, Chem. Ber. 100, 1032 (1967): N .
E. Miller, Inorg. Chem. 4 , 1458 (1965); J. Amer. Chem. SOC.87, 390
( 1965).
[S] ’H-decoupled, H,PO, ext., in CH2C12at 30 C.-’H-NMR (TMS
ext.): GCH,P= - 1.77 and - 2.09 ppm (d, 9 H), J ( H C P ) = 10.5 and 12.5 Hz,
respectively; GCH,Si= -0.42ppm (s, 18H).
[6] H . Srhmidbaur, J . Adlkofer, and W Biichner, Angew. Chem. 85,448
(1973); Angew. Chem. internat. Edit. 12.415 (1973).
[7] Satisfactory analyses are available for all the compounds named
here. We thank DiplLChem. H . Pelz for the mass spectra.
[8] These signals are further split by long-range interactions.
Anguw. Chem. internal. Edit. 1 Vol. 12 ( 1 9 7 3 )
No. 5
LO
-
60
80
[2aosrl
[mll
Fig. I. Elution profile of a mixture of L-rhamnose (a), D-mannose (b),
D-galactose (c), D-gluCoSe (d), and D-ribose (e) on “boric acid gel”; for
conditions see Experimental.
w
O2
t
1780821
20
[mil
40
20
imll
40
---j
Fig. 2. a) Separation of maltose (a) and isomaltose (b) and b) of lactose
(a) and rafiinose (b) on “boric acid gel”; for conditions see Experimental.
[*] Dipl.-Chem. K. Reske
[**I
Max-Planck-Institut fur Immunbiologie
78 Freiburg, Stubeweg 51 (Germany)
Dr. H. Schott
Institut fur Biologie 111 der Universitat
78 Freiburg, Schanzlestrasse 9-1 1 (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft.
417
We have found the complexes of the sugar with the gel
matrix to correspond to the sugar-borate complexes in
solution; their formation is pH-dependent. Optimal separation is obtained at pH > 9. The configuration of the sugar
hemiacetal ring is of special importance for complex formation as it is well known that sugars form borate complexes
preferentially in their furanose formiz1; Fig. 1 confirms
this finding. Furanose formation of the terminal glucose
also provides an explanation for the separation of maltose
from isomaltose (Fig. 2a). An increase in the number of
cis-hydroxyl groups leads to more extensive complex formation; thus lactose and raffinose can be separated quantitatively (Fig. 2b). The disaccharide pairs maltose and cellobiose, and maltose and lactose, however, show only very
slight differences in their elution maxima since none of
them yields a furanose form and they all contain the same
number of cis-hydroxyl groups.
Compared with the procedures used hithertoF3- ’I, chromatography on “boric acid gels” offers the following advantages :
1. The use of volatile buffers permits rapid working up
of the fractions since the separated sugar components can
be isolated quantitatively in high purity without desalting.
Also the absence of borate residues is of particular importance in structural chemical work with oligosaccharidesr6!
2. By suitable choice of gel and gel volumes both monoand oligo-saccharides can be optimally separated, even
if they differ only very slightly in complex formation constants.
Experimental:
A chromatographic column (1/20 cm) is filled with swollen
“boric acid gel”[*’,then washed with 0.5 N HCl, and finally
washed neutral. The sugar mixture (each 1 mg per monoor oligo-saccharide) is dissolved in the eluant (0.2 ml),
placed on the column and eluted with 0.1 % aqueous
ammonia (pH = 10.5), fractions of 4ml per hour being
collected. Aliquot parts (0.21111) of the fractions are monitored by the phenol/sulfuric acid reagent for presence Of
sugars[’] (test batch: 0.2ml of fraction solution +0.1 ml
418
of 90% phenol + 1 ml of HzO, shake, then add 3ml of
concentrated H2SO4).The sugars that are separated are
identified by borate electrophoresis.
Received: February 13, 1973 [Z 808 IE]
German version. Angew. Chem X5. 412 (1973)
[I] H . Schorr, Angew. Chem. 84, 819 (1972): Angew. Chem. internat.
Edit. I / , 824 (1972); H . Schorr er a/., Biochemistry 12. 932 (1973).
[2] J . Biieseken, Advan. Carbohydr. Chem. 4,189 (1949).
[3] J . L. Fruhn and J . A . Mills. Austral. J . Chem. 12: 65 (1959).
[4] L. P. Zi//, J . X. Kkpm, and G. M . Chcniae, J. Amer. Chem Soc.
75, 1339 (1953): R. B. Krsfrr, Anal. Chem. 39, 1416 (1967).
[S] H. L. Weith, J . L. Wirhrrs, and P. 7 Gilham, Biochemistry Y, 4396
( 1970).
[6] K . Rrsku and K . Jann, Eur J. Biochem. 3 / , 320 (1972).
171 M . Dubois, K . H. Gillus, J . K . Humilton, P A . Rehers, and R. Smith,
Anal. Chem. 28,350 (1955)
A Stable 2-Azapentalene1”]
By Klaus Hafner and Frank Schmidt[*]
After the synthesis of simple carbocyclic pentalenes“] the
aza analogs attract particular interest because their properties are likely to depend markedly on the position of
the nitrogen atoms. As %-electron systems 1- ( I ) and
2-azapentalene (2), as well as polyazapentalenes with Cfusion of the two five-membered rings, should not be “aro-
matic”. In spite of many attempts no such bicyclic azapentalene has hitherto been prepared. The thermal instability
of benzo[b]- and benzorf] [llazapentalene precludes their
[*I
Prof. Dr. K . H a h e r and Dr. F. Schmidt
Institut fur Organische Chemie
der Technischen Hochschule
61 Darmstadt, Schlossgartenstrasse 2 (Germany)
[**I This work was supported by the Deutsche Forschungsgerneinschaft
and the Fonds der Chemischen Industrie.
Anyrw. Chum. inrernar.
Edir. 1 V d I 2 ( 1 9 7 3 ) 1 No. 5
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polymer, neutral, separating, dihydroxyboryl, sugar, chromatography, column, substituted
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