Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 1, pp. 134−138.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
S.M. Butrim, T.D. Bil’dyukevich, N.S. Butrim, T.L. Yurkshtovich, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 1,
AND POLYMERIC MATERIALS
Sulfation of Carboxy Starch with Sodium Pyrosulfate
in Dimethyl Sulfoxide
S. M. Butrim, T. D. Bil’dyukevich, N. S. Butrim, and T. L. Yurkshtovich
Research Institute of Physicochemical Problems, Belarussian State University, Minsk, Belarus
Received April 15, 2009
Abstract—Chemical modification of potato carboxy starch in the sodium pyrosulfate–dimethyl sulfoxide system
was studied with the aim of preparing water-soluble highly substituted sulfo esters. The dependence of the degree
of sulfo group substitution on the reaction conditions was studied in detail. The optimal conditions ensuring
formation of water-soluble sulfo esters of carboxy starch with the maximal sulfur content were determined.
The carboxy starch sulfo ester samples synthesized were characterized by elemental analysis, IR and
spectroscopy, and high-performance exclusion chromatography.
Polysaccharide derivatives with ionogenic groups
are of interest as polymeric carriers for immobilization
of drugs and enzymes. Among them, particular attention
is attracted by sulfo esters which exhibit intrinsic
anticoagulant and antithrombotic activity  and,
at certain degrees of substitution, also antiviral and
immunomodulating activity . The presence of carboxy
groups in polysaccharide sulfate expands or enhances
the physiological activity, reduces the toxicity, and
increases the selectivity of binding of low-molecular-
This study deals with O-sulfation of carboxyl-containing
starches with various degrees of substitution in the sodium
pyrosulfate–dimethyl sulfoxide system  with the aim to
prepare water-soluble sulfo esters of carboxy starch. The
choice of this system is governed by its availability and
technological acceptability, because the sulfating agent
used is sodium pyrosulfate, which is low-toxic and safe in
handling (in contrast to traditionally used sulfating agents:
chlorosulfonic acid and sulfuric anhydride) [4, 5], and the
solvent used is DMSO, which is considerably less harmful
than pyridine and dimethylformamide most frequently used
in sulfating systems [6, 7].
As investigation objects we used three samples of
carboxy starch, differing in the degree of substitution
with respect to carboxy groups (DS(COOH) = 0.25, 0.41,
and 0.70). For comparison we used native potato starch,
GOST (State Standard) 7699–78. All the chemicals used
were of chemically pure or analytically pure grade and
were used without additional puriﬁ cation.
Preparation of carboxy starch sulfo esters can be
described by the scheme (see above).
In the ﬁ rst step we performed selective oxidation of
primary hydroxy groups of D-anhydroglucopyranose
units (AGU) of potato starch to carboxy groups with
a solution of dinitrogen tetroxide in chloroform,
following the procedure described in . O-Sulfation
was performed as follows: 3 g of the polysaccharide was
placed in a ﬂ ask with a ground-glass stopper, and sodium
pyrosulfate and DMSO were added. The contents were
mixed and kept for 20 min at room temperature. Then
the ﬂ ask was placed in a water thermostat and heated at
40–80°C for 1.5–24 h with intermittent stirring. After the
lapse of the required time, the ﬂ ask was quickly cooled
and the contents were poured into 50 ml of ethanol.
The precipitate that formed was additionally washed
with 100 ml of ethanol, dissolved in distilled water, and
neutralized with a dilute NaOH solution to pH 8.5. After
that, low-molecular-weight impurities were removed by
dialysis on cellophane membranes with distilled water