Russian Journal of Applied Chemistry, Vol. 74, No. 9, 2001, pp. 1604 1605. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 9,
2001, pp. 1555 1556.
Original Russian Text Copyright
2001 by Ginak, Aronova, Rutto.
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COMMUNICATIONS
Alkylation of Crystalline Salts of 1,3-Thiazolidine-2,4-diones
with Alkyl Halide Vapors
A. I. Ginak, E. B. Aronova, and M. V. Rutto
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received April 9, 2001
Abstract Alkylation of 1,3-thiazolidine-2,4-diones with alkyl halide vapors was performed. The composition
of the reaction mixtures was determined by thin-layer chromatography.
Alkylated derivatives of 1,3-thiazolidine-2,4-diones
are promising compounds exhibiting antibiotic, acari-
cidal, herbicidal, and other useful properties. How-
ever, the traditional procedure of their synthesis by
alkylation of alkali metal and ammonium salts of
1,3-thiazolid-4-ones yields a mixture of isomers origi-
nating from addition of the alkyl radical to the hetero-
To confirm this assumption, we alkylated the crys-
talline alkali metal salts with ethyl iodide vapor:
=
O
Z
C
C
N
Et
O
C
C
N
EtI
,
M+
=
=
C O
O
=
C
Z
S
S
I V
VI X
cyclic nitrogen atom and exocyclic oxygen atom at the
2
2-position. The latter reaction yields 2-alkoxy-
-
where Z = H (I, VI), PhCH (II, VII), 4-NO C H CH
2
2 6 4
1,3-thiazolin-4-ones, unstable by-products decom-
posing in the course of the reaction, which results in
decreased yield and contamination of the target prod-
ucts. The side addition of the alkyl radical to the
exocyclic oxygen atom is quite natural, since 1,3-thia-
zolidine-2,4-diones are ambifunctional compounds
showing dual reactivity in nucleophilic substitutions
in solutions [1]. Attempts to affect the isomer ratio by
varying the nucleophilicity of the substrate, polariza-
bility of the reagent, and polarity of the medium have
not improved the situation; in all the cases either an
isomer mixture was formed or the alkylation rate dras-
tically decreased; therefore, alkylation in solutions
was considered to have no practical significance [2].
(III, VIII), 4-(CH ) C H CH (IV, IX), 4-CH C H
3 2
6
4
3 6 4
CH (V, X); M = Li, Na, K.
Crystals of I V were treated with ethyl iodide
vapor. Special experiments showed that the result is
independent of the amount of the alkylating agent and
reaction conditions.
The composition of the reaction mixture was deter-
mined by quantitative thin-layer chromatography
(TLC). We found that the reaction yields only the
3
products of addition of the alkyl group at the N atom
(see table). Quantitative analysis shows that the mate-
rial balance is well kept throughout the experiment,
i.e., the initial concentration calculated from the
weight of the salt sample is equal to the sum of the
running concentrations of the salt and reaction prod-
uct. These concentrations were measured with an error
of 5%.
A successful attempt of selective synthesis of alkyl
derivatives of 1,3-thiazolin-4-ones by a solid-phase
reaction [3 5] creates a prerequisite for purposeful
synthesis of 3-alkyl-substituted 1,3-thiazolidine-2,4-
diones by solid-phase synthesis. 1,3-Thiazolidine-2,4-
diones form a close-packed crystal lattice with the
space group Pbca in which the molecules are packed
We also examined the effect of the counterion in
the substrate on its reactivity and revealed no differ-
+
+
ence in the reaction pathway between the Li , Na ,
K , and Cs salts.
+
+
3
2
in the form of planar hydrogen-bonded (N H O
2
C ) dimers [6]. In their alkali metal salts, the counter-
EXPERIMENTAL
2
3
ion is equidistant from the O and N reaction centers
[7], which makes the nitrogen atom accessible for the
electrophilic attack by an alkyl group, whereas shield-
1,3-Thiazolidinedione and its 5-arylmethylene
derivatives were prepared according to [8]. The com-
pounds were recrystallized from ethanol and identified
2
ing of the O atom prevents formation of by-products.
1070-4272/01/7409-1604$25.00 2001 MAIK Nauka/Interperiodica
Ginak
