940 Shen et al.
Asian J. Chem.
TABLE-2
EFFECT OF REACTION TIME ON THEYIELD OF THE PRODUCT
Reaction time (min)
120
60
150
75
180
85
210
70
240
65
Yield (%)
Reaction characteristics
Not complete
Not complete
Moderate
Byproducts
Byproducts
with high yields, under mild conditions. The structure of the
1
target compound was confirmed by IR, H NMR, MS and the
of urea to 2-aminoethanethiol hydrochloride is 1.5:1.0, reaction
temperature 180 ± 5 ºC, reaction time 3 h. Take the toluene as
the extractive solvent, by 2-aminoethanethiol hydrochloride,
yield may reach 85-90 %. Through the optimized response
condition, the urea amount used reduced to 20 compared to
the literature.
purity was 98 % as determined by HPLC. The melting point
of the product was 51 ºC, which was identical with reported
8
value in the literature .We also optimized the reaction conditions
by testing several parameters, such as reaction time (Table-1),
reaction temperature (Table-2) and different amounts of raw
material (Table-3).
Conclusion
We have successfully reduced the number of steps and
-thiazolidinone is now accessible in one steps with good
2
TABLE-3
yields. we optimized the reaction conditions by testing several
parameters, such as extraction solvent, different amounts of
raw material, reaction temperature and reaction time, etc. Short
steps, high yield and ease of operation of the present approach
would permit the hitherto most efficient access to 2-thiazoli-
dinone.
EFFECT OF THE MOLAR RATIO OF UREA TO 2-
AMINOETHANETHIOL HYDROCHLORIDE REACTION
TEMPERATURE ON THEYIELD OF THE PRODUCT
Molar ratio (mol ratio)
Yield (%)
1.0
70
81
1.2
75
85
1.5
85
98
2.0
85
98
Purity (%)
With reaction temperature lower than 180 ºC, the reaction
took place more slowly and a reaction time of 4-5 h,And when
the reaction temperature higher than 180 ºC, the reaction took
place more quickly and a reaction time of 1-2 h, but the yield
was also reduced, so moderate reaction temperature was 180 ºC.
The reaction proceeded faster, it is found that raw materials
were not completed and the yield decreased, on the other side
byproducts were formed in long reaction time, so appropriate
reaction time was 3 h.
REFERENCES
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P. Vicini, A. Geronikaki, K. Anastasia, M. Incerti and F. Zani, Bioorg.
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P.C. Lv, C.F. Zhou, J. Chen, P.G. Liu, K.R. Wang, W.J. Mao, H.Q. Li,
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M. Yagisawa, M. Kitano and Y. Morimoto, EP 0387028,1990-09-12.
As can be seen from the Table-3, the suitable molar ratio
of urea to 2-aminoethanethiol hydrochloride is 1.5:1.0, the
9
urea amount used reduced 20 compared to the literature .
6. Kawamatsu Yutaka Kogyo K.K., JP 58177983, 1983-10-18.
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By experiments utilizing an orthogonal design, optimum
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8
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