1790
R. Ghorbani-Vaghei and A. Khazaei
with BNBTS were isolated simply by filtering off the sulfonamide 2
and evaporating the solvent from the filtrate. The method has advan-
tages in terms of yields, simplicity of reaction conditions, short reaction
times, and lack of side products. The recovered starting material 2 was
rebrominated and used many times without reducing the yield.
CONCLUSION
From the results obtained, we find that the described procedure and
the reaction conditions are simple. The new reagent (BNBTS) is stable
and the recovered reagent can be reused.
Infrared (IR) and nuclear magnetic resonance (NMR) spectra were
recorded using a Shimadzu 435-U-04 spectrophotometer (KBr pellets)
and a 90 MHz Jeol FT-NMR spectrometer, respectively.
GENERAL PROCEDURE FOR DEPROTECTION
OF 1,3-OXATHIOLANES USING BNBTS
A solution of the 1,3-oxathiolane (1.0 mmol) in acetonitrile (2 ml) was
added quickly to a well-stirred solution of BNBTS (4 mmol) in aqueous
80% acetonitrile (10 ml) at room temperature. The mixture was stirred
for the specified time (Table I). After completion of the reaction, the
insoluble sulphonamide 2 was removed by filteration and washed with
cold acetonitrile (5 ml). The solvent was then evaporated and ether was
added. The ethereal phase was washed with saturated aqueous sodium
carbonate and water and then was dried with MgSO4 and evaporated
to give the product.
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