The application of N,N′-dibromo-N,N′ -1,2-ethanediylbis-(p-toluenesulphonamide) as a powerful reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones

Article abstract of DOI:10.1016/j.tetlet.2003.08.003

Aliphatic and benzylic alcohols are readily oxidized to aldehydes and ketones in good yields under mild conditions by N,N′-dibromo-N,N′ -1,2-ethanediylbis(p-toluenesulphonamide) [BNBTS].

Full text of DOI:10.1016/j.tetlet.2003.08.003

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 44 (2003) 7525–7527
The application of N,N%-dibromo-N,N%-1,2-ethanediylbis-
(p-toluenesulphonamide) as a powerful reagent for the oxidation
of primary and secondary alcohols to aldehydes and ketones
Ramin Ghorbani-Vaghei* and Ardeshir Khazaei
Department of Chemistry, Faculty of Science, Bu-Ali Sina University, Hamadan, Iran
Received 5 June 2003; revised 28 July 2003; accepted 1 August 2003
Abstract—Aliphatic and benzylic alcohols are readily oxidized to aldehydes and ketones in good yields under mild conditions by
N,N%-dibromo-N,N%-1,2-ethanediylbis(p-toluenesulphonamide) [BNBTS].
© 2003 Elsevier Ltd. All rights reserved.
The selective oxidation of primary and secondary alco-
hols to aldehydes and ketones in organic chemistry is
very important and can be achieved by many reagents,1
that can be used, either in an isolated form2 or gener-
ated ‘in situ’.3 One of the classic reagents is N-chloro-
succinimide which is used for the oxidation of
alcohols.4 Other oxidizing agents are polymer-sup-
ported hypobromite which oxidizes secondary alcohols
to ketones,5 and polymer-supported iodate which oxi-
dizes catechols to quinones.6 N-Chloronylon 6,6 is used
for the oxidation of alcohols7 and sulphides.8
Primary and secondary alcohols were found to be oxi-
dized to aldehydes and ketones using BNBTS/dimethyl
sulfide without overoxidation to carboxylic acids
(Scheme 1).
The results of the conversion of various alcohols to
aldehydes and ketones are presented in Table 1.
These oxidizing agents are relatively expensive and
difficult to prepare, therefore it was decided to study
the application of N,N%-dibromo-N,N%-1,2-ethanediyl-
bis(p-toluenesulphonamide) [BNBTS],9 which is rela-
tively easy to make. We now report a convenient
method for conversion of alcohols to aldehydes and
ketones using BNBTS (Fig. 1).
Figure 1.
Scheme 1.
* Corresponding author. Fax: (+98) 811 8272404; e-mail: ghorbani@basu.ac.ir
0040-4039/$ - see front matter © 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2003.08.003

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R. Ghorbani-Vaghei, A. Khazaei / Tetrahedron Letters 44 (2003) 7525–7527
Table 1. Oxidation with BNBTS
Scheme 2.

R. Ghorbani-Vaghei, A. Khazaei / Tetrahedron Letters 44 (2003) 7525–7527
7527
Since BNBTS contain two bromine atoms which are
attached to nitrogen atoms it is very possible that this
reagent releases Br+ in situ which can act as an elec-
trophilic species.9 Therefore the following mechanism
can be suggested for the conversion of alcohols to
aldehydes and ketones (Scheme 2).
reduced pressure gave the crude product. The product
being dissolved in ether and the ether solution washed,
dried and concentrated.
References
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The advantages of BNBTS are as fellows:
1. The preparation of BNBTS is easy.
2. BNBTS is stable in atmospheric conditions for two
months.
3. After complete of reaction and evaporation of
CH2Cl2, the sulphonamide is recovered and can be
reused many times without decreasing the yield.
IR and 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 oxidation of alcohols with N,N%-
dibromo-N,N%-1,2-ethanediylbis
(p-tolouenesulphon-
amide). The cool dimethyl sulphide (2 ml) was added
dropwise to a magnetically stirred solution of BNBTS
(5 mmol) in dry CH2Cl2 (30 ml) at about 0°C under
nitrogen in a round bottom is flask (250 ml) equipped
with a reflux condenser and a calcium chloride guard
tube. It was cooled to −15°C. The alcohol (5 mmol) in
CH2Cl2 (10 ml) was added dropwise to the mixture, and
stirred for 3 h under the same conditions. Then triethy-
lamine (5 ml) in CH2Cl2 (5 ml) was added dropwise to
the mixture, which was then allowed to reach room
temperature. The solution was poured into distilled
water (10 ml). The insoluble sulphonamide 2 was
removed by filtration and washed with cold methylene
chloride (10 ml). The organic layer was separated from
the aqueous layer. Removal of the solvent under
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