Deoximation with N-bromosulfonamides

Full text of DOI:10.1023/B:RUJO.0000003204.55086.06

Russian Journal of Organic Chemistry, Vol. 39, No. 7, 2003, pp. 1053 1054. From Zhurnal Organicheskoi Khimii, Vol. 39, No. 7, 2003, pp. 1117 1118.
Original English Text Copyright
2003 by Tajbaksh, Khazaei, Shabani Mahalli, Ghorbani Vaghei.
SHORT
COMMUNICATIONS
Deoximation with N-Bromosulfonamides*
M. Tajbaksh1, A. Khazaei2, M. Shabani Mahalli1, and R. Ghorbani Vaghei2
1
Department of Chemistry, College of Sciences, University of Mazandaran, Babolsar, Iran
Phone: +981125234338; Fax: +981125242029; e-mail: tajbaksh@umcc.ac.ir
2
Department of Chemistry, Bu-Ali Sina University, Hamadan, Iran
Received December 20, 2001
Ketone and aldehyde oximes are readily crystalliz-
able substances which are widely used for purification
and identification of carbonyl compounds. Oximes
can be converted into amides via the Beckmann rear-
rangement [1]. Insofar as oximes may also be prepared
from noncarbonyl compounds [2 6], regeneration of
carbonyl compounds therefrom is an alternative
method of synthesis of aldehydes and ketones. A clas-
sical procedure for the recovery of ketones and alde-
hydes from the corresponding oximes is based on
their acid hydrolysis which removes the amine from
the equilibrium. However, the scope of application
of this reaction is limited, for acid-sensitive aldehydes
and ketones cannot be obtained in such a way.
Some reagents used for deoximation [7 9] are often
hazardous or very toxic, expensive or difficultly
accessible, or they should be taken freshly prepared.
The reactions with such reagents require drastic condi-
tions, take a long time, and involve laborious treat-
ment of the reaction mixture. Therefore, milder, more
selective, nonhazardous, and inexpensive reagents are
still required for these transformations.
In the present communication we report on a con-
venient and efficient procedure for deoximation of
ketone and aldehyde oximes to the corresponding
carbonyl compounds with the aid of N,N-dibromo-
benzenesulfonamide. As follows from the data in
Table 1, a number of aldehyde and ketone oximes
Table 1. Deoximation of aldehyde and ketone oximes with N,N-dibromobenzenesulfonamide
Run no.
Substrate
Producta
Reaction time, min Yield, %
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Benzophenone oxime
Benzophenone
15
10
5
10
30
10
20
10
5
10
10
20
20
10
40
94
96
97
92
86
97
88
94
91
88
92
91
90
87
88
p-Bromoacetophenone oxime
o-Methoxybenzaldehyde oxime
p-Phenylacetophenone oxime
o,p-Dimethoxyacetophenone oxime
p-Chloroacetophenone oxime
p-Methylbenzaldehyde oxime
p-Chlorobenzaldehyde oxime
p-Chlorobenzophenone oxime
Benzaldehyde oxime
2,3-Butanedione 2-oxime
Cyclohexanone oxime
Camphor oxime
Cinnamaldehyde oxime
4-tert-Butylcyclohexanone oxime
p-Bromoacetophenone
o-Methoxybenzaldehyde
p-Phenylacetophenone
o,p-Dimethoxyacetophenone
p-Chloroacetophenone
p-Methylbenzaldehyde
p-Chlorbenzaldehyde
p-Chlorobenzophenone
Benzaldehyde
2,3-Butanedione
Cyclohexanone
Camphor
Cinnamaldehyde
4-tert-Butylcyclohexanone
a
The products were identified by physical constants and IR spectra and by comparison with authentic samples.
____________
*
The article was submitted by the authors in English.
1070-4280/03/3907-1053$25.00 2003 MAIK Nauka/Interperiodica

1054
TAJBAKSH et al.
Table 2. Deoximation with N,N-dibromobenzenesulfonamide (A) and N-bromosuccinimide (B) [9]
A
B
Substrate
Product
time, min
yield, %
time, min
yield, %
Benzophenone oxime
Benzophenone
15
10
10
20
94
97
94
91
7
10
1
93
93
93
89
p-Chloroacetophenone oxime
p-Chlorbenzaldehyde oxime
Cyclohexanone oxime
p-Chloroacetophenone
p-Chlorobenzaldehyde
Cyclohexanone
4
were rapidly and cleanly converted into their parent
carbonyl compounds with N,N-dibromobenzenesul-
fonamide in excellent yields (Scheme 1). The products
were isolated by filtering off benzenesulfonamide and
removal of the solvent from the filtrate. Table 2 com-
pares the efficiency and applicability of the proposed
procedure with the results obtained with N-bromo-
succinimide [9].
were obtained on Varian instruments operating at 60
and 90 MHz; CCl4 was used as solvent, and TMS, as
internal reference.
Typical deoximation procedure. A mixture of
5 mmol of appropriate oxime, 15 ml of CCl4, and
5 mmol of N,N-dibromobenzenesulfonamide was
stirred for a time specified in Table 1. The progress
of the reaction was monitored by TLC. Benzenesul-
fonamide was filtered off and washed with CCl4
(2 10 ml), and the filtrate was evaporated under
reduced pressure.
Scheme 1
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[10]. The purity of the products was checked by TLC.
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1
Elmer 1310 spectrophotometer. The H NMR spectra
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 7 2003