Bismuth nitrate-mediated deprotection of oximes

Article abstract of DOI:10.1081/SCC-120004840

Bismuth nitrate in wet silica gel was found to be an excellent reagent for the regeneration of ketones from oximes.

Full text of DOI:10.1081/SCC-120004840

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BISMUTH NITRATE-MEDIATED DEPROTECTION OF OXIMES
a
a
a
b
Susanta Samajdar , Manas K. Basu , Frederick F. Becker & Bimal K. Banik
a
M. D. Anderson Cancer Center , Department of Molecular Pathology , The University of
Texas , Box 89, 1515 Holcolmbe Blvd., Houston, TX, 77030, U.S.A.
b
M. D. Anderson Cancer Center , Department of Molecular Pathology , The University of
Texas , Box 89, 1515 Holcolmbe Blvd., Houston, TX, 77030, U.S.A.
Published online: 16 Aug 2006.
To cite this article: Susanta Samajdar , Manas K. Basu , Frederick F. Becker & Bimal K. Banik (2002) BISMUTH NITRATE-
MEDIATED DEPROTECTION OF OXIMES, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 32:13, 1917-1921, DOI: 10.1081/SCC-120004840
To link to this article: http://dx.doi.org/10.1081/SCC-120004840
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SYNTHETIC COMMUNICATIONS, 32(13), 1917–1921 (2002)
BISMUTH NITRATE-MEDIATED
DEPROTECTION OF OXIMES
Susanta Samajdar, Manas K. Basu,
Frederick F. Becker, and Bimal K. Banik*
The University of Texas, M. D. Anderson Cancer
Center, Department of Molecular Pathology, Box 89,
1515 Holcolmbe Blvd., Houston, TX 77030, USA
ABSTRACT
Bismuth nitrate in wet silica gel was found to be an excellent
reagent for the regeneration of ketones from oximes.
Oximes are widely used in synthetic chemistry in the characterization
[
1]
and purification of carbonyl compounds. As a result, many methods are
used for the regeneration of carbonyl compounds from these derivatives.
Among these, acid-induced cleavage and more recently, oxidative transfor-
mation has been demonstrated as useful for this purpose. The widely used
reagents for the deoximation reaction include various pyridine salts of chro-
[
2]
[3]
[4]
[5]
mium, dinitrogentetroxide, trimethylsilyl chloroformate, Dowex-50,
[6]
[7]
dimethyl dioxirane, zirconium sulfophenyl phosphonate. To overcome
the various shortcomings of these methods, recently Varma et al. have
demonstrated the cleavage of semicarbazones and phenyl hydrazones with
*
Corresponding author. E-mail: bbanik@mail.mdanderson.org
917
1
Copyright & 2002 by Marcel Dekker, Inc.
www.dekker.com

1
918
SAMAJDAR ET AL.
Table 1. Bismuth Nitrate-Mediated Deoximation of Ketones
ꢀ
Yield Time
(%)
M.p./B.p. ( C)
a
lit /obs
Entry Substarte Product
1
(h)
97
2
169–171/168
202/200
2
3
89
5
989
232/231
4
87
9
5
302/299
5
6
90
85
48–49/48
1.5 113–116 (6 mm/Hg)/
1
12–115 (6 mm/Hg)
7
92
10
82–85/83
a
Available from Aldrich Chemical Company.
[
8]
ammonium persulfate-clay using microwave irradiation. They have also
shown an oxidative cleavage of ketoximes on wet silica by sodium periodate
[
9]
under microwave irradiation. Although, the methods reported by Varma
et al. are valuable from the synthetic standpoint, extreme precautions have
to be taken as these reactions were performed under microwave irradiation
or ultrasonic irradiation with an oxidant. Therefore, efficient methods that
can regenerate the carbonyl compounds from oximes at less stringent
conditions would be useful.
We have been engaged in the use of polyaromatic compounds as
[10]
anticancer agents and recently have demonstrated the synthesis of diben-
[
11]
zofluorenone derivatives with this activity. In order to do a systematic
structure-activity study we require a number of pure benzylic ketones.

DEPROTECTION OF OXIMES WITH BISMUTH NITRATE
1919
[
12]
In continuation of our research on bismuth nitrate,
we now report a
general method of the regeneration of ketones from their oxime derivatives
in excellent yield without using any microwave irradiation or ultrasonic
irradiation. We believe this is the first report of using bismuth nitrate as
the reagent for the deprotection of oximes.
Several oximes were deoximated using bismuth nitrate in silica gel
in the presence of a small amounts of water under reflux condition in
tetrahydrofuran (THF). Aliphatic (entry 1), benzylic (entry 6), dibenzylic
(
yield (85–98%) by this method (Table 1).
entry 7) and aromatic (entry 2–5) ketoximes were deprotected in excellent
[
12]
While we demonstrated a facile aromatic nitration reaction
with
bismuth nitrate in the presence of solid support, we did not observe any
nitration of aromatic substrates under this condition during the cleavage
reaction. We found a few drops of water and silica gel are essential for the
success of the reaction. While THF was the optimal solvent, we can have a
different solvent compositions (methanol, ethanol, acetonitrile etc). The
reaction failed to produce the ketones without bismuth nitrate or silica gel.
In summary, a facile regeneration method of ketones from their
[
13]
respective oximes using bismuth nitrate in wet silica has been developed.
ACKNOWLEDGMENTS
We gratefully acknowledge the funding support received for this
research project from the Golden Family Fund for cancer research and
NIH Cancer Center Support Grant, 5-P30-CA16672-25, in particular the
shared resources of the Pharmacology and Analytic Center Facility.
REFERENCES
1
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Rearrangement of Ketoximes in Dry Media. Synlett 1995, 1259 and
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2. (a) Maloney, J.R.; Lyle, R.E.; Scavedra, J.E.; Lyle, G.G. Oxidative
Deoximation with Pyridinium Chlorochromate. Synthesis 1978,
212; (b) Drabowicz, J. Rapid Deoximation with Pyridinium
Chlorochromate/Hydrogen Peroxide System. Synthesis 1980, 125.

1
920
SAMAJDAR ET AL.
3
4
5
6
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Method for the Regeneration of Carbonyl Compounds from Oximes
and Semicarbazones. J. Org. Chem. 1988, 53, 878.
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Synthetic Methods and Reactions. 183. Efficient and mild Oxidation of
Ketoximes to Their Parent Ketones with Dimethyldioxirane. Synlett
1993, 427.
7
8
. Curini, M.; Rosati, O.; Pisani, E. Heterogeneous Catalysis in Carbonyl
Regeneration from Oximes, Semicarbazones, and Tosylhydrazones by
Zirconium Sulfophenyl Phosphonate. Synlett 1996, 333.
. Varma, R.S.; Meshram, H.M. Solid State Cleavage of Semicarbazones
and Phenylhydrazones with Ammonium Persulfate-clay Using
Microwave or Ultrasonic Irradiation. Tetrahedron Lett. 1997, 38,
7973.
9
. Varma, R.S.; Dahiya, R.; Saini, R.K. Solid State Regeneration of
Ketones from Oximes on Wet Silica Supported Sodium Periodate
Using Microwaves. Tetrahedron Lett. 1997, 38, 8819.
1
0. (a) Becker, F.F.; Banik, B.K. Polycyclic Aromatic Compounds as
Anticancer Agents: Synthesis & Biological Evaluation of Some
Chrysene Derivatives. Bioorg. & Med. Chem. Lett. 1998, 8, 2877; (b)
Banik, B.K.; Becker, F.F. Synthesis, Electrophilic Substitution and
Structure–Activity Relationship Studies of Polycyclic Aromatic
Compounds for the Development of Anticancer Agents. Curr. Med.
Chem. 2001, 000; (c) Banik, B.K.; Becker, F.F. Polycyclic Aromatic
Compounds as Anticancer Agents: 4. Structure–Activity Relationships
of Chrysene and Pyrene Derivatives. Bioorg. & Med. Chem. 2001, 9,
593.
1
1. Becker, F.F.; Mukhopadhyay, C.; Hackfeld, L.; Banik, I.; Banik, B.K.
Polycyclic Aromatic Compounds as Anticancer Agents: Synthesis and
Biological Evaluation of Dibenzofluorene Derivatives. Bioorg. & Med.
Chem. 2000, 8, 2693.
1
2. Samajdar, S.; Becker, F.F.; Banik, B.K. Surface-mediated Highly
Efficient Regioselective Nitration of Aromatic Compounds by
Bismuth Nitrate. Tetrahedron Lett. 2000, 41, 8017.
1
3. A representative procedure is as follows: To a suspension of oximes
(
1 mmol) in silica gel (1.5 g) and THF (10 mL) was added bismuth

DEPROTECTION OF OXIMES WITH BISMUTH NITRATE
1921
nitrate pentahydrate (485 mg, 1 mmol) and water (2 mL). The mixture
was refluxed for the specified time as indicated in the Table 1. It was
then filtered to remove the silica gel, extracted with dichloromethane
(
25 mL), washed successively with saturated sodium bicarbonate
solution, dried, evaporated and filtered through a short silica gel
column to obtain the pure ketone.
Received in the USA June 23, 2001