n-Butyltriphenylphosphonium peroxodisulfate (Bu(n)PPh3)2S2O8: An efficient and inexpensive reagent for the cleavage of carbon-nitrogen double bonds under non-aqueous and aprotic conditions

Article abstract of DOI:10.1039/a806963h

An efficient and convenient conversion of oximes, phenylhydrazones, p- nitrophenylhydrazones and semicarbazones to the corresponding carbonyl compounds with n-butyltriphenylphosphonium peroxodisulfate is reported.

Full text of DOI:10.1039/a806963h

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1
02 J. CHEM. RESEARCH (S), 1999
J. Chem. Research (S),
n-Butyltriphenylphosphonium Peroxodisulfate
n
1999, 102±103$
(
Reagent for the Cleavage of Carbon±Nitrogen Double
Bu PPh ) S O : an Efficient and Inexpensive
3 2 2 8
Bonds under Non-aqueous and Aprotic Conditions$
Iraj Mohammadpoor-Baltork,* Abdol Reza Hajipour and
a
b
Reza Haddadi
a
Department of Chemistry, Esfahan University, Esfahan 81744, Iran
b
College of Chemistry, Esfahan University of Technology, Esfahan 84156, Iran
An efficient and convenient conversion of oximes, phenylhydrazones, p-nitrophenylhydrazones and semicarbazones to
the corresponding carbonyl compounds with n-butyltriphenylphosphonium peroxodisulfate is reported.
Oximes, phenylhydrazones, p-nitrophenylhydrazones and
semicarbazones are useful intermediates in organic synthesis
because they are utilized as protecting groups in carbonyl
chemistry. These derivatives are also highly crystalline and
very useful for the isolation, characterization and puri®-
cation of carbonyl compound. Regeneration of carbonyl
compounds from their derivatives under mild and aprotic
conditions is a useful transformation and is an important
process in synthetic organic chemistry.
hydrazones and semicarbazones and only a few reports are
available dealing with the conversion of these derivatives to
1
7±21
their corresponding carbonyl compounds.
Thus, there
is still a need to develop a new and facile procedure for the
regeneration of the parent carbonyl compounds from their
above-mentioned derivatives.
We now report an ecient and general method for the
e€ective cleavage of the C.N bond of oximes, phenyl-
hydrazones, p-nitrophenylhydrazones and semicarbazones
with n-butyltriphenylphosphonium peroxodisulfate under
non-aqueous and aprotic conditions.
The classical method for the recovery of aldehydes and
ketones from oximes is hydrolysis under acidic conditions
1
which removes the hydroxylamine from the equilibrium.
This method however, is not suitable for acid sensitive
compounds. Several oxidative methods have been intro-
duced for deoximation which have found some advantages
2
±16
over acidic hydrolysis. Little attention has been paid to
the oxidative cleavage of phenylhydrazones, p-nitrophenyl-
n
Table 1 Oxidative cleavage of carbon±nitrogen double bonds with (Bu PPh
3
)
2
S
2
O
8
a
b,c
Entry
Substrate
t/min
Product
Yield(%)
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
Benzaldoxime
4-Chlorobenzaldoxime
3-Nitrobenzaldoxime
4-Nitrobenzaldoxime
3-Methoxybenzaldoxime
Cinnamaldoxime
Salicylaldehyde oxime
4-Chloroacetophenone oxime
Acetophenone oxime
4-Phenylacetophenone oxime
Benzophenone oxime
Cyclohexanone oxime
3-Nitrobenzaldehyde phenylhydrazone
4-Chlorobenzaldehyde phenylhydrazone
3-Methoxybenzaldehyde phenylhydrazone
Acetophenone phenylhydrazone
4-Phenylacetophenone phenylhydrazone
Benzophenone phenylhydrazone
25
30
30
35
30
20
60
40
35
30
30
45
35
30
30
45
30
30
35
30
40
45
45
40
45
40
35
Benzaldehyde
89
87
86
80
89
89
76
94
96
96
97
92
70
77
82
96
97
98
72
74
93
96
90
70
73
83
89
4-Chlorobenzaldehyde
3-Nitrobenzaldehyde
4-Nitrobenzaldehyde
3-Methoxybenzaldehyde
Cinnamaldehyde
Salicylaldehyde
4-Chloroacetophenone
Acetophenone
4-Phenylacetophenone
Benzophenone
Cyclohexanone
3-Nitrobenzaldehyde
4-Chlorobenzaldehyde
3-Methoxybenzaldehyde
Acetophenone
4-Phenylacetophenone
Benzophenone
4-Chlorobenzaldehyde
3-Methoxybenzaldehyde
Acetophenone
4-Chloroacetophenone
Benzophenone
4-Methoxybenzaldehyde
4-Chlorobenzaldehyde
Acetophenone
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
d
4-Chlorobenzaldehyde-4-NPH
3-Methoxybenzaldehyde-4-NPH
d
d
Acetophenone-4-NPH
4-Chloroacetophenone-4-NPH
Benzophenone-4-NPH
d
d
4-Methoxybenzaldehyde semicarbazone
4-Chlorobenzaldehyde semicarbazone
Acetophenone semicarbazone
Benzophenone semicarbazone
Benzophenone
a
b
All products were identified by comparison of their physical and spectral data with those of authentic samples. Isolated yields.
c d
In the reactions of aldehyde derivatives 10±20% of the corresponding carboxylic acids were isolated. 4-NPH represents
4
-nitrophenylhydrazone.
This reagent can be readily and cheaply prepared by
adding an aqueous solution of potassium peroxodisulfate
to a solution of n-butyltriphenylphosphonium bromide in
water±acetone (10:1). This white, non-hygroscopic solid is
*
To receive any correspondence.
$This is a Short Paper as de®ned in the Instructions for Authors,
Section 5.0 [see J. Chem. Research (S), 1999, Issue 1]; there is there-
fore no corresponding material in J. Chem. Research (M).

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J. CHEM. RESEARCH (S), 1999 103
very stable and can be stored for months without losing its
activity. It is soluble in acetonitrile, dichloromethane and
Received, 20th September 1998; Accepted, 20th October 1998
Paper E/8/06963H
4
chloroform, and slightly soluble in CCl and diethyl ether.
The treatment of oximes, phenylhydrazones, p-nitro-
phenylhydrazones and semicarbazones with 1.5 equivalents
of n-butyltriphenylphosphonium peroxodisulfate in aceto-
nitrile at re¯ux gave the corresponding carbonyl compounds
in 70±98% yield as shown in Table 1. It is noteworthy
that the reaction medium was almost neutral, so that some
sensitive functionalities such as the carbon±carbon double
bond remained intact (entry 6).
References
1 E. B. Hersberg, J. Org. Chem., 1948, 13, 542.
2
3
4
J. R. Maloney and R. E. Lyle, Synthesis, 1978, 212.
J. Drabowicz, Synthesis, 1980, 125.
J. G. Lee, K. H. Kwak and J. P. Hwang, Synth. Commun., 1992,
22, 2435.
H. Firouzabadi, N. Iranpoor, F. Kiaeezadeh and J. Toofan,
5
Tetrahedron, 1986, 42, 719.
6 A. Wall, P. A. Ganeshpure and S. Satish, Bull. Chem. Soc. Jpn.,
993, 66, 1847.
In conclusion, we have developed a new and ecient
method for the regeneration of aldehydes and ketones from
their derivatives under non-aqueous and aprotic conditions.
1
7
8
L. Singh and R. N. Ram, Synth. Commun., 1993, 23, 3139.
N. Chidambaram, K. Satyanarayana and S. Chandrasekaran,
Synth. Commun., 1989, 19, 1727.
Experimental
9
B. Tamami and N. Goudarzian, Eur. Polym. J., 1992, 28, 1035.
Preparation of n-Butyltriphenylphosphonium Peroxodisulfate.Ð
To a solution of n-butyltriphenylphosphonium bromide (4.43 g,
10 H. Firouzabadi, E. Mottaghinejad and M. Seddighi, Synth.
Commun., 1989, 19, 3469.
1
1 mmol) in water±acetone (10:1, 120 ml) was added a solution of
11 Y. T. Yang, T. S. Li and Y. L. Li, Synth. Commun., 1993, 23,
1121.
12 R. Sanabria, R. Miranda, V. Lara and F. Delgado, Synth.
Commun., 1994, 24, 2805.
13 H. Firouzabadi and I. Mohammadpoor-Baltork, Synth. Commun.,
1994, 24, 489.
14 B. P. Bandgar, S. I. Shaikh and S. Iyer, Synth. Commun., 1996,
26, 1163.
15 I. Mohammadpoor-Baltork, M. M. Sadeghi, N. Mahmoodi and
B. Kharamesh, Ind. J. Chem., 1997, 36B, 438.
16 A. R. Hajipour and N. Mahboubghah, J. Chem. Res. (S), 1998,
122.
potassium peroxodisulfate (1.5 g, 5.5 mmol) in water (30 ml) and the
mixture was stirred at room temperature for 15 min. The resulting
white solid was ®ltered, washed with cold distilled water (15 ml)
and dried in a desiccator over calcium chloride. Yield 4.4 g (95%)
(Found: C, 63.58; H, 5.75; S, 7.86. C44
H, 5.78; S, 7.71%).
Regeneration of Carbonyl Compounds from Oximes, Phenyl-
hydrazones, p-Nitrophenylhydrazones and Semicarbazones. General
Procedure.ÐIn a round-bottomed ¯ask (50 ml) equipped with a
condenser and a magnetic stirrer, a solution of the substrate
48 8 2 2
H O P S requires C, 63.61;
(
1 mmol) in MeCN (20 ml) was prepared. n-Butyltriphenylphos-
phonium peroxodisulfate (1.245 g, 1.5 mmol) was added to this
solution and re¯uxed for 20±60 min. The progress of the reaction
was monitored by TLC (eluent: CCl ±Et O, 3:1). The reaction
4 2
17 B. C. Ranu and D. C. Sarkar, J. Org. Chem., 1988, 53, 878.
18 R. Ballini and M. Petrini, J. Chem. Soc., Perkin Trans. 1, 1988,
2563.
mixture was cooled to room temperature and ®ltered. The solid
material was washed with MeCN (20 ml). The ®ltrates were
combined and evaporated. The resulting crude material was puri®ed
on a silica gel plate or silica gel column with appropriate eluent.
Evaporation of the solvent a€orded the pure carbonyl compound;
yield 70±98% (Table 1).
19 H. Firouzabadi, M. Seddighi, Z. Arab Ahmadi and A. R.
Sardarian, Synth. Commun., 1989, 19, 3385.
20 D. H. R. Barton, D. J. Lester and S. V. Ley, J. Chem. Soc.,
Chem. Commun., 1977, 445.
21 I. Mohammadpoor-Baltork and Sh. Pouranshirvani, Synth.
Commun., 1996, 26, 1.