An efficient tandem oxidative-protection reaction of benzylic alcohols to corresponding arylhydrazones and oximes

Article abstract of DOI:10.1080/10426500601015724

A mild and efficient one-pot synthesis of hydrazones and oximes from the reaction of the oxidation product of benzyl alcohols and phenols by 3,6-bis(triphenylphosphonium)cyclohexene dichromate with phenylhydrazine, 2,4-dinitrophenylhydrazine, and hydroxylamine is described. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500601015724

This article was downloaded by: [TOBB Ekonomi Ve Teknoloji]
On: 22 December 2014, At: 13:17
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Phosphorus, Sulfur, and Silicon
and the Related Elements
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gpss20
An Efficient Tandem Oxidative-
Protection Reaction of Benzylic
Alcohols to Corresponding
Arylhydrazones and Oximes
Rashid Badri a & Mohammad Reza Shushizadeh a
a Chemistry Department , Shahid Chamran
University , Ahvaz, Iran
Published online: 30 Jan 2007.
To cite this article: Rashid Badri & Mohammad Reza Shushizadeh (2007) An Efficient
Tandem Oxidative-Protection Reaction of Benzylic Alcohols to Corresponding
Arylhydrazones and Oximes, Phosphorus, Sulfur, and Silicon and the Related Elements,
182:3, 601-605, DOI: 10.1080/10426500601015724
To link to this article: http://dx.doi.org/10.1080/10426500601015724
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the
information (the “Content”) contained in the publications on our platform.
However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness,
or suitability for any purpose of the Content. Any opinions and views
expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the
Content should not be relied upon and should be independently verified with
primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages,
and other liabilities whatsoever or howsoever caused arising directly or

indirectly in connection with, in relation to or arising out of the use of the
Content.
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden. Terms & Conditions of access and use can be found at
http://www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur, and Silicon, 182:601–605, 2007
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500601015724
An Efficient Tandem Oxidative-Protection Reaction
of Benzylic Alcohols to Corresponding Arylhydrazones
and Oximes
Rashid Badri
Mohammad Reza Shushizadeh
Chemistry Department, Shahid Chamran University, Ahvaz, Iran
A mild and efficient one-pot synthesis of hydrazones and oximes from the reaction
of the oxidation product of benzyl alcohols and phenols by 3,6-bis(triphenyl-
phosphonium)cyclohexene dichromate with phenylhydrazine, 2,4-dinitrophenyl-
hydrazine, and hydroxylamine is described.
Keywords 3,6-bis(triphenylphosphonium)cyclohexene dichromate; hydrazones; oximes;
oxidation; synthesis
INTRODUCTION
The oxidative conversion of alcohols and phenols to corresponding car-
bonyl compounds and quinones by the dichromate anion (Cr2O2−),1−6
and the simultaneous reaction of these derivatives with hydrazin7es and
hydroxylamine offers a convenient one-pot synthetic route to hydra-
zones and oximes. The traditional dichromate anion oxidation of alco-
hols and phenols and the transformation of the products to hydrazones
and oximes is a two-step synthesis, which is conducted under aqueous
acidic conditions. Such conditions are usually associated with further
oxidation of aldehydes to corresponding carboxylic acids and acetals,
and therefore, they reduce yields.
A number of different chromium(VI)-based oxidants for the oxidation
of organic substrates under non-aqueous and aprotic conditions, e.g.,
n-butyltriphenylphosphonium dichromate,7 and benzyltriphenylphos-
phonium dichromate,8 are reported in the literature. Here we report
an extension of our previous studies9−11 of the one-pot conversion of
benzylic alcohols and phenols to hydrazones and oximes.
Received August 12, 2005; accepted August 16, 2006.
We thank Shahid Chamran University, Ahvaz, Iran, for financial support of this work.
Address correspondence to Rashid Badri, Chemistry Department, College of Science,
Shahid Chamran University, Ahvaz, 6137-4-3169, Iran. E-mail: rashidbadri@yahoo.com
601

602
R. Badri and M. R. Shushizadeh
TABLE I Solvent-Free Synthesis of 2,4-Dinitrophenylhydrazonesa
Time
(min)
Yield
(%)
M.P. (lit.12
(◦C)
)
Substrate
Product
20
35
20
85
80
86
Benzaldehyde-2,4-DNPH
235 (237)
248 (250)
237 (239)
CH2OH
CH3
Acetophenone-2,4-DNPH
CHOH
4-methylbenzaldehyde-2,4-DNPH
CH2OH
H3
C
25
25
76
85
4-nitrobenzaldehyde-2,4-DNPH
319 (320)
252 (254)
CH2OH
CH2OH
O
2N
4-methoxybenzaldehyde-2,4-DNPH
H3CO
25
15
31
72
95
80
Benzoin-2,4-DNPH
187 (189)
230 (231)
229 (231)
CHOHCO
p-benzoquinone-2,4-DNPH
p-benzoquinone-2,4-DNPH
HO
OH
OH
OH
30
82
—
p-naphtoquinone-2,4-DNPH
277 (278)
—
OH
120
—
aAll products were confirmed by comparison with authentic samples (IR, 1H NMR,
and TLC). The yield of isolated pure hydrazones. DNPH = 2,4-dinitrophenylhydrazone.
RESULTS AND DISCUSSION
The preparation of the oxidant 3,6-bis(triphenylphosphonium)cyclo-
hexene dichromate (BTPCD) was accomplished according to the
reported procedure.11 Thus the reaction of 3,6-dibromocyclohexene
with triphenylphosphine in refluxing chloroform afforded 3,6-
bis(triphenylphosphonium)cyclohexene dibromide in an 80% yield.
Treatment of this compound with K2Cr2O7 in H2O furnished the ox-
idant BTPCD in a 78% yield (Scheme 1).
SCHEME 1

Oxidative Protection of Benzylic Alcohols
603
BTPCD was ground to a fine powder and then thoroughly mixed
in a 1:1 molar ratio with alcohol or phenol. After 5 min, one equiva-
lent of 2,4-dinitrophenylhydrazine, phenylhydrazine, or hydroxylamine
was added to the reaction mixture. Grinding of the mixture was con-
tinued until TLC analysis indicated the completion of the reaction
(9–35 min). The results obtained are summarized in Tables I–III.
The results in all three tables indicate that benzyl alcohols and sub-
stituted derivatives thereof carrying both electron-withdrawing and
electron-donating groups were converted to the corresponding 2,4-
dinitrophenylhydrazones (Table I), phenylhydrazones (Table II), and
oximes (Table III), in good to excellent yields. Application of this oxida-
tion procedure to some phenols was also examined (Tables I–III). Among
the phenols, p-hydroquinone underwent these conversions faster (9–15
min) than phenol itself and other derivatives. In contrast, β-naphtol
TABLE II Solvent-Free Synthesis of Phenylhydrazonesa
Time
(min)
Yield
(%)
M.P. (lit.12
(◦C)
)
Substrate
Product
10
93
Benzaldehyde-PH
156 (158)
CH3
18
17
84
89
Acetophenone-PH
104 (105)
114 (114)
CHOH
4-methylbenzaldehyde-PH
CH2OH
CH2OH
H3C
21
72
4-nitrobenzaldehyde-PH
158 (159)
O2N
20
18
9
90
75
98
83
4-methoxybenzaldehyde-PH
Benzoin-PH
119 (120)
105 (106)
150 (152)
150 (152)
CH2OH
H3CO
CHOHCO
p-benzoquinone-PH
p-benzoquinone-PH
HO
OH
22
OH
OH
24
85
—
p-naphtoquinone-PH
205 (206)
—
OH
120
—
aAll products were confirmed by comparison with authentic samples (IR, 1H NMR,
and TLC). Yield of isolated pure hydrazones. PH = phenylhydrazone.

604
R. Badri and M. R. Shushizadeh
TABLE III Solvent-Free Synthesis of Oximesa
Time
(min)
Yield
(%)
M.P. (lit.12
(◦C)
)
Substrate
Product
15
25
90
86
90
70
89
75
94
82
79
—
Benzaldehyde-oxime
35 (35)
58 (59)
CH2OH
Acetophenone-oxime
4-methylbenzaldehyde-oxime
4-nitrobenzaldehyde-oxime
4-methoxybenzaldehyde-oxime
Benzoin-oxime
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
23
109 (110)
128 (129)
131 (133)
150 (151)
239 (240)
239 (240)
205 (207)
—
18
20
22
12
p-benzoquinone-oxime
p-benzoquinone-oxime
p-naphtoquinone-oxime
—
35
26
120
aAll products were confirmed by comparison with authentic samples (IR, 1
NMR, and TLC). Yield of isolated pure oximes.
H
did not react even after 2 h of grinding and was recovered without any
change.
CONCLUSION
In summary, the conditions presented here afforded an efficient one-pot
synthesis of hydrazones and oximes in moderate to good yields. Neutral
and mild reaction conditions as well as simple work-up are advantages
of this method.
EXPERIMENTAL
All starting materials were purchased from Merck (Darmstadt,
Germany) and Aldrich (London, England). Melting points were

Oxidative Protection of Benzylic Alcohols
605
measured on a Mettler FP5 apparatus and are uncorrected. IR spec-
1
tra were recorded on a Shimadzu 470 infrared spectrometer. H NMR
spectra were recorded with a 250 MHz Bruker spectrometer. The purity
of substrates and the course of the reactions was checked by TLC using
silica-gel polygram SIGL/UV254 plates.
GENERAL PROCEDURE
A mixture of the substrate (0.5 mmol) and oxidant (0.5 mmol) were
ground in a mortar for 5 min at an ambient temperature. To this mix-
ture was either added 2,4-dinitrophenylhyrazine (0.5 mmol), phenyl-
hydrazine (0.5 mmol), or hydroxylamine (0.5 mmol) in one portion,
and grinding was continued until TLC monitoring showed comple-
tion of the reaction (9–35 min). Then the mixture was washed with
dichloromethane or diethylether (20 mL). The combined solutions were
filtered and dried over anhydrous magnesium sulfate. Evaporation of
the solvent afforded the pure products (for yields, see Tables I–III).
REFERENCES
[1] E. J. Corey and J. W. Suggs, Tetrahedron Lett., 2647 (1975).
[2] F. S. Guzeic Jr. and F. A. Luzzio, J. Org. Chem., 47, 1787 (1982).
[3] E. Santeniello, F. Milani, and R. Casati, Synthesis, 749 (1983).
[4] N. Chidambaram, K. Satyanarayana, and S. Chandrasekaran, Tetrahedron Lett.,
30, 2429 (1989).
[5] G. Rosini and R. Ballini, Synthesis, 543 (1983).
[6] K. G. Akomanchi, L. G. Lyer, and R. Meenakshi, Synth. Commun., 21, 419 (1991).
[7] B. I. Mohammad Poor, M. M. Sadegi, N. Mahmoodi, and B. Kharamesh, Ind. J.
Chem., 36A, 438 (1997).
[8] A. R. Hajipour and S. E. Mallekpour, J. Chem. Res., 132 (2000).
[9] R. Badri and M. Soleymani, Synth. Commun., 33, 1325 (2003).
[10] R. Badri and M. Soleymani, Synth. Commun., 32, 2385 (2002).
[11] R. Badri and A. Mostoufi, Phosphorus, Sulfur, and Silicon, 77, 2331 (2002).
[12] (a) R. L. Shriner, C. K. F. Hermann, T. C. Morrill, D. Y. Curtin, and R. C. Fuson, The
Systematic Identification of Organic Compounds, 7th ed. (1997); (b) B. S. Furniss,
A. J. Hannaford, V. Rogers, P. W. G. Smith, and A. R. Tetchell, Vogel’s: Textbook of
Practical Organic Chemistry, 4th ed. (1978).