Highly efficient and selective oxidation of secondary alcohols to ketones under organic solvent and transition metal free conditions

Article abstract of DOI:10.1016/j.tet.2006.04.097

The aqueous HBr/H₂O₂ was found to be highly efficient and green catalytic system for the selective oxidation of the secondary alcohols to ketones in excellent yields under organic solvent free conditions. The results of the oxidation of the secondary alcohols with solid alternatives of the aqueous hydrogen peroxide like SPC or SPB are also described.

Full text of DOI:10.1016/j.tet.2006.04.097

Tetrahedron 62 (2006) 6841–6847
Highly efficient and selective oxidation of secondary
alcohols to ketones under organic solvent and
transition metal free conditions
*
Suman L. Jain, Vishal B. Sharma and Bir Sain
Chemical and Biotechnology Division, Indian Institute of Petroleum, Dehradun-248005, India
Received 3 February 2006; revised 15 April 2006; accepted 28 April 2006
Available online 24 May 2006
Abstract—The aqueous HBr/H2O2 was found to be highly efficient and green catalytic system for the selective oxidation of the secondary
alcohols to ketones in excellent yields under organic solvent free conditions. The results of the oxidation of the secondary alcohols with solid
alternatives of the aqueous hydrogen peroxide like SPC or SPB are also described.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
under very mild conditions. Our further observation that
this system works more efficiently under organic solvent
free conditions prompted us to describe the full details of
this improved protocol along with the applications of solid
oxidants in the place of aqueous hydrogen peroxide
(Schemes 1 and 2).
The development of catalytic synthetic methodologies using
clean oxidants like molecular oxygen and hydrogen per-
oxide with a view to replace environmentally prohibitive
stoichiometric oxidants is an area of current interest.1
Hydrogen peroxide is an attractive, atom-economic, and
environmentally benign oxidant as it is cheap, easily avail-
able, and produces only water as by-product. In the recent
years, it has been extensively used in developing a variety of
synthetically important oxidation methodologies like epox-
idation, oxidation of alcohols, aldehydes, and sulfides using
transition metal based catalysts both in homogeneous and
heterogeneous phases.2 The oxidation of secondary alcohols
to carbonyl compounds is an important synthetic transfor-
mation1a,3 and a variety of transition metal based catalysts,
such as methyltrioxorhenium4 dinuclear iron complexes,5
R1
R1
H
Oxidant, aq. HBr (20 mol%)
C
C
O
80 °C
R2
R2
Scheme 1.
OH
R1
R2
R1
R2
H
SPC or SPB, aq. HBr (20 mol%)
C
C
O
AcOH, 50 °C
OH
vanadium phosphorus oxide,6 cobalt(II) complexes,7 Fe3þ
/
montmorillonite-K10 system,8 and sodium tungstate9 using
hydrogen peroxide as oxidant, have been reported in the lit-
erature to accomplish it. However, most of these methods are
associated with the limitations such as use of toxic, expen-
sive metals, lower yields of the products, and oxidation of
only activated such as benzylic and allylic alcohols. In the
recent past, increasing emphasis is being placed toward the
development of transition metal free ecofriendly synthetic
methodologies to avoid the use of toxic and expensive
metals and their complexes. In our preliminary communica-
tion,10 we have reported a new and highly efficient method-
ology for the oxidation of secondary alcohols to ketones with
aqueous H2O2 in the presence of catalytic amounts of HBr
Scheme 2.
2. Results and discussion
The oxidation of various secondary alcohols, both activated
and non-activated, was carried out by heating the reaction
mixture of substrate (1 mmol), aqueous 30 wt % hydrogen
peroxide (2 mmol), and catalytic amount of aqueous HBr
(20 mol %) at 80 ꢀC under organic solvent free conditions.
All the alcohols were selectively converted to the corre-
sponding ketones in excellent yields and these results are
presented in Table 1. Among the various alcohols studied,
benzoins were found to be the most reactive and required
shorter reaction times for their oxidation (Table 1, entries
17 and 18). Furthermore, aromatic substituted alcohols
were found to be more reactive than aliphatic/alicyclic
(Table 1, entries 1 and 2). Alcohols having both secondary
Keywords: Oxidation; Secondary alcohols; Ketones; Solid oxidant.
* Corresponding author. Tel.: þ91 135 2660071; fax: þ91 135 2660202;
e-mail: birsain@iip.res.in
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.04.097

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S. L. Jain et al. / Tetrahedron 62 (2006) 6841–6847
Table 1. Oxidation of secondary alcohols to ketones
Entry
Substrate
Product
Method A
Reaction time (h)
Method B
Reaction time (h)
Yielda
98
Yielda
96
CH
OH
C
O
1
0.50
1.0
CH3
CH3
CHOH
C
O
2
3
0.75
94
89
1.0
90
80
OH
O
2.0
2.0
O
4
5
6
3.5
75
82
76
3.0
5.5
4.0
72
75
70
OH
C
H
CH3(CH2)4C
OH
CH3(CH2)4C
C
CH
CH
5.00
4.50
O
CH3
CH3
OH
O
OH
O
7
2.5
85
3.5
82
CH3
CH3
OH
O
O
8
9
1.75
2.0
82
89
2.0
2.5
80
86
Ph
Ph
COOMe
CH3
COOMe
CH3
OH
OH
O
OH
OH
10
2.0
87
2.75
84
OH
O
11
12
1.5
3.5
82
75
2.5
4.0
80
70
C4H9
OH
C4H9
O
Ph
Ph
OH
O
13
2.75
85
3.5
82
But
But
(continued)

S. L. Jain et al. / Tetrahedron 62 (2006) 6841–6847
6843
Table 1. (continued)
Entry
Substrate
Product
Method A
Method B
Reaction time (h)
Yielda
88
Reaction time (h)
Yielda
14
15
3.50
5.5
84
OH
OH
O
O
OH
OH
4.5
78
5.5
74
C
O
CH2OH
CH2OH
CH
OH
16
1.75
0.15
88
98
2.50
0.25
85
96
C
CH
C
O
C
O
17
O
OH
C
O
CH O
OCH3
CH O
OCH3
C
O
CH
OH
C
O
3
3
18
19
0.25
2.5
97
89
0.33
3.5
96
80
H
C
CH3(CH2)12
C
C(CH2)12CH3
O
CH3(CH2)12
C(CH2)12CH3
O
OH O
Method A—Reaction conditions: secondary alcohol (1 mmol), 30% H2O2 (2 mmol), and 48% aqueous HBr (20 mol %) at 80 ꢀC under organic solvent free
conditions.
Method B—Reaction conditions: secondary alcohol (1 mmol), 70% TBHP (2.5 mmol), and 48% aqueous HBr (20 mol %) at 80 ꢀC under organic solvent free
conditions.
Isolated yields.
a
as well as primary hydroxyl groups such as 2-ethyl-1,3-
hexanediol, 2-hydroxymethylcyclohexanol, and 1-phenyl-
1,2-ethanediol were selectively converted into 2-ethyl-1-
hydroxy-3-hexanone, 2-hydroxymethylcyclohexanone, and
2-hydroxy-1-phenylethanone, respectively, under these con-
ditions, showing the usefulness of this method for the selec-
tive oxidation of secondary alcohols in the presence of
primary alcohols (Table 1, entries 10, 15, and 16). Similarly,
other functional groups such as double and triple bonds were
found to be inert under these conditions (Table 1, entries 5
and 12). To evaluate the efficiency of this method, we also
carried out the oxidation of benzhydrol to benzophenone
in different organic solvents and these results are shown
in Table 2. Although among the various organic solvents
studied, acetonitrile was found to be more suitable, but in
general, organic solvent free condition was found to be
the best and required shorter reaction time. The effect of the
reaction temperature was also evaluated and found that
the oxidation of benzhydrol to benzophenone was slow at
room temperature but could be conducted efficiently at
80 ꢀC. Further increase in temperature affected the oxidation
adversely in terms of yield of the benzophenone, probably
due to fast decomposition of H2O2 at higher temperature.
2.1. Effect of various bromine sources
To evaluate the effect of various bromine sources, the oxida-
tion of benzhydrol was studied using catalytic amount of dif-
ferent bromine sources (20 mol %) in place of aqueous HBr
with aqueous 30% hydrogen peroxide as an oxidant under
similar reaction conditions and the results are presented
in Table 3. Although the use of molecular bromine and
Table 2. Effect of various solventsa
Table 3. Effect of various bromine sources under neat conditionsa
Entry Substrate
Solvent
Method A
Method B
Reaction Yieldb Reaction Yieldb
Entry
Substrate
Bromine
source
Reaction
times (h)
Yields
(%)b
time (h)
time (h)
1
2
3
4
5
Benzhydrol Acetonitrile
Benzhydrol Methanol
Benzhydrol Toluene
Benzhydrol Dichloroethane 1.5
Benzhydrol Neat 0.50
0.75
2.0
4.5
92
40
35
85
98c
1.5
3.0
5.0
2.5
1.0
94
35
42
80
96c
1
2
3
4
5
6
Benzhydrol
Benzhydrol
Benzhydrol
Benzhydrol
Benzhydrol
Benzhydrol
Aqueous HBr
Br2
NaBr
0.5
0.5
4.0
4.0
1.5
1.0
98
94
30
85
85c
92
KBr
KBrþV2O5
PyHBr3
a
Reaction conditions: substrate (1 mmol), 30% H2O2 (2 mmol), and 48%
aqueous HBr (20 mol %), solvent (3 ml) under refluxing condition.
Isolated yield.
a
Reaction conditions as mentioned in Table 1.
Isolated yields.
Using acetonitrile as solvent.
b
c
b
c
As mentioned in Table 1.

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S. L. Jain et al. / Tetrahedron 62 (2006) 6841–6847
pyridiniumhydrobromide perbromide yielded comparable
results, the use of salts such as NaBr and KBr gave very
poor yield of the benzophenone. It was also observed that
the addition of the catalytic amount of vanadium pentoxide
in the reaction mixture of benzhydrol and aqueous H2O2
containing catalytic amount of KBr, accelerated the reaction
rate and the oxidation was completed within 1.5 h (Table 3,
entry 5).
It is worth mentioning that in contrast to aqueous H2O2
and SPC, sodium perborate could oxidize benzhydrol to
benzophenone in the presence of catalytic amount of KBr
(20 mol %) using acetic acid as a solvent (Table 4, entry 3).
The plausible mechanistic pathway for these reactions may
involve the formation of hypobromous acid 2 by the reaction
of peroxide oxidant with hydrobromic acid,10 and its reac-
tion with secondary alcohol 1 to afford hypobromite species
3 which on abstraction of hydrogen yielded corresponding
ketone as shown in Scheme 3.
2.2. Effect of various oxidants
Further with a view to evaluate the efficiency of other oxi-
dants, the oxidation of benzhydrol was carried out with mo-
lecular oxygen and aqueous 70% tert-butylhydroperoxide in
the presence of catalytic amount of aqueous HBr under sim-
ilar reaction conditions. While the reaction did not proceed
with molecular oxygen, the use of TBHP as an oxidant
yielded results comparable to aqueous H2O2. To evaluate
the relative efficiencies of TBHP and aqueous H2O2 as
oxidants, we studied the oxidation of various activated and
non-activated alcohols with 70% TBHP in the presence of
catalytic amount of aqueous HBr under organic solvent free
conditions and the results obtained are presented in Table 1.
All the alcohols were selectively converted to the corre-
sponding ketones and reactivity order was found to be the
same as obtained by using H2O2 as an oxidant. Benzoins
in general were again found to be the most reactive while
alcohols containing aromatic substituents were found to be
more reactive than aliphatic/alicyclic alcohols. Oxidation
of benzhydrol when carried out with TBHP in different sol-
vents yielded results similar to hydrogen peroxide and again
organic solvent free condition was found to be the most
efficient. (Table 2).
A
+
B
OH
Br
HOBr
t
A= HO, BuO
2
B= H, Br, PyHBr2
R1
R2
R1
CH R2
CH
+
H2O
+
HOBr
OBr
3
OH
1
C
O
R2
+
R1
HBr
Scheme 3.
3. Conclusion
In summary, the present method describes an efficient, selec-
tive, and environmentally friendly synthetic methodology for
the oxidation of various secondary alcohols to ketones under
transition metal and organic solvent free conditions. The use
of SPC and SPB as solid oxidants due to their ease of syn-
thesis/handling, storage stability, and high hydrogen per-
oxide content makes it more advantageous than previously
reported methods. Furthermore, the simplicity of the system,
versatility toward a range of activated and non-activated
alcohols, selective oxidation of secondary alcohols in the
presence of primary alcoholic and other functional groups,
simple reaction conditions, and excellent yields of the prod-
ucts make this method a facile, ideal, and attractive synthetic
tool for the oxidation of secondary alcohols to ketones.
The use of solid peroxy compounds, such as sodium perbo-
rate (SPB) and sodium percarbonate (SPC) due to their stor-
age stability, crystalline nature, ease of handling, and higher
hydrogen peroxide contents, has gained considerable atten-
tion in the recent years in various chemical transforma-
tions.11 We therefore studied the oxidation of secondary
alcohols to ketones with these solid oxidants using catalytic
amount of aqueous HBr (Scheme 2). The protocol developed
consists of oxidation of secondary alcohol (1 mmol) with
solid oxidant (SPC/SPB) (2.5 mmol) in the presence of
catalytic amount of aqueous HBr (20 mol %) in acetic acid
(10 mmol) at 50 ꢀC without using any organic solvent as
reaction media (Table 4). All the alcohols were selectively
and efficiently converted to the corresponding ketones in
excellent yields. The presence of acetic acid was found to
be essential in these reactions and in its absence the oxi-
dation of benzhydrol in acetonitrile under similar reaction
conditions was found to be very slow and gave poor yield
of the benzophenone (Table 4, entry 1). This is probably
due to the fast release of hydrogen peroxide from the solid
oxidants in the presence of acetic acid.12 To examine the
effect of temperature, oxidation of benzhydrol was carried
out at different reaction temperatures under similar reaction
conditions, using SPC and SPB as solid oxidants. While the
reaction was found to be slow at room temperature, at 50 ꢀC
the reaction rate was maximum and further increase in the
reaction temperature decreases the reaction rate and afforded
poor yield of the benzophenone probably due to faster
decomposition of solid oxidants at higher temperature.13
4. Experimental
4.1. General
The melting points were determined in open capillaries on
a Buchi apparatus and are uncorrected. The 1H NMR spectra
were recorded on Bruker 300 MHz spectrometer and the
chemical shifts (d) are expressed in parts per million relative
to tetramethylsilane (TMS) as an internal standard. The IR
spectra were recorded on a Perkin–Elmer FTIR X 1760
instrument.
4.2. General experimental procedure for the oxidation
of secondary alcohols using aqueous HBr/H2O2 system
To a stirred solution of secondary alcohol (1 mmol) and
aqueous 30% H2O2 (2 mmol) was added aqueous HBr
(20 mol %) and the mixture was heated at 80 ꢀC under
organic solvent free conditions for the period given in

S. L. Jain et al. / Tetrahedron 62 (2006) 6841–6847
6845
Table 4. Oxidation of secondary alcohols with solid oxidants SPC and SPB
Entry
Substrate
Method A
Reaction time (h)
Method B
Reaction time (h)
Yielda
45
Yielda
40b
CH
OH
1
4.5
1.0
—
6.5
1.5
1.25
1.5
CH
OH
2
3
4
96
—
92
94
90c
90
CH
OH
CH3
CHOH
1.5
OH
5
3.00
90
3.75
86
6
7
8
5.0
82
82
72
6.5
4.5
6.0
80
75
70
OH
C
H
CH3(CH2)4C
OH
CH
6.5
CH3
5.70
OH
OH
9
5.70
72
6.0
70
CH3
OH
10
11
3.5
2.5
85
82
4.5
2.5
80
78
Ph
COOMe
OH
Ph
OH
OH
12
13
5.0
5.5
75
72
6.5
6.0
69
74
CH2OH
CH
OH
(continued)

6846
S. L. Jain et al. / Tetrahedron 62 (2006) 6841–6847
Table 4. (continued)
Entry
Substrate
Method A
Method B
Reaction time (h)
Reaction time (h)
Yielda
89
Yielda
82
C
O
CH
OH
14
2.0
3.50
0.25
CH O
OCH3
CH
OH
C
O
3
15
0.25
97
94
Method A—Reaction conditions: secondary alcohol (1 mmol), 48% aqueous HBr (20 mol %), SPC (2.5 mmol), and acetic acid (10 mmol) at 50 ꢀC under
organic solvent free conditions.
Method B—Experiments carried out with SPB.
Isolated yields.
a
b
Experiment carried out in acetonitrile without acetic acid.
Experiment was carried out using KBr instead of aqueous HBr without any catalyst.
c
Table 1. Progress of the reaction was monitored by TLC
(SiO2). At the end of the reaction the excess hydrogen perox-
ide was destroyed by aqueous bisulfite followed by filtration
through a Buckner funnel. After filtration, the reaction mix-
ture was taken in dichloromethane and organic layer was
washed with water (three times). The combined organic layer
was dried over anhydrous MgSO4 and the solvent was evap-
orated under vacuum to afford crude product, which was
purified by column chromatography on silica gel using ethyl
acetate/hexane (9:1) as an eluent. Evaporation of the solvent
yielded corresponding ketones. Reaction times and yields of
the products are given in Table 2.
(ꢂ)-Camphor (Table 1, entry 4):17 mp 172–173 ꢀC (lit. 175–
177 ꢀC)15 IR (KBr): 2935, 1715, 1440, 1369 cmꢁ1. 1H NMR
(CDCl3) d ppm: 0.97 (s, 6H, CH3), 1.05–1.40 (m, 5H, CH2,
CH), 1.90 (s, 3H, CH3), 2.10–2.20 (m, 2H, CH2).
1-Octyne-3-one (Table 1, entry 5): oil, IR (KBr): 3278, 2950,
2105, 1680, 1180 cmꢁ1. 1H NMR (CDCl3) d ppm: 0.89–0.95
(m, 3H CH3), 1.10–1.40 (m, 6H, CH2), 2.30–2.35 (m, 2H,
CH2), 3.10 (s, 1H, ^CH).
(ꢁ)-Menthone (Table 1, entry 6):14 bp 203–204 ꢀC/760 mm
(lit. 207–210 ꢀC/760 mm)15 IR (KBr) 2940, 1710, 1443,
1
1369 cmꢁ1. H NMR (CDCl3) d ppm: 0.80–0.95 (m, 10H,
4.3. Typical experimental procedure for oxidation
of secondary alcohols using aqueous HBr/solid
oxidant system
CH3, CH2), 1.38–1.75 (m, 5H, CH2, CH), 2.18–2.52 (m,
3H, CH3).
4-Methylcyclohexanone (Table 1, entry 7):18 colorless oil, IR
1
In a stirred mixture of benzhydrol (0.18 g, 1 mmol), SPB
(0.39 g, 2.5 mmol), and acetic acid (0.6 ml, 10 mmol) was
added dropwise aqueous HBr (20 mol %, 0.2 mmol,
0.03 ml) at 50 ꢀC. The mixture was stirred for 2 h. After
completion of the reaction, the solvent was evaporated under
vacuum. The residue thus obtained was extracted with water
and dichloromethane. The organic layer was removed and
washed again with water (two times). Finally, the organic
layer was removed and dried over anhydrous MgSO4. The
solvent was evaporated under reduced pressure to yield
pure benzophenone (0.171 g, 94%). All the products were
identified by comparing their physical and spectral data
(KBr): 2932, 2869, 1720, 1156 cmꢁ1. H NMR (CDCl3)
d ppm: 0.92 (d, J¼6.8 Hz, 3H, CH3), 1.10–1.25 (m, 5H,
CH2, CH), 1.24–1.32 (m, 4H, CH2).
Methyl benzoylformate (Table 1, entry 8):19 bp 247–248 ꢀC
(lit. 248–250 ꢀC/760 mm),15 IR (KBr): 3076, 2941, 1740,
1680, 1315, 1204. H NMR (CDCl3) d ppm: 3.95 (s, 3H,
CH3), 7.40–8.20 (m, 5H, Ar H).
1
2-Methylcyclohexanone (Table 1, entry 9):18 colorless oil, IR
(KBr): 2935, 2863, 1718, 1370, 1156 cmꢁ1 1H NMR
.
(CDCl3) d ppm: 1.00 (d, J¼7.0 Hz, 3H, CH3), 1.34–1.36
1
(IR and H NMR) with the literature values. The physical
and spectral data of the products are given below.
(m, 6H, CH2), 1.62–1.80 (m, 3H).
2-Hydroxymethylcyclohexanone (Table 1, entry 10):20 color-
Benzophenone (Table 1, entry 1):14 mp 47 ꢀC (lit. 48–
less oil, IR (KBr) 3421, 2960, 1710, 1169 cmꢁ1. H NMR
1
49 ꢀC)15 IR (KBr): 3028, 1661, 1489, 1204, 1151 cmꢁ1
.
(CDCl3) d ppm: 1.36–2.61 (m, 9H, CH2), 2.79 (br s, 1H,
OH), 3.50–3.67 (m, 2H, CH2).
1H NMR (CDCl3) d ppm: 7.30–7.55 (m, 6H, Ar H), 7.90–
8.00 (m, 4H, Ar H).
Hexan-2-one (Table 1, entry 11):16 oil, IR (KBr): 2961, 2937,
Acetophenone (Table 2, entry 2):16 oil, IR (KBr): 3086,
1718, 1368, 1165 cmꢁ1. H NMR (CDCl3) d ppm: 0.90 (t,
1
2923, 1685, 1430, 1267, 1160 cmꢁ1
d ppm: 2.50 (s, 3H, CH3), 7.45–7.85 (m, 5H, Ar H).
.
1H NMR (CDCl3)
J¼7.2 Hz, 3H, CH3), 1.27–1.32 (m, 2H, CH2), 1.52–1.58
(m, 2H), 2.14 (s, 3H, CH3) 2.43 (t, J¼7.2 Hz, 2H, CH2).
Cyclohexanone (Table 1, entry 3):14 bp 153 ꢀC/760 mm (lit.
1-Phenyl-1-hepten-3-one (Table 1, entry 12):21 colorless oil,
155 ꢀC/760 mm)15 IR (KBr): 2940, 1712, 1449, 1235 cmꢁ1
.
IR (KBr): 3010, 2961, 2937, 1720, 1364, 1162 cmꢁ1
.
1H NMR (CDCl3) d ppm: 1.80–2.15 (m, 6H, CH2), 2.30–
2.38 (m, 4H, CH2).
1H NMR (CDCl3) d ppm: 0.90 (t, J¼7.0 Hz, 3H, CH3),
1.35–1.55 (m, 4H, CH2), 2.58 (t, J¼6.2 Hz, 2H, CH2),

S. L. Jain et al. / Tetrahedron 62 (2006) 6841–6847
6847
2. (a) Jones, C. W. Application of Hydrogen Peroxide and
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(b) Strukul, G. Catalytic Oxidations with Hydrogen Peroxide
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9. (a) Sato, K.; Aoki, M.; Takagi, J.; Noyori, R. J. Am. Chem. Soc.
1997, 119, 12386; (b) Sato, K.; Takagi, J.; Aoki, M.; Noyori, R.
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6.74 (d, 1H, J¼13.2 Hz, aCH), 7.28–7.60 (m, 6H, aCH and
Ar H).
4-tert-Butyl cyclohexanone (Table 1, entry 13):23a,24a mp
45–47 ꢀC (lit. 47–50 ꢀC)15 IR (KBr): 2955, 1718, 1468,
1
1366 cmꢁ1. H NMR (CDCl3) d ppm: 0.90 (s, 9H, CH3),
1.30–1.60 (m, 5H), 2.10–2.35 (m, 4H).
Cyclopentanone (Table 1, entry 14):23b,24b bp 129–130 ꢀC/
760 mm (130–131 ꢀC/760 mm)15 IR (KBr) 2942, 1446,
1
1236 cmꢁ1. H NMR (CDCl3) d ppm: 1.82–210 (m, 4H,
CH2), 2.34–2.40 (m, 4H, CH2).
3-Hydroxymethyl-4-heptanone (Table 1, entry 15):20 color-
1
less liquid. IR (KBr): 3422, 1705 cmꢁ1. H NMR (CDCl3)
d ppm: 0.90 (t, J¼7.4 Hz, 3H, CH3), 0.95 (t, J¼7.5 Hz,
3H, CH3), 1.39–1.70 (m, 4H, CH2), 2.14 (br s, 1H, OH),
2.45 (t, J¼7.3 Hz, 2H, CH2), 2.60–2.68 (m, 1H, CH),
3.70–3.75 (m, 2H, CH2).
2-Hydroxy-1-phenylethanone (Table 1, entry 16):22 mp 83–
84 ꢀC (lit. 84–85 ꢀC) IR (KBr): 3428, 1682 cmꢁ1 1H
.
NMR (CDCl3) d ppm: 2.98 (s, 1H, OH), 4.85 (s, 2H,
CH2), 7.50–7.85 (m, 5H, Ar H).
Benzil (Table 1, entry 17):14 mp 92–93 ꢀC (lit. 94–95 ꢀC)15
1
IR (KBr): 3043, 1678, 1659, 1594, 1315, 1176 cmꢁ1. H
NMR (CDCl3) d ppm: 7.52–7.61 (m, 6H, Ar H), 7.80–7.89
(m, 4H, Ar H).
12. Vaino, A. R. J. Org. Chem. 2000, 65, 4210.
13. Elvers, B.; Hawkins, S. Ullmanns Encyclopedia of Industrial
Chemistry; VCH: Weinheim, 1991; Vol. A-19, p 117.
14. Velusamy, S.; Punniyamurthy, T. Org. Lett. 2004, 6, 217.
15. Aldrich Handbook of Fine Chemicals and Laboratory
Equipments; Sigma–Aldrich: Milwaukee, WI, 2003–2004.
16. Qian, W.; Jin, E.; Bao, W.; Zhang, Y. Tetrahedron 2006, 62,
556.
17. Surendra, K.; Srilakshmi Krishnaveni, N.; Arjun Reddy, M.;
Nageswar, M.; Rama Rao, K. J. Org. Chem. 2003, 68, 2058.
18. Ragagnin, G.; Betzemeier, B.; Quici, S.; Knochel, P. Tetra-
hedron 2002, 58, 3985.
4,40-Dimethoxybenzil (Table 1, entry 18):25 mp 130–131 ꢀC
(lit. 132–134 ꢀC)15 IR (KBr): 3046, 2959, 1682, 1598, 1314,
1
1171 cmꢁ1. H NMR (CDCl3) d ppm: 3.80 (s, 6H, CH3),
6.94 (d, J¼8.0 Hz, 4H, Ar H), 7.94 (d, J¼8.0 Hz, 4H, Ar H).
14,15-Octacosanedione (Table 1, entry 19): mp 67–69 ꢀC
(lit. 70–72 ꢀC)26 IR (KBr) 2941, 2877, 1724, 1449, 1389,
1
1163 cmꢁ1. H NMR (CDCl3) d ppm: 0.89–1.00 (m, 6H,
CH3), 1.10–1.72 (m, 44H, CH2), 2.30 (m, 4H, CH2).
19. (a) Pouchart, C. J. The Aldrich Library of NMR Spectra, II ed.;
1983; Vol. 2, p 277 D; (b) Pouchart, C. J. The Aldrich Library of
Infrared Spectra, III ed.; 1981; p 1026 D.
Acknowledgements
20. Kim, D. W.; Hong, D. J.; Seo, J. W.; Kim, H. S.; Kim, H. K.;
Song, C. E.; Chi, D. Y. J. Org. Chem. 2004, 69, 3186.
21. Kim, S.; Lee, J. J. Org. Chem. 1983, 48, 2608.
22. Kuhakarn, C.; Kittigowittana, K.; Pohmakotr, M.; Reutrakaul,
V. Tetrahedron Lett. 2005, 61, 8995.
We are thankful to the Director, IIP for his kind permission
to publish these results. Suman L. Jain and Vishal B. Sharma
are thankful to CSIR, New Delhi for the award of Research
Fellowships.
23. (a) Pouchart, C. J. The Aldrich Library of NMR Spectra, II ed.;
1983; Vol. 1, p 397 B; (b) Pouchart, C. J. The Aldrich Library of
NMR Spectra, II ed.; 1981; Vol. 1, p 393 B.
References and notes
1. (a) Punniyamurthy, T.; Velusamy, S.; Iqbal, J. Chem. Rev. 2005,
105, 2329; (b) Sheldon, R. A.; Kochi, J. K. Metal Catalyzed
Oxidations of Organic Compounds; Academic: New York,
NY, 1981; (c) Simandi, L. I. Catalytic Activation of Dioxygen
by Metal Complexes; Kluwer Academic: Netherlands, 1992;
(d) Clark, J.; Macquarrie, D. Handbook of Green Chemistry &
Technology; Blackwell: MA, 2002.
24. (a) Pouchart, C. J. The Aldrich Library of Infrared Spectra,
III ed.; 1983; p 257 H; (b) Pouchart, C. J. The Aldrich
Library of Infrared Spectra, III ed.; 1981; p 255 C.
25. (a) Pouchart, C. J. The Aldrich Library of NMR Spectra, II ed.;
1983; Vol. 2, p 59 B; (b) Pouchart, C. J. The Aldrich Library of
NMR Spectra, III ed.; 1981; p 882 A.
26. Bouquet, F.; Paquot, C. Bull. Soc. Chim., France 1948, 1165.