Reusable Palladium Nanoparticles Catalyzed Oxime Ether Directed Mono Ortho-Hydroxylation under Phosphine Free Neutral Condition

Article abstract of DOI:10.1002/adsc.201801340

An efficient, reusable and stable binaphthyl stabilized Pd-nanoparticles (Pd-BNP) catalyzed the direct ortho-C?H hydroxylation of acetophenone oxime ethers under neutral and phosphine ligand-free condition has been developed. A readily available, economic, safe and greener oxidant oxone has been used in this direct ortho-hydroxylation. The scope of the reaction has been studied with various acetophenone oxime ethers including electron rich to electron deficient system and the reaction afforded only mono hydroxylated products in a highly regioselective manner. Several control experiment results confirmed that the oxone is the hydroxyl source. The Pd-BNP catalyst has been reused up to five times. The heterogeneous test confirmed that the reaction is catalyzed by the heterogeneous Pd-BNP catalyst. (Figure presented.).

Full text of DOI:10.1002/adsc.201801340

Title: Reusable Palladium Nanoparticles Catalyzed Oxime Ether
Directed Mono Ortho-Hydroxylation under Phosphine Free
Neutral Condition
Authors: Rajib Saha, Naziya Parveen, Naorem Nihesh, and
Govindasamy Sekar
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.201801340
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
FULL PAPER
DOI: 10.1002/adsc.201((will be filled in by the editorial staff))
Reusable Palladium Nanoparticles Catalyzed Oxime Ether
Directed Mono Ortho-Hydroxylation under Phosphine Free
Neutral Condition
Rajib Saha, Naziya Perveen, Naorem Nihesh and Govindasamy Sekar *
Department of Chemistry, Indian Institute of Technology Madras, Chennai-600036, India
Email: gsekar@iitm.ac.in
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.((Please
delete if not appropriate))
Abstract. An efficient, reusable and stable binaphthyl stabilized Pd-nanoparticles (Pd-BNP) catalyzed
the direct ortho-C-H hydroxylation of acetophenone oxime ethers under neutral and phosphine ligand-
free condition has been developed. A readily available, economic, safe and greener oxidant oxone has
been used in this direct ortho-hydroxylation. The scope of the reaction has been studied with various
acetophenone oxime ethers including electron rich to electron deficient system and the reaction
afforded only mono hydroxylated products in a highly regioselective manner. Several control
experiment results confirmed that the oxone is the hydroxyl source. The Pd-BNP catalyst has been
reused up to five times. The heterogeneous test confirmed that the reaction is catalyzed by the
heterogeneous Pd-BNP catalyst.
Keywords:
Palladium;
Nanoparticles;
Hydroxylation;
Oxime ethers;
Oxone
in several biologically active molecules and natural
products (Figure 1). [7]
Introduction
A conversion of most fundamental and inert C-H
bonds of organic molecules to other useful
functional groups has many practical advantages.[1]
Particularly, the direct C-H functionalization
strategy stands unique as an unfunctionalized
molecule can be functionalized.[2] To functionalize a
particular C-H bond in a molecule, transition metal
catalysts and the directing group were introduced.[3]
The transition metal can interact with inactive C-H
bonds in presence of directing group and generate a
thermodynamically stable five- or six-membered
active metallacyclic intermediate.[4] Subsequently,
the interaction of particular reagents with the active
intermediate gives the desired product.[4] A wide
range of reactions has been studied to date involving
the cleavage of ortho aromatic C(sp2)-H bonds with
an appropriate directing group.[5] Now, the choice of
the directing group has been made in such a way that
after completion of the reaction, it can be removed
by simple chemical operation. N-methoxy oxime
ether is one such useful versatile directing groups,[6]
which can be easily removed by simple acid workup
after the reaction.
Figure
1
Representative examples of ortho-
acylphenols with biological activity
In the past few decades, several methods have
been developed to synthesize phenols. Among all,
transition metal catalyzed the direct oxidative
hydroxylation of C-H bonds have emerged as a
powerful strategy to synthesize phenols.[8] Earlier,
for the synthesis of 2-hydroxy acetophenone, two
common classical approaches such as Fries
rearrangement or Friedel-Craft acylation of phenol
were used (Scheme 1a).[9] But the problem
associated with these classic approaches is that it
produces a mixture of both para and 2-hydroxy
acetophenone products which is very difficult to
separate. To overcome the formation of a mixture of
products, the direct ortho-hydroxylation of ketones
or ketoxime ethers has been introduced to synthesize
of 2-hydroxy acetophenone (Scheme 1b).[10-12]
Particularly, the transition metal catalyzed direct
hydroxylation is an enormously simple and
The hydroxylation of an aromatic C-H bond is of
considerable importance in both industry and
academics. The ortho-acylphenol subunits are found
1
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
attractive approach to synthesize 2-hydroxy
acetophenone.
synthesis of ortho acylphenol from acetophenone
oxime ethers. Here in, we report the external ligand-
free, Pd-BNP catalyzed, regioselective mono
hydroxylation of acetophenone oxime ether for the
synthesis of 2-hydroxy acetophenone under neutral
reaction condition (Scheme 1d).
The last two decades, the synthesis of 2-hydroxy
acetophenone via C-H activation with PIFA
(phenyliodine(III) bis(trifluoracetate)), PIDA/TFA
(phenyliodine diacetate)/(trifluro acetic acid), or
K2S2O8/TFA reagents followed by hydrolysis of the
corresponding ester intermediates has developed
(Scheme 1b).[10-13] In spite of its significance, there
are few common challenges associated with the
direct hydroxylation of C-H bond, such as i) the
hydroxylation of high electron deficient substrates
are less efficient, and ii) the use of acids such as
AcOH and TFA as a solvent boundary of the
functional group tolerance. Recently, Jiao et al.
reported a homogeneous palladium-catalyzed direct
ortho C−H hydroxylation of ketoxime ether using
triphenyl phosphine ligand for smooth conversion
(Scheme 1c).[14] Although the methodology is good
enough for the electron deficient system, the
reaction requires external phosphine ligand for
smooth conversions. Also, the challenge of
separation of a trace amount of metal impurity from
the product in case of homogeneous catalysis
remains unsolved. Other hands, the advantages of
using Pd-NPs as catalysts are good selectivity, low
catalyst loading, and enhanced reactivity because of
their high catalytic surface area.[15]
Results and Discussion
For the synthesis of ortho-hydroxy acetophenone
oxime ethers, the initial investigation was started by
using 4-nitro-substituted acetophenone oxime ether
1a and Pd-BNP (5 mol%) catalyst, IBX (2-
Iodoxybenzoic acid) as oxidant in DCE (1,2-
dichloroethane) solvent. Baffledly, the reaction gave
the hydroxylated product 2a in trace amount. On
changing the solvent to 1,1,2-trichloroethane, the
yield of the desired product was observed in 14%
(Table 1, entry 1). Hence, the initial optimization of
the reaction condition was carried out with 1,1,2-
trichloroethane. Oxidants such as aq. TBHP, K2S2O8,
and O2 were found to be ineffective (entries 2-4).
Surprisingly, the oxone gave the yield of the
hydroxylated product in 60% (entry 5). Except for
CHCl2CH2Cl (1,1,2,-TCE), other solvents with
medium polarity like CH3CN, THF and dioxane, and
highly polar protic solvents like DMSO and DMF
were unable to improve the yield of product (entries
6-10). In fact, the presence of highly polar protic
solvents like AcOH hydrolysed the oxime to the
ketone (entry 11). It is noteworthy that 1,1,2,2-TCE
(1,1,2,2-tetrachloroethane) gave the best yield of 2a
in 70% (entry 12). While screening the amount of
oxidant, it was observed that increased the amount
of oxone from 4 equivalents to 5 equivalents,
decreased the yield of the product 2a (entry 13).
However, a gradual increase in the yield was
observed as the amount of oxone was decreased
from 4 to 2 equivalents (entry 14).
However, the further reduction of oxone
equivalents did not give better yield. Then the
quantity of catalyst was varied. Increasing the
catalyst loading did not help in improving the yield
of the product. However, there was a significant
increase in the yield (84%) when the catalyst loading
was decreased to 4 mol% (entry 17). Further
reduction in the catalyst load did not prove helpful.
On increasing the temperature to 110 oC, an increase
in the yield (88%) was observed (entry 19). Further
increase in the temperature reduced the yield of the
product 2a. There was no product formation in the
absence of Pd-BNP catalyst.
Scheme 1 Synthesis of ortho-acylphenols
Our ongoing efforts in Pd-NPs catalyzed organic
transformation[16] prompted us to explore the
2
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
Table 1 Optimization of reaction parametersa
Table
2
Pd-nanoparticles catalyzed ortho-
hydroxylation of acetophenone oxime ethera
Entry
1
Oxidants
IBX
Solvent
1,1,2-TCE
1,1,2-TCE
1,1,2-TCE
1,1,2-TCE
1,1,2-TCE
MeCN
Yield(%)b
14
0
9
2
3
TBHP (aq)
K2S2O8
Oxygen
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
Oxone
4
5
0
60
30
15
22
7
6
7
THF
8
9
dioxane
DMF
10
11
DMSO
AcOH
0
0
12
CHCl2CHCl2 70
CHCl2CHCl2 64
CHCl2CHCl2 80
CHCl2CHCl2 69
CHCl2CHCl2 74
CHCl2CHCl2 84
CHCl2CHCl2 79
CHCl2CHCl2 88
CHCl2CHCl2 77
13c
14d
15e
16d,f
17d,g
18d,h
19d,g,i
20d,g,j
aReaction conditions: 1a (0.25 mmol), 12 mg of Pd-BNP
(5 mol%, 11 wt% by ICP-OES analysis) in 2 mL solvent
at 100 oC in 24 h. bIsolated yield. c5.0 equiv. of oxone was
d
e
used. 2.0 equiv. of oxone was used. 1.0 equiv. of oxone
aReaction conditions: 1 (0.25 mmol), Catalyst (4 mol%) and
2.0 equiv. of oxone in 2 mL solvent at 110 oC.
f
g
was used. 6.0 mol% of Pd-BNP was used. 4.0 mol% of
h
Pd-BNP was used. 3.0 mol% of Pd-BNP was used.
iReaction was carried out at 110 oC. Reaction was carried
j
out at 120 oC.
Having this optimized reaction condition in hand,
we explored the scope of the substrates and the
results are summarized in Table 3. Significantly, the
direct hydroxylation of substrates with electron-
withdrawing and electron-donating, such as NO2,
COOH, COOMe, OMe, and Me respectively were
very efficient and gave high yields of hydroxylated
products 2a-2c and 2i-2j. Furthermore, the halogen
substituents such as F, Cl and Br were well tolerated
under the optimized reaction conditions and gave
good yields (81-89%) of products (2d-2f). The
substrates comprise a substitution at meta position,
provided less sterically crowded isomers (2g and 2k).
The ortho substituted substrates were unable to give
the hydroxylated product 2l due to the steric
crowding between the ortho substituent and the
directing group. Then, the optimization reaction was
tested with different O-methyl and O-alkyl keto
oximes ether substrates. Interestingly, in disparity to
previous reports[10-14] which showed a mixture of
products in many examples, the Pd-BNP catalyzed
For further improvement in the yield of product (2a),
several palladium nanoparticles have been
introduced for ortho hydroxylation and the results
are summarized in Table-2. By using oxone as
o
oxidant, CHCl2CHCl2 as a solvent at 110 C, other
palladium nanoparticles such as phenyl stabilized
palladium nanoparticle (Pd-PNP), 4-docalyl-phenyl
stabilized nanoparticles (Pd-DPNP), 4-docaoxyl-
phenyl stabilized nanoparticles (Pd-DOPNP), 8-
quinonyl stabilized nanoparticles (Pd-QNP), 4-
methyl-phenyl stabilized nanoparticles (Pd-TNP)
and commercially available palladium- nanoparticles
( 20-30 nm) have been used to increase the yield of
product (entries 1-7). Among all the nanoparticles
used, the Pd-BNP showed higher catalytic activity
than others. Notably, the commercial available Pd/C
gave very low yield (28%) of hydroxylated product
(2a).
3
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
ortho-hydroxylation is highly selective toward the
mono hydroxylated products (2m–2p). Notably, the
reaction did not produce dihydroxylated products or
C(sp3)-H functionalized products which is confirmed
Table 4 Pd-BNP catalyzed ortho-hydroxylation of
amide substituted acetophenone oxime ether
1
by GCMS and H NMR analysis of crude reaction
mixture. The O-alkyl oximes such as O-ethyl
acetophenone oximes and O-benzyl acetophenone
oximes gave the corresponding hydroxyl product in
moderate to good yield under optimized reaction
conditions (2q-2w). When O-methyl benzophenone
oxime was treated under standard reaction
conditions, it gave the corresponding mono
hydroxylated product (2x) in 76%. However, 2-
benzoyl pyridine oxime ether did not give
hydroxylated product 2y.
aReaction conditions: 1 (0.25 mmol), 9.6 mg of Pd-BNP
(4 mol%, 11 wt% by ICP-OES analysis) and 2.0 equiv. of
oxone in 2 mL solvent at 110 oC.
Table 3 Pd-BNP catalyzed ortho-hydroxylation of
N-methoxy acetophenone oxime ether
To check the scalability of Pd-BNP catalyzed direct
hydroxylation of acetophenone oxime ethers, a gram
scale reaction was carried out by using 1 gram of 1a
under the optimized reaction condition. This reaction
gave 75% yield of corresponding ortho-
hydroxylated product in 24 h (Scheme 2a). Further,
the treatment of ortho-hydroxylated product 2a with
40% HCl aqueous solution in THF solvent at
ambient temperature gave the corresponding N-OMe
cleaved products 3 in 96% yield (Scheme 2b).
Scheme 2 (a) Gram scale synthesis, (b) hydrolysis
of oxime ether group.
The alkaline photo-irradiation of hydroxyl
acetophenone oxime ether 2h gave the
corresponding
benzoxazole moiety 4 in good yield (Scheme 3).
biologically
active
2-methyl
aReaction conditions: 1 (0.25 mmol), 9.6 mg of Pd-BNP (4
mol%, 11 wt% by ICP-OES analysis) and 2.0 equiv. of
oxone in 2 mL solvent at 110 oC.
Then, the methodology has been applied for the
synthesis of amide substituted ortho acylphenols
(Table 4). Interestingly, amides with the electron-
donating group, electron neutral group and halogen
substituents gave good yields of corresponding
mono hydroxylated products without affecting the
amide group 2x-2ae. Notably, the thioamides
containing ortho-hydroxy acetophenones yielded the
products 2af and 2ag in 79% and 82% yields.
Scheme 3 synthesis of benzoxazole.
To know the source of the hydroxyl group, few
control experiments were carried out. The hydroxyl
group can be furnished by molecular oxygen,
4
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
moisture or oxone. When the reaction was carried
out in presence of 3 equiv. of H2O18, the yield of
product diminished meaningfully without detection
of 18O in the product (Scheme 4a). Then the reaction
was conducted in absence of molecular oxygen.
Under the nitrogen atmosphere, this reaction gave
the corresponding hydroxylated product 2a in 80%
(Scheme 4b). From the above two control
experiments, it can be ruled out that the source of
oxygen atom for hydroxyl group is from molecular
oxygen or H2O. The oxidant oxone may be the
source for the hydroxyl group (Scheme 4). It is well
recognized that the oxone can generate hydroxyl
radical or superoxide in the reaction medium which
may act as a source of the hydroxyl group.[17]
Oxone can generate HOCl in presence of chloride
ion. This HOCl can be the source of OH group.
When a controlled experiment was carried out in
presence of HCl or NaCl in toluene solvent, no
product formation was observed. So the OH group is
not generated from HOCl (Scheme 6a and 6b). All
the control experiments suggested that the source of
the hydroxyl group is oxone.
Scheme
6
Control experiments of ortho
hydroxylation
It is expected that the oxone oxidizes the Pd(0) to
Pd(II) on the surface of the catalyst during the
reaction. The reaction residue contains a major
amount of Pd(II) which is confirmed by XPS
analysis (See SI). Further, the reaction residue
containing Pd(II) is reduced to Pd(0) using NaBH4.
After reduction, the insoluble part in the reaction
mixture was solubilised in water, however, Pd-BNP
remained insoluble in water. After completion of the
reduction, nanoparticles were settled down by
centrifuging the reaction mixture. Then it was
washed with ethanol, dried and reused for the next
catalytic cycles. The catalyst was reused up to five
cycles and desired product 2a was isolated in yields
of 84%, 80%, 79%, 76% and 70% in successive runs
(Figure 2).
Scheme
hydroxylation
4
Control experiments of ortho
To determine whether the reaction proceeded via a
radical path or not, the reaction was carried out in
presence of 2 equivalents of radical trapping agent
TEMPO. However, in presence of TEMPO, the
reaction proceeded smoothly and gave the 83% yield
of product (Scheme 5a). Then the superoxide
trapping experiment was carried out in presence of
9,10-dimethyl anthracene under the optimized
reaction condition. The endoperoxide product
1
formation through [4+2] cycloaddition between O2
and 9,10-dimethyl anthracene is not observed. This
result shows that the superoxide might have not
generated in this reaction (Scheme 5b).
Figure 2 Bar diagram of yield of product 2a and
Scheme
5
Control experiments of ortho
recycled Pd-BNP for the five catalytic cycles
hydroxylation
5
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
After five cycles, HRTEM was recorded for the
recycled Pd-BNP. Particle size of nanoparticles was
similar before the reaction and after five catalytic
cycles. From TEM image, it was confirmed that
there is no agglomeration of nanoparticles (Figure 3).
The mercury poisoning test (See SI) suggested that
the reaction catalyzed by heterogeneous Pd-BNP not
by leached homogeneous Pd complex.
Conclusion
In summary, an efficient method of Pd-BNP
catalyzed ortho-hydroxylation of acetophenones
oxime ether has developed. This methodology gave
a highly regioselective mono hydroxylated product.
Differently substituted acetophenones, including
electron deficient acetophenones, also gave a good
yield of corresponding hydroxylated product. The
hydroxylated product was successfully converted to
corresponding benzoxazole and keto derivatives by
photo-irradiation and acid hydrolysis of oxime group
respectively. The heterogeneous nature of Pd-BNP
was confirmed by mercury poisoning test and hot
filtration test. The Pd-BNP was recovered and
reused up to five cycles without loss of its activity,
and HRTEM images showed that there is no
significant loss of NPs size.
Figure 3 HRTEM image of fresh Pd-BNP (left) and
after five catalytic cycles of Pd-BNP (right)
To confirm that the reaction is catalyzed by
heterogeneous Pd-BNP and not by the leached
homogeneous Pd, several experiments have been
conducted such as hot centrifugation test and
mercury poisoning test. In hot centrifugation test, the
Pd-BNP was removed from the reaction mixture by
centrifuging in the middle of the reaction at two
different time intervals from two different set of
reactions. After that, the oxidant oxone was added
into both filtrates (liquid portions) and the reaction
Experimental Section
1a (98 mg, 0.5 mmol), Pd-BNP (19 mg, 4 mol%) and
oxone (614 mg, 2 equiv) were added to an 20 mL reaction
tube with a magnetic stir bar under air. CHCl2CHCl2 (2.0
mL) was added and then the mixture was stirred at 110o C
for 24 h. After completing the reaction, the solution was
diluted with ethyl acetate (10 mL) and washed with brine
(3 mL) followed by ethyl acetate (3x15 mL). Then the
organic layer was dried over anhydrous Na2SO4 and
filtered. Then the filtrate was evaporated under reduced
pressure. The crude reaction mixture was purified by
column chromatography on silica gel to get the desired
hydroxylated product.
o
was allowed to continue at 110 C. It was observed
that the reaction did not proceed in both liquid
portions. These results clearly show that the active
species is Pd-BNP and not the homogeneous leached
Pd. (Figure 4).
1-(2-Hydroxy-4-nitrophenyl)ethanone O-methyl oxime
(2a) Yield 88%; 46 mg; white solid; melting point 116-
118 oC; 1H NMR (DMSOd6, 400 MHz) 2.21 (s, 3H), 3.95
(s, 3H), 7.57 (d, J = 8.0 Hz, 1H), 7.60-7.81 (m, 2H), 11.11
(s, 1H); 13C NMR (DMSOd6, 100 MHz) δ 13.9, 62.0,
110.7, 128.3, 130.1, 148.2, 155.7, 156.5 ppm; FTIR (film)
3690, 3055, 2306, 1525, 1424, 1265, 738 cm-1; HRMS
(m/z): [M+H]+ calcd for C9H11N2O4: 211.0718; found:
211.0720.
(E)-3-Hydroxy-4-(1-(methoxyimino)ethyl)benzoic acid
(2b) Yield 78%; 41 mg; white solid; melting point 132-
134 oC; 1H NMR (DMSOd6, 400 MHz) 2.22 (s, 3H), 3.94
(s, 3H), 7.41 (d, J = 7.6 Hz, 2H), 7.47 (d, J = 8.4 Hz, 1H),
10.72 (s, 1H), 13.03 (s, 1H); 13C NMR (DMSOd6, 100
MHz) δ 13.5, 62.0, 117.0, 119.8, 125.0, 129.0, 132.5,
156.2, 156.9, 166.9 ppm; FTIR (film) 3691, 3056, 2685,
2306, 1699, 1565, 1424, 1265, 1044, 897, 727 cm-1;
HRMS (m/z): [M+H]+ calcd for C10H12NO4: 210.0766;
found: 210.0769.
Figure 4 Hot centrifugation test for the catalyst
removal after 5 h (black), 10 h (red).
6
This article is protected by copyright. All rights reserved.

10.1002/adsc.201801340
Advanced Synthesis & Catalysis
Methyl-(E)-3-hydroxy-4-(1-(methoxyimino)ethyl)-
benzoate (2c) Yield 81%; 45 mg; white solid; melting
(DMSOd6, 400 MHz) 2.22(s, 3H), 2.25 (s, 3H), 3.9 (s,
3H), 6.70(d, J = 9.2 Hz, 2H), 7.33 (d, J = 7.6 Hz, 1H),
10.77 (s, 1H); 13C NMR (DMSOd6, 100 MHz) δ 12.3,
20.8, 61.9, 116.6, 117.0, 118.0, 128.2, 140.7, 156.7, 158.0
ppm; FTIR (film) ) 3689, 3056, 2306, 1603, 1428, 1266,
896, 740 cm-1; HRMS (m/z): [M+H]+ calcd for
C10H14NO2 : 180.1025; found : 180.1051.
o
1
point 104-106 C; H NMR (CDCl3, 400 MHz) 2.32 (s,
3H), 3.91 (s, 3H), 4.03 (s, 3H), 7.46 (d, J = 8.4 Hz, 1H),
7.54 (dd, J = 8.4 Hz, 1.6Hz, 1H), 7.61 (d, J = 1.2 Hz, 1H),
11.33 (s, 1H); 13C NMR (CDCl3, 100 MHz) δ 11.8, 52.4,
62.8, 118.6, 120.0, 122.2, 127.6, 127.7, 132.0, 157.8,
157.9, 166.7 ppm; FTIR (film) 3688, 3056, 2986, 2306,
1565, 1428, 1266, 897, 748 cm-1; HRMS (m/z): [M+Na]+
calcd for C11H13NO4Na : 246.0742; found: 246.0724.
(E)-1-(2-Hydroxy-4-methoxyphenyl)ethan-1-one
O-
methyl oxime (2j) Yield 80%; 39 mg; colourless liquid;
1H NMR (DMSOd6, 400 Hz) 2.22(s, 3H), 3.75 (s, 3H),
3.91 (s, 3H), 6.39 – 6.55 (m,2H), 7.39 (d, J = 8.8 Hz, 1H),
11.08 (s, 1H); 13C NMR (DMSOd6, 100 MHz) δ 12.1,
55.2, 61.8, 101.4, 105.8, 112.1, 129.5, 158.0, 158.5, 161.3
ppm; FTIR (film) ) 3670, 3056, 2941, 2683, 2304, 1623,
1602, 1265, 1045, 740 cm-1; HRMS (m/z): [M+K]+ calcd
for C10H13NO3K : 234.0533; found : 234.0517.
1-(4-Flouro2-hydroxyphenyl)ethanone
O-methyl
oxime (2d) Yield 84%; 38 mg; white solid; melting point
o
1
50-52 C; H NMR (DMSOd6, 400 MHz) 2.22 (s, 3H),
3.92 (s, 3H), 6.69-6.76 (m, 2H), 7.46 (dd, J = 6.8 Hz, JH-F
= 9.2 Hz, 1H), 11.11 (s, 1H); 13C NMR (DMSOd6, 100
MHz) δ 13.0, 61.9, 103.4 (J = 24.3 Hz), 106.1 (J = 21.9
Hz), 117.0, 130.4 (J = 12.6 Hz), 157.1, 158.3, 163.6 (J =
244.4 Hz) ppm; FTIR (film) 3686, 3056, 2984, 2302,
1612, 1423, 1267, 1051, 738 cm-1; HRMS (m/z): [M+H]+
calcd for C9H11FNO2: 184.0773; found: 184.0782.
(E)-1-(2-Hydroxy-5-methylphenyl)ethan-1-one
O-
methyl oxime (2k) Yield 85%; 38 mg; colourless liquid;
1H NMR (CDCl3, 400 MHz) 2.30 (s, 6H), 4.00 (s, 3H),
6.87 (d, J = 8.4 Hz, 1H), 7.06 (d, J = 8.4 Hz, 1H), 7.19 (s,
1H), 11.07 (s, 1H); 13C NMR (CDCl3, 100 MHz) δ 11.6,
20.8, 62.5, 117.2, 118.1, 127.9, 128.1, 131.6, 155.7,
158.4 ppm; FTIR (film) 3687, 3055, 2306, 1603, 1428,
1267, 896, 740 cm-1; HRMS (m/z): [M+H]+ calcd for
C10H14NO2: 180.1025; found: 180.1031.
1-(4-Chloro-2-hydroxyphenyl)ethanone
O-methyl
oxime (2e) Yield 81%; 40 mg; white solid; melting point
o
1
50-52 C; H NMR (DMSOd6, 400 MHz) 2.20 (s, 3H),
3.93 (s, 3H), 6.90-6.97 (m, 2H), 7.41 (d, J = 8.4 Hz, 1H),
10.97 (s, 1H); 13C NMR (DMSOd6, 100 MHz) δ 13.7,
61.9, 116.2, 119.1, 119.6, 130.1, 134.5, 156.9, 157.3 ppm;
FTIR (film) 3686, 3056, 2304, 1590, 1428, 1266, 742 cm-
(E)-1-(2-Hydroxy-4-methoxyphenyl)propan-1-one O-
methyl oxime (2m) Yield 83%; 43 mg; colourless liquid;
1H NMR (DMSOd6, 400 MHz ) 1.05 (t, J = 7.6 Hz, 3H),
2.74 (q, J = 7.6 Hz, 2H), 3.75 (s, 3H), 3.91 (s, 3H), 6.45
(d, J = 2.8 Hz, 1H), 6.48 (dd, J = 2.8, 8.8 Hz, 1H), 7.37
(d, J = 8.8 Hz, 1H), 11.11 (s, 1H); 13C NMR (DMSOd6,
100 MHz) δ 11.2, 18.8, 55.2, 61.9, 101.6, 105.9, 110.8,
129.3, 159.0, 161.3, 162.8 ppm; FTIR (film) ) 3688, 3055,
2942, 2684, 2301, 1627, 1604, 1424, 1265, 1049, 736 cm-
1; HRMS (m/z): [M+H]+ calcd for C11H16NO3 : 210.1130;
found : 210.1150.
1
;
HRMS (m/z): [M+H]+ calcd for C9H11NO2Cl:
200.0478; found: 200.0506.
1-(4-Bromo-2-hydroxyphenyl)ethanone
O-methyl
oxime (2f) Yield 85%; 52 mg pale yellow solid; melting
o
1
point 82-84 C; H NMR (DMSOd6, 400 MHz) 2.20 (s,
3H), 3.93 (s, 3H), 7.05 (dd, J = 8.4 Hz, 1.6 Hz, 1H), 7.09
(d, J = 2.0 Hz, 1H), 7.33 (d, J = 8.4 Hz, 1H), 10.93 (s,
1H); 13C NMR (DMSOd6, 100 MHz) δ 13.1, 61.9, 119.1,
120.0, 122.0, 123.0, 130.1, 156.9, 157.3 ppm; FTIR (film)
3690, 3055, 2306, 1604, 1425, 1265, 732 cm-1; HRMS
(m/z): [M+Na]+ calcd for C9H10BrNO2Na:265.9792;
found:265.9791.
(E)-8-Hydroxy-3,4-dihydronaphthalen-1(2H)-one O-
methyl oxime (2n) Yield 79%; 38 mg; colourless liquid;
1H NMR (400 MHz, DMSO-D6): δ 1,76 (t, J=6.4 Hz, 2
H), 2.60-2.80 (m, 4 H), 3.95 (s, 3H), 6.64-6.77 (m, 2 H),
7.11-7.20 (m, 1 H); 11.18 (s, 1H), 13C NMR (100 MHz,
DMSO-D6): δ 20.6, 24.1, 29.2, 62.2, 113.7, 114.5, 119.3,
130.5, 141.1, 157.7, 159.2; ppm; FTIR (film) ) 3690,
3055, 2685, 2412, 2306, 1602, 1425, 1265, 897, 746 cm-1;
HRMS (m/z): [M+H]+ calcd for C11H14NO2 : 192.1024;
found : 192.1027.
1-(5-Bromo-2-hydroxyphenyl)ethanone
O-methyl
oxime (2g) Yield 89%; 54 mg colourless Liquid 1H NMR
(DMSOd6,400 MHz) 2.18 (s, 3H), 3.93 (s, 3H), 6.86 (d, J
= 8.8 Hz, 1H), 7.40 (dd, J = 8.4 Hz, 2.4 Hz, 1H), 10.68 (s,
1H); 13C NMR (DMSOd6, 100 MHz) δ 13.3, 61.9, 110.0,
118.6, 123.0, 130.8, 132.9, 155.6, 156.3 ppm; FTIR (film)
3690, 3055, 2986, 2306, 1609, 1562, 1423, 1265, 1046,
896 cm-1; HRMS (m/z): [M+H]+ calcd for
C9H10BrNO2:243.9973 ; found:243.9971.
1-(2-Hydroxyphenyl)-2-phenyl-ethan-1-one O-methyl
oxime (2o) Yield 80%; 48 mg; white semisolid; 1H NMR
(DMSOd6, 400 MHz) 3.99 (s, 3H), 4.21 (s, 2H), 6.80 (td,
J = 8.0, 12 Hz, 1H), 6.88 (dd, J = 8.4, 1.2 Hz, 1H), 7.12 –
7.30 (m, 6H), 7.37 (dd, J = 8.0, 1.6 Hz, 1H), 10.70 (s,
1H); 13C NMR (DMSOd6, 100 MHz) δ 31.5, 62.1, 116.6,
118.9, 119.0, 126.3, 128.3, 128.5, 129.2, 130.7, 136.3,
156.8, 159.3 ppm; FTIR (film) ) 3691, 3055, 2685, 2306,
1425, 1265, 1051, 896, 743 cm-1; HRMS (m/z): [M+H]+
calcd for C15H16NO2 : 242.1181; found : 242.1205.
1-(2-Hydroxyphenyl)ethanone O-methyl oxime (2h)
Yield 82%; 34 mg; colourless liquid; 1H NMR (DMSOd6,
400 MHz) 2.24(s, 3H), 3.93 (s, 3H), 6.80-6.99 (m, 2H),
7.22-7.30 (m, 1H), 7.43 (dd, J= 7.6, 1.2 Hz, 1H), 10.69 (s,
1H); 13C NMR (DMSOd6, 100 MHz) δ 12.7, 61.9, 116.5,
119.0, 128.5, 130.6, 156.5, 157.8 ppm; FTIR (film) 3682,
3055, 2986, 2306, 1423, 1266, 1031, 897, 740 cm-1;
HRMS (m/z): [M+H]+ calcd for C9H12NO2 : 166.0868;
found: 166.0870.
(E)-1-(2-hydroxy-4-methoxyphenyl)-2-phenylethan-1-
one O-methyl oxime (2p) Yield 81%; 55 mg; white
solid; melting point 50-52 oC; 1H NMR (CDCl3, 400 MHz
1-(2-Hydroxy-4-methylphenyl)ethanone
O-methyl
oxime (2i) Yield 85%; 38 mg; colourless liquid; 1H NMR
7
This article is protected by copyright. All rights reserved.

10.1002/adsc.201801340
Advanced Synthesis & Catalysis
3.78 (s, 3H), 4.02 (s, 3H), 4.20 (s, 2H), 6.39 (dd, J = 8.8,
2.8 Hz, 1H), 6.51 (d, J = 2.8 Hz, 1H), 7.17 – 7.25 (m, 3H),
7.25 – 7.33 (m, 3H), 11.53 (s, 1H); 13C NMR (CDCl3, 100
MHz) δ 31.4, 55.4, 62.6, 101.9, 106.5, 110.9, 126.6, 128.3,
128.4, 129.3, 136.3, 159.7, 160.2, 161.8 ppm; FTIR
(film) ) 3691, 3056, 2837, 2686, 2306, 1628, 1425, 1265,
897, 708 cm-1; HRMS (m/z): [M+H]+ calcd for
C16H18NO3: 272.1286; found: 272.1338.
(E)-1-(2-Hydroxy-5-methylphenyl)ethan-1-one
O-
benzyl oxime (2v) Yield 76%; 48 mg; colourless
liquid;1H NMR (400 MHz, CDCl3):  = 2.23 (s, 3H), 2.34
(s, 3H), 5.20 (s, 2H), 6.58 (d, J = 8.4, Hz, 1H), 7.05 (d, J
= 8.0, Hz, 1H), 7.19 (s, 1H), 7.29-7.50 (m, 5H), 10.92 (s,
1H), ppm; 13C NMR (100 MHz, CDCl3):  = 11.9, 20.8,
117.2, 118.2, 127.9, 128.0, 128.4, 128.6, 128.7, 131.6,
137.1, 155.7 and 158.9 ppm; FTIR (film): ν = 3686, 3070,
1607, 1495, 1263, 1024, 734 cm-1. HRMS (m/z): [M+H]+
calcd for : C16H18NO2: 256.1337; found: 256.1341.
(E)-1-(2-Hydroxyphenyl)ethan-1-one O-ethyl oxime
(2q) Yield 78%; 35 mg; colourless liquid; 1H NMR
(CDCl3, 400 MHz 1.35 (t, J = 6.8 Hz, 3H), 2.31 (s, 3H),
4.24 (q, J = 7.2 Hz, 2H), 6.80 – 6.92 (m, 1H), 6.96 (dd, J
= 8.0, 1.2 Hz, 1H), 7.21 – 7.28 (m, 1H), 7.40 (dd, J = 8.0,
1.6 Hz, 1H), 11.40 (s, 1H); 13C NMR (CDCl3, 100 MHz)
δ 11.6, 14.6, 70.4, 117.4, 118.7, 119.1, 127.6 130.7, 158.0,
158.2 ppm; FTIR (film) 3450, 3050, 984, 1632, 1265, 738
cm-1; HRMS (m/z): [M+H]+ calcd for C10H14NO2:
180.1024; found: 180.1033.
(E)-1-(4-Fluoro-2-hydroxyphenyl)ethan-1-one
O-
benzyl oxime (2w) Yield 80%; 52 mg; white solid;
melting point 74-76 oC; 1H NMR (400 MHz, CDCl3):  =
2.33 (s, 3H), 5.18 (s, 2H), 6.54-6.63 (m, 1H), 6.65 (d, J =
2.4 Hz, 1H), 7.31-7.45 (m, 6H), 11.43 (s, 1H), ppm; 13C
NMR (100 MHz, CDCl3):  = 12.1, 76.8, 104.5 (J2= 24.1
Hz), 106.5 (J2= 21.9 Hz), 115.2, 128.5, 128.6, 128.9 (J3=
11.0) 129.1, 136.9, 158.3, 159.8 (J3= 12.8) 164.1 (J1=
250.6) ppm; FTIR (film): ν = 3686, 3051, 2980, 1616,
1427, 1267, 725 cm-1. [M+Na]+ calcd for C15H14FNO2Na:
282.0906; found: 282.0919.
(E)-1-(2-Hydroxy-4-methoxyphenyl)ethan-1-one
O-
ethyl oxime (2r) Yield 80%; 42 mg; colourless liquid; 1H
NMR (CDCl3, 400 MHz 1.34 (t, J = 6.8 Hz, 3H), 2.28 (s,
3H), 3.80 (s, 3H), 4.21 (q, J = 6.8 Hz, 2H), 6.45 (dd, J =
8.8, 2.4 Hz, 1H), 6.49 (d, J = 2.8, 1H), 7.30 (d, J = 8.8,
1H), 11.63 (s, 1H); 13C NMR (CDCl3, 100 MHz) δ 11.7,
14.6, 55.4, 70.2, 101.8, 106.2, 112.1, 128.6, 157.9, 159.9,
161.7 ppm; FTIR (film) 3685, 3055, 2986, 1424, 1265,
897, cm-1; HRMS (m/z): [M+H]+ calcd for C11H16NO3:
210.1130; found: 210.1112.
(E)-(2-Hydroxyphenyl)(phenyl)methanone O-methyl
oxime (2x) Yield 76%; 43 mg; white solid; melting point
o
1
48-50 C; H NMR (400 MHz, CDCl3):  = 3.90 (s, 3H),
6.76-6.85 (m, 1H), 6.88 (dd, J = 8.0, 2.0 Hz, 1H), 6.93
(dd, J = 8.4, 1.2 Hz, 1H), 7.24-7.30 (m, 1H), 7.30-7.36 (m,
2H), 7.41-7.50 (m, 3H), 10.44 (s, 1H), ppm; 13C NMR
(100 MHz, CDCl3):  = 62.3, 116.6, 118.9, 120.1, 128.2,
128.4, 128.9, 130.4, 130.9, 132.2, 156.8 and 158.6 ppm;
FTIR (film): ν = 3055, 2986, 1423, 1266, 740 cm-1 HRMS
(m/z): [M+Na]+ calcd for C14H13NO2Na: 250.0843; found:
250.0847.
(E)-1-(2-hydroxy-4-methoxyphenyl)ethan-1-one
O-
benzyl oxime (2s) Yield 77%; 46 mg; white semisolid;
1H NMR (CDCl3, 400 MHz) 2.31 (s, 3H), 3.79 (s, 3H),
5.17 (s, 2H), 6.41 – 6.50 (m, 2H), 7.29 (d, J = 8.8 Hz, 1H),
7.31 – 7.36 (m, 1H), 7.36 – 7.46 (m, 4H), 11.36 (s, 1H);
13C NMR (CDCl3, 100 MHz) δ 11.9, 55.4, 76.6, 101.7,
106.3, 111.9, 128.4, 128.5, 128.7, 128.8, 137.2, 158.7,
159.7, 161.8 ppm; FTIR (film) 3687, 3056, 2988, 1627,
1424, 1265, 740 cm-1.
(E)-N-(3-Hydroxy-4-(1(methoxyimino)ethyl)phenyl)-
benzamide (2z) Yield 82%; 58 mg; white solid; melting
o
1
point 174-176 C; H NMR (400 MHz, CDCl3):  = 2.29
(s, 3H), 3.99 (s, 3H), 7.18 (d, J = 2.0 Hz, 1H), 7.33 (d, J =
2.0 Hz, 1H), 7.35-7.43 (m, 1H), 7.43-7.51 (m, 2H), 7.54
(tt, J = 14.8, 7.2 Hz, 1H) 7.81-7.88 (m, 2H), 7.92 (s, 1H),
11.45 (s, 1H), ppm; 13C NMR (100 MHz, CDCl3):  =
11.6, 62.5, 108.1, 110.9, 115.0, 127.2, 128.5, 128.9, 132.1,
134.9, 140.2, 158.1, 158.8 and 165.9 ppm; FTIR (film): ν
= 3686, 3056, 2986, 1528, 1427, 1265, 724 cm-1 ; HRMS
(m/z): [M+H]+ calcd for C16H17N2O3: 285.1239; found:
285.1252.
(E)-1-(2-Hydroxyphenyl)propan-1-one O-benzyl oxime
1
(2t) Yield 82%; 52 mg; pale white semisolid; H NMR
(DMSOd6, 400 MHz) 1.06 (t, J = 7.2 Hz, 3H), 2.79 (q, J =
7.6 Hz, 2H), 5.19 (s, 2H), 6.82 – 6.93 (m, 2H), 7.20 –
7.29 (m, 1H), 7.29 – 7.36 (m, 1H), 7.36 – 7.47 (m, 5H),
10.7 (s, 1H); 13C NMR (DMSOd6, 100 MHz) δ 10.9, 19.3,
75.5, 116.6, 118.4, 119.1, 127.9, 128.1, 128.4 (2C), 130.6,
137.4, 156.9, 163.0 ppm; FTIR (film) 3691, 3055, 2685,
2411, 2306, 1604, 1424, 1265, 897, 741 cm-1 HRMS
(m/z): [M+H]+ calcd for : C16H18NO2: 256.1337; found:
256.1316.
(E)-N-(4-Hydroxy-3-(1-(methoxyimino)ethyl)phenyl)-
benzamide (2aa) Yield 83%; 59 mg; white solid; melting
o
1
point 120-122 C; H NMR (400 MHz, CDCl3):  = 2.33
(s, 3H), 4.03(s, 3H), 6.97 (t, J = 8.0 Hz, 1H), 7.19 (d, J =
8.0 Hz, 1H), 7.42-7.63 (m, 3H), 7.95 (d, J = 6.8 Hz, 2H),
8.57 (d, J = 8.0 Hz, 1H),) 8.75 (s, 1H), 12.05 (s, 1H),
ppm; 13C NMR (100 MHz, CDCl3):  = 11.7, 62.7, 117.5,
119.3, 121.0, 122.1, 127.2, 127.6, 128.9, 131.9, 135.3,
146.9, 158.8 and 165.5; FTIR (film): ν = 3432, 3056,
2986, 1673, 1530, 1265, 741 cm-1 ; HRMS (m/z): [M+K]+
calcd for C16H16N2O3K: 323.0798; found: 323.0811.
(E)-1-(2-Hydroxy-4-methylphenyl)ethan-1-one
O-
benzyl oxime (2u) Yield 78%; 50 mg; colourless liquid;
1H NMR (400 MHz, CDCl3):  = 2.31 (s, 3H), 2.33 (s,
3H), 5.19 (s, 2H), 6.69 (dt, J = 8.0, 1.2 Hz, 1H), 6.76 (s,
1H), 7.28 (d, J = 8.0, Hz, 1H), 7.30-7.36 (m, 1H), 7.36-
7.45 (m, 4H), 11.09 (s, 1H), ppm; 13C NMR (100 MHz,
CDCl3):  = 11.9, 21.4, 76.7 116.0, 117.8, 120.2, 127.5,
128.4, 128.5, 128.7, 137.1, 141.5, 157.8 and 158.8 ppm;
FTIR (film): ν = 3416, 3054, 2983, 1629, 1426, 1267,
1034, 734 cm-1. HRMS (m/z): [M+H]+ calcd for :
C16H18NO2: 256.1337; found: 256.1340.
(E)-N-(3-Hydroxy-4-(1-(methoxyimino)ethyl)phenyl)-
2-methylbenzamide (2ab) Yield 81%; 60 mg; white
solid; melting point 168-170 oC;1H NMR (400 MHz,
CDCl3):  = 2.34 (s, 3H), 2.56 (s, 3H), 4.01 (s, 3H), 6.98
(t, J = 8.4 Hz, 1H), 7.21 (d, J = 8.0 Hz, 1H), 7.24-7.35 (m,
8
This article is protected by copyright. All rights reserved.

10.1002/adsc.201801340
Advanced Synthesis & Catalysis
2H), 7.37 (t, J = 8.0 Hz, 1H), 7.57 (d, J = 7.6 Hz, 1H),)
8.29 (s, 1H), 8.57 (d, J = 8.0 Hz 1H), 11.97 (s, 1H) ppm;
13C NMR (100 MHz, CDCl3):  = 11.7, 20.2, 62.2, 117.6,
119.3, 121.1, 122.2, 126.1, 127.2, 127.6, 130.4, 131.4,
136.6, 136.8, 146.9, 158.8 and 168.1; FTIR (film): ν =
8.0 Hz, 1H), 7.20 (dd, J = 8.0, 1.2 Hz, 1H), 7.42-7.60 (m,
1H) 7.94 (d, J = 6.8 Hz, 1H), 8.57 (d, J = 8.0 Hz, 1H),
8.74 (s, 1H), 12.04 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3):  = 11.7, 62.7, 117.5, 119.3, 121.0, 122.1, 127.2,
127.6, 128.9, 138.9, 135.3, 146.9, 158.8 and 165.5; FTIR
(film): ν = 3055, 2987, 1532, 1422, 1265, 738, 705 cm-1.
HRMS (m/z): [M+Na]+ calcd for C16H16N2NaO2S:
323.0830; found: 323.0804.
3688, 3056, 2986, 2306, 1530, 1427, 1265, 755 cm-1
;
HRMS (m/z): [M+H]+ calcd for C16H19NO3: 299.1396;
found: 299.1405.
(E)-N-(4-Hydroxy-3-(1-(methoxyimino)ethyl)phenyl)-
2-methylbenzamide (2ac) Yield 85%; 63 mg; white
Acknowledgements
o
1
solid; melting point 136-138 C; H NMR (400 MHz,
CDCl3):  = 2.32 (s, 3H), 2.52 (s, 3H), 4.02 (s, 3H), 7.15
(s, 1H), 7.26-7.30 (m, 2H), 7.33 (d, J = 8.4 Hz, 1H), 7.39
(q, J = 8.4 Hz, 2H),) 7.49 (d, J = 7.6 Hz, 1H), 7.57 (s, 1H),
11.47 (s, 1H) ppm; 13C NMR (100 MHz, CDCl3):  =
11.6, 19.9, 62.5, 107.8, 110.6, 115.0, 126.0, 128.5, 130.6,
131.4, 136.3, 136.7, 140.2, 158.0, 158.8 and 168.1 ppm ;
FTIR (film): ν = 3416, 3056, 2986, 1427, 1265, 743 cm-1.
HRMS (m/z): [M+H]+ calcd for C16H19NO3: 299.1396;
found: 299.1407.
We thank IIT Madras for financial support
(Project No. CHY/16-17/846/RFIR/GSEK). R.S
thanks IIT Madras for senior research fellowship
and N.P thanks UGC for senior research
fellowship.
References
(E)-N-(3-Hydroxy-4-(1-(methoxyimino)ethyl)phenyl)-
3-methoxybenzamide (2ad) Yield 87%; 68 mg; white
solid; melting point 80-82 oC; 1H NMR (400 MHz,
CDCl3):  = 2.33 (s, 3H), 3.88 (s, 3H), 4.03 (s, 3H), 6.96
(t, J = 8.0 Hz, 1H), 7.08 (dd, J = 8.4, 1.6 Hz, 1H) 7.19 (dd,
J = 8.0, 0.8 Hz, 1H), 7.39 (t, J = 8.0 Hz, 1H), 7.46 (d, J =
7.6 Hz, 1H), 7.51 (s, 1H), 8.56 (d, J = 8.0 Hz, 1H), 8.73 (s,
1H), 12.03 (s, 1H), ppm; 13C NMR (100 MHz, CDCl3): 
= 11.7, 55.6, 62.7, 112.5, 117.5, 118.1, 118.9, 119.3,
120.9, 122.1, 127.6, 129.9, 136.8, 146.9, 158.8, 160.1 and
165.3 ppm; FTIR (film): ν = 3416, 3056, 2986, 1427,
1265, 743 cm-1 ; HRMS (m/z): [M+Na]+ calcd for
C17H18ClN2NaO4: 337.1164; found: 337.1174.
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(E)-4-Chloro-N-(3-hydroxy-4-(1-(methoxyimino)-
ethyl)phenyl)-benzamide (2ae) Yield 87%; 69 mg; white
o
1
solid; melting point 150-152 C; H NMR (400 MHz,
CDCl3):  = 2.33 (s, 3H), 4.03 (s, 3H), 6.96 (t, J = 8.0 Hz,
1H), 7.20 (dd, J = 8.4, 1.2 Hz, 1H) 7.46 (d, J = 8.4 Hz,
2H), 7.87 (d, J = 8.4 Hz, 2H), 8.52 (d, J = 8.0 Hz, 1H),
8.67 (s, 1H), 12.07 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3):  = 11.7, 62.7, 117.6, 119.3, 121.0, 122.3, 127.4,
128.6, 129.1, 133.6, 138.2, 146.9, 158.8 and 164.3 ppm;
FTIR (film): ν = 3439, 3057, 2987, 1638, 1428, 1266, 743
cm-1; HRMS (m/z): [M+Na]+ calcd for C16H15ClN2NaO3:
341.0668; found: 341.0676.
(E)-N-(3-Hydroxy-4-(1-(methoxyimino)ethyl)-
phenyl)benzothioamide (2af) Yield 79%; 59 mg; light
o
1
yellow solid; melting point 168-170 C; H NMR (400
MHz, CDCl3):  = 2.28 (s, 3H), 3.98 (s, 3H), 7.19 (d, J =
2.0 Hz, 1H), 7.31-7.40 (m, 2H) 7.41-7.50 (m, 2H), 7.50-
7.56 (m, 1H), 7.81-7.90 (m, 2H), 7.96 (s, 1H), 11.45 (s,
1H) ppm; 13C NMR (100 MHz, CDCl3):  = 11.6, 62.5,
108.1, 110.9, 115.0, 127.2, 128.5, 128.9, 132.1, 134.9,
140.2, 158.0, 158.8, and 165.9; FTIR (film): ν = 3429,
3056, 2986, 1426, 1266, 742 cm-1; HRMS (m/z): [M+Na]+
calcd for C16H16N2NaO2S: 323.0830; found: 323.0803.
(E)-N-(4-Hydroxy-3-(1-(methoxyimino)ethyl)-
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phenyl)benzothioamide (2ag) Yield 82%; 62 mg;; light
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yellow solid; melting point 118-120 C; H NMR (400
MHz, CDCl3):  = 2.33 (s, 3H), 4.03 (s, 3H), 6.97 (t, J =
9
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10.1002/adsc.201801340
Advanced Synthesis & Catalysis
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FULL PAPER
Reusable Palladium Nanoparticles Catalyzed
Oxime Ether Directed Mono Ortho-
Hydroxylation under Phosphine Free Neutral
Condition
Adv. Synth. Catal. 2018, Volume, Page – Page
Rajib Saha, Naziya Perveen, Naorem Nihesh and
Govindasamy Sekar *
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