Werner transition-metal complex (WTMC)-mediated mild and efficient chemo-selective acylation of phenols and anilines under solvent-free condition

Article abstract of DOI:10.1002/jccs.201800013

Werner-type transition-metal complexes (WTMC) such as [Co(NH₃)₅Cl]Cl₂, Cu[(NH₃)₄]SO₄, Mn(acac)₃, Ni[(NH₃)₆]Cl₂, Ni[(en)₃]S₂O₃, and Hg[Co(SCN)₄] efficiently promote the chemoselective acetylation of phenols and anilines under solvent-free condition. The results of this study clearly shows that the optimal condition for the acetylation of anilines/phenols (1 mmol) (2a–r) with acetic anhydride (1.2 mmol) in the presence of WTMC (1 mmol) and two drops of H₃PO₄ on heating for 10 min under solvent-free condition gives the corresponding acetanilides/phenyl acetate (3a–r) in good to excellent yield. Furthermore, the method is simple, efficient, chemoselective, and eco-friendly under solvent-free condition for the acetylation of anilines and phenols promoted by WTMC by using acetic anhydrate as the acetylating agent. The simple preparation of the catalyst, easy procedure of the acetylation reaction, and simple work-up indicate the importance of WTMC for such reactions.

Full text of DOI:10.1002/jccs.201800013

Received: 10 January 2018
Revised: 11 March 2018
Accepted: 27 March 2018
DOI: 10.1002/jccs.201800013
A R T I C L E
Werner transition-metal complex (WTMC)-mediated mild and
efficient chemo-selective acylation of phenols and anilines under
solvent-free condition
Abdulla Sarief1 | SK Manirul Haque1 | Syed Mudabbir Feroze2 | Mohammed Arifuddin2
1Department of Chemical and Process Engineering
Werner-type transition-metal complexes (WTMC) such as [Co(NH3)5Cl]Cl2, Cu
Technology, Jubail Industrial College, Jubail,
Saudi Arabia
2Department of Medicinal Chemistry, National
[(NH3)4]SO4, Mn(acac)3, Ni[(NH3)6]Cl2, Ni[(en)3]S2O3, and Hg[Co(SCN)4] effi-
ciently promote the chemoselective acetylation of phenols and anilines under
solvent-free condition. The results of this study clearly shows that the optimal con-
dition for the acetylation of anilines/phenols (1 mmol) (2a–r) with acetic anhydride
(1.2 mmol) in the presence of WTMC (1 mmol) and two drops of H3PO4 on heat-
Institute of Pharmaceutical Education and
Research (NIPER), Hyderabad, India
Correspondence
SK Manirul Haque, Department of Chemical and
Process Engineering Technology, Jubail Industrial
College, P.O. Box No-10099, Jubail 31961, Saudi
Arabia.
ing for 10 min under solvent-free condition gives the corresponding acetanilides/
phenyl acetate (3a–r) in good to excellent yield. Furthermore, the method is sim-
ple, efficient, chemoselective, and eco-friendly under solvent-free condition for the
acetylation of anilines and phenols promoted by WTMC by using acetic anhydrate
as the acetylating agent. The simple preparation of the catalyst, easy procedure of
the acetylation reaction, and simple work-up indicate the importance of WTMC for
such reactions.
Email: haque_m@jic.edu.sa
KEYWORDS
acetylation, anilines, phenols, solvent-free condition, Werner-type
transition-metal complexes (WTMC)
catalysts such as cobalt chloride (CoCl2),[8] Sc(OTf )3,
[9]
1
| INTRODUCTION
montmorillonite K10,[11] HY zeolite,[12]
[10]
TaCl5,
[14]
In(OTf )3,[13]Cu(OTf )2,
silica gel-supported sulfuric
Complex organic molecules are formed through synthesis and
depend on the functional groups of each compound.[1] The
most common multistep organic transformation reaction is
acylation. The acetyl group is frequently used as the protecting
group because it can be easily deprotected and is stable in
acidic media.[2] Hydroxyl and amine groups are also used as
the protecting groups. The acetyl group is more popular
because of its simple structure and easy protection by hydroly-
sis in the presence of a base.[3] Generally, acetic anhydride or
acetyl chloride, with triethyl amine and pyridine acting as cata-
lyst, is utilized for the acylation reaction.[4–6] It was found that
the presence of 4-(dimethylamino) pyridine (DMAP) will sub-
stantially increase the rate of the reaction.[7] The acylation of
alcohols, phenols, and amines is catalyzed with a variety of
acid,[15,16] yittria/zirconia-based Lewis acid,[17] InCl3/Mont. K
10,[18] sodium dodecyl sulfate (SDS),[19] ammonium acetate in
acetic acid,[20] manganese (III) bis(2-hydroxyanil)acetylaceto-
nato complex,[21]silica sulfate,[22] p-MeC6H4SO2NBr2,
[23]
DBDMH or TCCA,[24] ZnCl2,
H6P2W18O62 Á 24H2O,[26]
[25]
vanadyl sulfate,[27] La(NO3)3 Á 6H2O,[28] 2,4,6-triacyloxy-
l,3,5-triazine (TAT),[29] zinc dust,[30]ionic liquid based on
morpholin,[31] borated zirconia,[32] DMAP-saccharin,[33]
copper-catalyzed azidation reaction of anilines(primary
amine),[34] acylation of phenol and salicylic acid in the pres-
ence of zirconium phosphate (ZP) nanoparticles,[35] oxidative
acylation of phenols with N-heteroarylmethanes under transi-
tion metals,[36] N-alkylation of amines with alcohols in
© 2018 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
J Chin Chem Soc. 2018;1–6.
http://www.jccs.wiley-vch.de
1

2
SARIEF ET AL.
presence of PNP manganese pincer complexes,[37] trifluoro-
methanesulfonic acid (TfOH)-catalyzed acylation of phenol
and its derivaties,[38] bacterial acyltransferase acylation of phe-
nolic compounds,[39] and acylation of BN-arenes using BN-
arene and acyl chloride in order to synthesize the indanone
BN-analog.[40] The disadvantages of all the above methods are
their high cost, vigorous reaction condition, toxicity of the
reagent, poor yield, instability, hygroscopic nature of the
reagent, and tedious work-up procedures. Therefore, there is
still a need for a method for the protection of phenols and
amines.
Reactions without any solvent are in vogue now for the
synthesis of important compounds, and this trend is increas-
ing day by day. The compounds used for acylation are toxic
and volatile, which have serious environmental problems. At
the same time, the catalytic reaction requires less quantity of
the solvent, so green synthesis is more popular. The solid-
state reaction can be achieved only with reactants or com-
bined with silica, alumina, zeolites, and clay. Increased rate
of reaction, fewer byproducts, and streoselectivity of the
product are the other advantages.[41]
Complex natural products are produced using transition
metals and their complexes as catalysts. Oxidation, epoxida-
tion, and hydrogenation reactions are catalyzed by metal
complexes.[42,43] In continuation of our efforts toward
exploring the application of Werner-type transition-metal
complexes (WTMCs),[44–46] here we report a mild and effi-
cient chemoselective acetylation of phenols and anilines
mediated by WTMCs under solvent-free condition with
acetic anhydride to yield the corresponding acetanilide and
acetate in excellent yield (Scheme 1). To the best of our
knowledge, WTMCs have not been used for the protection
of phenols and amines.
advantage of the proposed method is the short time taken:
only 1 hr compared to 48 hr while using the sodium carbon-
ate method.[48]
In order to optimize the reaction conditions, various sol-
vents were tested (Table 1) in the preparation of acetanilide
from aniline and acetic anhydride at room temperature. The
reaction smoothly reached completion without any solvent
and with high isolated yield. The reaction in the case of
using solvents (solution phase) was either sluggish (as it
takes a long time) or resulted in the formation of a complex
that was difficult to isolate. In the case of toluene and aceto-
nitrile, no reaction took place even after allowing it to pro-
ceed overnight. In the case of ethanol and THF, a complex
formed that was not isolatable (this is beyond our present
scope of our work, so we have not concentrated on this
aspect). As expected, the reaction preceded smoothly under
solvent-free condition with 60% yield in 1 hr. Thus, we
focused further on the optimization of the reaction condi-
tions under solvent-free condition to obtain even better
yield.
The reaction condition was optimized by conducting the
acetylation of aniline with acetic anhydride in the presence
of various quantities of WTMC. The results of the optimiza-
tion are summarized in Table 2, which clearly shows that the
optimal condition for the acetylation was the reaction of
TABLE 1 Solvent effect on WTMC-promoted acetylation of aniline at
room temperature
S. No
Solvent
Toluene
CH3CN
Ethanol
Time
Conversion (%)
No reaction
1
2
3
Overnight
Overnight
Overnight
No reaction
Complex formed
(not isolatable)
4
5
THF
2 hr
1 hr
Complex formed
(not isolatable)
2
| RESULTS AND DISCUSSION
Neat (solvent-free)
60%
WTMCs (ML5) such as [Co(NH3)5Cl]Cl2, Cu[(NH3)4]SO4,
Mn(acac)3, Ni[(NH3)6]Cl2, Ni[(en)3]S2O3, and Hg[Co
(SCN)4] were prepared following the methods described in
Advanced Practical Inorganic Chemistry.[47]Our investiga-
tion clearly shows that WTMCs efficiently promote the che-
moselective acetylation of phenols and anilines under
solvent-free condition. The results were compared with those
of known methods of phenol synthesis in the presence of
acetic anhydride catalyzed by sodium bicarbonate, and it
was found that the reaction was very mild and that the reac-
tion took place only with phenols and anilines. Another
TABLE 2 Effect on WTMC on the acetylation of aniline under solvent-
free condition
Conversion
(%)
S. No
Reagent
Reaction condition
Room temperature/1 hr
Heating/1 hr
1
2
WTMC (5 mol%)
10
WTMC (5 mol%)
10
+ 2 drops of H3PO4
3
4
WTMC (20 mol%)
Room temperature/1 hr
Heating/1 hr
20
20
WTMC (20 mol%)
+ 2 drops of H3PO4
5
6
WTMC (50 mol%)
Room temperature/1 hr
Heating/1 hr
30
35
WTMC (50 mol%)
+ 2 drops of H3PO4
7
8
9
WTMC (1 mol)
WTMC (1 mol)
Room temperature/1 hr
Heating/1 hr
50
60
98
WTMC (1 mol)
Heating/10 min
+ 2 drops of H3PO4
SCHEME 1 Acetylation of phenols and anilines mediated by transition-
metal complexes
10
Two drops of H3PO4
Reflux/24 hr
No reaction

SARIEF ET AL.
3
aniline (1 mmol) with acetic anhydride (1.2 mmol) in the
presence of WTMC (1 mmol) and two drops of H3PO4 on
heating for 10 min, which gave 98% yield of acetanilide.
Although H3PO4 was used as the catalyst in the synthesis of
aspirin from salicylic acid by using acetic anhydride,[49] and
the acylation of phenol and amine with copper(I) and
nickel(II) in the presence of imidazole is mild at room
temperature,[50,51] no systematic studies have been done for
the acetylation of phenols and anilines.
To explore the generality of the optimal condition
obtained from the above sets of experiments, different sub-
strates were chosen, including anilines and phenols. Excel-
lent results were obtained with substituted anilines and
phenols, which are summarized in Table 3.
TABLE 3 WTMC-promoted acetylation of anilines and phenols under solvent-free condition
Co[(NH3)5Cl]Cl2
Cu[(NH3)4]SO4
Mn(acac)3
Time
Yieldb
(%)
Time
(min)
Yieldb
Time
(min)
Yieldb
(%)
S. no.
1
Substrate (2)
Products (3)a
(min)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
(%)
95
94
92
93
91
88
88
90
86
84
94
94
90
88
78
90
84
80
Aniline (2a)
Acetanilide (3a)
98
96
93
94
92
90
90
92
88
86
96
96
92
90
80
92
86
82
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
93
92
90
91
90
88
86
88
84
82
92
92
88
86
74
88
82
78
2
4-Methylaniline (2b)
2-Methylaniline (2c)
4-Isopropylaniline (2d)
2,4-Dimethylaniline (2e)
2,4,6-Trimethylaniline (2f)
4-Chloroaniline (2g)
4-Fluoroaniline (2h)
4-Nitroaniline (2i)
4-Methylacetanilide (3b)
2-Methylacetanilide (3c)
4-Isopropylacetanilide (3d)
2,4-Dimethylacetanilide (3e)
2,4,6-Trimethylacetanilide (3f)
4-Chloroacetanilide (3g)
10
3
10
4
10
5
10
6
10
7
10
8
4-Fluoroacetanilide (3h)
10
9
4-Nitroacetanilide (3i)
10
10
11
12
13
14
15
16
17
18
4-Methyl-3-nitroaniline (2j)
Phenol (2k)
4-Methyl-3-nitroacetanilide (3j)
Phenylacetate (3k)
10
10
1-Naphtol (2l)
1-Naphtylacetate (3l)
10
3-Chlorophenol (2m)
2,6-Dichlorophenol (2n)
3-Chloro-4-fluorophenol (2o)
Salicylic acid (2p)
3-Chlorophenylacetate (3m)
2,6-Dichlorophenylacetate (3n)
3-Chloro-4-fluorophenylacetate (3o)
Aspirin (O-acetylsalicylic acid) (3p)
4-Acetamidophenyl acetate (3q)
2-Acetamido-4-chlorophenylacetate (3r)
10
10
10
10
4-Aminophenol (2q)
2-Amino-4-chloro-phenol (2r)
10
10
Ni[(NH3)6]Cl2
Ni[(en)3]S2O3
Hg[Co(SCN)4]
Time
(min)
Yield
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
S. no.
1
Substrate (2)
Products (3)
(%)
96
94
90
92
90
90
88
92
86
84
94
94
92
90
80
Aniline (2a)
Acetanilide (3a)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
93
92
88
91
89
88
84
90
84
82
92
92
90
88
76
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
91
90
88
90
87
86
82
86
82
80
90
90
88
86
72
2
4-Methylaniline (2b)
2-Methylaniline (2c)
4-Isopropylaniline (2d)
2,4-Dimethylaniline (2e)
2,4,6-Trimethylaniline (2f)
4-Chloroaniline (2g)
4-Fluoroaniline (2h)
4-Nitroaniline (2i)
4-Methylacetanilide (3b)
2-Methylacetanilide (3c)
4-Isopropylacetanilide (3d)
2,4-Dimethylacetanilide (3e)
2,4,6-Trimethylacetanilide (3f)
4-Chloroacetanilide (3g)
4-Fluoroacetanilide (3h)
4-Nitroacetanilide (3i)
3
4
5
6
7
8
9
10
11
12
13
14
15
4-Methyl-3-nitroaniline (2j)
Phenol (2k)
4-Methyl-3-nitroacetanilide (2j)
Phenylacetate (3k)
1-Naphtol (2l)
1-Naphtylacetate (3l)
3-Chlorophenol (2m)
2,6-Dichlorophenol (2n)
3-Chlorophenylacetate (3m)
2,6-Dichlorophenylacetate (3n)
3-Chloro-4-fluorophenyl acetate (3o)
3-Chloro-4-fluorophenol
(2o)
16
17
18
Salicylic acid (2p)
Aspirin (O-acetylsalicylic acid) (3p)
4-acetamidophenyl acetate (3q)
10
10
10
90
84
80
10
10
10
90
80
78
10
10
10
86
80
76
4-Aminophenol (2q)
2-Amino-4-Chloro-phenol
2-Acetamido-4-chlorophenylacetate
(2r)
(3r)
a
All the products are known compounds and were characterized by 1H-NMR, IR, mass spectral data, and comparison with authentic samples and literature values.
Isolated yields of the purified products.
b

4
SARIEF ET AL.
The results in Table 3 clearly indicate the generality of
WTMC as an attractive agent for such reactions. Further
studies are in progress in our laboratory.
the acetylation reaction of anilines and phenols. The present
method is chemoselective, as it gives good yield with acti-
vated anilines (2b–2h) and phenols (2m–2p). In the case of
deactivated anilines (2i–2j), the yield was moderate. Surpris-
ingly, when the reaction was carried out in the presence of
both amino and phenolic OH groups (2q–2r), diacetylation
took place, indicating the acetylation of aniline NH as well
as phenolic OH.
The present method when applied to the acetylation of
the thiophenol, benzylamine, cyclohexylamine, benzyl alco-
hol, 4-aminobenzyl alcohol, 4-hydroxybenzyl alcohol, and
octanol failed to produce the corresponding acetylated prod-
ucts. Surprisingly, under the optimized condition the reac-
tion did not proceed and a complex mass was formed that
was not soluble in any organic solvent. This might be due to
the formation of coordinated complex inorganic molecules.
Although the mechanism of the present reaction is not
clear, it is assumed that the reaction proceeds via the forma-
tion of a chelate with acetic anhydride, forming the transition
state A, which in turn leads to the transition state B. The sub-
strate (phenol or aniline) in the next step attacks the carbonyl
carbon of the acyl ion and leads to the removal of acetic acid
and to the corresponding acetylated product and ML5 com-
plex. The plausible mechanism is shown in Scheme 2.
4
| EXPERIMENTAL
4.1 | General remarks
Melting points were determined in open capillaries and are
uncorrected. All chemicals and solvents were of analytical
grade and used without any purification. Infrared spectra
were recorded on a Perkin-Elmer infrared spectrometer with
NaCl optics, and samples were scanned as neat or as KBr
thin films. 1H-NMR spectra were recorded on a Bruker
Avance 300 MHz spectrometer. The samples were prepared
in CDCl3/DMSO-d6, and TMS was used as the internal stan-
dard; the chemical shift values are given in δ scale. The pro-
gress of the reaction was monitored by TLC on precoated
silica gel 60-GF 254 (0.5 mm) plates. Mass spectra were
recorded on an ESI mass spectrometer.
4.2 | General procedure for the acylation of anilines
(2a–2j)
One millimolar of anilines (2a–2j) and 1.2 mmol of acetic
anhydride were added in a 50-mL round-bottom (RB) flask.
Then, WTMC (1 mmol) and two drops of phosphoric acid
were added to the mixture. The mixture was heated at 75 ꢀC
for 10 min under solvent-free condition. After completion of
the reaction (as indicated by TLC), the reaction mixture was
transferred into 20 mL of ice-water and placed on an ice tub.
After cooling, the solid/crystals of the corresponding acetan-
ilides were formed. The solid was filtered off and dried to
get the pure products (3a–3j).
3
| CONCLUSIONS
In conclusion, we have developed a simple, efficient, che-
moselective, and eco-friendly method for the solvent-free
acetylation of anilines and phenols promoted by WTMCs by
using acetic anhydrate as the acetylating agent. Simple prep-
aration of the catalyst, easy procedure of the acetylation
reaction, and simple work-up indicate the importance of
4.3 | General procedure for the acetylation of phenols
(2k–2r)
One millimolar of phenols (2k–2r) and 1.2 mmol of acetic
anhydride were added in 50-mL RB flask. Then, 1 mmol of
WTMC and two drops of phosphoric acid were added to the
ꢀ
mixture. The mixture was heated at 75 C for 10 min. After
completion of the reaction (as indicated by TLC), the reac-
tion mixture was transferred to 20 mL of ice-water and
placed on an ice tub. After cooling, the solid/crystals of the
corresponding phenyl acetate were formed. The solid was
filtered off and dried to get the pure products (3k–3r).
Note: In the case of liquid products, the reaction mixture
was extracted with ethyl acetate, which upon evaporation
gave the corresponding phenyl acetates.
4.4 | Spectral data for the synthesized compounds
Acetanilide (3a): mp 108–110 C; IR, KBr, cm−1: 3310
ꢀ
SCHEME 2 Plausible mechanism for the acetylation of phenols and
anilines
1
(NH of C=O), 1685 (C=O), 1354, 1161, 1035, 865. H-

SARIEF ET AL.
5
−1
ꢀ
NMR (500 MHz, CDCl3) δ 8.06 (s, 1H), 7.51 (s, 2H), 7.28
(s, 1H), 7.09 (s,1H), 2.14 (s, 3H): MS: m/z: 136.07 (M+1).
4-Nitroacetanilide (3i): mp 212–213 C; IR KBr, cm
:
3274 (NH of C=O), 1679 (C=O), 1373, 1179, 1089, 838:
1H-NMR (500 MHz, CDCl3) δ 8.21 (d, J = 8.9 Hz, 2H),
7.71 (d, J = 9.1 Hz, 2H), 7.70–7.60 (m, 1H), 2.25 (s, 3H).
13C-NMR (126 MHz, CDCl3) δ 168.95 (s) 152.57 (s),
139.10 (s), 126.38 (s), 125.08 (s), 119.00 (s), 113.39 (s),
24.78 (s). MS: m/z: 181.06 (M+1).
ꢀ
4-Methylaccetanilide (3b): mp 151–153 C; IR KBr,
cm−1: 3290 (NH of C=O), 1662 (C=O), 1366, 1169, 1027,
1
877. H-NMR (500 MHz, CDCl3) δ 7.76 (s, 1H), 7.37 (d,
J = 8.3 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 2.30 (s, 3H), 2.14
(s, 3H): 13C-NMR (126 MHz, CDCl3) δ 168.90 (s), 138.83
(s), 137.89 (s), 128.74 (s), 125.16 (s), 120.80 (s), 117.23 (s),
24.42 (s), 21.45 (s). MS: m/z: 150.09 (M+1).
4-Methyl-3-nitroacetanilide (3j): liquid; IR KBr, cm−1
:
3353 (NH of C=O), 1647 (C=O), 1369, 1168, 1065, 828.
1H-NMR (500 MHz, CDCl3) δ 8.11 (s, 1H), 7.80–7.64 (m,
2H), 7.27 (s, 1H), 5.00 (s, 1H), 2.55 (s, 3H), 2.21 (s, 3H).
MS: m/z: 195.07 (M+1).
ꢀ
2-Methylacetanilide (3c): mp 109–111 C; IR KBr,
cm−1: 3285 (NH of C=O), 1669 (C=O), 1362, 1181, 1013,
1
852. H-NMR (500 MHz, CDCl3) δ 7.83 (s, 1H), 7.35 (s,
1H), 7.30–7.25 (m, 1H), 7.17 (t, J = 7.8 Hz, 1H), 6.91 (d,
J = 7.5 Hz, 1H), 2.30 (s, 3H), 2.14 (s, 3H). 13C -NMR
(126 MHz, CDCl3) δ 168.73 (s), 135.43 (s), 133.93 (s),
129.42 (s), 120.24 (s), 24.36 (s), 20.86 (s). MS: m/z:
150.09 (M+1).
Phenylacetate (3k): Liquid; IR, KBr, cm−1: 1761
(C=O), 1369, 1184, 1052, 891. 1H-NMR (500 MHz,
CDCl3) δ 7.40–7.35 (m, 2H), 7.24–7.20 (m, 1H), 7.10–7.06
(m, 2H), 2.29 (s, 3H). 13C-NMR (126 MHz, CDCl3) δ
169.55 (s), 150.70 (s), 129.45 (s), 125.86 (s), 121.59 (s),
21.16 (s). MS: m/z: 137.06 (M+1).
4-Isopropylacetanilide (3d): Liquid; IR KBr, cm−1
:
3247 (NH of C=O), 1659 (C=O), 1369, 1180, 1053, 824.
1H-NMR (500 MHz, CDCl3) δ 7.59 (s, 1H), 7.40 (d,
J = 8.5 Hz, 2H), 7.16 (d, J = 8.4 Hz, 2H), 2.86 (dd,
J = 13.8, 6.9 Hz, 1H), 2.14 (s, 3H), 1.22 (d, J = 6.9 Hz,
6H). 13C-NMR (126 MHz, CDCl3) δ 168.55 (s), 145.03 (s),
135.63 (s), 126.83 (s), 120.26 (s), 33.59 (s), 24.42 (s), 24.01
(s). MS: m/z: 178.12 (M+1).
1-Naphtylacetate (3l): Liquid; IR, KBr, cm−1: 1720
(C=O), 1365, 1158, 1037, 875. 1H-NMR (500 MHz,
CDCl3) δ 7.83–7.75 (m, 2H), 7.67 (d, J = 8.3 Hz, 1H), 7.44
(dt, J = 5.4, 3.0 Hz, 2H), 7.41–7.37 (m, 1H), 7.17 (dd,
J = 7.5, 1.0 Hz, 1H), 2.39 (s, 3H). 13C-NMR (126 MHz,
CDCl3) δ 169.28 (s), 128.67 (s), 124.46 (d, J = 24.1 Hz),
120.54 (s), 120.31 (s), 120.04 (s), 24.33 (s). MS: m/z:
186.04 (M+1).
ꢀ
2,4-Dimethylacetanilide (3e): mp 128–130 C; IR KBr
cm−1: 3271 (NH of C=O), 1645 (C=O), 1364, 1160, 1036,
3-Chlorophenylacetate (3m): mp 212–213 C; IR,
ꢀ
1
1
874. H-NMR (500 MHz, CDCl3) δ 7.52 (d, J = 8.6 Hz,
KBr, cm−1: 1679 (C=O), 1373, 1179, 1089, 838. H-NMR
1H), 7.07 (d, J = 13.5 Hz, 1H), 7.00 (s, 2H), 2.29 (s, 3H),
2.21 (s, 3H), 2.19 (s, 3H). 13C-NMR (126 MHz, CDCl3) δ
168.59 (s), 135.32 (s), 132.91 (s), 131.18 (s), 130.05 (s),
127.27 (s), 124.02 (s), 24.10 (s), 20.89 (s), 17.76 (s). MS: m/
z: 164.10 (M+1).
(500 MHz, CDCl3) δ 7.30 (t, J = 8.1 Hz, 1H), 7.21 (ddd,
J = 8.1, 1.8, 1.0 Hz, 1H), 7.13 (t, J = 2.1 Hz, 1H), 7.00
(ddd, J = 8.2, 2.2, 0.9 Hz, 1H), 2.29 (s, 3H). MS: m/z:
171.48 (M+1).
2,6-Dichlorophenylacetate (3n): Liquid; IR KBr, cm−1
:
1
2,4,6-Trimethylacetanilide (3f ): Liquid; IR KBr cm−1
:
1775 (C=O), 1368, 1178, 1070, 887. H-NMR (500 MHz,
CDCl3) δ 7.34 (d, J = 8.1 Hz, 2H), 7.11 (t, J = 8.1 Hz, 1H),
2.39 (s, 3H). 13C-NMR (126 MHz, CDCl3) δ 167.28 (s),
144.09 (s), 128.94 (s), 128.63 (s), 127.15 (s), 20.21 (s). MS:
m/z: 206.05 (M+1).
3232(NH of C=O), 1665 (C=O), 1370, 1155, 1053, 862:
1H-NMR (500 MHz, CDCl3) δ 6.94 (s, 1H), 6.88 (s, 2H),
2.22 (s, 3H), 2.20 (s, 3H), 2.18 (s, 6H). 13C-NMR
(126 MHz, CDCl3) δ 169.21 (s), 138.18 (s), 137.20 (s),
136.16 (s), 135.24 (s), 131.13 (s), 129.33 (s), 128.93 (s),
22.97 (s), 20.94 (s), 18.27 (s): MS: m/z: 178.12 (M+1).
4-Chloroacetanilide (3g): mp 175–176 ꢀC; IR KBr,
cm−1: 3300 (NH of C=O), 1661 (C=O), 1370, 1179, 1086,
3-Chloro-4-Fluorophenyl acetate (3o): Liquid; IR KBr,
cm−1: 1735 (C=O), 1358, 1154, 1033, 871. 1H-NMR
(500 MHz, CDCl3) δ 7.19 (dd, J = 6.2, 2.8 Hz, 1H), 7.14 (t,
J = 8.7 Hz, 1H), 6.98 (ddd, J = 9.0, 3.9, 2.9 Hz, 1H), 2.29
(s, 3H). 13C-NMR (126 MHz, CDCl3) δ 168.64 9 s), 156.49
(s), 154.85 (s), 146.49 (s), 123.82 (s), 121.14 (s), 116.51 (s),
20.68 (s). MS: m/z: 198.02 (M+1).
1
838: H NMR (500 MHz, CDCl3) δ 7.46 (d, J = 8.6 Hz,
2H), 7.28 (d, J = 11.0 Hz, 3H), 2.18 (s, 3H). 13C-NMR
(126 MHz, CDCl3) δ 168.29 (s), 136.42 (s), 129.31 (s),
129.02 (s), 121.08 (s), 24.57 (s). MS: m/z: 170.ꢀ03 (M+1).
4-Fluoroacetanilide (3h): mp 153–154 C; IR KBr,
cm−1: 3272 (NH of C=O), 1663 (C=O), 1367, 1158, 1055,
ꢀ
Aspirin (O-Acetylsalicylic acid) (3p): mp 133–134 C;
IR, KBr, cm−1: 2846, 1680 (C=O), 1303, 1134, 1077, 838.
1H-NMR (500 MHz, CDCl3) δ 8.12 (dd, J = 7.9, 1.7 Hz,
1H), 7.62 (td, J = 7.8, 1.7 Hz, 1H), 7.35 (td, J = 7.6, 0.9 Hz,
1H), 7.14 (dd, J = 8.1, 0.9 Hz, 1H), 2.35 (s, 3H). 13C-NMR
(126 MHz, CDCl3) δ 170.21 (s), 169.79 (s), 151.29 (s),
134.92 (s), 132.54 (s), 126.19 (s), 124.04 (s), 122.27 (s),
21.02 (s). MS: m/z: 181.13 (M+1).
1
859. H-NMR (500 MHz, CDCl3) δ 7.61 (s, 1H), 7.45 (dd,
J = 9.0, 4.8 Hz, 2H), 6.99 (t, J = 8.6 Hz, 2H), 2.16 (s, 3H).
13C-NMR (126 MHz, CDCl3) δ 168.80 (s), 160.42 (s),
158.48 (s), 121.97 (d, J = 7.9 Hz), 115.69 (s), 115.51 (s),
24.24 (s). MS: m/z: 154.06 (M+1).

6
SARIEF ET AL.
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SUPPORTING INFORMATION
Additional Supporting Information may be found online in
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How to cite this article: Sarief A, Haque SM,
Feroze SM, Arifuddin M. Werner transition-metal
complex (WTMC)-mediated mild and efficient
chemo-selective acylation of phenols and anilines
under solvent-free condition. J Chin Chem Soc. 2018;
1–6. https://doi.org/10.1002/jccs.201800013
[22] Y. Zhao, L. B. Liu, Z. Chen, T. S. Li, T. S. Jin, Synthetic Comm. 2006, 36,
1221.