KAl (SO 4) 2.12H 2O or KHSO 4: Efficient and inexpensive catalysts for the one-pot synthesis of β-acetamido ketones by dakin-west reaction

Article abstract of DOI:10.1080/15533174.2011.609514

Aromatic aldehydes were reacted in a vessel with enolizable ketones, acetonitrile, and acetyl chloride at ambient temperature in the presence of KAl(SO₄)₂.12H₂O to furnish the corresponding β-acetamido ketones in excellent

Full text of DOI:10.1080/15533174.2011.609514

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KAl (SO4)2.12H2O or KHSO4: Efficient and Inexpensive
Catalysts for the One-Pot Synthesis of β-Acetamido
Ketones by Dakin–West Reaction
Majid M. Heravi a , Masoumeh Zakeri b , Narges Mohammadi a & Hoda Haghi a
a Department of Chemistry, School of Sciences, Alzahra University , Vanak , Tehran , I. R.
Iran
b Young Researchers Club, Islamic Azad University, North Tehran Branch , Tehran , I. R. Iran
Published online: 23 Mar 2012.
To cite this article: Majid M. Heravi , Masoumeh Zakeri , Narges Mohammadi & Hoda Haghi (2012) KAl (SO4)2.12H2O or KHSO4:
Efficient and Inexpensive Catalysts for the One-Pot Synthesis of β-Acetamido Ketones by Dakin–West Reaction, Synthesis and
Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 42:2, 178-182, DOI: 10.1080/15533174.2011.609514
To link to this article: http://dx.doi.org/10.1080/15533174.2011.609514
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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 42:178–182, 2012
Copyright ꢀ Taylor & Francis Group, LLC
C
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2011.609514
KAl (SO4)2.12H2O or KHSO4: Efficient and Inexpensive
Catalysts for the One-Pot Synthesis of ␤-Acetamido Ketones
by Dakin–West Reaction
Majid M. Heravi,1 Masoumeh Zakeri,2 Narges Mohammadi,1 and Hoda Haghi1
1Department of Chemistry, School of Sciences, Alzahra University, Vanak, Tehran, I. R. Iran
2Young Researchers Club, Islamic Azad University, North Tehran Branch, Tehran, I. R. Iran
ical Lewis acid which has been used in various organic trans-
formations such as the synthesis of cis-isoquinolonic acids[16]
and the synthesis of oxindol.[17] Alum is a cheap, water-soluble,
non-toxic, and commercially available compound that can be
used in the laboratory without special precautions. KHSO4 is
one of the components of a triple salt with the formula 2KHSO5-
KHSO4-K2SO4, oxone, which is used as an efficient, mild, safe,
and green reagent in the synthesis of 1,1-diacetates[18] and facile
synthesis of quinoxalines.[19] Though the role of the KHSO4 is
not clear, we think that it can act as a mild Brønsted acid.
Herein we report an efficient and convenient procedure for
the synthesis of β-acetamido ketones using KAl(SO4)2.12H2O
or KHSO4 as catalysts (Scheme 1).
Aromatic aldehydes were reacted in a vessel with enolizable
ketones, acetonitrile, and acetyl chloride at ambient temperature
in the presence of KAl(SO4)2.12H2O to furnish the corresponding
β-acetamido ketones in excellent yields. KHSO4 has also been used
as another catalyst for this reaction at room temperature. Key fea-
tures of this methodology are operational simplicity, mild reaction
conditions, and excellent yields.
Keywords alum, β-Acetamido ketones, Dakin–West reaction,
KHSO4
INTRODUCTION
In recent years, the synthesis of β-acetamido carbonyl com-
pounds via multicomponent condensation reactions has been
reported. β-acetamido carbonyl compounds are skeletons that
exist in a number of biologically or pharmacologically important
compounds.[1,2] Some catalysts including CoCl2,[3] Montmo-
rillonite K10 clay,[4] SiO2–H2SO4,[5] triflate salts,[6] zeolite,[7]
iodine,[8] BiCl3,[9] ZrOCl2.8H2O,[10] iron (III) chloride,[11]
CeCl3.7H2O,[12] heteropolyacids,[13] Zr(HSO4)4/SiO2,[14] and
ZnO[15] have been employed for the synthesis of β-acetamido
carbonyl compounds. Though the previous methodologies are
quite useful, most of the methods encounter some limitations,
such as requirement of expensive catalysts, longer reaction time,
low yield, and tedious workup. Therefore, there is still a demand
for simple and facile methodologies for the preparation of β-
acetamido carbonyl compounds using new catalysts with more
efficiency. In comparison with the recently reported methods for
preparation of β-acetamido carbonyl compounds, our method
gives a straightforward procedure with reduced reaction time
and mild reaction conditions than the more of catalysts.
Recently, alum chemistry has attracted much attention as KAl
(SO4)2.12H2O. It has emerged as a safe alternative and econom-
EXPERIMENTAL
1
New products were characterized by Mp, IR, H NMR, 13
C NMR, and MS. Melting points were measured by using
the capillary tube method with an electrothermal 9200 appa-
ratus. 1H and 13C NMR spectra were recorded on a Bruker AQS
AVANCE-500 and 125.77 MHz spectrometer using TMS as an
internal standard (CDCl3 solution). IR spectra were recorded
from KBr disk on the FT-IR Bruker Tensor 27. Mass analysis
was performed using Agilent Technology (HP).
Typical Procedure for the Synthesis of β-Acetamido
Ketones
A solution of aldehyde (5 mmol), ketone (5 mmol), acetyl
chloride (1.5 ml), and acetonitrile (0.5 ml) in the presence of an
appropriate amount of catalyst (10 mol%) was stirred at ambient
temperature. Progress of the reaction was monitored by TLC.
After completion of the reaction, the mixture was filtered and
the filtrate was poured into 50 ml ice water. The solid product
was filtered, washed with diethyl ether, and recrystallized from
ethyl acetate/n-hexane or ethanol/water to give the pure product.
All products were identified by comparing their MS, 1H NMR,
and IR spectra with those of authentic samples.
Received 13 June 2011; accepted 28 July 2011.
Address correspondence to Majid M. Heravi, Department of Chem-
istry, School of Sciences, Alzahra University, Vanak, Tehran, I. R. Iran.
E-mail: mmh1331@yahoo.com
178

SYNTHESIS OF β-ACETAMIDO KETONES
179
SCH. 1. Synthesis of β-acetamido carbonyl compounds.
J = 8 Hz, ArH), 7.85–7.86 (2H, d, J = 7.5 Hz, ArH), 8.07–8.08
(1H, d, J = 8.5 Hz, ArH) ppm; 13C NMR (125 MHz, CDCl3):
δ 23.4, 43.4, 46.4, 123.5, 123.8, 125.5, 126.1, 126.9, 128.5,
128.6, 129.0, 129.2, 131.2, 133.6, 134.3, 137.0, 137.1, 169.9,
198.2 ppm; MS: m/z 317 [M+], 274, 258, 229, 212, 198, 170,
156, 129, 105, 77, 43.
New Spectral Data of the Products
Compound 10: N-(1-(3-bromophenyl)-3-(4-nitrophenyl)-3-
oxopropyl)acetamide
IR (KBr): 3275, 3085, 2930, 1695, 1655, 1600, 1555, 1340
cm−1; 1H NMR (500 MHz, CDCl3): 2.0 (3H, s, CH3), 3.40–3.44
(1H, dd, J = 6 and J = 17 Hz, CH), 3.69–3.74 (1H, dd, J =
5.5 and J = 11.5 Hz, CH), 5.54–5.57 (1H, m, CH), 7.16–7.19
(1H, t, J = 8 Hz, ArH), 7.24–7.25 (1H, d, J = 6.5 Hz, ArH),
7.29–7.31 (1H, d, J = 7 Hz, ArH), 7.36–7.37 (1H, d, J = 7.5
Hz), 7.45–7.48 (2H, t, J = 8.5 Hz, ArH), 7.53 (1H, s, NH),
7.57–7.60 (1H, t, J = 8.4 Hz, ArH), 7.90–7.91 (1H, d, J = 7 Hz,
ArH) ppm; 13C NMR (125 MHz, CDCl3): δ 23.6, 43.6, 49.8,
123.1, 125.7, 125.8, 129.1, 130.0, 130.6, 134.1, 136.8, 137.2,
144.1, 170.3, 198.4 ppm; MS: m/z 390 [M+], 347, 302, 288,
240, 226, 212, 200, 184, 157, 119, 105, 91, 77, 43.
RESULTS AND DISCUSSION
In connection with our ongoing work on heterocyclic
compounds synthesis[20] and in view of our interest in the
KAl(SO4)2.12H2O and KHSO4 catalyzed reactions[19] we now
wish to report a facile and rapid, one-pot three-component pro-
cedure of preparation of β-acetamido carbonyl compounds with
KAl(SO4)2.12H2O and KHSO4 as non-toxic, reusable, inexpen-
sive, and easily available reagents, at room temperature.
In the initial experiments, to study the feasibility of the dif-
ferent common Lewis acids catalyzed a Dakin–West reaction,
the reaction of benzaldehyde (5 mmol) and acetophenone (5
Compound 16: N-(1-(naphthalen-1-yl)-3-oxo-3-phenylpropyl)
acetamide
IR (KBr): 3285, 3065, 2980, 1740, 1685, 1650, 1590, 1405, mmol) in acetonitrile (0.5 ml) and acetyl chloride (1.5 ml) at
1
1365 cm−1, H NMR (500 MHz, CDCl3): δ 1.91–1.95 (3H, room temperature was selected as a model. The Lewis acids such
s, CH3), 3.54–3.59 (1H, dd, J = 1.77 and J = 17 Hz, CH), as MgBr2, SnCl2, SbCl3, phenyl phosphonic acid, and phenyl
3.72–3.77 (1H, dd, J = 6 and J = 16.5 Hz, CH), 6.30–6.34 phosphonic acid/SiO2 promoted the reaction in 35–85% yields.
(1H, dd, J = 6.5 and J = 14 Hz, CH), 7.29–7.37 (4H, m, ArH), (Table 1, entries 4–8). Under the same conditions, Cu-Silicat
7.42–7.44 (1H, m, ArH), 7.46–7.48 (2H, m, ArH), 7.50 (1H, and Fe-Silicat gave β-acetamido carbonyl compounds in 40%
s, NH), 7.68–7.70 (1H, d, J = 8 Hz, ArH), 7.78–7.80 (1H, d, yield after 3 h and 45% yield after 3 h, respectively (Table 1,
TABLE 1
Effect of catalysts on the three-component Dakin–West reaction to give β-acetamido ketones
Entry
Catalyst
Time (h)
Yield (%)∗
1
2
3
4
5
6
7
8
9
10
KAl(SO4)2.12H2O (10 mol%)
KHSO4 (10 mol%)
MCM-41(0.1 g)
SnCl2 (10 mol%)
SbCl3 (10 mol%)
1
1
3
2.30
3
3
3.30
3
3
95
90
55
85
35
75
70
45
40
45
MgBr2 (10 mol%)
Phenyl phosphonic acid (10 mol%)
Phenyl phosphonic acid/SiO2 (0.1 g)
Cu-Silicat (0.1 g)
Fe-Silicat (0.1 g)
3
∗The yields refer to isolated products.

180
M.M. HERAVI ET AL.
TABLE 2
One-pot condensation of aryl aldehydes, aryl ketones, acetyl chloride, and acetonitrile to give the corresponding β-acetamido
ketones catalyzed by KHSO4 and alum
Time (h)/Yield
(%)∗
Mp (◦C)
Entry
1
Ar
Arꢁ
Products
KHSO4
Alum
1/95
Found
Lit.
C6H5
C6H5
C6H5
1/90
106–107
102–104[21]
2
4-CH3C6H5
1.5/80
1/85
97–99
112–114[22]
3
4
4-OCH3C6H5
4-ClC6H5
C6H5
C6H5
1.30/80
2/85
1/80
103-106
152–154
115–117[14]
146–148[14]
1.5/90
5
6
7
4-FC6H5
C6H5
2/80
2/80
2/72
2/80
1.5/85
12/80
107–108
144–147
148–149
109–111[25]
148–150[23]
148–149[24]
4-BrC6H5
4-NO2C6H5
C6H5
C6H5
C6H5
8
9
3-BrC6H5
C6H5
2/80
1.30/78
2/75
2/85
1.5/80
2/80
169–171
88–90
170–172[14]
74–76[14]
—
4-NO2C6H5
4-NO2C6H5
10
3-BrC6H5
103–104
11
12
13
4-CH3C6H5
4-OCH3C6H5
4-ClC6H5
4-NO2C6H5
4-NO2C6H5
4-NO2C6H5
2/70
2/75
2/80
1.5/70
2/78
120–122
96–100
83–85[14]
87–89[14]
2/80
140–143
116–118[14]
14
3-NO2C6H5
C6H5
2/75
1.5/85
187–190
190–191[23]
15
16
4-FC6H5
4-NO2C6H5
C6H5
2/70
3/65
2/78
3/70
331–332
176
330[22]
—
1-Naphthaldehyde
17
4-CH3C6H5
Methyl aceto acetate
3/50
3/55
131–133
130[24]
(Continued on next page)

SYNTHESIS OF β-ACETAMIDO KETONES
181
TABLE 2
One-pot condensation of aryl aldehydes, aryl ketones, acetyl chloride, and acetonitrile to give the corresponding β-acetamido
ketones catalyzed by KHSO4 and alum (Continued)
Time (h)/Yield
(%)∗
Mp (◦C)
Entry
18
Ar
Arꢁ
Products
KHSO4
3/55
Alum
3/68
Found
Lit.
4-FC6H5
Methyl aceto acetate
117–120
116[24]
19
20
4-ClC6H5
4-BrC6H5
Methyl aceto acetate
Methyl aceto acetate
3/58
3/60
3/60
3/60
142–144
187–189
167–169[22]
188–190[22]
∗The yields refer to isolated products.
Al3+
H
O
OAC
O
CH3COCl
O
CH3CN
O
N=CCH3
O
NHAC
H2O
SCH. 2. Probable mechanism of alum catalyzed multicomponent reactions for the preparation of β-acetamido carbonyl compounds.
entries 9, 10). MCM-41 promoted the reaction in 55% yield ence of an electron-donating or an electron-withdrawing group
(Table 1, entry 3). However, among the catalysts studied for on the aromatic ring of aldehyde or acetophenone did not affect
this reaction, KAl(SO4)2.12H2O and KHSO4 were found to be the reaction time and yields. To extend the preparative utility
the most effective catalysts for this transformation because they and generality of this multicomponent reaction, a variety of
resulted in the highest conversion to the desired product (Table aromatic aldehydes were treated with methyl acetoacetate un-
1, entries 1, 2). Generally, there was no reaction in the absence der the same experimental conditions, and the corresponding
of catalyst. We also evaluated the amount of KHSO4 required β-acetamido keto esters were obtained in good yields.
for this transformation. As less as 10 mol% of the KHSO4 can
The most probable mechanism for this reaction is illustrated
catalyze the reaction to the same extent, it needs a little longer in Scheme 2. The presence of acetyl chloride is necessary for
reaction time (>2 h). It was found that 10 mol% of KHSO4 the transformation and the reaction in its absence gave none of
and alum could effectively catalyze the reaction. No substantial the desired product even after 2 h.
improvement in the yield was found with further increase of the
catalysts. Hence, the optimal amount of catalysts was chosen as
CONCLUSIONS
10 mol% in the following reactions.
Encouraged by this result, a wide variety of aromatic
aldehydes, containing both electron-withdrawing and electron-
donating substituents, were treated under the same experimental
conditions and afforded the corresponding β-acetamido ketones
in good to excellent yields (Table 2). We found that, the pres-
In this article, we reported a simple, clean, convenient, and
efficient method for the synthesis of β-acetamido carbonyl com-
pounds using KHSO4 or KAl (SO4)2.12H2O as catalyst under
mild reaction conditions at room temperature and without ob-
taining any side products. Some of the major advantages of this

182
M.M. HERAVI ET AL.
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