Heteropoly acids as solid green Bronsted acids for a one-pot synthesis of β-acetamido ketones by Dakin-West reaction

Article abstract of DOI:10.1016/j.bmcl.2005.11.080

An efficient improved procedure for the synthesis of β-acetamido ketones has been developed by a heteropoly acid (HPA) catalyzed three-component coupling protocol. The present methodology offers several advantages such as excellent yields, simple procedur

Full text of DOI:10.1016/j.bmcl.2005.11.080

Bioorganic & Medicinal Chemistry Letters 16 (2006) 1221–1226
Heteropoly acids as solid green Brønsted acids
for a one-pot synthesis of b-acetamido ketones
by Dakin–West reaction
a,
a
a,b
*
Ezzat Rafiee, Fariba Tork and M. Joshaghani
a
Department of Chemistry, Faculty of Science, Razi University, Kermanshah 67149, Iran
b
Kermanshah Oil Refining Company, Kermanshah, Iran
Received 4 October 2005; revised 13 November 2005; accepted 22 November 2005
Available online 9 December 2005
Abstract—An efficient improved procedure for the synthesis of b-acetamido ketones has been developed by a heteropoly acid (HPA)
catalyzed three-component coupling protocol. The present methodology offers several advantages such as excellent yields, simple
procedure, short reaction times, and mild conditions.
Ó 2005 Elsevier Ltd. All rights reserved.
In recent decades, use of eco-friendly applicable
industrial and green catalysts has been of interest.
Thus, green chemistry has been defined as a set of
principles that reduces or eliminates the use or gener-
ation of hazardous substances throughout the entire
two or more synthetic steps, which are performed
without isolation of any intermediates thus reducing
time and saving both energy and raw material. The
diversity, efficiency, and rapid access to small and
highly functionalized organic molecules make this ap-
proach of central interest in the construction of com-
binatorial libraries and optimization in drug discovery
1
life of chemical materials. Along this line, using het-
eropoly acids (HPAs) which are strong, low in toxic-
ity, highly stable toward humidity, and air-stable has
1
9
processes. Dakin–West reaction is the best known
20,21
2
found more attention. They have been widely used
as acid catalysts for organic synthesis and found sev-
route for the synthesis of b-acetamido ketones.
These compounds are versatile intermediates, in that
3
–9
eral industrial applications.
The HPA-based solid
their skeletons exist in a number of biologically
2,23
2
acid catalysts, especially those comprising the stron-
gest Keggin-type HPAs such as H PW O (PW),
H PMo O (PMo) or H SiW O (SiW), are more
or pharmacologically important compounds.
Recently, Singh and co-workers proposed a procedure
for the formation of these compounds in the presence
3
12 40
3
12 40
4
12 40
2
4
active than conventional inorganic and organic acids
9
of Cu(OTf)2. b-Acetamido ketones have also been
synthesized using Zn(II), Bi(III), Sn(II), Sc(III) tri-
–12
such as zeolites, SiO /Al O , and H PO /SiO .
2
2
2
3
3
4
2
4
HPAs have many advantages over liquid acid
catalysts including being noncorrosive and environ-
mentally benign, thus presenting fewer disposal
flates, BF , CuCl , BiCl , LaCl , LiClO , InCl ,
3 2 3 3 4 3
2
5
26
CoCl , , montmorillonite K-10 clay, and H SO /
2
2
4
2
7
SiO2 as catalyst. Although these methods are valu-
able, they suffer from one or more of the following
disadvantages such as high temperature, long reaction
time, low yield, and tedious workup. Hence, the devel-
opment of new catalysts with more efficiency is still in
demand.
1
3
problems.
Multicomponent reactions (MCRs) are one of the
most important protocols in organic synthesis and
1
4–18
medicinal chemistry.
These processes consist of
In continuation of our interest on the catalytic activities
2
8
of heteropoly anions, here, a very efficient and envi-
ronmentally benign catalysis by the strong HPAs for
the synthesis of b-acetamido ketones is reported
(Scheme 1).
Keywords: b-Acetamido ketones; Heteropoly acid; Dakin–West reac-
tion; Multi component reactions (MCRs).
*
Corresponding author. Tel./fax: +98 831 4274559; e-mail: e.rafiei@
razi.ac.ir
0
960-894X/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2005.11.080

1222
E. Rafiee et al. / Bioorg. Med. Chem. Lett. 16 (2006) 1221–1226
R2
HPA, CH COCl
3
X
X
+
R1
R1
CH CN, R.T.
3
R2
NHAcO
Scheme 1.
Table 1. Effect of catalysts on the three-component Dakin–West reaction to give b-acetamido ketones
O
CHO
Catalyst
+
H C
3
CH CN, CH COCl
3
3
a
Yield (%)
Entry
Catalyst
Temperature (°C)
T (h)
1
2
3
4
5
6
7
8
9
—
80
10
50 (min)
0
95
88
90
60
69
68
82
64
75
78
79
77
77
59
19
91
80
PW (5 mol %)
PMo (5 mol %)
SiW (5 mol %)
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
80
50 (min)
50 (min)
2
4
Zn(OTf)
Bi(OTf)
Sn (OTf)
Sc(OTf)
Cu(OTf)
Yb(OTf)
BF .OEt
CuCl
BiCl
2
(10 mol %)
(10 mol %)
(10 mol %)
30
30
24
3
2
4
2
30
24
3
(10 mol %)
30
2
4
2
(10 mol %)
(10 mol %)
30
30
2
4
1
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
3
2
2
4
3
(100 mol %)
30
2
4
2
(100 mol %)
30
24
3
(100 mol %)
30
24
LaCl
3
(100 mol %)
30
2
4
LiClO
4
(100 mol %)
30
24
InCl
SiO
3
(100 mol %)
/H SO (0.3 g)
30
65 (min)
7
2
7
2
2
4
26
Montmorillonite K-10 (2 g)
70
a
Isolated yield.
At first the three-component condensation reaction of
benzaldehyde, acetophenone, and acetyl chloride was
performed in the presence of catalytic amount of several
HPAs (Table 1, entries 2–4). The synthesis could not be
achieved in the absence of the catalyst (Table 1, entry 1).
The reaction was more efficient in the presence of HPAs
times at room temperature. It is noteworthy that,
no acetylation of an aromatic hydroxyl group was
observed when salicylaldehyde was used, and the cor-
responding b-acetamido ketones were isolated in an
excellent yield (Table 2, entries 12–14). Aliphatic
aldehyde and acyclic aliphatic ketone gave unsatisfac-
tory results (Table 2, entries 17 and 19) but show
good results at reflux condition (Table 2, entries 18
2
4,26,27
when compared to the literature procedures
Table 1, entries 5–18).
(
3
0
and 20). As expected, the results show tungsten
HPAs (PW and SiW) are preferred over molybdenum
HPA (PMo) as acid catalysts and PW—the strongest
acid in the HPA series—is particularly recommended.
To establish the optimal conditions, a set of experi-
ments varying the amount of the catalysts, quantities
of acetyl chloride, and temperature were carried out.
The best conditions to prepare the b-acetamido ke-
tones were achieved when 5 mol %, 8 mol %,
and 8 mol % of PW, PMo, and SiW were used,
respectively. These conditions were applied to a series
of substituted aromatic and aliphatic aldehydes and
2
4,26,27
Based on the literature the authors suggest a
reaction mechanism that is shown in Scheme 2.
In summary, a new and important catalytic activity of
HPAs (cheap, commercially available, noncorrosive,
and environmentally benign compounds) has been stud-
ied for the synthesis of b-acetamido ketones in excellent
yields under mild reaction conditions. The simple exper-
imental procedure combined with the easy workup, the
mild reaction conditions, and excellent yields of prod-
ucts are the strong features of the method presented
herein.
2
9
ketones.
As shown in Table 2 aromatic aldehydes or acetoph-
enones with both electron-withdrawing or -donating
substitution performed afforded the b-acetamido
ketones without the formation of any side products,
in excellent yields and in relatively short reaction

E. Rafiee et al. / Bioorg. Med. Chem. Lett. 16 (2006) 1221–1226
1223
Table 2. Synthesis of b-acetamido ketones at room temperature in the presence of catalytic amounts of H
3
PW12
O
40, H
3
PMo12O40 or H
3
SiW12
O
40
CHO
HPA
X
X
+
R1
R1
CH CN, CH COCl, R.T.
3
3
R2
NHAcO
1
R
2
R
a
Yield (%)/time (min)
Entry
Product
b
c
d
PW
PMo
SiW
O
1
C
6
H
5
C
6
H
5
95/50
90/30
92/30
3
2
3
C
6
H
5
4-NO
2
C
6
H
4
90/35
93/35
90/70
90/40
90/40
95/40
NO2
C
6
H
5
4-BrC
6 4
H
Br
3
4
5
6
4-ClC
6
H
4
C
C
C
C
6
6
6
6
H
H
H
H
5
5
5
5
92/45
80/40
90/50
93/60
85/40
90/50
90/50
90/40
90/50
Cl
3 6 4
4-CH OC H
CH O
3
3
2-ClC
6
H
4
Cl
3
7
8
4-CNC
6
H
4
75/60
85/50
85/60
85/40
80/40
90/60
NC
4-CH
3
C
6
H
4
4-NO
2
C
6
H
4
CH3
NO2
9
4-ClC
6
H
4
4-BrC
6
H
4
90/80
87/60
97/40
90/60
95/40
91/60
Cl
Cl
Br
1
0
4-ClC
6
H
4
2 6 4
4-NO C H
NO2
(continued on next page)

1224
E. Rafiee et al. / Bioorg. Med. Chem. Lett. 16 (2006) 1221–1226
Table 2 (continued)
1
R
2
R
a
Yield (%)/time (min)
Entry
Product
b
PW
c
d
PMo
SiW
1
1
2
4-CH OC
3
6
H
4
4-NO
2
C
6
H
4
90/70
75/60
87/50
80/90
90/50
90/80
CH O
NO2
3
1
6
2-HOC H
4
6 5
C H
OH
3
1
1
3
4
2-HOC
6
H
4
4-NO
2
C
6
H
4
85/70
87/50
85/60
90/60
87/60
90/60
OH
OH
NO2
2-HOC
6
H
4
4-BrC
6
H
4
Br
1
1
1
5
6
7
3-NO
2
C
6
H
4
4-BrC
6
H
4
90/70
85/60
90/50
90/40
95/50
93/40
Br
NO2
3-NO
2
C
6
H
4
C
6
H
5
NO2
e
CH
3
CH
CH
5
2
C
6
H
5
0/120
20/120
20/120
CH CH2
3
f
f
f
1
8
9
CH
3
2
C
6
H
5
35/120
40/120
35/120
CH CH
3
2
1
C
C
6
H
C
6
H
10
O
O
50/80
20/80
20/80
f
f
f
2
0
6
H
5
C
6
H
10
85/80
80/80
80/80
a
b
c
d
e
f
31
Isolated yield, All products were identified by comparing their NMR and IR values with those for authentic samples.
The mole ratio of aldehyde to ketone to H PW12 40 is 1:1:0.05.
The mole ratio of aldehyde to ketone to H PMo12
SiW12
3
O
3
O
40 is 1:1:0.08.
The mole ratio of aldehyde to ketone to H
Reaction did not occur.
3
O40 is 1:1:0.08.
The reaction performed at reflux condition.

E. Rafiee et al. / Bioorg. Med. Chem. Lett. 16 (2006) 1221–1226
1225
O
3
OCOCH3
H
3
+
CH COCl, H
3
R1
H
+
Cl
N
O
R1
R1
H
NCCH3
O
CH3
R1
CH3
CH3
O
O
CH3
O
O
HN
O
O
N
H C
R
2
O
CH3
3
N
O
CH3
R2
R1
R2
R1
+
R1
Scheme 2.
Acknowledgments
20. Dakin, H. D.; West, R. J. Biol. Chem. 1928, 78, 745.
2
2
1. Buchanan, G. L. Chem. Soc. Rev. 1988, 17, 91.
2. Casimir, J. R.; Turetta, C.; Ettouati, L.; Paris, J. Tetra-
hedron Lett. 1995, 36, 4797.
The authors thank the Razi University Research Coun-
cil and Kermanshah Refinery Company for support of
this work.
2
3. Godfrey, A. G.; Brooks, D. A.; Hay, L. A.; Peters, M.;
McCarthy, J. R.; Mitchell, D. J. Org. Chem. 2003, 68,
2
623.
2
2
4. Pandey, G.; Singh, R. P.; Garg, A.; Singh, V. K.
Tetrahedron Lett. 2005, 46, 2137.
5. (a) Bhatia, B.; Reddy, M. M.; Iqbal, J. J. Chem. Res.,
Synop. 1994, 713; (b) Rao, I. N.; Prabhakaran, E. N.; Das,
S. K.; Iqbal, J. J. Org. Chem. 2003, 68, 4079.
References and notes
1
2
. (a) Anastas, P. T.; Warner, J. C. Green Chemistry, Theory
and Practice; Oxford University Press: New York, 1998;
(
b) Clark, J. H. Green Chem. 1999, 1, 1.
26. Bahulayan, D.; Das, S. K.; Iqbal, J. J. Org. Chem. 2003,
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27. Khodaei, M. M.; Khosropour, A. R.; Fattahpour, P.
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Jafari, A. A. J. Iranian Chem. Soc. 2005, 2, 85, and
references cited therein; (c) Firouzabadi, H.; Iranpoor, N.;
Jafari, A. A. Synlett 2005, 299.
. Kozhevnikov, I. V. Catal. Rev.-Sci. Eng. 1995, 37, 311.
. Ono, Y.; Thomas, J. M.; Zamaraev, K. I. Perspectives in
Catalysis; Blackwell: London, 1992.
28. (a) Rafiee, E.; Tangestaninejad, S.; Habibi, M. H.;
Mikhani, V. Bioorg. Med. Chem. Lett. 2004, 14, 3611;
(b) Kozhevnikova, E. F.; Rafiee, E.; Kozhevnikov, I. V.
Appl. Catal. A 2004, 260, 25; (c) Rafiee, E.; Tangestanine-
jad, S.; Habibi, M. H.; Mikhani, V. Bull. Kor. Chem. Soc.
2004, 25, 599; (d) Rafiee, E.; Tangestaninejad, S.; Habibi,
M. H.; Mikhani, V. Synth. Commun. 2004, 34, 3673; (e)
Rafiee, E.; Tangestaninejad, S.; Habibi, M. H.; Mikhani,
V. Russ. J. Org. Chem 2005, 41, 403.
29. Typical procedure for the synthesis of b-acetamido
ketones: A solution of aryl aldehyde (1 mmol), ketone
(1 mmol), acetyl chloride (0.3 mL), and acetonitrile (3 mL)
in the presence of appropriate amount of catalyst (Table 2)
was stirred at ambient temperature. The progress of the
reaction was monitored by TLC. After completion of the
reaction, the solution was poured into 50 mL ice water.
The solid product was filtered, washed with ice water, and
recrystallized from ethyl acetate/n-heptane to give the pure
product. All products were identified by comparing their
3
4
5
. Kozhevnikov, I. V.. In Catalysis for Fine Chemicals,
Catalysis by Polyoxometalates; Wiley: Chichester, 2002;
Vol. 2.
6
7
. Izumi, Y.; Matsuo, K.; Urabe, K. J. Mol. Catal. 1983, 18,
2
99.
. Okuhara, T.; Mizuno, N.; Misono, M. Appl. Catal. A
001, 222, 63.
. Misono, M. Chem. Commun. 2001, 1141.
. Kozhevnikov, I. V. Chem. Rev. 1998, 98, 171.
0. Tiofeeva, M. N.; Dimidov, A. V.; Kozhevnikov, I. V.
J. Mol. Catal. 1993, 79, 21.
1. Drago, R. S.; Dias, J. A.; Maier, T. J. Am. Chem. Soc.
997, 119, 7702.
2. Okuhara, T.; Mizuno, N.; Misono, M. Adv. Catal. 1996,
1, 113.
2
8
9
1
1
1
1
1
3
1
4
NMR and IR values with those for authentic samples.
3. Izumi, Y.; Urabe, K.; Onaka, M. Zeolite, Clay and
Heteropoly Acids in Organic Synthesis; Kodansha/VCH:
Tokyo, 1992.
30. Kozhevnikov, I. V.; Kloetstra, K. R.; Sinnema, A.;
Zandbergen, H. W.; Bekkum, H. V. J. Mol. Catal. 1996,
114, 287.
1
1
1
4. Weber, L. Drug Discovery Today 2002, 7, 143.
5. D o¨ mling, A. Curr. Opin. Chem. Biol. 2002, 6, 306.
6. (a) Weber, L.; Illegen, K.; Almstetter, M. Synlett 1999,
31. Spectroscopic data of products: b-Acetamido-b-(phen-
1
yl)propiophenone (Table 2, entry 1). Mp: 101–103 °C, H
NMR (CDCl , 200 MHz) d 2.03 (s, 3H), 3.34 (dd, J = 6.6
3
3
66; (b) Armstrong, R. W.; Combs, A. P.; Tempest, A. P.;
Brown, S. D.; Keating, T. A. Acc. Chem. Res. 1996, 29,
23.
and 9.7 Hz, 1H), 3.67 (dd, J = 6.6 and 9.7 Hz, 1H), 5.60
(m, 1H) 6.87 (s, 1H), 7.58 (d, J = 9.1 Hz, 5H), 7.76 (d,
À1
1
J = 9.1 Hz, 5H); IR (KBr, cm ) 3252, 3046, 1667, 1624,
1574, 1288, 1082, 878, 819.
1
1
1
7. Ugi, I.; Werner, B.; D o¨ mling, A. Molecules 2003, 8, 53.
8. D o¨ mling, A. Curr. Opin. Chem. Biol. 2000, 4, 318.
9. (a) Thompson, L. A.; Ellman, J. A. Chem. Rev. 1996, 96,
b-Acetamido-b-(phenyl)-4-nitropropiophenone (Table 2,
1
entry 2). Mp: 74–76 °C, H NMR (200 MHz, CDCl ) d
3
5
1
55; (b) Dolle, R. E.; Nelson, K. H. J. Comb. Chem. 1996,
, 235.
2.00 (s, 3H), 3.32 (d, J = 13.8 Hz, 1H), 3.52 (d,
J = 13.8 Hz, 1H), 5.70 (s, 1H), 7.32 (m, 4H), 7.88 (m,

1226
E. Rafiee et al. / Bioorg. Med. Chem. Lett. 16 (2006) 1221–1226
À1
3
1
H), 8.08 (m, 2H); IR (KBr, cm ) 3260, 3027, 2270, 1676,
637, 1557, 1397, 1222, 969, 817, 667, 556.
1690, 1644, 1585, 1542, 1510, 1353, 1077, 1000, 820, 670,
573.
b-Acetamido-b-(phenyl)-4-bromopropiophenone (Table 2,
b-Acetamido-b-(4-methoxyphenyl)-4-nitropropiophenone
(Table 2, entry 11). Mp: 87–89 °C, H NMR (200 MHz,
3
CDCl )d 2.05 (s, 3H), 3.12 (s, 3H), 3.52 (d, J = 15.2 Hz, 1H),
1
1
entry 3). Mp: 98–100 °C, H NMR (200 MHz, CDCl
3
) d
2.1 (s, 3H), 3.40 (dd, J = 8.1, 10.07 Hz, 1H), 3.81 (dd,
J = 8.1, 10.07 Hz, 1H), 5.6 (s, 1H), 6.8 (d, 1H), 7.2–7.5 (m,
3.77 (d, J = 15.2 Hz, 1H), 5.97 (s, 1H), 7.32 (m, 4H), 7.69 (m,
3H), 8.02 (m, 2H); IR (KBr, cm ) 3243, 3023, 2265, 1667,
À1
À1
5
H), 7.6 (d, 2H), 7.8 (d, 2H); IR (KBr, cm ) 3296, 1690,
685, 1644, 1545, 1395, 1372, 1070, 995, 816, 759, 705.
1
1634, 1589, 1379, 1227, 969, 819, 676, 568.
b-Acetamido-b-(2-hydroxyphenyl)propiophenone (Table 2,
b-Acetamido-b-(4-chlorophenyl)propiophenone (Table 2,
1
1
entry 4). Mp: 144–146 °C, H NMR (CDCl , 200 MHz) d
entry 12). Mp: 130–132 °C; H NMR (200 MHz, CDCl ) d
3
3
2.00 (s, 3H), 3.40 (dd, J = 6.9 and 9.9 Hz, 1H), 3.71 (dd,
J = 6.9 and 9.9 Hz, 1H), 5.54 (m, 1H), 7.02 (m, 5H), 7.45
m, 3H), 7.84 (d, J = 9.1 Hz, 2H); IR (KBr, cm ) 3270,
2.00 (s, 3H), 3.49 (d, J = 7.2 Hz, 1H), 3.68 (d, J = 7.1 Hz, 1H),
6.87 (s, 1H), 7.50–7.72 (m, 5H), 7.95 (d, J = 5.9 Hz, 2H), 8.23
(d, J = 5.2 Hz, 2H); IR (KBr, cm ) 3286, 2845, 1679, 1638,
À1
À1
(
3
082,1668, 1635, 1556, 1255, 1104, 887, 823, 687.
1595, 1501, 1446, 1341, 1289, 851, 747, 681, 588.
b-Acetamido-b-(2-hydroxyphenyl)-4-nitropropiophenone
(Table 2, entry 13). Mp: 102–104 °C, H NMR (200 MHz,
3
CDCl ) d 2.01 (s, 3H), 3.38 (d, J = 7.1 Hz, 1H), 3.65 (d,
b-Acetamido-b-(4-methoxyphenyl)propiophenone (Table
1
H
1
2,
entry 5). Mp: 115–117 °C,
NMR (CDCl
3
,
2
00 MHz) d 2.09 (s, 3H), 2.47 (s, 3H), 3.51 (dd, J = 7.1
and 10.0 Hz, 1H), 3.84 (dd, J = 7.1 and 10.0 Hz, 1H), 5.58
(m, 1H) 7.39 (s, 1H), 7.52 (m, 5H), 7.96 (m, 4H); IR (KBr,
cm ) 3263, 3051, 1672, 1630, 1581, 1290, 1081, 878, 817.
J = 7.1 Hz, 1H), 5.98 (s, 1H), 6.79 (s, 1H), 7.44–7.69 (m,
4H), 7.95–8.25 (m, 5H);IR (KBr, cm ) 3275, 3025,
2843, 1665, 1634, 1595, 1536, 1511, 1341, 1275, 847, 739,
677, 580.
À1
À1
b-Acetamido-b-(2-chlorophenyl)propiophenone (Table 2,
1
entry 6). Mp: 135–137 °C, H NMR (CDCl , 200 MHz) d
b-Acetamido-b-(2-hydroxyphenyl)-4-bromopropiophenone
3
1
2.06 (s, 3H), 3.43 (dd, J = 7.1 and 10.0 Hz, 1H), 3.71 (dd,
J = 7.1 and 10.0 Hz, 1H), 5.60 (m, 1H), 7.12 (m, 5H), 7.52
m, 3H), 7.90 (d, J = 9.3 Hz, 2H); IR (KBr, cm ) 3250,
(Table 2, entry 14). Mp: 126–128 °C. H NMR (200 MHz,
3
CDCl ) d 2.12 (s, 3H), 3.33 (d, J = 7.3 Hz, 1H), 3.68 (d,
À1
(
J = 7.3 Hz, 1H), 5.38 (s, 1H), 6.68 (s, 1H), 7.34–7.80 (m, 5H),
8.02–8.26 (m, 4H); IR (KBr, cm ) 3250, 3026, 2855, 1658,
À1
3062, 1660, 1640, 1563, 1261, 1109, 890, 833, 682.
b-Acetamido-b-(4-cyanophenyl)propiophenone (Table 2,
1629, 1577, 1515, 1459, 1350, 1278, 860, 745, 679, 593.
b-Acetamido-b-(3-nitrophenyl)-4-bromopropiophenone
1
entry 7). Mp: 85–88 °C; H NMR (200 MHz, CDCl
3
) d
.92 (s, 3H), 3.34 (dd, J = 5.1, 16.07 Hz, 1H), 3.62 (dd,
1
1
J = 5.9, 16.1 Hz, 1H), 5.65 (d, J = 7.03, 1H), 7.45 (m, 4H),
(Table 2, entry 15):Mp: 115–118 °C, H NMR (CDCl3,
200 MHz) d 2.13 (s, 3H), 3.50 (dd, J = 6.5 and 9.6 Hz, 1H),
3.85 (dd, J = 6.5 and 9.6 Hz, 1H), 5.70 (m, 1H) 7.24 (s, 1H),
7.54–7.87 (m, 4H), 7.96 (m, 4H); IR (KBr, cm ) 3264, 3035,
À1
7
.80 (m, 3H), 8.02 (s, 1H); IR (KBr, cm ) 3294, 3035,
250, 1690, 1650, 1541, 1439, 1225, 978, 752, 677, 548.
À1
2
b-Acetamido-b-(4-methylphenyl)-4-nitropropiophenone
1690, 1637, 1585, 1510, 1353, 1285, 1077, 998, 824, 658, 576.
b-Acetamido-b-(3-nitrophenyl)propiophenone (Table 2,
1
(
Table 2, entry 8). Mp: 83–85 °C, H NMR (200 MHz,
CDCl ) d 1.99 (s, 3H), 2.33 (s, 3H), 3.44 (d, J = 14.5 Hz,
H), 3.73 (d, J = 14.5 Hz, 1H), 6.01 (s, 1H), 7.54 (m, 4H),
1
3
entry 16). Mp: 110–112 °C; H NMR (200 MHz, CDCl
3
) d
1
7
2
1.87 (s, 3H), 3.11 (d, J = 15.9 Hz, 1H), 3.52 (d, J = 12.1 Hz,
1H), 5.50 (s, 1H), 7.30 (m, 5H), 7.80 (d, J = 6.2 Hz, 2H), 8.00
À1
.97 (m, 3H), 8.10 (m, 2H); IR (KBr, cm ) 3256, 3034,
276, 1668, 1629, 1601, 1386, 1231, 974, 823, 674, 561.
À1
(d, J = 6.2 Hz, 2H); IR (KBr, cm ) 3290, 3024, 2245, 1680,
1649, 1542, 1440, 1215, 987, 750, 680, 545.
b-Acetamido-b-(4-chlorophenyl)-4-bromopropiophenone
1
(
Table 2, entry 9). Mp: 140–142 °C, H NMR (200 MHz,
CDCl ) d 2.08 (s, 3H), 3.34 (dd, J = 7.1 and 10.1 Hz, 1H),
.75 (dd, J = 7.1 and 10.1 Hz, 1H), 5.70 (m, 1H) 7.36 (s,
b-Acetamidopentaniophenone (Table 2, entries 17 and 18).
1
3
Mp: 98–100 °C, H NMR (CDCl
3
, 200 MHz)d 1.11 (t,
3
1
(
J = 10.1, 3H), 1.55 (m, 2H), 2.00 (s, 3H), 3.21 (dd, J = 5.9
and 9.5 Hz, 1H), 3.60 (dd, J = 5.9 and 9.5 Hz, 1H), 5.51 (m,
1H) 7.29 (s, 1H), 7.62–7.70 (m, 5H); IR (KBr, cm ) 3246,
3030, 2868, 1659, 1631, 1275, 1077, 884, 827. N-{1-phenyl-1-
[2-oxocyclohexyl]}acetamide (Table 2, entry 19 or 20). Mp:
133–135 °C, HNMR(CDCl , 200 MHz)d1.80 (s, 3H), 2.22–
2.24 (m, 8H), 5.49 (s, 1H), 7.12 (s, 1H), 7.60–7.74 (m, 3H),
8.25–8.32 (m, 2H); IR (KBr, cm ) 3384, 2932, 1650, 1602,
1524, 1227, 858, 758, 694.
H), 7.65 (d, J = 9.1 Hz, 4H), 7.96 (d, J = 9.1 Hz, 4H); IR
KBr, cm ) 3263, 3053, 1680, 1632, 1585, 1293, 1085, 887,
À1
À1
827.
b-Acetamido-b-(4-chlorophenyl)-4-nitropropiophenone
1
1
(
Table 2, entry 10). Mp: 116–118 °C, H NMR (200 MHz,
3
CDCl ) d 2.10 (s, 3H), 3.50 (dd, J = 6.8 and 9.9 Hz, 1H),
3
À1
3
7
.90 (dd, J = 6.8 and 9.9 Hz, 1H), 5.69 (s, 1H) 7.10 (s, 1H),
.30–7.82 (m, 6H), 8.12 (m, 3H); IR (KBr, cm ): 3264,
À1