One-pot and three-component synthesis of substituted pyrimidines catalysed by boron sulfuric acid under solvent-free conditions

Article abstract of DOI:10.3184/174751914X14069964360841

An efficient, simple and one-pot synthesis of pyrimidine derivatives by a three-component reaction of ketones, triethyl orthoformate, and ammonium acetate in the presence of boron sulfuric acid as a reusable and efficient catalyst under solvent-free conditions is reported. The reusability of catalyst, simplicity of the starting materials, short reaction time, one-pot, and good yields of products are the main advantages.

Full text of DOI:10.3184/174751914X14069964360841

524 RESEARCH PAPER
VOL. 38 SEPTEMBER, 524–527
JOURNAL OF CHEMICAL RESEARCH 2014
One-pot and three-component synthesis of substituted pyrimidines
catalysed by boron sulfuric acid under solvent-free conditions
Mehdi Soheilizada*, Mehdi Adiba and Sami Sajjadifarb
aSchool of Chemistry, College of Science, University of Tehran, PO Box 14155-6455, Tehran, Iran
bDepartment of Chemistry, Payame Noor University, PO Box 19395-4697 Tehran, Iran
An efficient, simple and one-pot synthesis of pyrimidine derivatives by a three-component reaction of ketones, triethyl
orthoformate, and ammonium acetate in the presence of boron sulfuric acid as a reusable and efficient catalyst under solvent-
free conditions is reported. The reusability of catalyst, simplicity of the starting materials, short reaction time, one-pot, and
good yields of products are the main advantages.
Keywords: boron sulfuric acid, multi-component reactions, pyrimidine, solvent-free, triethyl orthoformate
Due to their productivity, atom economy, straightforward
reaction design, convergence and facile execution, multi-
component reactions (MCRs) have emerged as a highly
efficient tool in modern synthetic organic chemistry and are
widely used for the preparation of chemically and biologically
important compounds.1–3
OH
F
F
NH2
H
O
NH2
F
O
N
N
N
OH
H2N
N
O
N
H
O
N
H
C
3
Pyrimidines, an important class of nitrogen-containing
heterocyclic compounds, have attracted much attention because
of their wide range of biological properties such as anti-HIV,
anti-tubercular, antitumour, antineoplastic, anti-inflammatory,
diuretic and cardiovascular activities.4 Compounds containing
pyrimidine moiety possess a wide range of pharmacological
and therapeutic activities. The structures of some of the
pyrimidine biologically active compounds are shown in Fig. 1.
For example, flucytosine 1 is a fluorinated pyrimidine used
as nucleosidal antifungal agent for the treatment of serious
systemic infections.5 Bacimethrin 2, a pyrimidine antibiotic, is
active against several staphylococcal infections.6 Gemcitabine
3, a pyrimidine antimetabolite, shows excellent antitumour
activity against murine solid tumours.7
Several synthetic methods have been reported for the
preparation of pyrimidine ring systems. In the most common
synthetic methods, the pyrimidine ring is constructed by the
reaction of 1,3-dicarbonyl component with a reagent bearing
an N–C–N fragment such as urea,8 amidine,9 or guanidine.10 In
recent years, a few synthetic methods have also been reported
for the preparation of pyrimidines from ketones using TsOH,11
ZnCl212 and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide
(TBBDA)13 as the catalyst.
3
2
1
Fig. 1 Examples of some pyrimidine biologically active compounds.
Boron sulfuric acid (BSA) is a novel solid acid catalyst that
was introduced by Kiasat and Fallah-Mehrjardi (Scheme 1) for
the regioselective conversion of epoxides to thiocyanohydrins
under solvent-free reaction conditions.16 BSA as a trifunctional
inorganocatalyst is a strong acid that efficiently catalyses many
reactions. Therefore, the development of MCRs using BSA as
an acid catalyst has been considered by our research group.17–20
Results and discussion
Continuing our efforts directed towards the straightforward
preparation of biologically active target molecules through
MCRs, we now report a novel, efficient and environmentally
benign protocols for the synthesis of substituted pyrimidines
8a–m by three-component condensation of ketones 5a–m,
triethyl orthoformate 6, and ammonium acetate 7 catalysed
by BSA as a valuable catalyst under solvent-free conditions in
good yields (Scheme 2). TLC and NMR spectroscopic analysis
of the reaction mixtures clearly indicated formation of the
corresponding pyrimidines 8. No product other than 8 could be
detected by NMR spectroscopy (Scheme 2, Table 1).
Recently, more attention has been paid to the application
of inorganic acidic salts in organic synthesis.14,15 Simplicity
in handling, decreased reactor and plant corrosion problems,
more environmentally safe disposal in different chemical
processes and minimal or no waste nor by-products are some
of the advantages of using solid acids in organic synthesis.
N2(g)
B(OH)3
+
3 ClSO3H
B(OSO3H)3
+
3 HCl(g)
r.t.
Scheme 1 Preparation of boron sulfuric acid.
OSO3H
R2
R1
R2
OEt
B
N
H
OSO3
HO3SO
solvent-free
100°C
+
+
NH4OAc
EtO
OEt
R1
N
O
a-m
8
a-m
5
7
6
R1= H, CH3, PhCH2
R2= aryl, alkyl
Scheme 2 Synthesis of substituted pyrimidines.
* Correspondent. E-mail: m.soheilizad@yahoo.com

JOURNAL OF CHEMICAL RESEARCH 2014 525
Table 1 Synthesis of pyrimidine derivatives 8 using BSA as a catalyst
Table 2 Optimisation of the reaction conditionsa
O
Et
O
Entry
8a
8b
8c
8d
8e
8f
8g
8h
8i
R1
R2
Yield/%a
N
Acid catalyst
+
+
NH4OAc
C6H5–
H
H
H
H
H
H
H
H
H
H
H
82
80
85
80
86
83
74
72
76
73
75
80
70
Ph
H
C
3
EtO
OEt
solvent-free
100°C
Ph
N
4-Me–C6H4–
4-MeO–C6H4–
3,4-MeO–C6H3–
4-Cl–C6H4–
4-Br–C6H4–
4-NO2–C6H4–
3-NO2–C6H4–
4-pyridyl
5a
8a
7
6
Entry
Acid catalyst
–
Amount/mol%
Time/h
Yield/%b
1
2
3
4
5
6
7
8
9
–
8
2
2
2
2
2
2
2
2
2
1
3
0
22
34
75
48
38
42
68
82
82
73
82
CH3CO2H
CF3CO2H
10
10
10
10
10
10
5
20
30
20
20
B(OSO3H)3
4-CH3–C6H4SO3H
CF3SO2H
8j
8k
8l
3-pyridyl
2-thienyl
H2SO4
C6H5–
Me–
Me–
C6H5CH2–
B(OSO3H)3
B(OSO3H)3
B(OSO3H)3
B(OSO3H)3
B(OSO3H)3
8m
aIsolated yields.
10
11
12
In the absence of acid catalyst, no product was formed, even
after a long reaction time (Table 2, entry 1). So, the effect
of various acid catalyst in the reaction of acetophenone 5a,
triethyl orthoformate 6, and ammonium acetate 7 (Table 1,
entry 8a) was investigated as a model reaction. Therefore,
in order to find an effective acid catalyst, we examined this
condensation reaction in the presence of several acid catalysts.
It could be seen that the best yield of the product is obtained by
BSA (20 mol%, 0.06 g) at 100 °C (Table 2, entry 9). The results
are introduced in Table 2.
aA mixture of acetophenone (1 mmol), triethyl orthoformate (3 mmol),
ammonium acetate (2 mmol), and the various amount of acid catalyst
under solvent-free conditions at 100 °C.
bIsolated yields of 8a.
reaction times (entries 2 and 3), and relatively low yields of
product (entries 2 and 3) limit the use of these methods. These
results clearly demonstrate that BSA is an equally or more
efficient catalyst for this reaction.
The structures of the isolated products were deduced on the
base of IR, 1H and 13C NMR spectroscopy, mass spectrometry
and elemental analysis. The mass spectrum of 8c displayed
the molecular ion (M+) peak at m/z 186 which was consistent
with 1:2:2 adduct of 4-methoxyacetophenone 5c, triethyl
orthoformate 6, and ammonium acetate 7, with the loss of
The reusability of BSA as catalyst was investigated for the
synthesis of 4-phenylpyrimidine 8a. After each run, ethanol
was added and the catalyst was filtered. The recycled BSA
was dried and reused for further runs. A mild depression in the
catalytic activity of the catalyst was observed after four runs
(Fig. 2). This shows that the BSA is an effective and recyclable
catalyst for the synthesis of pyrimidines.
1
water and six EtOH molecules. The H NMR spectrum of
In summary, BSA is an extremely efficient acidic catalyst
for the preparation of substituted pyrimidines through a
one-pot, three-component condensation of ketones, triethyl
orthoformate, and ammonium acetate under solvent-free
conditions. The reusability of catalyst, simplicity of the starting
materials, short reaction time, one-pot, good yields and use of
the solvent-free conditions of products are the main advantages
of this method.
8c exhibited a sharp singlet (at δꢀ=3.93 ppm) arising from
the methoxy group, as well as two doublets (at δꢀ=7.05 and
8.10 ppm, J=8.6 Hz) for the four H-atoms of 4-methoxyphenyl
substituent. Also, two doublets (at δꢀ=7.67 and 8.72 ppm,
J=5.4 Hz) were observed arising from the two H-atoms of
pyrimidine ring. Another H-atom of pyrimidine ring was seen
1
as a sharp singlet line (at δꢀ=9.24 ppm). The H decoupled
13C NMR spectrum of 8c showed a characteristic signal (at
δꢀ=55.8 ppm) arising from the methoxy group. The signals
of C-atoms of the 4-methoxyphenyl moiety were observed at
114.8, 116.5, 129.1 and 129.3 ppm, along with other four distinct
resonances (at δꢀ=157.5, 159.4, 162.6 and 163.8 ppm) for the
pyrimidine ring in agreement with the proposed structure.
A suggested mechanism for the formation of pyrimidine
8 is shown in Scheme 3. It is reasonable to assume that first,
ketone 5 and ammonia liberated from NH4OAc 7, are converted
to imine 9. Next, the prepared imine 9 is condensed with the
intermediate 10, which is inꢀ situ prepared by protonation
of acetal 6 with BSA, to form the intermediate 11. Then,
intermediate 11 reacts with the ammonia to produce the
isolable vinylamidine intermediate 12.18 Finally, the reaction
of vinylamidine 12 with another intermediate 10, leads
to formation of the corresponding pyrimidine 8 through
intramolecular cyclisation of the intermediate 13.
Experimental
All chemicals were purchased from Merck and Fluka. All yields refer
to isolated products. IR spectra of the compounds were obtained on a
PerkinElmer GX FT-IR spectrometer. Elemental analyses for C, H and
N were performed using a Heraeus CHN-O-Rapid analyser. 1H and 13
C
NMR spectra were measured with Bruker NMR Avance (at 300 and
75 MHz), and Bruker DPX-250 (at 500 and 125 MHz) spectrometers
with TMS as an internal standard. Melting points were determined in
a capillary tube and are not corrected. The progress of reaction was
followed with TLC using silica gel SILG/UV 254 and 365 plates. The
products 8h and 8k are novel compounds, and their structures were
deduced by IR, 1H and 13C NMR spectroscopy, mass spectrometry and
elemental analysis. Other products are known compounds, and were
characterised by comparing of their physical and spectroscopic data
with those previously reported.12,13
Synthesisꢀofꢀsubstitutedꢀpyrimidinesꢀ8a–m;ꢀgeneralꢀprocedure
To compare the advantage of the use of BSA over the
reported procedure, the synthesis of 4-phenylpyrimidine 8a
was considered as a representative example (Table 3). Although
most of these processes have distinct advantages, the use of
high catalyst loading (entry 1), high temperature (entry 1), long
A mixture of ketone (1 mmol), 0.44 g triethyl orthoformate (3 mmol),
0.14 g NH4OAc (2 mmol) and 0.06 g BSA (20 mol%) was heated at
100 °C for 2 h. After completion of the reaction as indicated by TLC,
the reaction mixture was cooled, quenched by adding 10 cm3 water,
extracted with chloroform (3×20 cm3), and the extract was dried with

526 JOURNAL OF CHEMICAL RESEARCH 2014
7
NH4OAc ( )
R2
R1
NH3
H2O
R2
R1
NH
O
R2
R1
5
9
OEt
NH3
N
2
EtOH
11
OEt
OEt
OEt
NH4OAc
B(OSO3H)3
7
( )
EtO
Et H
O
Et
O
EtO
H
R2
R1
6
1
0
NH2
N
12
2 Et
H
O
OEt
R2
R1
R2
R1
N
N
N
N
EtOH
8
13
Scheme 3 Suggested mechanism for synthesis of pyrimidine derivatives 8.
Table 3 Comparison of BSA with reported catalysts for the synthesis of 4-phenylpyrimidine 8a
Entry
Cat. (mol%)
Conditions
Time/h
Temp./ºC
Yield/%
Ref.
1
2
3
4
TsOH (100)
ZnCl2 (10)
TBBDA (10)
BSA (20)
Microwave
Toluene
Solvent-free
Solvent-free
0.22
72
13
215
100
110
100
89
70
66
82
11
12
13
2
This work
Na2SO4. The filtrate was evaporated under vacuum, and the crude
product was recrystallised from ethyl acetate/n-hexane to afford the
pure products.
4-Phenylpyrimidine (8a): Pale yellow powder; m.p. 58–60 °C (lit.12
57.8–58.5 °C); 1H NMR (500 MHz, CDCl3): δꢀ=7.56–7.59 (3H, m),
7.80 (1H, d, J=5.4 Hz), 8.14–8.16 (2H, m), 8.83 (1H, d, J=5.4 Hz), 9.33
(1H, s) ppm; 13C NMR (125 MHz, CDCl3): δꢀ120.2, 127.5, 129.2, 130.1,
133.6, 159.3, 160.5, 163.7 ppm; IR (KBr, cm–1): 2958, 1622, 1538, 1342,
1115; EI-MS, m/z (%):156 (M+, 100), 79 (55).
4-(4-Methylphenyl)pyrimidine (8b): Pale yellow powder; m.p.
61–63 °C (lit.13 62–63 °C); 1H NMR (500 MHz, DMSO-d6): δꢀ 2.40
(3H, s, CH3), 7.36 (2H, d, J=7.8 Hz), 8.05 (1H, d, J=5.4 Hz), 8.12
(2H, d, J=7.8 Hz), 8.83 (1H, d, J=5.4 Hz), 9.2 (1H, s) ppm; 13C NMR
(125 MHz, DMSO-d6): δꢀ21.8 (CH3), 117.6, 127.7, 130.5, 134.0, 142.1,
158.7, 159.6, 163.4 ppm; IR (KBr, cm–1): 2962, 16142, 1565, 1378, 1152;
EI-MS, m/z (%):170 (M+, 30), 91 (30), 79 (25).
4-(4-Methoxyphenyl)pyrimidine (8c): Yellow powder; m.p. 80–82 °C
(lit.12 79.7–80.3 °C); 1H NMR (500 MHz, CDCl3): δꢀ3.93 (3H, s, OCH3),
7.05 (2H, d, J=8.6 Hz), 7.67 (1H, d, J=5.4 Hz), 8.10 (2H, d, J=8.6 Hz),
8.72 (1H, d, J=5.4 Hz), 9.24 (1H, s) ppm; 13C NMR (125 MHz,
CDCl3): δꢀ55.8 (OCH3), 114.8, 116.5, 129.1, 129.3, 157.5, 159.4, 162.6,
163.8 ppm; IR (KBr, cm–1): 2958, 1609, 1576, 1322, 1202; EI-MS, m/z
(%):186 (M+, 100), 107 (35), 79 (55).
4-(3,4-Dimethoxyphenyl)pyrimidine (8d): Yellow powder; m.p.
83–85 °C (lit.13 84–86 °C); 1H NMR (500 MHz, CDCl3): δꢀ3.99 (3H, s,
OCH3), 4.00 (3H, s OCH3), 7.00 (1H, d, J=8.4 Hz), 7.67 (1H, d, J=8.4),
7.69 (1H, d, J=5.4 Hz) 7.80 (1H, s), 8.74 (1H, d, J=5.4 Hz), 9.25 (1H,
s) ppm; 13C NMR (125 MHz, CDCl3): δꢀ56.2, 56.4, 110.2, 111.5, 116.6,
120.7, 129.6, 149.9, 152.2, 157.5, 159.3, 163.8 ppm; IR (KBr, cm–1):
2935, 1608, 1576, 1324, 1186; EI-MS, m/z (%): 216 (M +, 100), 137 (40),
79 (25).
4-(4-Chlorophenyl)pyrimidine (8e): Yellow powder; m.p. 75–77 °C
1
(lit.12 75.9–76.8 °C); H NMR (500 MHz, DMSO-d6): δꢀ7.63 (2H, d,
J=8.6 Hz), 8.12 (1H, d, J=5.4 Hz), 8.25 (2H, d, J=8.6 Hz), 8.89 (1H, d,
J=5.4 Hz), 9.26 (1H, s) ppm; 13C NMR (125 MHz, DMSO-d6): δꢀ118.0,
129.6, 130.0, 135.6, 137.0, 159.1, 159.6, 162.3 ppm; IR (KBr, cm–1):
2958, 1598, 1588, 1259; EI-MS, m/z (%):190 (M+, 100), 79 (45).
Fig. 2 The reusability of the BSA for the synthesis of 8a in four cycles.

JOURNAL OF CHEMICAL RESEARCH 2014 527
4-(4-Bromophenyl)pyrimidine (8f): Pale yellow powder; m.p.
70–72 °C (lit.13 71–73 °C); 1H NMR (500 MHz, CDCl3): δꢀ7.67 (2H, d,
J=8.6 Hz), 7.74 (1H, d, J=5.4 Hz), 8.00 (2H, d, J=8.6 Hz), 8.82 (1H,
d, J=5.4 Hz), 9.30 (1H, s) ppm; 13C NMR (125 MHz, CDCl3): δꢀ117.2.
126.4, 129.1, 132.7, 135.7, 157.9, 159.4, 163.4 ppm; IR (KBr, cm–1):
2938, 1594, 1544, 1368, 1135; EI-MS, m/z (%):233 (M+, 100), 327 (35).
4-(4-Nitrophenyl)pyrimidine (8g): Yellow powder; m.p. 103–105 °C
(lit.13 100–102 °C); 1H NMR (500 MHz, CDCl3): δꢀ 7.84 (1H, d,
Jꢀ=ꢀ5.4 Hz), 8.32 (2H, d, J=8.8 Hz), 8.42 (2H, d, J=8.8 Hz), 8.94 (1H,
d, J=5.4 Hz), 9.40 (1H, s) ppm; 13C NMR (125 MHz, CDCl3): δꢀ118.0,
124.6, 128.6, 133.7, 142.7, 158.5, 159.7, 162.0 ppm; IR (KBr, cm–1):
2922, 1601, 1566, 1498, 1125; EI-MS, m/z (%):201 (M+, 100), 122 (20),
79 (30).
4-(3-Nitrophenyl)pyrimidine (8h): Yellow powder; m.p. 110–112 °C;
1H NMR (300 MHz, DMSO-d6): δꢀ7.81 (1H, s), 8.27–8.39 (2H, m), 8.62
(1H, d, J=6.6 Hz), 8.97 (2H, m), 9.31 (1H, s) ppm; 13C NMR (75 MHz,
DMSO-d6): δꢀ118.2, 121.9, 126.0, 131.2, 133.7, 138.8, 148.9 159.1, 159.3,
160.7 ppm; IR (KBr, cm–1): 2928, 1615, 1577, 1529, 1351; EI-MS, m/z
(%):201 (M+, 100), 79 (45). Anal. calcd for C10H7N3O2 (201.1): C, 59.70;
H, 3.51; N, 20.89%; Found: C, 59.6; H, 3.6; N, 20.9%.
4-Benzyl-5-methylpyrimidine (8m): Pale yellow powder; m.p.
28–30 °C (lit.13 oil); 1H NMR (500 MHz, CDCl3): δꢀ2.40 (3H, s, CH2),
3.78 (3H, s, CH3), 7.00–7.08 (4H, m), 7.46 (1H, s), 8.50 (1H, s), 9.08 (1H,
s) ppm; 13C NMR (125 MHz, CDCl3): δꢀ18.2, 35.9, 126.7, 128.4, 128.9,
129.8, 137.6, 148.3, 156.7, 166.0 ppm; IR (KBr, cm–1): 2938, 1607, 1578,
1532, 1378, 1180; EI-MS, m/z (%): 184 (M +
(30).
‏ , 40), 93 (100), 91 (30), 79
The authors gratefully acknowledge Payame Noor University
(PNU) of Ilam for financial support of this research.
Receivedꢀ9ꢀJuneꢀ2014;ꢀacceptedꢀ18ꢀJulyꢀ2014
Paperꢀ1402731ꢀdoi:10.3184/174751914X14069964360841
Publishedꢀonline:ꢀ25ꢀSeptemberꢀ2014
References
1
J. Zhu H. Bienaymé, Multicomponentꢀreactions. Wiley-VCH, Weinheim,
Germany, 2005.
2
3
4
A. Dömling, Chem.ꢀRev., 2006, 106, 17.
A. Dömling and I. Ugi, Angew.ꢀChem.ꢀInt.ꢀEd., 2000, 39, 3169.
D.J. Brown, R.F. Evans, W.B. Cowden, M.D. Fenn, Chemistryꢀ ofꢀ
heterocyclicꢀcompounds:ꢀtheꢀpyrimidines, Vol. 52, Wiley-VCH, Weinheim,
Germany, 1994.
4-(Pyridin-4-yl)pyrimidine (8i): Pale yellow powder; m.p. 80–82 °C
(lit.13 79–81 °C); 1H NMR (500 MHz, DMSO-d6): δꢀ 8.14 (2H, d,
J=5.8 Hz), 8.23 (1H, d, J=5.2 Hz), 8.80 (2H, d, J=5.8 Hz), 9.00 (1H, d,
J=5.2 Hz), 9.35 (1H, s) ppm; 13C NMR (125 MHz, DMSO-d6): δꢀ118.9,
121.8, 144.0, 151.6, 159.7, 159.8, 161.3 ppm; IR (KBr, cm–1): 2922, 1610,
1567, 1236, 1120; EI-MS, m/z (%): 157 (M+, 100), 79 (40), 78 (30).
4-(Pyridin-3-yl)pyrimidine (8j): Pale yellow powder; m.p. 85–87 °C
5
6
A. Polak and H.J. Scholer, Chemotherapy, 1975, 21, 113.
J.J. Reddick, S. Saha, J. Lee, J.S. Melnick, J. Perkins and T.P. Begley,
Bioorg.ꢀMed.ꢀChem.ꢀLett., 2001, 11, 2245.
7
L.W. Hertel, G.B. Border, J.S. Kroin, S.M. Rinzel, G.A. Poore, G.C. Todd
and G.B. Grindey, CancerꢀRes., 1990, 50, 4417.
1
(lit.13 85–86 °C); H NMR (500 MHz, CDCl3): δꢀ7.53 (1H, dd, J=8.0,
4.4 Hz), 7.81 (1H, d, J=5.3 Hz), 8.49 (1H, d, J=8.0), 8.80 (1H, d,
J=4.4 Hz) 8.88 (1H, d, J=5.3 Hz), 9.34 (1H, s), 9.36 (1H, s) ppm; 13C
NMR (125 MHz, CDCl3): δꢀ 117.5, 124.3, 133.1, 135.3, 148.6, 151.9,
158.3, 159.8, 161.8 ppm; IR (KBr, cm–1): 2908, 1612, 1589, 1344, 1182;
EI-MS, m/z (%): 157 (M +, 100), 79 (30), 78 (20).
4-(Thiophene-2-yl)pyrimidine (8k): Yellow powder; m.p. 58–60 °C;
1H NMR (400 MHz, DMSO-d6): δꢀ7.22 (1H, s), 7.82 (1H, s), 8.01 (1H,
d, J=12.3 Hz), 8.75 (1H, s), 9.06 (1H, s) ppm; 13C NMR (100 MHz,
DMSO-d6): δꢀ118.8, 127.2, 127.7, 128.6, 142.5, 156.8, 158.3, 161.8 ppm;
IR (KBr, cm–1): 2925, 1624, 1577, 1536, 1322, 1108; EI-MS, m/z (%):
162 (M+, 40), 83 (25), 79 (100). Anal. calcd for C8H6N2S (162.2): C,
59.23; H, 3.73; N, 17.27; S, 19.77; found: C, 60.2; H, 3.8; N, 17.2; S,
19.7%.
5-Methyl-4-phenylpyrimidine (8l): Pale yellow powder; m.p.
32–33 °C (lit.13 30.2–30.4 °C); 1H NMR (500 MHz, CDCl3): δꢀ2.42 (3H,
s, CH3), 7.44–7.46 (3H, m), 7.58–7.60 (2H, m), 8.61 (1H, s), 9.11 (1H, s)
ppm; 13C NMR (125 MHz, CDCl3): δꢀ17.1 (CH3), 128.2, 128.5, 128.8,
129.4, 137.7, 156.4, 158.5, 165.1 ppm; IR (KBr, cm–1): 2988, 1602, 1577,
1520, 1374, 1130; EI-MS, m/z (%):170 (M+, 100), 93 (25), 79 (60).
8
9
W.R. Sherman and E.C. Taylor, Org.ꢀSynth., 1963, 4, 247.
G.W. Kenner, B. Lythgoe, A.R. Todd and A. Topham, J.ꢀChem.ꢀSoc., 1943,
388.
10 D.M. Burgess, J.ꢀOrg.ꢀChem., 1956, 21, 97.
11 S. Tyagarajan and P.K. Chakravarty, TetrahedronꢀLett., 2005, 46, 7889.
12 T. Sasada, F. Kobayashi, N. Sakai and T. Konakahara, Org.ꢀLett., 2009, 11,
2161.
13 R. Ghorbani-Vaghei, R. Karimi-Nami, Z. Toghraei-Semiromi, M. Amiri,
Z. Salimi and M. Ghavidel, C.ꢀR.ꢀChim., 2014, 17, 324.
14 P. Salehi, M.A. Zolfigol, F. Shirini and M. Baghbanzadeh, Curr.ꢀ Org.ꢀ
Chem., 2006, 10, 2171.
15 P. Salehi, M.A. Zolfigol and M.A. Fard, J.ꢀBraz.ꢀChem.ꢀSoc., 2004, 15, 773.
16 A.R. Kiasat and M. Fallah-Mehrjardi, J.ꢀBraz.ꢀChem.ꢀSoc., 2008, 19, 1595.
17 S. Sajjadifar, S.A. Mirshokraie, N. Javaherneshan, O. Louie, Am.ꢀJ.ꢀOrg.ꢀ
Chem.,ꢀ2012, 2, 1.
18 S. Sajjadifar, E. Khosravani and S. Shiri, Int.ꢀJ.ꢀChem.ꢀTech.ꢀRes., 2013, 5,
1969.
19 M.A. Zolfigol, A. Khazaei, H. Vahedi, M. Mokhlesi, S. Sajadifar and M.
Pirveysian, Phosphorus,ꢀSulfur,ꢀSiliconꢀRelat.ꢀElem., 2012, 187, 295.
20 M.A. Zolfigol, H. Vahedi, A.H. Massoudi, S. Sajjadifar, O. Loui and N.
Javaherneshan, Clin. Biochem., 2011, 44, 219.