Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2, 3-d]pyrimidine derivatives

Article abstract of DOI:10.1016/j.cclet.2014.05.043

A series of novel 2-trifluoromethylthieno[2,3-d]pyrimidine derivatives were synthesized by a facile three-step procedure that afforded advantages of mild reaction conditions, simple protocol and good yields. The structures of the final compounds were confirmed by IR, NMR, EI-MS, elemental analysis, and X-ray diffraction. Preliminary bioassay results showed that some of the analogs exhibit excellent antitumor activity against MCF-7 and HepG2, especially compounds 3a, 3b, 3e and 3h exhibited higher activity than the positive control gefitinib.

Full text of DOI:10.1016/j.cclet.2014.05.043

G Model
CCLET 3024 1–5
Chinese Chemical Letters xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Chinese Chemical Letters
journal homepage: www.elsevier.com/locate/cclet
1
2
Original article
3
4
Facile synthesis and antitumor activity of novel
2-trifluoromethylthieno[2,3-d]pyrimidine derivatives
a
a
Q1 Xin-Jian Song a,b, , Ping Yang , Hui Gao , Yan Wang
*
a,**
,
5
6
Xing-Gao Dong a, Xiao-Hong Tan a,b
7
8
a Key Laboratory of Biologic Resources Protection and Utilization of Hubei Province, Hubei Minzu University, Enshi 445000, China
b College of Forestry and Horticulture, Hubei Minzu University, Enshi 445000, China
A R T I C L E I N F O
A B S T R A C T
Article history:
A series of novel 2-trifluoromethylthieno[2,3-d]pyrimidine derivatives were synthesized by a facile
three-step procedure that afforded advantages of mild reaction conditions, simple protocol and good
yields. The structures of the final compounds were confirmed by IR, NMR, EI-MS, elemental analysis, and
X-ray diffraction. Preliminary bioassay results showed that some of the analogs exhibit excellent
antitumor activity against MCF-7 and HepG2, especially compounds 3a, 3b, 3e and 3h exhibited higher
activity than the positive control gefitinib.
Received 9 April 2014
Received in revised form 19 May 2014
Accepted 21 May 2014
Available online xxx
Keywords:
ß 2014 Xin-Jian Song. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights
reserved.
Thieno[2,3-d]pyrimidine
Gewald reaction
Trifluoromethyl
Facile synthesis
Antitumor activity
9
10
1. Introduction
group at the C-2 position and different substituents at the C-4 29
position to explore the potential of thieno[2,3-d]pyrimidines as 30
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
A pyrimidine nucleus fused with another heterocycle is widely
used in the design and discovery of novel bioactive molecules and
drugs [1]. For example, many anticancer agents that act as tyrosine
kinase inhibitors typically contain an aminopyrimidine group as a
core moiety. Different quinazoline derivatives, such as gefitinib [2],
erlotinib [3] and lapatinib [4] (Fig. 1), have gained market approval
worldwide. Recently, the thieno[2,3-d]pyrimidine core, which is
evaluated as a bioisostere of the quinazoline core, was used in the
mechanism-based design and synthesis of new antitumor agents
[5–8]. Introducing a fluorine-containing substituent, particularly
the trifluoromethyl group, led to higher biological activity and
lower toxicity compared with their non-fluorinated analogs [9,10].
A number of thieno[2,3-d]pyrimidine derivatives with different
substituents at the C-2 and C-4 positions were found to exert
potential antitumor activity [11–14]. However, trifluoromethyl-
substituted thieno[2,3-d]pyrimidines at the C-2 position have
seldom been reported [10,15]. In this work we prepared new
thieno[2,3-d]pyrimidines by introducing the trifluoromethyl
antitumor compounds.
31
Synthetic protocols for 2,4-disubstituted thieno[2,3-d]pyrimi- 32
dines usually involve a conversion of 2-substituted-thieno[2,3- 33
d]pyrimidin-4-ones to 4-chloro-2-substituted-thieno[2,3-d]pyri- 34
midines, which commonly undergo multi-step procedures 35
(Scheme 1) [16–20]. These procedures possess disadvantages, 36
such as rigorous conditions, long reaction time, complex handling, 37
and poor total yields. Therefore, developing a facile process to 38
produce 2,4-disubstituted thieno[2,3-d]pyrimidines is necessary. 39
We utilized a new convenient and efficient method to synthesize a 40
series of novel N4-substituted 2-trifluoromethyl-6,7-dihydro-5H- 41
clopenta[4,5]thieno[2,3-d]pyrimidin-4-amines by reaction of 42
appropriate amines with 4-chloro-2-trifluoromethyl-6,7-dihy- 43
dro-5H-clopenta[4,5]thieno[2,3-d]pyrimidine,
which
started 44
directly from 2-amino-5,6-dihydro-4H-cyclopenta[b]thiophene- 45
3-carbonitrile and trifluoroacetic acid (TFA) in the presence of 46
phosphorous oxychloride by a one-pot procedure. Our original 47
synthetic strategy is outlined in Scheme 2.
48
2. Experimental
49
*
Corresponding author at: Key Laboratory of Biologic Resources Protection and
Q2
Utilization of Hubei Province, Hubei Minzu University, Enshi 445000, China.
All the chemicals used in the synthesis were of analytical grade. 50
IR spectra were recorded on Nicolet NEXUS 470 FT-IR 51
spectrophotometer in the 4000–400 cmÀ1 range. NMR spectra 52
**
Corresponding author.
a
E-mail addresses: whxjsong@163.com (X.-J. Song), hbwangy@sohu.com
(Y. Wang).
http://dx.doi.org/10.1016/j.cclet.2014.05.043
1001-8417/ß 2014 Xin-Jian Song. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Please cite this article in press as: X.-J. Song, et al., Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2,3-
d]pyrimidine derivatives, Chin. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.cclet.2014.05.043

G Model
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X.-J. Song et al. / Chinese Chemical Letters xxx (2014) xxx–xxx
Fig. 1. Representative examples of anticancer quinazoline compounds.
Scheme 1. Preparation of 4-chloro-2-substituted-thieno[2,3-d]pyrimidines based on literature methods.
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
were obtained on a Varian XL-400 MHz spectrometer with TMS as
the internal standard and DMSO-d6 as the solvent. MS spectra were
performed by a Thermo DSQ II mass spectrometer using the
electron ionization (EI) method. Elemental analysis was carried out
on a Vario EL III CHNSO analyzer, the accepted deviation of
experimental values from the calculated ones is 0.3%. X-ray
diffraction data were collected on a Bruker Smart APEX-II CCD
Synthesis of 4-chloro-2-trifluoromethyl-6,7-dihydro-5H-clo-
penta[4,5]thieno[2,3-d]pyrimidine (2): A mixture of compound 1
(0.82 g, 5 mmol), TFA (0.5 mL), toluene (8 mL) and phosphoryl
trichloride (1.5 mL) was heated to 80 8C with good stirring. The
progress of the reaction was monitored by TLC with petroleum
ether–ethyl acetate (3:1, v/v) as a developing solvent. Toluene was
removed by vacuum distillation after the completion of the
reaction. The residue was poured over crushed ice and neutralized
with a saturated sodium bicarbonate solution. The aqueous
mixture was extracted with diethyl ether and the organic layer
was washed with water followed by saturated aqueous sodium
chloride. After evaporation of the solvent, the residue was
recrystallized from n-hexane to afford the yellowish compound
2 in 65% yield. Mp 142–143 8C. Anal. Calcd. for C10H6ClF3N2S: C
43.10, H 2.17, N 10.05; found: C 42.95, H 2.32, N 9.93.
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
diffractometer equipped with a graphite-monochromatized Mo K
a
˚
(
l
= 0.71073 A) radiation. Melting points were measured with an
X-4 digital melting-point apparatus and uncorrected.
Synthesis of 2-amino-5,6-dihydro-4H-cyclopenta[b]thiophene-
3-carbonitrile (1): Cyclopentanone (0.84 g, 10 mmol), malononi-
trile (0.66 g, 10 mmol), elemental sulfur (0.35 g, 11.0 mmol), K2CO3
(0.28 g, 2.0 mmol) and 15 mL of dry ethanol were stirred at reflux
for 3 h. The insoluble material was filtered off, and the solvent was
removed by evaporation under reduced pressure. The crude
product was washed with water and recrystallized from ethanol
to give yellowish crystals in 81% yield. Mp 152–153 8C (Lit. [21]:
151 8C).
Synthesis of compounds 3a–3k: A mixture of compound 2
(1.39 g, 5 mmol), appropriate amine (5 mmol), and K2CO3 (1.38 g,
10 mmol) in acetonitrile (10 mL) was heated under reflux for
2–3 h. When the reaction was completed (TLC), acetonitrile was
removed by evaporation, the residue was washed with water and
purified by normal chromatography to afford the desired products
3a–3k as white solid.
Compound 3a: Yield 86%, mp 128–129 8C; 1H NMR (400 MHz,
DMSO-d6):
d
7.80 (s, 1H, NH), 7.41–7.20 (m, 5H, Ar-H), 4.72 (s, 2H,
95
Ar-CH2), 3.08–2.88 (m, 4H, 5- and 7-CH2), 2.43–2.40 (m, 2 H, 6-
96
97
98
99
100
101
102
103
104
105
106
107
CH2); 19F NMR (376 MHz, DMSO-d6):
d
À69.02; IR (KBr, cmÀ1):
3418 (N–H), 1573 (C55N), 1344, 1126 (CF3); EI-MS (%): m/z 349 (M+,
75.9), 106 (78.4), 91 (100); Anal. Calcd. for C17H14F3N3S: C 58.44, H
4.04, N 12.03; found: C 58.27, H 3.89, N 11.94.
Compound 3b: Yield 78%, mp 145–146 8C; 1H NMR (400 MHz,
DMSO-d6):
Ar-CH2), 3.07–2.90 (m, 4H, 5- and 7-CH2), 2.42–2.39 (m, 2 H, 6-
CH2); 19F NMR (376 MHz, DMSO-d6):
d 7.71 (s, 1H, NH), 7.33–7.03 (m, 4H, Ar-H), 4.71 (s, 2H,
d
À69.17, À114.04; IR (KBr,
cmÀ1): 3425 (N–H), 1568 (C55N), 1361, 1137 (CF3); EI-MS (%): m/z
367 (M+, 77.6), 124 (100), 109 (65.2); Anal. Calcd. for C17H13F4N3S:
C 55.58, H 3.57, N 11.44; found: C 55.70, H 3.46, N 11.52.
Scheme 2. The synthetic route of title compounds 3a–3k.
Please cite this article in press as: X.-J. Song, et al., Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2,3-
d]pyrimidine derivatives, Chin. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.cclet.2014.05.043

G Model
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X.-J. Song et al. / Chinese Chemical Letters xxx (2014) xxx–xxx
3
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
Compound 3c: Yield 82%, mp 135–136 8C; 1H NMR (400 MHz,
DMSO-d6): 7.83 (s, 1H, NH), 7.43–7.09 (m, 4H, Ar-H), 4.67 (s, 2H,
Ar-CH2), 3.09–2.92 (m, 4H, 5- and 7-CH2), 2.50–2.40 (m, 2 H, 6-
CH2); 19F NMR (376 MHz, DMSO-d6):
cmÀ1): 3469 (N–H), 1590 (C55N), 1339, 1143 (CF3); EI-MS (%): m/z
367 (M+, 46.8), 124 (58.8), 109 (100); Anal. Calcd. for C17H13F4N3S:
C 55.58, H 3.57, N 11.44; found: C 55.43, H 3.72, N 11.28.
Compound 3d: Yield 79%, mp 153–154 8C; 1H NMR (400 MHz,
Compound 3j: Yield 73%, mp 123–124 8C; 1H NMR (400 MHz, 160
d
DMSO-d6):
Ar-CH2), 3.57 (s, 3H, OCH3), 2.98–2.81 (m, 4H, 5- and 7-CH2), 2.37– 162
2.30 (m, 2H, 6-CH2); 19F NMR (376 MHz, DMSO-d6):
d 7.70 (s, 1H, NH), 7.09–6.64 (m, 4H, Ar-H), 4.55 (s, 2H, 161
d
À69.00, À116.30; IR (KBr,
d
À69.06; IR 163
(KBr, cmÀ1): 3432 (N–H), 1579 (C55N), 1339, 1132 (CF3); EI-MS (%): 164
m/z 379 (M+, 68.2), 136 (100), 121 (57.5); Anal. Calcd. for 165
C18H16F3N3OS: C 56.98, H 4.25, N 11.08; found: C 57.11, H 4.34, 166
N 11.20.
Compound 3k: Yield 83%, mp 118–119 8C; 1H NMR (400 MHz, 168
DMSO-d6): 7.77 (s, 1H, NH), 7.33–6.84 (m, 4H, Ar-H), 4.62 (s, 2H, 169
Ar-CH2), 3.68 (s, 3H, OCH3), 3.07–2.91 (m, 4H, 5- and 7-CH2), 2.49– 170
167
DMSO-d6):
d 7.74 (s, 1H, NH), 7.43–7.26 (m, 4H, Ar-H), 4.79 (s, 2H,
Ar-CH2), 3.13–2.95 (m, 4H, 5- and 7-CH2), 2.50–2.45 (m, 2H, 6-
d
CH2); 19F NMR (376 MHz, DMSO-d6):
d
À69.12; IR (KBr, cmÀ1):
3452 (N–H), 1580 (C55N), 1367, 1121 (CF3); EI-MS (%): m/z 383 (M+,
64.6), 140 (61.3), 125 (100); Anal. Calcd. for C17H13ClF3N3S: C
53.20, H 3.41, N 10.95; found: C 53.31, H 3.56, N 11.10.
2.40 (m, 2H, 6-CH2); 19F NMR (376 MHz, DMSO-d6):
d
À 69.08; IR 171
(KBr, cmÀ1): 3474 (N–H), 1596 (C55N), 1367, 1115 (CF3); EI-MS (%): 172
m/z 379 (M+, 17.0), 136 (4.9), 121 (100); Anal. Calcd. for 173
Compound 3e: Yield 84%, mp 126–127 8C; 1H NMR (400 MHz,
C18H16F3N3OS: C 56.98, H 4.25, N 11.08; found: C 56.86, H 4.17, 174
DMSO-d6):
d
7.87 (s, 1H, NH), 7.42–7.31 (m, 4H, Ar-H), 4.67 (s, 2H,
N 10.85.
175
176
Ar-CH2), 3.08–2.89 (m, 4H, 5- and 7-CH2), 2.50–2.40 (m, 2H,
6-CH2); 19F NMR (376 MHz, DMSO-d6):
d
À69.01; IR (KBr, cmÀ1):
3. Results and discussion
3462 (N–H), 1568 (C55N), 1333, 1121 (CF3); EI-MS (%): m/z 383 (M+,
70.0), 140 (64.4), 125 (100); Anal. Calcd. for C17H13ClF3N3S: C
53.20, H 3.41, N 10.95; found: C 53.40, H 3.27, N 10.86.
The synthesis was initiated by allowing readily available 177
cyclopentanone to react with malononitrile and sulfur to form 178
thiophene 1 based on the modified Gewald procedure. In this 179
context, we have found that the Gewald reaction efficiently occurs 180
in the presence of potassium carbonate (K2CO3) as a heterogeneous 181
base catalyst under reflux in ethanol. To the best of our knowledge, 182
the use of K2CO3 in the synthesis of 2-aminothiophenes has not 183
been reported. To show the merits of the present work, we 184
compared results obtained from K2CO3 with those previously 185
reported [21–27]. Table 1 reveals that K2CO3 is an inexpensive, 186
highly efficient, and green catalyst that can produce thiophene 1 in 187
short time and favorable yield. The key intermediate 2 was 188
efficiently prepared directly from thiophene 1, TFA, and phospho- 189
Compound 3f: Yield 75%, mp 150–151 8C; 1H NMR (400 MHz,
DMSO-d6):
Ar-CH2), 3.13–2.96 (m, 4H, 5- and 7-CH2), 2.50–2.45 (m, 2H, 6-
CH2), 2.38 (s, 3H, CH3); 19F NMR (376 MHz, DMSO-d6):
d 7.72 (s, 1H, NH), 7.30–7.11 (m, 4H, Ar-H), 4.68 (s, 2H,
d
À69.10; IR
(KBr, cmÀ1): 3468 (N–H), 1585 (C55N), 1339, 1121 (CF3); EI-MS (%):
m/z 363 (M+, 44.0), 120 (19.9), 105 (100); Anal. Calcd. for
C18H16F3N3S: C 59.49, H 4.44, N 11.56; found: C 59.64, H 4.29, N
11.46.
Compound 3g: Yield 80%, mp 124–125 8C; 1H NMR (400 MHz,
DMSO-d6):
Ar-CH2), 2.97–2.80 (m, 4H, 5- and 7-CH2), 2.37–2.27 (m, 2H, 6-
CH2), 2.10 (s, 3H, CH3); 19F NMR (376 MHz, DMSO-d6):
d 7.67 (s, 1H, NH), 7.15–6.94 (m, 4H, Ar-H), 4.52 (s, 2H,
d
À69.06; IR
rous oxychloride using toluene as a solvent via a one-pot 190
(KBr, cmÀ1): 3413 (N–H), 1580 (C55N), 1334, 1137 (CF3); EI-MS (%):
m/z 363 (M+, 40.6), 120 (30.9), 105 (100); Anal. Calcd. for
C18H16F3N3S: C 59.49, H 4.44, N 11.56; found: C 59.37, H 4.53, N
11.75.
procedure, which presents several advantages, such as milder 191
reaction conditions, simpler handling, and better yields, compared 192
with traditional multi-step methods (Routes A–C in Scheme 1). 193
Subsequently, the chloride 2 reacts with appropriate amines to 194
Compound 3h: Yield 81%, mp 157–158 8C; 1H NMR (400 MHz,
form 3.
195
DMSO-d6):
Ar-CH2), 3.11–2.94 (m, 4H, 5- and 7-CH2), 2.49–2.44 (m, 2H, 6-
CH2); 19F NMR (376 MHz, DMSO-d6):
d
7.89 (s, 1H, NH), 7.64–7.59 (m, 4H, Ar-H), 4.77 (s, 2H,
The structures of compounds 3a–3k were characterized by IR, 196
1H NMR, 19F NMR, EI-MS, and elemental analysis. 1H NMR spectra 197
d
À61.18, À69.09; IR (KBr,
show the expected occurrence of signals from the NH (
7.52), aryl protons ( 7.65–6.60), benzyl CH2 4.80–4.50), and 199
three cycloalkyl methylene protons (
3.15–2.25). The 19F signal 200
assigned to the trifluoromethyl (CF3) group at the C-2 position of 201
d 7.90– 198
cmÀ1): 3429 (N–H), 1568 (C55N), 1322, 1126 (CF3); EI-MS (%): m/z
417 (M+, 73.6), 174 (100), 159 (39.2); Anal. Calcd. for C18H13F6N3S:
C 51.80, H 3.14, N 10.07; found: C 51.92, H 3.30, N 9.89.
Compound 3i: Yield 74%, mp 154–155 8C; 1H NMR (400 MHz,
d
(d
d
the thieno[2,3-d]pyrimidine ring appears near
d
À69.0. In addition, 202
DMSO-d6):
Ar-CH2), 3.83 (s, 3H, OCH3), 3.12–2.96 (m, 4H, 5- and 7-CH2), 2.49–
2.44 (m, 2H, 6-CH2); 19F NMR (376 MHz, DMSO-d6):
d
7.52 (s, 1H, NH), 7.18–6.84 (m, 4H, Ar-H), 4.70 (s, 2H,
EI mass spectra gave the anticipated M+ peak. The spectroscopic 203
data are in good agreement with the proposed chemical structures 204
d
À69.09; IR
of the synthesized compounds.
205
(KBr, cmÀ1): 3468 (N–H), 1585 (C55N), 1361, 1121 (CF3); EI-MS (%):
m/z 379 (M+, 59.5), 136 (32.1), 121 (100); Anal. Calcd. for
C18H16F3N3OS: C 56.98, H 4.25, N 11.08; found: C 57.15, H 4.09,
N 11.23.
To further confirm the structures of these compounds and 206
provide a basis for the studies of structure–activity relationships, 207
the crystal structure of compound 3h was determined by single- 208
crystal X-ray diffraction. A colorless single crystal of compound 3h 209
Table 1
Comparison of different methods for synthesizing thiophene 1 via Gewald reaction of cyclopentanone and malononitrile.
a
Entry
Catalyst
Condition
Time
Yield (%)
Ref.
1
2
3
4
5
6
7
8
9
K2CO3
Ethanol, reflux
Ethanol, 60 8C
DMF, 60 8C
3 h
12 h
10 h
4 h
81
85
79
65
57
55
49
47
31
This work
[22]
Calcined Mg–Al hydrotalcite
L
-Proline
[23]
Bovine serum albumin
KF-alumina
DMF, 50 8C
[24]
Ethanol, MWb
Ethanol, reflux
Solvent free, 100 8C
Ethanol, reflux
Ethanol, reflux
8 min
[21]
KF-alumina
5.5 h
[21]
Nano ZnO
6 h
4 h
2 h
[25]
KG-60-piperazine
Morpholine
[26]
[27]
a
Isolated yield.
b
Microwave heating.
Please cite this article in press as: X.-J. Song, et al., Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2,3-
d]pyrimidine derivatives, Chin. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.cclet.2014.05.043

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X.-J. Song et al. / Chinese Chemical Letters xxx (2014) xxx–xxx
Table 2
The in vitro antitumor activity against MCF-7 and HepG2 for title compounds 3a–
3k.
IC50 (m )
mol LÀ1
a
Entry
Compd.
Ar
Breast MCF-7
Liver HepG2
1
2
3a
C6H5
11.79
5.18
13.50
7.31
3b
3-FC6H4
3
3c
4-FC6H4
28.83
52.57
13.84
83.62
>100
15.02
>100
63.89
>100
23.52
20.16
25.92
8.63
4
3d
2-ClC6H4
4-ClC6H4
2-CH3C6H4
4-CH3C6H4
4-CF3C6H4
2-CH3OC6H4
3-CH3OC6H4
4-CH3OC6H4
5
3e
6
3f
>100
>100
16.72
>100
>100
>100
18.36
7
3g
8
3h
3i
9
10
11
12
3j
3k
Gefitinib
a
IC50: compound concentration required to inhibit tumor cell proliferation by
50%.
The in vitro antitumor activity of the newly synthesized
compounds 3a–3k against MCF-7 (human breast cancer) and
HepG2 (human hepatocellular liver carcinoma) cell lines was
evaluated by the standard MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyl tetrazolium bromide] assay [29] using gefitinib as a
positive control. As described in Table 2, the results of preliminary
bioassay reveal that compounds 3a, 3b, 3c, 3d, 3e and 3h exhibit
good antitumor activity against MCF-7 and HepG2. Moreover, 3a,
3b, 3e and 3h possessed higher antitumor activity than the positive
control gefitinib. The results imply that different substituents at
different positions of the benzene ring significantly affect the
antitumor activity of the resultant compounds. Incorporation of
electron-donating groups, such as methyl (as in 3f and 3g) and
methoxy (as in 3i–3k) groups, in the benzene ring led to a decrease
of the antitumor activity against both cell lines. Further studies will
focus on structural optimization and structure–activity relation-
ships of this class of compounds.
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
Fig. 2. Molecular structure of compound 3h.
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
with dimensions of 0.23 mm  0.21 mm  0.18 mm was placed on
a Bruker SMART APEX-II diffractometer equipped with a graphite-
˚
monochromatized Mo Ka (l = 0.71073 A) radiation at 298(2) K for
analysis. The structure was solved by the direct methods with
SHELXS-97 [28] and expanded using the Fourier difference
techniques. A total of 9146 reflections were collected in the range
of 2.37 ꢀ
dent ones (Rint = 0.0397), of which 2134 were observed with
I > 2 (I) and used in the subsequent refinements. The molecular
u
ꢀ 25.258 using a
c–v scan mode with 3294 indepen-
s
structure and packing diagram are depicted in Figs. 2 and 3,
respectively. X-ray diffraction analysis reveals that the thieno[2,3-
d]pyrimidine ring, which exhibits good coplanar nature with a
˚
maximum deviation of 0.020(6) A at atom C(10), forms a dihedral
angle of 75.7(3)8 with the benzene ring. The molecular structure is
stabilized by intermolecular N(3)–H(3)Á Á ÁN(1) hydrogen bonds
together with
p–p stacking interactions between the benzene and
thiophene rings.
4. Conclusion
244
A
series of novel 2-trifluoromethylthieno[2,3-d]pyrimidine
245
246
247
248
249
250
251
252
253
254
derivatives were synthesized by a facile three-step procedure.
The procedure exhibits several advantages, such as mild reaction
conditions, simple protocol, and good yields. Their structures were
characterized by IR, 1H NMR, 19F NMR, EI-MS and elemental
analysis, and the structure of 3h was further elucidated by single-
crystal X-ray diffraction. The preliminary bioassay results imply
that some of the compounds exhibit excellent antitumor activity
against MCF-7 and HepG2 cells. These compounds will be further
studied in future research.
Acknowledgment
255
This work was financially supported by the National Natural Q3 256
Science Foundation of China (No. 21262012) and the Open Fund of
Key Laboratory of Biologic Resources Protection and Utilization
of Hubei Province (No. PKLHB1314).
257
258
259
References
260
[1] R. Adepu, D. Rambabu, B. Prasad, et al., Novel thieno[2,3-d]pyrimidines: their
design, synthesis, crystal structure analysis and pharmacological evaluation, Org.
Biomol. Chem. 10 (2012) 5554–5569.
[2] J.G. Paez, P.A. Janne, J.C. Lee, et al., EGFR mutations in lung cancer: correlation
with clinical response to gefitinib therapy, Science 304 (2004) 1497–
1500.
[3] B. Higgins, K. Kolinsky, M. Smith, et al., Antitumor activity of erlotinib (OSI-774,
Tarceva) alone or in combination in human non-small cell lung cancer tumor
xenograft models, Anticancer Drugs 15 (2004) 503–512.
261
262
263
264
265
266
267
268
269
Fig. 3. Packing diagram of compound 3h.
Please cite this article in press as: X.-J. Song, et al., Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2,3-
d]pyrimidine derivatives, Chin. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.cclet.2014.05.043

G Model
CCLET 3024 1–5
X.-J. Song et al. / Chinese Chemical Letters xxx (2014) xxx–xxx
5
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
[4] Z.A. Liu, A. Fusi, A. Schmittel, et al., Eradication of EGFR-positive circulating tumor
cells and objective tumor response with lapatinib and capecitabine, Cancer Biol.
Ther. 10 (2010) 860–864.
[5] Y. Dai, Y. Guo, R.R. Frey, et al., Thienopyrimidine ureas as novel and potent
multitargeted receptor tyrosine kinase inhibitors, J. Med. Chem. 48 (2005)
6066–6083.
[6] J.C. Aponte, A.J. Vaisberg, D. Castillo, et al., Trypanoside, anti-tuberculosis, leish-
manicidal, and cytotoxic activities of tetrahydrobenzothienopyrimidines, Bioorg.
Med. Chem. 18 (2010) 2880–2886.
[7] N.S. Habib, R. Soliman, A.A. El-Tombary, S.A. El-Hawash, O.G. Shaaban, Synthesis
and biological evaluation of novel series of thieno[2,3-d]pyrimidine derivatives as
anticancer and antimicrobial agents, Med. Chem. Res. 22 (2013) 3289–3308.
[8] B.Q. Cai, H.X. Jin, X.J. Yan, P. Zhu, G.X. Hu, 3D-QSAR and 3D-QSSR studies of
thieno[2,3-d]pyrimidin-4-yl hydrazone analogues as CDK4 inhibitors by CoMFA
analysis, Acta Pharmacol. Sin. 35 (2014) 151–160.
[9] W.K. Hagmann, The many roles for fluorine in medicinal chemistry, J. Med. Chem.
51 (2008) 4359–4369.
[10] X.J. Song, Z.C. Duan, Y. Shao, X.G. Dong, Facile synthesis of novel fluorinated
thieno[2,3-d]pyrimidine derivatives containing 1,3,4-thiadiazole, Chin. Chem.
Lett. 23 (2012) 549–552.
[11] T. Horiuchi, M. Nagata, M. Kitagawa, K. Akahane, K. Uoto, Discovery of novel
thieno[2,3-d]pyrimidin-4-yl hydrazone-based inhibitors of Cyclin D1-CDK4: syn-
thesis, biological evaluation and structure–activity relationships. Part 2, Bioorg.
Med. Chem. Lett. 17 (2009) 7850–7860.
[12] A.G. Golub, V.G. Bdzohla, N.V. Briukhovetska, et al., Synthesis and biological
evaluation of substituted (thieno[2,3-d]pyrimidin-4-ylthio)carboxylic acids
as inhibitors of human protein kinase CK2, Eur. J. Med. Chem. 46 (2011)
870–876.
[13] T. Beckers, A. Sellmer, E. Eichhorn, et al., Novel inhibitors of epidermal growth
factor receptor: (4-(arylamino)-7H-pyrrolo[2,3-d]pyrimidin-6-yl)(1H-indol-2-
yl)methanones and (1H-indol-2-yl)(4-(phenylamino)thieno[2,3-d]pyrimidin-6-
yl)methanones, Bioorg. Med. Chem. 20 (2012) 125–136.
[14] S.E. Abbas, N.M.A. Gawad, R.F. George, Y.A. Akar, Synthesis, antitumor and
antibacterial activities of some novel tetrahydrobenzo[4,5]thieno[2,3-d]pyrimi-
dine derivatives, Eur. J. Med. Chem. 65 (2013) 195–204.
[15] P. Yang, Y. Wang, Z.C. Duan, et al., Synthesis, crystal structure, and biological
activity of 4-chlorobenzaldehyde (2-trifluoromethyl-5,6,7,8-tetrahydroben-
zo[4,5]thieno[2,3-d]pyrimidin-4-yl)hydrazone monohydrate, Chin. J. Struct.
Chem. 32 (2013) 1023–1030.
[16] T. Horiuchi, J. Chiba, K. Uoto, T. Soga, Discovery of novel thieno[2,3-d]pyrimi-
din-4-yl hydrazone-based inhibitors of Cyclin D1-CDK4: synthesis, biological
evaluation, and structure–activity relationships, Bioorg. Med. Chem. Lett. 19 311
(2009) 305–308.
312
[17] R.J. Gillespie, D.R. Adams, D. Bebbington, et al., Antagonists of the human 313
adenosine A2A receptor. Part 1: discovery and synthesis of thieno[3,2-d]pyrimi- 314
dine-4-methanone derivatives, Bioorg. Med. Chem. Lett. 18 (2008) 2916–2919.
315
[18] M. Hayakawa, H. Kaizawa, H. Moritomo, et al., Synthesis and biological evaluation 316
of 4-morpholino-2-phenylquinazolines and related derivatives as novel PI3 317
kinase p110a inhibitors, Bioorg. Med. Chem. 14 (2006) 6847–6858.
318
[19] M.R. Prasad, D.P. Kishore, Multistep, microwave assisted, solvent free synthesis and 319
antibacterial activity of 6-substituted-2,3,4-trihydropyrimido[1,2-c]9,10,11,12- 320
tetrahydrobenzo[b]thieno[3,2-e]pyrimidines, Chem. Pharm. Bull. 55 (2007) 321
776–779.
322
[20] A.E. Kassab, E.M. Gedawy, Synthesis and anticancer activity of novel 2-pyridyl 323
hexahyrocyclooctathieno[2,3-d]pyrimidine derivatives, Eur. J. Med. Chem. 63 324
(2013) 224–230.
325
[21] M. Sridhar, R.M. Rao, N.H.K. Baba, R.M. Kumbhare, Microwave-accelerated 326
Gewald reaction: synthesis of 2-aminothiophenes, Tetrahedron Lett. 48 (2007) 327
3171–3172.
328
[22] R. Rajagopal, T.M. Jyothi, T. Daniel, K.V. Srinivasan, B.S. Rao, Calcined Mg–Al 329
hydrotalcite as a heterogeneous base catalyst for Gewald aminothiophene syn- 330
thesis, Synth. Commun. 31 (2001) 3113–3117.
331
[23] T. Wang, X.G. Huang, J. Liu, et al., An efficient one-pot synthesis of substituted 2- Q4332
aminothiophenes via three-component Gewald reaction catalyzed by L-proline, 333
Synlett (2010) 1351–1354.
334
[24] D.D. Zhao, L. Li, F. Xu, Q. Wu, X.F. Lin, Bovine serum albumin-catalyzed one-pot 335
synthesis of 2-aminothiophenes via Gewald reaction, J. Mol. Catal. B-Enzym. 95 336
(2013) 29–35.
337
[25] R. Tayebee, F. Javadi, G. Argi, Easy single-step preparation of ZnO nano-particles 338
by sedimentation method and studying their catalytic performance in the syn- 339
thesis of 2-aminothiophenes via Gewald reaction, J. Mol. Catal. A-Chem. 368–369 340
(2013) 16–23.
341
[26] E. Rezaei-Seresht, R. Tayebee, M. Yasemi, KG-60-piperazine as a new heteroge- 342
neous catalyst for Gewald three-component reaction, Synth. Commun. 43 (2013) 343
1859–1864.
344
[27] P. Malherbe, R. Masciadri, R.D. Norcross, H. Ratni, A.W. Thomas, Thieno-pyridine 345
derivatives as allosteric enhancers of the GABAB receptors, US2006135552 346
(2006).
347
348
[28] G.M. Sheldrick, A short history of SHELX, Acta Cryst. A64 (2008) 112–122.
[29] M.C. Alley, D.A. Scudiero, A. Monks, et al., Feasibility of drug screening with panels 349
of human tumor cell lines using a microculture tetrazolium assay, Cancer Res. 48 350
(1988) 589–601.
351
Please cite this article in press as: X.-J. Song, et al., Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2,3-
d]pyrimidine derivatives, Chin. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.cclet.2014.05.043