A facile synthesis and biological activity of novel tetrahydrobenzo[4′,5′]thieno[3′,2′:5,6]pyrido[4, 3-d]pyrimidin-4(3H)-ones

Article abstract of DOI:10.1016/j.bmcl.2009.09.117

The synthesis and biological activity of 2-substituted-8,9,10,11-tetrahydrobenzo[4′,5′]thieno[3 ′,2′:5,6] pyrido[4,3-d]pyrimidin-4(3H)-ones are described. Bioassay results indicated that these compounds have antifungal activity against Botrytis cinerea at

Full text of DOI:10.1016/j.bmcl.2009.09.117

Bioorganic & Medicinal Chemistry Letters 19 (2009) 6713–6716
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Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
A facile synthesis and biological activity of novel
tetrahydrobenzo[40,50]thieno[30,20:5,6]pyrido[4,3-d]pyrimidin-4(3H)-ones
b,
c,a
Qingyun Ren a, Yong-Ju Liang b, Hongwu He a, , Liwu Fu , Yucheng Gu
*
*
a Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, PR China
b State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou 510060, PR China
c Jealott0s Hill International Research Centre, Syngenta, Bracknell, Berkshire RG42 6EY, United Kingdom
a r t i c l e i n f o
a b s t r a c t
The synthesis and biological activity of 2-substituted-8,9,10,11-tetrahydrobenzo[40,50]thieno[30,20:5,6]
pyrido[4,3-d]pyrimidin-4(3H)-ones are described. Bioassay results indicated that these compounds have
antifungal activity against Botrytis cinerea at a concentration of 50 mg/L. In addition, compounds 5m and
5n were effective to both KB cells and their parent multidrug resistant KBv200 cells with the overexpres-
sion of ABCB1. For example, compound 5m showed the best inhibition against KB and KBv200 cells with
Article history:
Received 14 June 2009
Revised 17 September 2009
Accepted 30 September 2009
Available online 3 October 2009
IC50 values of 17.4 and 25.4
l
M, respectively.
Keywords:
Ó 2009 Elsevier Ltd. All rights reserved.
Pyrido[4,3-d]pyrimidin-4(3H)-one
Aza-Wittig reaction
Synthesis
Antifungal activity
Antitumor activity
5
5
4
5
4
Derivatives of pyridopyrimidines have received much attention
because of their potential biological activity as isosteres of quina-
zolines or pteridines. For example, some related 4-(phenylamino)
pyrido[d]pyrimidines have been reported as selective inhibitors
of tyrosine phosphorylation by the epidermal growth-factor recep-
tor (EGFR), and have become an important class of potential anti-
cancer drugs.1,2 All five possible pyridopyrimidine systems,
pyrido[2,3-d]pyrimidine I, pyrido[3,4-d]pyrimidine II, pyrido[4,3-
d]pyrimidine III, pyrido[3,2-d]pyrimidine IV and pyrido[1,2-
a]pyrimidine V have been reported. The pyrido[2,3-d]pyrimidine
system has been studied in more detail because examples have
medicinal applications as inhibitors of tyrosine kinase3 (AK) or
dihydrofolate reductase3,4 (DHFR). However, few reports1,5 are
available so far on the biological activity of pyrido[4,3-d]pyrimi-
dine derivatives.
4
6
6
6
7
3
2
3
2
3
2
N
N
N
N
N
N
1
N
1
N
8
[2,3-d]
N
1
7
7
8
8
[4,3-d]
[3,4-d]
III
II
I
5
N
5
4
4
6
6
N
3
3
2
N
N
2
N
1
7
7
8
8
1
[3,2-d]
[1,2-a]
IV
V
For the reason given above, the synthesis of pyridopyrimidine
derivatives is challenging. The methods described so far for the
preparation of some representative derivatives of this ring system
involve two general routes: (a) formation of the pyridine ring by
cyclization of suitable substituents of a pyrimidine; (b) formation
of the pyrimidine ring by cyclization of a suitable pyridine deriva-
tive.6 However, these methods often require forcing conditions,
long reaction times and complex synthetic pathways.
The aza-Wittig reactions of iminophosphoranes have received
increasing attention in view of their utility in the synthesis of N-
heterocyclic compounds.7 Recently, we have become interested
in the synthesis of new bioactive heterocycles such as thiazolopyri-
midinones,8 thienopyrimidinones,9 and triazolopyrimidinones,10
all prepared from various iminophosphoranes, with the aim of
evaluating their biological activity. Herein, we would like to de-
scribe a facile synthesis of fused pyrido[4,3-d]pyrimidine deriva-
tives from the easily accessible iminophosphorane 1. The
preliminary results of an in vitro bioassay indicated that some of
these compounds display favorable cytotoxic and moderate anti-
fungal activity.
* Corresponding authors.
E-mail addresses: he1208@mail.ccnu.edu.cn, ren0227@yahoo.cn (H. He), fulw@
mail.sysu.edu.cn (L. Fu).
0960-894X/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2009.09.117

6714
Q. Ren et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6713–6716
Ph
N
N
N
R
CN
PhNCO
COOEt
COOEt
MeCOCH2COOEt
SnCl4
S
S
NH2
S
N
4
3
2 R= NH2
PPh3
C2Cl6, Et3N
1 R= N=PPh3
OR
RO
N
Ph
NHPh
N
N
N
ROH
MeCN, base
O
COOEt
S
S
N
5a-l
6
The 2-amino-4,5,6,7-tetrahydro[1]benzothiophene-3-carboni-
trile 3 was converted into 5,6,7,8-tetrahydro[1]benzothieno[2,3-
b]pyridine 2 via reaction with ethyl acetoacetate and tin tetrachlo-
ride under heating.11 The iminophosphorane 1 was subsequently
obtained in a satisfactory yield when 2 was treated with triphenyl-
phosphine, hexachloroethane and Et3N.12 Iminophosphorane 1 re-
acted with phenyl isocyanate and gave carbodiimide 4. The direct
reaction of carbodiimide 4 with phenols, in the absence of a cata-
lyst, did not produce 2-aryloxy-thieno[30,20:5,6]pyrido[4,3-d]pyr-
imidin-4(3H)-ones 5. However, it was found that the reaction
gave 5a–l in good yields when heated for 1–2 h in the presence
of a catalytic amount of K2CO3 (Table 1).13 The formation of 5
can be rationalized in terms of an initial nucleophilic addition of
phenoxides to the carbodiimides 4 to give the intermediate 6
which cyclizes to give 5a–l. The cyclization took place smoothly,
whether the substituents on the phenols were electron-withdraw-
ing or electron-releasing.
Table 1
Yields and in vitro cytotoxicity (IC50, lM) of pyrido[4,3-d]pyrimidine 5
NR1R2
OR
Ph
Ph
N
N
N
N
N
N
O
O
S
S
5a-l
5m-n
Compds
RO or NR1R2
Yielda Cytotoxicity
Cytotoxicity
(%)
against KBb,c
against KBv200b,c
5a
4-Cl-3-CH3–
C6H3O
82
84.3
72.2
5b
5c
4-Br–C6H4O
2-Cl-5-CH3–
C6H3O
87
90
68.9
>100
>100
>100
5d
2,4-Di-F–
C6H3O
88
>100
>100
5e
5f
C6H5O
4-CH3–
C6H4O
3-F–C6H4O
3-CH3–
C6H4O
2-Cl-4-F–
C6H3O
4-NO2–
C6H4O
3,5-2F–
C6H3O
91
98
54.2
48.3
61.9
67.3
In refluxing toluene, 4 did not react with primary alkylamines to
give the target compounds. However, when the solvent was chan-
ged to CH2Cl2 and in the presence of a catalytic amount of EtONa,
5g
5h
88
88
>100
>100
>100
>100
compound
4 was converted smoothly to the 2-alkylamino-
8,9,10,11-tetrahydrobenzo[40,50]thieno[30,20:5,6]pyrido[4,3-d]pyr-
imidin-4(3H)-ones 5m–n in satisfactory yields at room
temperature.14
5i
5j
5k
5l
87
97
92
83
>100
>100
52.5
>100
>100
39.9
NR1R2
Ph
N
Ph
N
N
N
N
R1R2NH
3-OCH3–
C6H4O
CH3(CH2)2NH 65
CH3(CH2)3NH 72
>100
>100
COOEt
O
CH2Cl2,base
S
N
5m
5n
Fluorouracil
17.4
32.0
12.5
25.4
32.8
—
S
5m-n
4
a
Isolated yields based on iminophosphorane 1.
IC50 is the concentration of compound required to inhibit the cell growth by 50%
All the compounds of the 5 series were obtained as white or yel-
low solids after recrystallization from ethanol. Their structures
were fully characterized by IR, 1H NMR, EI-MS and elemental anal-
ysis. For example, the IR spectrum of 5m revealed absorption
bands at 1677 (C@O), 3145 (C6H5), and 3381 (NH) cmꢀ1. The corre-
sponding 1H NMR spectrum showed the 5-Me group at d(H) 2.96
(s), and the CH2 signals of the cyclohexenyl ring appeared at d(H)
1.91, 2.88, and 3.31. The other signals resonated at d(H) 7.26–
7.65 (m, 5 arom. H), 0.88 (t, J = 7.2 Hz, Me), 1.60 (q, J = 7.2 Hz,
CH2), and 3.41–3.44 (m, NCH2). The mass spectrum of 5m showed
the molecular ion peak at m/z 404 as the base peak (100%). The
structures of 5m and the other analogs were further confirmed
on the basis of elemental analysis. In the case of 5k, single-crystal
X-ray diffraction was employed to confirm the structure.15
b
compared to an untreated control.
c
KB cells were the drug sensitive human oral carcinoma cells and KBV200 cells
were the multidrug resistant cells with overexpression of ABCB1 cells induced by
vincristine.
activity against KB and KBv200 with IC50 17.4 and 25.4 lM, respec-
tively (Table 1). Although its inhibitory activity against KB is lower
than that of fluorouracil, the cytotoxicity against KB of title com-
pounds could be further improved by incorporating appropriate
functional groups.
The preliminary antifungal activity of compounds 5 series was
also measured at a concentration of 50 mg/L using a reported pro-
cedure5 and the inhibition rates are listed in Table 2. It was found
that most of the compounds induced a good inhibition effect
against Botrytis cinerea comparable to a commercial fungicide tria-
dimefon, with the inhibitory rate of 98%, 99% and 100% for com-
pounds 5g, 5h and 5n, respectively. They did have any obvious
The biological activity of the series of compounds 5 was inves-
tigated, and the results showed that some of them exhibited cyto-
toxicity against various KB and KBv200 cancer lines.16 As indicated
in Table 1, most of the compounds showed good to moderate cyto-
toxicity against KB. Compounds 5m showed the best inhibitory

Q. Ren et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6713–6716
6715
Table 2
recrystallized from EtOH to give the target compounds.
Compound 5a. A white solid. Mp 233–234 °C. IR (KBr)
1561, 1400 cmꢀ1
3.04 (s, 3H, MeC(5)), 2.80–2.83 (m, 2H, CH2), 2.47–2.51 (m, 2H, CH2), 2.40 (s,
3H, Me), 1.81–1.84 (m, 2H, CH2), 1.63–1.66 (m, 2H, CH2). MS (70 eV) m/z (%):
489 (34), 488 (28), 487 (M+, 100), 472 (12), 362 (18), 346 (27), 215 (14). Anal.
Calcd for C27H22ClN3O2S: C, 66.45; H, 4.54; N, 8.61. Found: C, 66.11; H, 4.57; N,
8.45.
m
: 1702 (C@O), 1617,
Antifungal activity (relative inhibition (%), 50 mg/L) of pyrido[4,3-d]pyrimidine 5
.
1H NMR (400 MHz CDCl3) d (ppm): 6.91–7.62 (m, 8H, ArH),
Compds
Rhizoctonia Botrytis Gibberella Botryosphaeria Bipolaris
solani
cinerea
zeae
berengera
maydis
5a
5b
5c
5d
5e
5f
5g
5h
5i
5j
5k
5l
5m
5n
22
68
63
63
65
61
84
91
79
68
74
76
24
89
73
83
88
78
85
80
98
99
88
85
83
66
57
100
78
31
65
23
38
15
31
58
65
54
46
31
42
20
83
59
39
83
50
50
56
56
78
78
67
61
61
67
29
76
—
52
81
48
71
76
76
90
81
67
67
48
76
47
79
—
Compound 5b. A white solid. Mp 246–247 °C. IR (KBr)
m: 1701 (C@O), 1613,
1560, 1401 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.03–7.60 (m, 9H, ArH),
.
3.04 (s, 3H, MeC(5)), 2.80–2.83 (m, 2H, CH2), 2.43–2.47 (m, 2H, CH2), 1.81–1.84
(m, 2H, CH2), 1.63–1.66 (m, 2H, CH2). 13C NMR (150 MHz CDCl3) d (ppm):
163.5, 162.7, 157.7, 154.2, 149.9, 149.5, 137.3, 135.6, 134.5, 131.6, 129.7, 129.6,
128.1, 125.1, 124.6, 120.7, 109.6, 26.4, 25.7, 22.8, 22.4, 20.1. MS (70 eV) m/z (%):
519 (84), 518 (43), 517 (M+, 100), 363 (18), 243 (14), 215 (14), 77 (92). Anal.
Calcd for C26H20BrN3O2S: C, 60.24; H, 3.89; N, 8.11. Found: C, 60.51; H, 3.85; N,
8.04.
Compound 5c. A white solid. Mp 237–238 °C. IR(KBr)
m: 1695 (C@O), 1618,
1561, 1400 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.05–7.60 (m, 8H, Ar-H),
.
3.05 (s, 3H, MeC(5)), 2.78–2.81 (m, 2H, CH2), 2.34–2.37 (m, 5H, CH3+CH2),
1.78–1.80 (m, 2H, CH2), 1.56–1.59 (m, 2H, CH2). MS (70 eV) m/z (%): 487 (M+,
100), 473(13), 451(18), 361(24), 316(24), 214(48), 77(99). Anal. Calcd for
C27H27ClN3O2S: C, 66.45; H, 4.54; N, 8.61. Found: C, 66.68; H, 4.76; N, 8.75.
Triadimefon 91
Compound 5d. A white solid. Mp 25–226 °C. IR(KBr)
m: 1699 C@O), 1615, 1560,
1402 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 6.93–7.62 (m, 8H, Ar-H), 3.05 (s,
.
influence on the growth of Rhizoctonia solani, Gibberella zeae, Bipo-
laris maydis and Botryosphaeria berengera.
3H, MeC(5)), 2.80–2.83 (m, 2H, CH2), 2.43–2.46 (m, 2H, CH2), 1.80–1.83 (m, 2H,
CH2), 1.61–1.64 (m, 2H, CH2). MS (70 eV) m/z (%): 477 (M++2, 4), 475 (M+, 14),
398(3), 215(6), 128(22), 119(17), 77(100). Anal. Calcd for C26H19F2N3O2S: C,
65.67; H, 4.03; N, 8.84. Found: C, 65.75; H, 4.19; N, 8.95.
In summary, we have developed a novel approach for the synthe-
sis of 2-substituted-8,9,10,11-tetrahydrobenzo[40,50]thieno[30,20-
5,6]pyrido[4,3-d]pyrimidin-4(3H)-ones 5 via tandem aza-Wittig
and annulation reactions. The biological evaluation showed that
some compounds have fungicidal activities at 50 mg/L and some of
them were effective to both KB cells and KBv200 cells.
Compound 5e. A white solid. Mp 217–218 °C. IR (KBr)
m: 1698 (C@O), 1613,
1560, 1398 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.13–7.60 (m, 8H, ArH),
.
3.06 (s, 3H, MeC(5)), 2.79–2.81 (m, 2H, CH2), 2.41–2.44 (m, 2H, CH2), 1.77–1.79
(m, 2H, CH2), 1.56–1.59 (m, 2H, CH2). 13C NMR (150 MHz CDCl3) d (ppm):
162.1, 157.6, 152.8, 149.1, 146.0, 135.6, 134.8, 134.4, 133.3, 132.5, 131.6, 130.0,
129.6, 128.2, 128.0, 125.0, 124.8, 26.1, 25.8, 25.5, 22.4, 22.2. MS (70 eV) m/z (%):
441 (3), 440 (11), 439 (M+, 34), 424 (7), 363 (8), 91 (26), 77 (100). Anal. Calcd
for C26H21N3O2S: C, 71.05; H, 4.82; N, 9.56. Found: C, 70.96; H, 5.05; N, 9.62.
Acknowledgments
Compound 5f. A white solid. Mp 246–247 °C. IR (KBr)
m: 1699 (C@O), 1616,
1559, 1402 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.00–7.61 (m, 9H, ArH),
.
We thank Syngenta for the fellowship to Qingyun Ren and Dr. J.
Clough for the proofreading. The project is supported by National
Key Project for Basic Research Development Program of China (No.
2003CB114406), the National Natural Science Foundation of China
(Nos. 20372023, 20772042), 863 Project (No. 2006AA09Z419).
3.04 (s, 3H, MeC(5)), 2.78–2.81 (m, 2H, CH2), 2.43–2.45 (m, 2H, CH2), 2.39 (s,
3H, Me), 1.78–1.81 (m, 2H, CH2), 1.57–1.60 (m, 2H, CH2). MS (70 eV) m/z (%):
453 (M+, 100), 438 (24), 362 (21), 346 (25), 215 (18), 91 (44), 77 (53). Anal.
Calcd for C27H23N3O2S: C, 71.50; H, 5.11; N, 9.26. Found: C, 71.62; H, 5.10; N,
9.32.
Compound 5g. A white solid. Mp 213–214 °C. IR (KBr)
m: 1701 (C@O), 1619,
1562, 1402 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 6.94–7.62 (m, 9H, ArH),
.
3.04 (s, 3H, MeC(5)), 2.79–2.83 (m, 2H, CH2), 2.50–2.53 (m, 2H, CH2), 1.78–1.84
(m, 2H, CH2), 1.62–1.66 (m, 2H, CH2). MS (70 eV) m/z (%): 458 (7), 457 (M+, 45),
429 (12), 362 (19), 215 (10), 111 (33), 77 (100). Anal. Calcd for C26H20FN3O2S:
C, 68.25; H, 4.41; N, 9.18. Found: C, 68.39; H, 4.53; N, 9.35.
References and notes
1. Rewcastle, W. G.; Palmer, D. B.; Thompson, A. M.; Bridges, A. J.; Cody, D. R. J.
Med. Chem. 1996, 39, 1823.
2. Smail, J. B.; Palmer, B. D.; Rewcastle, G. W. J. Med. Chem. 1999, 42, 1803.
3. (a) Boschelli, D.; Wu, Z.-P.; Klutchko, S. R.; Showalter, H. D. J. Med. Chem. 1998,
41, 4365; (b) Jérôme, A. Tetrahedron 2004, 60, 4107.
4. (a) Rosowsky, A.; Chen, H. J. Org. Chem. 2001, 66, 7522; (b) DeGraw, J. I.;
Christie, P. H.; Colwell, W. T.; Sirotnak, F. M. J. Med. Chem. 1992, 35, 3204.
5. Ren, Q. Y.; Cui, Z. P.; He, H. W.; Gu, Y. C. J. Fluorine Chem. 2007, 128, 1369.
6. (a) Brown, T. B.; Stevens, M. F. J. Chem. Soc., Perkin Trans. I. 1975, 1023; (b)
Thompson, A. M.; Bridges, A. J.; Fry, D. W.; Kraker, A. J.; Denny, W. A. J.
Heterocycl. Chem. 1995, 38, 3780; (c) Bhuyan, P.; Boruah, R. C.; Sandhu, J. S. J.
Org. Chem. 1990, 55, 568; (d) Kajino, M.; Meguro, K. Heterocycles 1990, 31,
2153; (e) Hosmane, R. S.; Lim, B. B.; Summers, M. F.; Hosmane, N. S. J. Org.
Chem. 1988, 53, 5309.
Compound 5h. A white solid. Mp 206–207 °C. IR(KBr)
m: 1697 (C@O), 1616,
1560, 1399 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 6.92–7.61 (m, 9H, Ar-H),
.
3.05 (s, 3H, MeC(5)), 2.79–2.82 (m, 2H, CH2), 2.48–2.51 (m, 2H, CH2), 2.38 (s,
3H, CH3), 1.79–1.82 (m, 2H, CH2), 1.60–1.63 (m, 2H, CH2). MS (70 eV) m/z (%):
455 (36), 453 (M+, 100), 438 (14), 362 (10), 346 (13), 215 (4), 89 (34). Anal.
Calcd for C27H23N3O2S: C, 71.50; H, 5.11; N, 9.26. Found: C, 71.52; H, 5.48; N,
9.17.
Compound 5i. A white solid. Mp 26.6 °C. IR(KBr)
m: 1701 C@O), 1620, 1563,
1403 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.07–7.63 (m, 8H, Ar-H), 3.05 (s,
.
3H, MeC(5)), 2.79–2.82 (m, 2H, CH2), 2.36–2.39 (m, 2H, CH2), 1.79–1.82 (m, 2H,
CH2), 1.60–1.62 (m, 2H, CH2). MS (70 eV) m/z (%): 493 (3), 492 (4), 491 (M+, 7),
363 (8), 240 (16), 215 (17), 77 (100). Anal. Calcd for C26H19ClFN3O2S: C, 63.48;
H, 3.89; N, 8.54. Found: C, 63.72; H, 4.21; N, 8.65.
Compound 5j. A yellow solid. Mp 176–178 °C. IR(KBr)
m: 1703 (C@O), 1620,
7. Bonini, C.; Auria, M. D.; Funicello, M.; Romaniello, G. Tetrahedron 2002, 58,
3507.
1560, 1401 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 1.56–1.58 (m, 2H, CH2),
.
1.78–1.82 (m, 2H, CH2), 2.40–2.43 (m, 2H, CH2), 2.79–2.82 (m, 2H, CH2), 3.06 (s,
3H, MeC(5)), 7.27–8.35 (m, 9H, Ar-H). MS (70 eV) m/z (%): 486 (8), 485 (24),
484 (M+, 100), 469 (11), 456 (16), 362 (15), 77 (25). Anal. Calcd for
C26H20N4O4S: C, 64.45; H, 4.16; N, 11.56. Found: C, 64.36; H, 4.04; N, 11.74.
8. Liang, Y.; Fan, S.; Mo, W. Y.; He, H. W. J. Fluorine Chem. 2007, 128, 879.
9. Hu, Y. G.; Lu, M. Y.; Song, H. L.; Ding, M. W. Chin. J. Org. Chem. 2005, 25, 295.
10. Zhao, J. F.; Xie, C.; Ding, M. W.; He, H. W. Chem. Lett. 2005, 34, 1022.
11. Veronese, A. C.; Callegari, R.; Morelli, C. F. Tetrahedron 1995, 51, 12277.
12. Preparation of iminophosphorane 1: To a soln of 2 (1.06 g, 4 mmol) in MeCN
(15 ml), PPh3 (1.31 g, 5 mmol), C2Cl6 (1.19 g, 5 mmol) and, in this order, NEt3
(8.0 ml) were added. The mixture was stirred for 18–24 h at 0 °C. Then, the soln
was concentrated, and the residue was crystallized from EtOH afforded 1 in
90.2% yield. Mp 225–226 °C. 1H NMR: 0.99 (t, J = 7.2, Me); 1.40–1.64 (m,
CH2CH2); 2.41 (s, Me); 2.50–2.54 (m, CH2); 2.65–2.69 (m, CH2); 3.38 (q, J = 7.2,
CH2O); 7.44–7.62 (m, 15 arom. H). MS (70 eV) m/z (%): 552 (M++1 1.3), 551 (M+
3.49), 521 (100), 443 (6.2), 262 (9.5), 201 (40.5), 183 (81.4), 108 (12.4).
13. Preparation of compounds 5a–l: To a soln of 1 (1.1 g, 2 mmol) in anhyd CH2Cl2
(10 ml), phenyl isocyanate (0.24 g, 2 mmol) was added under N2 at rt. The
mixture was left standing for 30–40 min. Then, the solvent was removed in
vacuum, and Et2O/petroleum ether (1:2) was added to precipitate
triphenylphosphine oxide. Filtration and removal of the solvent gave the
crude carbodiimides 4, which were used directly without further purification.
To the solution of 4 in CH3CN (15 mL), substituted phenol (2 mmol) and
catalytic solid K2CO3 (0.024 g, 0.2 mmol) were added. The mixture was stirred
for 3–6 h at 75 °C and filtered, the filtrate was condensed and the residual was
Compound 5k. A white solid. Mp 237–238 °C; IR (KBr)
m: 1694 (C@O), 1615,
1561, 1401, 1259 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 6.78–7.61 (m, 8H,
.
ArH), 3.05 (s, 3H, MeC(5)), 2.81–2.84 (m, 2H, CH2), 2.60–2.63 (m, 2H, CH2),
1.82–1.85 (m, 2H, CH2), 1.68–1.71 (m, 2H, CH2). MS (70 eV) m/z (%): 477 (8),
476 (28), 475 (M+, 100), 460 (15), 447 (22), 362 (18), 77 (87). Anal. Calcd for
C26H19F2N3O2S: C, 65.67; H, 4.03; N, 8.84. Found: C, 65.75; H, 4.12; N, 8.89.
Compound 5l. A white solid. Mp 228–229 °C. IR(KBr)
m: 1701 (C@O), 1618,
1560, 1400 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 6.91–7.60 (m, 9H, Ar-H),
.
3.84 (s, 3H, OCH3), 3.05 (s, 3H, MeC(5)), 2.79–2.82 (m, 2H, CH2), 2.50–2.53 (m,
2H, CH2), 1.78–1.81 (m, 2H, CH2), 1.61–1.63 (m, 2H, CH2). MS (70 eV) m/z (%):
471 (43), 470 (100), 469 (M+, 95), 363 (12), 350 (14), 123 (43), 77 (26). Anal.
Calcd for C27H23N3O3S: C, 69.06; H, 4.94; N, 8.95. Found: C, 69.20; H, 5.27; N,
9.05.
14. Preparation of compounds 5m–n: To
a soln of 4 in CH2Cl2 (10 ml), the
appropriate alkylamine (2 mmol) was added and the mixture was stirred for
30 min. The solvent was removed and anhyd EtOH (10 ml) containing several
drops of a solution of EtONa in EtOH was added. The mixture was stirred for

6716
Q. Ren et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6713–6716
11–14 h at rt. After solvent had been removed, the residue was crystallized
from EtOH and afforded the target compounds.
Compound 5m. A pale yellow solid. Mp 243–244 °C. IR(KBr)
(C@O), 1557, 1517, 1450 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.26–7.65 (m,
5H, Ar-H), 4.36 (s, 1H, NH), 3.41–3.43 (m, 2H, NCH2), 2.96(s, 3H, MeC(5)), 2.88–
3.31 (m, 4H, 2 CH2), 1.88–1.92 (m, 4H, 2 CH2), 1.58–1.62 (m, 2H, CH2), 0.88
(t, J = 7.2 Hz, 3H, Me). 13C NMR (150 MHz CDCl3) d (ppm): 162.9, 162.0, 157.4,
152.7, 148.1, 134.4, 134.1, 131.8, 130.7, 129.7, 128.9, 124.7, 124.6, 41.8, 27.2,
26.9, 22.9, 22.7, 21.1, 19.0, 13.7. MS (70 eV) m/z (%): 406 (8), 405 (24), 404 (M+,
100), 389 (14), 363 (39), 285 (12), 216 (7), 91 (8). Anal. Calcd for C23H24N4OS: C,
68.29; H, 5.98; N, 13.85. Found: C, 68.11; H, 6.06; N, 14.00.
5H, Ar-H), 4.34 (s, 1H, NH), 3.44–3.48 (m, 2H, NCH2), 2.96 (s, 3H, MeC(5)), 2.87–
*
*
3.32 (m, 4H, 2 CH2), 1.90–1.93 (m, 4H, 2 CH2), 1.52–1.60 (m, 2H, CH2), 1.27–
1.33 (m, 2H, CH2), 0.91 (q, J = 7.2 Hz, 3H, Me). MS (70 eV) m/z (%): 418 (M+, 100),
403 (34), 389 (43), 376 (78), 362 (99), 346 (42), 285 (44), 91 (23). Anal. Calcd for
C24H26N4OS: C, 68.87; H, 6.26; N, 13.39. Found: C, 69.04; H, 6.62; N, 13.57.
15. Ren, Q. Y.; He, H. W.; Meng, X. G. Acta Crystallogr., Sect. E. 2006 62, 5029 (The
crystallographic data have been deposited at the Cambridge Crystallographic
Data Center(E-mail: deposit@ccdc.cam.ac.uk), the deposition number is CCDC-
627452.).
16. Cytotoxic activity was evaluated using a standard MTT assay after exposure of
cells to the tested compounds for 72 h. The results were presented as mean
values of three independent experiments done in quadreplicates. Coefficients
of variation were <10%.
m: 3381 (N–H), 1672
.
*
*
Compound 5n. A pale yellow solid. Mp 233–234 °C. IR (KBr)
m: 3445(N–H), 1677
(C@O), 1558, 1510, 1401 cmꢀ1 1H NMR (400 MHz CDCl3) d (ppm): 7.25–7.65 (m,
.