Synthesis and Antitumor Activity of 3-(2-Phenyl-1,3-thiazol-4-yl)-1H-indoles and 3-(2-Phenyl-1,3-thiazol-4-yl)-1H-7-azaindoles

Article abstract of DOI:10.1002/cmdc.201100078

Given the potent antimicrobial, antiviral, and antitumor activities of many natural products, there is an increasing interest in the synthesis of new molecules based on natural compound scaffolds. Based on a 2,4-bis(3'-indolyl)imidazole skeleton, two new series of phenylthiazolylindoles and phenylthiazolyl-7-azaindoles were obtained by Hantzsch reaction between substituted phenylthioamides and the α-bromoacetyl derivatives. Some azaindole derivatives, tested at the National Cancer Institute against a panel of ～60 tumor cell lines derived from nine human cancer cell types, showed inhibitory effects against all cell lines investigated at micromolar to nanomolar concentrations. Two of them exhibited a high affinity for CDK1, with IC₅₀ values of 0.41 and 0.85μM. These promising results will set the foundation for future investigations into the development of anticancer therapies. Marine mining: Given the promise of marine-derived bioactive indole alkaloids, we synthesized a series of phenylthiazolylindoles and phenylthiazolyl-7-azaindoles, and evaluated their antitumor activity against a panel of 60 cancer cell lines. Some derivatives showed IC₅₀ values in the micromolar to nanomolar range.

Full text of DOI:10.1002/cmdc.201100078

MED
DOI: 10.1002/cmdc.201100078
Synthesis and Antitumor Activity of 3-(2-Phenyl-1,3-
thiazol-4-yl)-1H-indoles and 3-(2-Phenyl-1,3-thiazol-4-yl)-
1H-7-azaindoles
Patrizia Diana,*[a] Anna Carbone,[a] Paola Barraja,[a] Alessandra Montalbano,[a]
Barbara Parrino,[a] Alessia Lopergolo,[b] Marzia Pennati,[b] Nadia Zaffaroni,[b] and
Girolamo Cirrincione[a]
Given the potent antimicrobial, antiviral, and antitumor activi-
ties of many natural products, there is an increasing interest in
the synthesis of new molecules based on natural compound
scaffolds. Based on a 2,4-bis(3’-indolyl)imidazole skeleton, two
new series of phenylthiazolylindoles and phenylthiazolyl-7-
azaindoles were obtained by Hantzsch reaction between sub-
stituted phenylthioamides and the a-bromoacetyl derivatives.
Some azaindole derivatives, tested at the National Cancer Insti-
tute against a panel of ~60 tumor cell lines derived from nine
human cancer cell types, showed inhibitory effects against all
cell lines investigated at micromolar to nanomolar concentra-
tions. Two of them exhibited a high affinity for CDK1, with IC50
values of 0.41 and 0.85 mm. These promising results will set the
foundation for future investigations into the development of
anticancer therapies.
Introduction
Over the last 50 years, the marine environment has been ex-
plored in the search for new bioactive compounds. In particu-
lar the indole alkaloids class has received a lot of attention be-
cause of their potent biological activities, such as, antimicrobi-
al, antiviral, and antitumor activities.[1–4] Nortopsentins A–C
having a characteristic 2,4-bis(3’-indolyl)imidazole skeleton, iso-
lated from Spongosorites ruetzleri, exhibited in vitro cytotoxicity
against P388 cells (IC50 values: 4.5–20.7 mm). Their N-methylat-
ed derivatives showed a significant improvement in P388 activ-
ity relative to that of the parent compounds (IC50 values 0.8–
2.1 mm).[5] However, a great limitation in the use of marine or-
ganisms for therapy is that only very small amounts of the bio-
logically active substances can be isolated from the natural
source.
was observed when one indolyl ring was replaced by a phenyl
moiety.[11]
Considering the antitumor activity exhibited by bis-indolyl-
thiazoles and that several compounds containing the thiazole
ring have shown marked antineoplastic activity,[12] we synthe-
sized new thiazole analogues in which one indole ring was re-
placed by a phenyl or an azaindole nucleus to verify whether
the phenyl or the aza substitution to the indole system in-
creases the antineoplastic activity. Herein we report the synthe-
sis of 3-(2-phenyl-1,3-thiazol-4-yl)-1H-indole of type 6 and 3-(2-
Because of their interesting biological activities, nortopsen-
tins have been considered important lead compounds for the
discovery of new biologically active derivatives.[6] We recently
reported the synthesis and antitumor activity of a different
series of bis-indolyl-5-membered heterocycles 1–4, in which
the imidazole moiety of nortopsentin was replaced by thio-
phene, pyrazole, isoxazole, and furan rings. Some of these
compounds showed antiproliferative activity against a wide
range of human tumor cell lines with GI50 values ranging from
micromolar to sub-micromolar concentrations.[7–9] Many other
analogues of marine nortopsentins such as 2,4-bis(3’-indolyl)-
thiazoles 5, in which the heterocyclic core of the system is con-
stituted by thiazole have been synthesized. These derivatives
showed strong inhibitory activity against a wide range of
human tumor cell lines.[10] Also 3,5-bis(2-indolyl)pyridine
showed cytotoxic activity against leukemia cells and inhibited
CDK1 at micromolar concentrations. A marked cytotoxic effect
[a] Prof. P. Diana, Dr. A. Carbone, Prof. P. Barraja, Dr. A. Montalbano,
Dr. B. Parrino, Prof. G. Cirrincione
Dipartimento di Scienze e Tecnologie Molecolari e Biomolecolari
Sezione Chimica Farmaceutica e Biologica
Universitꢀ degli Studi di Palermo
Via Archirafi 32, 90123 Palermo (Italy)
Fax: (+39)091-238-60-854
E-mail: diana@unipa.it
[b] Dr. A. Lopergolo, Dr. M. Pennati, Dr. N. Zaffaroni
Fondazione IRCCS Istituto Nazionale dei Tumori
Via Venezian 1, 20133 Milano (Italy)
1300
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemMedChem 2011, 6, 1300 – 1309

Indole and Azaindole Antitumor Agents
6a–l (60–82% yields) and 3-(2-phenyl-1,3-thiazol-4-yl)-1H-7-
azaindoles 7a–t (70–87% yields), respectively.
Table 1. 3-(2-Phenyl-1,3-thiazol-4-yl)-1H-indoles 6a–l and 3-(2-phenyl-1,3-
thiazol-4-yl)-1H-7-azaindoles 7a–t.
Biology
All of the isolated phenylthiazolylindoles 6a–l and phenylthia-
zolyl-7-azaindoles 7a–t were submitted to the National Cancer
Institute (NCI, Bethesda, MD, USA) for testing against a panel
of ~60 tumor cell lines grouped into disease subpanels: leuke-
mia, non-small-cell lung, colon, central nervous system, mela-
noma, ovarian, renal, prostate, and breast cancer. Among these
compounds submitted, eight indoles (6a, 6b, 6e, 6 f, 6g, 6h,
6k, and 6l) and 12 azaindoles (7a, 7g, 7h, 7i, 7j, 7k, 7l, 7m,
7n, 7o, 7p, and 7s) were prescreened at a single concentra-
tion (10À5 m). Compounds of type 6 were devoid of any signifi-
cant antiproliferative activity. Instead, compounds 7g, 7h, 7l,
7j, 7n, 7o, and 7p were further selected for full evaluation at
five different concentrations (10À4–10À8 m), as they satisfied the
threshold inhibition criteria established by the NCI. The antitu-
mor activity of compounds is determined by the pGI50 value
(GI50 is the molar concentration of compound that inhibits
50% net cell growth).
Compd
R
R1
R2
R3
Compd
R
R1
R2
R3
6a
6b
6c
6d
6e
6 f
6g
6h
6i
6j
6k
6l
7a
7b
7c
7d
H
H
H
H
H
H
H
H
H
H
H
H
Cl
Cl
F
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
7e
7 f
7g
7h
7i
7j
7k
7l
7m
7n
7o
7p
7q
7r
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
Me
F
H
H
H
H
H
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
Me
Me
OMe
OMe
Cl
Cl
Br
Br
F
F
H
H
H
F
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
Me
OMe
OMe
Cl
Cl
Br
Br
F
7s
7t
F
H
F
phenyl-1,3-thiazol-4-yl)-1H-7-azaindoles of type 7,
their antitumor activity, and kinase activity of the
most active compounds in these series (Table 1).
Results and Discussion
Synthesis of compound series 6 and 7
The synthesis of 3-(2-phenyl-1,3-thiazol-4-yl)-1H-in-
doles of type 6 and 3-(2-phenyl-1,3-thiazol-4-yl)-1H-7-
azaindoles of type 7 is based on the Hantzsch reac-
tion between the thioamides 8 and the a-bromoace-
tyl compounds of type 9 and 10. The key thioamides
8b, 8d, 8i, and 8j, which are not commercially avail-
able, were prepared in excellent yield (95–98%) by
holding the corresponding amides 11 b, 11 d, 11 i,
and 11 j at reflux in benzene with Lawesson’s reagent
(Scheme 1). This method is faster and more efficient
than the reaction of aryl nitriles with sulfides in pyri-
dine previously reported.[13]
The 3-acetylindole 12a and the 7-azaindole 13a
were converted into the corresponding N-methyl de-
rivatives 12b (90%) and 13b (96%), respectively,
using potassium tert-butoxide, tris[2-(2-methoxy-
ethoxy)ethyl]amine (TDA-1) as a catalyst, and methyl
iodide in anhydrous benzene. The 3-indole deriva-
tives 12a and 12b were converted into the 3-bro-
moacetylindoles 9a and 9b in good yield (70%) by
treatment with bromine in methanol at reflux.
Scheme 1. Synthesis of 3-(2-phenyl-1,3-thiazol-4-yl)-1H-indoles 6a–l and 3-(2-phenyl-1,3-
thiazol-4-yl)-1H-7-azaindoles 7a–t. Reagents and conditions: a) Lawesson’s reagent, ben-
zene, reflux, 15 min; b) tBuOK, benzene, TDA-1, RT, 3–8 h, then CH3I, RT, 1–2 h; c) Br2,
MeOH, reflux, 2 h; d) AlCl3, CH2Cl2, BrCH2COBr, reflux, 40 min; e) EtOH, RT, 24 h or reflux,
30 min.
The data listed in Table 2 reveal that N-methyl-7-azaindoles
are more active than the corresponding N-unsubstituted com-
3-Bromoacetyl-7-azaindoles 10a and 10b were efficiently
prepared by acylation of 7-azaindoles 13a and 13b with bro-
moacetyl bromide (80–92% yields). Reaction of thioamides of
type 8 and a-bromoacetyl compounds 9a,b and 10a,b in eth-
anol at reflux gave the 3-(2-phenyl-1,3-thiazol-4-yl)-1H-indole
pounds [compare mean graph midpoint of the couples 7p/7o,
7j/7i, 7h/7g, and 7l/7k (7i and 7k were not tested at five dif-
ferent concentrations)]. Among the N-methyl derivatives, the
most active was the 4-methylphenyl compound 7l. Replace-
ment of the methyl group with chloro (compound 7p) or with
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1301

P. Diana et al.
MED
higher cytotoxic profile against malignant peritoneal mesothe-
lioma cells (Table 4), suggesting that the substitution at posi-
tion 4 with a methyl group (compound 7l) slightly increases
the antiproliferative activity of the unsubstituted derivative 7j.
In contrast, halogen substitution at either positions 4 or 3 of
the phenyl moiety produces a substantial decrease in activity.
To better characterize the mechanism of action by which the
phenylthiazolyl-7-azaindoles exert their antiproliferative effect,
increasing amounts of 7j, 7p, 7h, and 7l were incubated with
purified recombinant CDK1/cyclin B, CDK5/p25, or GSK3b, and
their potential kinase inhibitory effect was measured using a
fluorimetric assay. As summarized in Table 5, no compound ex-
hibited activity toward both CDK5 and GSK3b, as indicated by
IC50 values considerably higher than 50 mm. As far as CDK1 is
concerned, 7j and 7l exhibited a higher affinity for the kinase,
with IC50 values of 0.41Æ0.08 mm and 0.85Æ0.13 mm, respec-
tively, whereas 7p and 7h showed activity toward CDK1 only
at very high concentrations (Table 5). Notably, the IC50 values
observed for both 7j and 7l are very similar to those obtained
using the same assay with roscovitine and purvalanol A (0.73Æ
0.06 mm and 0.59Æ0.08 mm, respectively), in agreement with
previous reports for inhibition of CDK1 by these com-
pounds.[14]
Table 2. Overview of the in vitro antitumor screening[a] results for com-
pounds 7g, 7h, 7j, 7l, 7n, 7o, and 7p.
[b]
pGI50
[c]
Compd
Ncl
N[d]
Range
MG_MID[e]
7g
7h
7j
58
59
59
60
60
59
59
29
59
59
60
42
9
4.11–6.89
4.45–5.98
4.63–5.28
4.87–7.50
4.03–6.11
4.01–7.56
4.64–5.59
4.43
4.77
4.86
5.54
4.46
4.16
4.88
7l
7n
7o
7p
59
[a] Data obtained from the NCI in vitro disease-oriented human tumor
cell line screen. [b] pGI50: Àlogc, for which c=concentration (molar) that
inhibits 50% net cell growth. [c] Number of cell lines investigated.
[d] Number of cell lines giving positive pGI50 values. [e] MG_MID: mean
graph midpoint; this is the arithmetic mean value for all tested cancer
cell lines. If the indicated effect was not attainable under the concentra-
tion range used, the highest tested concentration was used for the calcu-
lation.
hydrogen (compound 7j), or the introduction of a fluoro
group at position 3 (compound 7h) of the phenyl ring, signifi-
cantly decreases biological activity. The introduction of a me-
thoxy moiety at the same position (compound 7n) produced a
compound that is one order of magnitude less active than the
most active compounds tested. The most active N-methyl de-
rivatives, 7h, 7j, 7l, and 7p, showed inhibitory effects against
all cell lines tested in the micromolar to sub-micromolar range
and in two cases reached nanomolar concentrations. Table 3
shows that the N-methyl compound 7l is slightly selective for
the leukemia (pGI50 4.90–6.59), colon (pGI50 5.17–6.18), and
renal cancer (pGI50 5.16–7.50) subpanels as the calculated pGI50
MG_MID values of such panels are higher than the overall cell
line MG_MID values (DMG_MID 0.16–0.17). The most sensitive
cell lines were SR (pGI50 6.59) and K-562 (pGI50 6.12) of the leu-
kemia sub panel, KM12 (pGI50 6.18) and SW-620 (pGI50 5.92) of
the colon subpanel, and A498 (pGI50 7.50) of renal subpanel.
Compound 7l also showed good selectivity with respect to
the MDA-MB-435 (pGI50 6.50) of the melanoma subpanel and
NCI/ADR-RES (pGI50 5.93), of the ovarian subpanel. Derivative
7j showed good selectivity with respect to EKVX (pGI50 5.28) of
the non-small-cell lung subpanel. Derivatives 7g, 7o, and 7p
were selectively active with respect to the non-small-cell lung
cancer and especially active against HOP-92 (pGI50 6.89, 7.56,
and 5.59 respectively) and EKVX (pGI50 5.61, 6.23, and 5.55 re-
spectively). Compound 7n showed good selectivity with re-
spect to the A498 (pGI50 6.11) of the renal subpanel.
Detailed studies of the cellular pharmacology of 7j and 7l in
comparison with roscovitine and purvalanol A are currently on-
going. However, preliminary experiments have shown that,
consistent with the inhibition of CDK1, the exposure of asyn-
chronously growing STO cells to both compounds caused
changes in cell-cycle phase distribution (Figure 1). Specifically,
flow cytometric analysis of propidium iodide-stained cells
show that 72 h treatment with sub-cytotoxic, IC50, and IC80 con-
Considering that 7h, 7j, 7l, and 7p were the most potent
compounds of the series, they were also assayed against pan-
creatic carcinoma (MiaPaCa-2) and malignant peritoneal meso-
thelioma (STO) cell lines. Cells were exposed to increasing con-
centrations (from 0.05 to 50 mm) of the phenylthiazolyl-7-azain-
doles for 72 h, and their effect on cell proliferation was deter-
mined by the SRB assay. Assessment of IC50 values showed
that all compounds inhibited cell growth in a concentration-
dependent manner in both cellular models (Table 4). Neverthe-
less, compounds 7j and 7l were more active than compounds
7p and 7h for pancreatic carcinoma cells, and also exhibited a
Figure 1. Cell-cycle effects of 7j and 7l on asynchronously growing STO
cells. Cells were exposed to 1% DMSO (v/v) (control cells; ctrl), 7j (0.5, 0.8,
and 1 mm), or 7l (0.2, 0.4, and 1 mm) and cell-cycle phase distribution was as-
sessed at 72 h after treatment by flow cytometric analyses. The percentage
of cells in sub-G1 (grey), G1 (white), S (hashed), and G2/M (black) phases are
shown. Columns represent the mean of three independent experiments;
SDs always within Æ5%.
1302
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Indole and Azaindole Antitumor Agents
Table 3. In vitro inhibition of cancer cell line growth by compounds 7g, 7h, 7j, 7l, 7n, 7o, and 7p.
[a]
[a]
pGI50
pGI50
Cell line
7g
7h
7j
7l
7n
7o
7p
Cell line
7g
7h
7j
7l
7n
7o
7p
Leukemia
CCRF-CEM
HL-60(TB)
K-562
MOLT-4
RPMI-8226
SR
Melanoma
<4.00 4.45 4.64 4.90
<4.00 4.84 5.03 5.88
<4.00 4.63 4.86 6.12
<4.00 4.93 4.99 5.47
<4.00 4.60 4.84 5.15
<4.00 4.87 5.03 6.59
<4.00
5.04
5.30
4.72
4.43
5.01
<4.00 4.74 LOX IMVI
<4.00 4.99 MALME-3m
<4.00 4.89 M14
<4.00 4.91 MDA-MB-435
<4.00 4.91 SK-MEL-2
4.88 SK-MEL-28
SK-MEL-5
UACC-257
<4.00 4.76 UACC-62
6.23 5.55
<4.00 4.76 Ovarian Cancer
7.56 5.59 IGROV1
<4.00 4.83 OVCAR-3
4.01 4.86 OVCAR-4
<4.00 4.88 OVCAR-5
<4.00 4.79 OVCAR-8
<4.00 4.87 NCI/ADR-RES
SK-OV-3
<4.00 4.85 4.89 5.44
5.25 4.75 4.79 5.61
5.25 4.81 4.86 5.78
<4.00 4.84 4.95 6.50
<4.00 4.63 4.73 5.48
<4.00 4.75 4.80 4.99
<4.00 4.81 4.86 5.53
<4.00 4.66 4.68 4.93
<4.00 4.86 4.91 5.56
4.27
4.65
4.55
5.55
4.26
4.10
4.77
<4.00
4.89
<4.00 4.91
<4.00 4.83
<4.00 4.92
<4.00 4.89
<4.00 4.76
<4.00 4.82
<4.00 4.86
<4.00 4.70
<4.00 4.98
Non-Small-Cell Lung Cancer
A549/ATCC
EKVX
HOP-62
HOP-92
NCI-H226
NCI-H23
NCI-H322m
NCI-H460
NCI-H522
4.75 4.68 4.77 5.39
4.12
4.76
<4.00
5.70
<4.00
<4.00
<4.00
4.48
5.61 4.90 5.28 5.37
4.59 4.72 4.81 5.29
6.89 5.98 4.74 5.82
<4.00 4.71 4.78 5.07
4.15 4.76 4.79 5.25
5.09 4.67 4.78 5.29
4.22 4.72 4.79 5.64
4.56 4.63 4.87
<4.00 4.83 4.85 5.37
4.37 4.58 4.69 5.23
<4.00 4.69 4.71 5.93
4.92 4.60 4.73 5.45
<4.00
4.38
<4.00
<4.00
<4.00
4.92
5.32 4.65
<4.00 4.77
4.18 4.66
<4.00 4.85
<4.00 4.64
<4.00 4.80
<4.00 4.80
4.11
4.77 4.82 5.21
5.18 4.77 4.80 5.54
<4.00 4.80 4.85 5.85
4.83
<4.00
Colon Cancer
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
<4.00 4.80 4.86 5.70
<4.00 4.72 4.78 5.17
5.10 4.85 4.86 5.57
<4.00 4.85 4.89 5.66
<4.00 4.85 4.85 5.72
<4.00 4.80 4.90 6.18
<4.00 4.78 4.83 5.92
4.54
4.09
4.42
4.60
4.76
5.10
4.71
<4.00 4.86 Renal Cancer
<4.00 4.84 786-0
4.28 4.89 A498
<4.00 4.91 ACHN
<4.00 4.88 CAKI-1
<4.00 4.89 RXF 393
4.44 4.82 SN12C
TK-10
<4.00 4.79 4.84 5.36
7.50
4.29
6.11
4.04
4.74
4.26
<4.00
<4.00
<4.00
<4.00 4.79
<4.00
5.01 4.74 4.77 5.28
<4.00 4.79 5.15 5.69
4.64 4.80 4.83 5.80
<4.00 4.81 4.82 5.40
4.59 4.75 4.75 5.36
4.48 4.80 4.96 5.16
<4.00 4.85
<4.00 5.16
<4.00 4.86
<4.00 4.83
<4.00 4.91
<4.00 4.87
CNS Cancer
SF-268
SF-295
SF-539
SNB-19
SNB-75
U251
UO-31
4.42 4.76 4.77 5.37
4.43 4.83 4.82 5.60
4.16 4.81 4.85 5.50
4.65 4.70 4.80 5.40
5.08 4.45 4.63 5.33
4.60 4.81 4.87 5.45
4.08
4.69
4.03
<4.00
<4.00
4.11
<4.00 4.81
<4.00 4.81 Breast Cancer
4.45 4.83 MCF7
<4.00 4.86 MDA-MB-231/ATCC
<4.00 4.70 HS 578T
<4.00 4.84 BT-549
T-47D
5.28 4.75 4.90 5.73
4.42 4.77 4.87 5.33
5.53 4.71 4.93 5.51
4.35 4.68 4.77 5.15
5.63 4.84 5.22 5.78
<4.00 4.70 4.85 5.47
4.90
4.12
<4.00
4.17
4.90
5.42
<4.00 4.93
<4.00 4.88
<4.00 4.92
<4.00 4.73
5.03 5.29
Prostate Cancer
PC-3
DU-145
MDA-MB-468
<4.00 4.98
<4.00 4.79 4.84 5.46
<4.00 4.74 4.82 5.33
4.74
<4.00
<4.00 4.94
<4.00 4.82
[a] Data obtained from the NCI in vitro disease-oriented human tumor cell screen.
centrations of 7j and 7l resulted in a concentration-dependent
accumulation of cells in the G2/M phase, with a concomitant
increase in the sub-G1 apoptotic cell population (Figure 1).
Table 5. Kinase inhibition by compounds 7h, 7j, 7l, and 7p.
IC50 [mm][a]
Compd
CDK1
CDK5
GSK3b
7h
7j
7l
33.27Æ2.97
0.41Æ0.08
0.85Æ0.13
45.93Æ4.19
0.73Æ0.06
0.59Æ0.08
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
7p
Table 4. Cytotoxic activity of 7h, 7l, 7j, and 7p in MiaPaCA-2 and STO
cell lines.
Roscovitine
Purvalanol A
IC50 [mm][a]
[a] Inhibitor concentration at which enzyme activity is decreased by 50%,
as determined graphically from the curve for each compound; data rep-
resent the mean ÆSD of at least three independent experiments.
Compd
MiaPaCa-2
STO
7j
7p
7h
7l
5.7Æ0.8
39.6Æ3.9
41.6Æ2.4
4.3Æ0.6
0.83Æ0.04
5.7Æ0.8
17.2Æ2.9
0.41Æ0.06
Conclusions
[a] Concentration of drug required to inhibit growth by 50% as deter-
mined by SRB assay after 72 h continuous exposure to each compound;
data represent the mean ÆSD of at least three independent experi-
ments.
Phenylthiazolylindoles 6 and phenylthiazolyl-7-azaindoles 7
were conveniently synthesized by a Hantzsch reaction be-
tween aryl thioamides and a-bromoacetyl derivatives. None of
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1303

P. Diana et al.
MED
the thiazolylindoles 6, tested at a single concentration (10À5 m),
showed significant antiproliferative activity. Instead, seven de-
rivatives belonging to the 7-azaindole series 7 were tested at
five concentrations (10À4–10À8 m) and were active having GI50
values in the micromolar to sub-micromolar range and in two
cases reaching nanomolar levels. The most active compounds
were the N-methyl derivatives and four of them, 7h, 7j, 7l,
and 7p, were tested further against the pancreatic carcinoma
(MiaPaCa-2) and malignant peritoneal mesothelioma (STO)
with IC50 values in the range 4.3–41.6 mm and 0.41-17.2 mm, re-
spectively.
3-Acetyl-1-methylindole (12b): White solid (0.87 g, 80%): Rf =0.50
(CH2Cl2/EtOAc 9:1); mp: 108–1098C; H NMR (200 MHz, [D6]DMSO):
1
d=2.44 (s, 3H, CH3), 3.85 (s, 3H, CH3), 7.19–7.32 (m, 2H, H-5 and
H-6), 7.52 (dd, 1H, J=6.4, 1.8 Hz, H-7), 8.23 (dd, 1H, J=6.4, 1.8 Hz,
H-4), 8.29 ppm (s,1H, H-2); 13C NMR (50 MHz, [D6]DMSO): d=27.2
(q), 33.0 (q), 110.5 (d), 115.6 (s), 121.4 (d), 121.9 (d), 122.7 (d), 125.7
(s), 137.2 (s), 137.9 (d), 192.0 ppm (s); IR (KBr): n˜ =1643 cmÀ1 (CO);
Elemental analysis: calcd (%) for C11H11NO: C 76.28, H 6.40, N 8.09,
found: C 76.41, H 6.29, N 7.87.
General procedure for the preparation of 3-bromoacetylindoles
(9a,b): Bromine (0.1 mL, d=3.12 gmLÀ1, 1.9 mmol) was added
dropwise to a cold suspension of the appropriate 3-acetylindole
12a,b (1.9 mmol) in anhydrous MeOH (3 mL). The mixture was
heated at reflux for 2 h. After cooling the solvent was evaporated
under reduced pressure. The residue was treated with H2O (20 mL),
made alkaline by adding NaHCO3, (150 mg) and extracted with
EtOAc (3ꢂ50 mL). The organic phase was dried, evaporated under
reduced pressure, and purified by column chromatography using
CH2Cl2 as eluent.
To gain insight into the mechanism of action of this series of
compounds, 7h, 7j, 7l, and 7p were incubated with CDK1/
cyclin, CDK5/p25, or GSK3b. Interestingly, only the compounds
with the highest antiproliferative activity (7j and 7l) exhibited
affinity for CDK1, with IC50 values of 0.41 and 0.85 mm, respec-
tively. Such values were similar to those obtained in the same
assay with roscovitine and purvalanol A used as reference
drugs. Moreover, exposure of asynchronously growing STO
cells to both compounds caused changes in cell-cycle phase
distribution. In particular, a concentration-dependent accumu-
lation of cells in the G2/M phase was observed, with a concom-
itant increase in the sub-G1 apoptotic cell population.
3-Bromoacetylindole (9a): Brown solid (0.32 g, 70%): Rf =0.43
(CH2Cl2/EtOAc 98:2); mp: 113–1148C; 1H NMR (200 MHz,
[D6]DMSO): d=4.66 (s, 2H, CH2), 7.19–7.29 (m, 2H, H-5 and H-6),
7.49–7.54 (m, 1H, H-7), 8.17 (t, 1H, J=5.9 Hz, H-4), 8.50 (d, 1H, J=
3.2 Hz, H-2), 12.2 (bs, 1H, NH); 13C NMR (50 MHz, [D6]DMSO): d=
33.5 (t), 112.3 (d), 113.5 (s), 121.2 (d), 122.1 (d), 123.2 (d), 125.4 (s),
135.2 (d), 136.7 (s), 186.3 (s); IR (KBr): n˜ =3190 (NH), 1639 cmÀ1
(CO); Elemental analysis: calcd (%) for C10H8BrNO: C 50.45, H 3.39,
N 5.88, found: C 50.23, H 3.44, N 6.01.
Experimental Section
3-Bromoacetyl-1-methylindole (9b): Brown solid (0.33 g, 70%):
Rf =0.44 (CH2Cl2); mp: 205–2068C; 1H NMR (200 MHz, [D6]DMSO):
d=3.37 (s, 3H, CH3), 4.60 (s, 2H, CH2), 7.27–7.33 (m, 2H, H-5 and
H-6), 7.59 (dd, 1H, J=6.0, 1.9 Hz, H-7), 8.18 (dd, 1H, J=6.0, 1.9 Hz,
H-4), 8.50 ppm (s, 1H, H-2); 13C NMR (50 MHz, [D6]DMSO): d=33.3
(q), 33.4 (t), 110.9 (d), 112.3 (s), 121.3 (d), 122.5 (d), 123.3 (d), 125.9
Chemistry
General: All melting points were taken on a Bꢁchi–Tottoli capillary
apparatus and are uncorrected. IR spectra were determined in bro-
moform with a Jasco FT/IR 5300 spectrophotometer. 1H and
13C NMR spectra were measured at 200 and 50.3 MHz, respectively,
in [D6]DMSO or CDCl3 solution, using a Bruker Avance II series
200 MHz spectrometer [(CH3)4Si as internal reference]. Column
chromatography was performed with Merck silica gel 230–400
mesh ASTM or with Bꢁchi Sepacore chromatography module (pre-
packed cartridge system). Elemental analyses (C, H, N) were within
Æ0.4% of the theoretical values.
General procedure for the preparation of benzenecarbothioa-
mides (8b,d,i,j): Lawesson’s reagent (0.81 g, 2 mmol) was added
to a stirred solution of the proper amide 11 b,d,i,j (4 mmol) in an-
hydrous benzene (10 mL). The mixture was heated at reflux for
15 min. After cooling the solvent was evaporated under reduced
pressure and the residue was purified by column chromatography
using CH2Cl2 as eluent. Melting point, IR, and NMR data for the syn-
thesized compounds are in agreement with those reported previ-
ously.[13]
(s), 137.4 (s), 138.7 (d), 185.8 ppm (s); IR (KBr): n˜ =1643 (CO) cmÀ1
;
Elemental analysis: calcd (%) for C11H10BrNO: C 52.41, H 4.00, N
5.56, found: C 52.57, H 4.11, N 5.39.
Synthesis of 1-methyl-7-azaindole (13b): tBuOK (0.38 g,
3.4 mmol) and tris[2-(2-methoxyethoxy)ethyl]amine (TDA-1) (1–
2 drops) were added at 08C to a cold solution of derivative 13a
(0.30 g, 2.5 mmol) in anhydrous benzene (25 mL). The reaction mix-
ture was stirred at RT for 3 h, and then CH3I (0.2 mL, 2.5 mmol, d=
2.28 gmLÀ1) was added at 08C. TLC analysis (EtOAc) revealed that
methylation was complete after 1 h. The solvent was evaporated
under reduced pressure. The residue was treated with H2O, extract-
ed with CH2Cl2, dried (Na2SO4), evaporated, and purified by column
chromatography using CH2Cl2/EtOAc (9:1) as eluent.
1-Methyl-7-azaindole (13b): Oil (0.31 g, 96%): Rf =0.40 (CH2Cl2/
1
MeOH 9:1); H NMR (200 MHz, CDCl3): d=3.87 (s, 3H, CH3), 6.43 (d,
1H, J=3.4 Hz, H-3), 7.03 (dd, 1H, J=7.8, 4.8 Hz, H-5), 7.15 (d, 1H,
J=3.4 Hz, H-2), 7.88 (dd, 1H, J=7.8, 1.5 Hz, H-4), 8.33 ppm (d, 1H,
J=4.8 Hz, H-6); 13C NMR (50 MHz, CDCl3): d=31.1 (q), 99.1 (d),
115.3 (d), 120.4 (s), 128.6 (d), 128.9 (d+s), 142.6 ppm (d); Elemental
analysis: calcd (%) for C8H8N2: C 72.70, H 6.10, N, 21.20, found: C
72.55, H 6.03, N 21.38.
Synthesis of 3-acetyl-1-methylindole (12b): tBuOK (1.0 g,
8.6 mmol) and tris[2-(2-methoxyethoxy)ethyl]amine (TDA-1) (1–
2 drops) were added to a cold solution of 3-acetylindole 12a
(1.0 g, 6.3 mmol) in anhydrous benzene (50 mL). The reaction mix-
ture was stirred at RT for 8 h and then CH3I (0.4 mL, d=
2.28 gmLÀ1, 6.3 mmol) was added. TLC analysis (CH2Cl2/EtOAc 9:1)
revealed that methylation was complete after 2 h. The solvent was
evaporated under reduced pressure. The residue was treated with
H2O (50 mL), extracted with CH2Cl2 (3ꢂ50 mL), dried, evaporated,
and purified by column chromatography using CH2Cl2/EtOAc (9:1)
as eluent.
General procedure for the preparation of 3-bromoacetyl-7-
azaindoles (10a,b): Anhydrous AlCl3 (1.2 g, 8.8 mmol) was slowly
added to a solution of 2.5 mmol of the proper derivative 13a,b in
anhydrous CH2Cl2 (10 mL). The reaction mixture was heated under
reflux and
a solution of bromoacetyl bromide (0.2 mL, d=
1304
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ChemMedChem 2011, 6, 1300 – 1309

Indole and Azaindole Antitumor Agents
2.317 gmLÀ1, 2.5 mmol) in anhydrous CH2Cl2 (2 mL) was added
dropwise. The resulting solution was allowed to stir under reflux
for 40 min. After cooling, H2O and ice were slowly added and the
obtained precipitate (for derivative 10a) was filtered off or the oil
residue (for derivative 10b) was extracted with CH2Cl2 and purified
by column chromatography using CH2Cl2/EtOAc 9:1 as eluent.
130.6 (s), 136.5 (s), 139.9 (s), 151.6 (s), 166.0 ppm (s). IR (KBr): n=
˜
3020 cmÀ1 (NH); Elemental analysis: calcd (%) for C18H14N2S: C
74.45, H 4.86, N 9.65, found: C 74.67, H 4.92, N 9.45.
1-Methyl-3-[2-(4-methylphenyl)-1,3-thiazol-4-yl]-1H-indole (6d):
Cream solid (0.99 g, 65%): Rf =0.89 (CH2Cl2); mp: 141–1428C;
1H NMR (200 MHz, [D6]DMSO): d=2.38 (s, 3H, CH3), 3.87 (s, 3H,
CH3), 7.16–7.30 (m, 2H, H-5 and H-6), 7.35 (d, 2H, J=8.0 Hz, H-3’
and H-5’), 7.52 (dd, 1H, J=6.8, 1.7 Hz, H-7), 7.77 (s, 1H, H-2), 7.94
(d, 2H, J=8.0 Hz, H2’ and H-6’), 7.98 (s, 1H, H-5’’), 8.21 ppm (dd,
1H, J=6.8, 1.7 Hz, H-4); 13C NMR (50 MHz, [D6]DMSO): d=20.9 (q),
32.6 (q), 109.4 (d), 110.0 (s), 110.1 (d), 119.9 (d), 120.3 (d), 121.7 (d),
124.9 (s), 126.0 (2ꢂd), 129.1 (d), 129.7 (2ꢂd), 130.7 (s), 137.0 (s),
139.9 (s), 151.3 (s), 166.0 ppm (s); Elemental analysis: calcd (%) for
C19H16N2S: C 74.97, H 5.30, N 9.20, found: C 75.11, H 5.45, N 8.91.
3-Bromoacetyl-7-azaindole (10a): White solid (0.55 g, 92%): Rf =
0.36 (CH2Cl2/MeOH 9:1); mp: 280–2828C; 1H NMR (200 MHz,
[D6]DMSO): d=4.71 (s, 2H, CH2), 7.30 (dd, 1H, J=7.8, 4.7 Hz, H-5),
8.37 (d, 1H, J=4.7 Hz, H-6), 8.47 (d, 1H, J=7.8 Hz, H-4), 8.65 (bs,
1H, H-2), 12.7 ppm (bs, 1H, NH); 13C NMR (50 MHz, [D6]DMSO): d=
46.3 (t), 112.3 (s), 117.7 (s), 118.4 (d), 129.5 (d), 135.1 (d), 144.6 (d),
149.0 (s), 186.4 ppm (s); IR (KBr): n˜ =3556 (NH), 1678 cmÀ1 (CO); El-
emental analysis: calcd (%) for C9H7BrN2O: C 45.22, H 2.95, N 11.72,
found: C 45.40, H 2.82, N 11.54.
3-[2-(4-Methoxyphenyl)-1,3-thiazol-4-yl]-1H-indole (6e): Cream
solid (0.93 g, 60%): Rf =0.30 (CH2Cl2); mp: 213–2148C; 1H NMR
(200 MHz, [D6]DMSO): d=3.85 (s, 3H, CH3), 7.10 (d, 2H, J=8.8 Hz,
H-3’ and H-5’), 7.13–7.23 (m, 2H, H-5 and H-6), 7.44–7.52 (m,1H, H-
7), 7.74 (s,1H, H-2), 7.98 (s, 1H, H-5’’), 8.0 (d, 2H, J=8.8 Hz, H-2’
and H-6’), 8.19–8.23 (m, 1H, H-4), 11.4 ppm (s, 1H, NH); 13C NMR
(50 MHz, [D6]DMSO): d=55.4 (q), 108.8 (d), 110.9 (s), 111.8 (d),
114.5 (2ꢂd), 119.7 (d), 120.2 (d), 121.6 (d), 124.6 (s), 124.8 (d), 126.1
(s), 127.6 (2ꢂd), 1À316.6 (s), 151.6 (s), 160.7 (s), 165.7 ppm (s); IR
3-Bromoacetyl-1-methyl-7-azaindole (10b): White solid (0.50 g,
80%): Rf =0.62 (CH2Cl2/MeOH 9:1); mp: 116–1178C; 1H NMR
(500 MHz, [D6]DMSO): d=3.91 (s, 3H, CH3), 4.65 (s, 2H, CH2), 7.34
(dd, 1H, J=7.6, 4.7, Hz, H-5), 8.40–8.48 (m, 2H, H-4 and H-6),
8.70 ppm (s, 1H, H-2); 13C NMR (50 MHz, [D6]DMSO): d=31.7 (q),
32.9 (t), 110.8 (s), 118.1 (d), 118.7 (s), 129.8 (d), 138.7 (d), 144.4 (d),
À1
˜
148.1 (s), 186.1 ppm (s); IR (KBr): n=1650 cm (CO); Elemental
analysis: calcd (%) for C10H9BrN2O: C 47.46, H 3.58, N 11.07, found:
C 47.22, H 3.63, N 11.25.
˜
(KBr): n=3126 cm
(NH); Elemental analysis: calcd (%) for
General procedure for the preparation of 3-(2-phenyl-1,3-thia-
zol-4-yl)-1H-indoles (6a–l): A suspension of the proper thioamide
8a–f (5 mmol) and 3-bromoacetylindole 9a,b (5 mmol) in anhy-
drous EtOH (20 mL) was stirred at RT for 24 h. The solid formed
was filtered, dried, and purified by column chromatography using
CH2Cl2 as eluent.
C18H14N2OS: C 70.56, H 4.61, N 9.14, found: C 74.70, H 5.42, N 8.96.
1-Methyl-3-[2-(4-methoxyphenyl)-1,3-thiazol-4-yl]-1H-indole (6 f):
Cream solid (0.96 g, 60%): Rf =0.67 (CH2Cl2); mp: 1548C; 1H NMR
(200 MHz, [D6]DMSO): d=3.84 (s, 3H, CH3), 3.87 (s, 3H, CH3), 7.10
(d, 2H, J=8.8 Hz, H-3’ and H5’), 7.19–7.30 (m, 2H, H-5 and H-6),
7.51 (dd, 1H, J=6.9, 1.5 Hz, H-7), 7.71 (s,1H, H-2), 7.97 (s, 1H, H-
5’’), 7.99 (d, 2H, J=8.8 Hz, H-2’ and H-6’), 8.21 ppm (dd, 1H, J=6.9,
1.5 Hz, H-4); 13C NMR (50 MHz, [D6]DMSO): d=32.6 (q), 55.4 (q),
108.9 (d), 110.1 (s), 110.2 (d), 114.5 (2ꢂd), 119.9 (d), 120.3 (d), 121.7
(d), 125.0 (s), 126.1 (s), 127.6 (2ꢂd), 129.0 (d), 137.0 (s), 151.2 (s),
160.8 (s), 165.8 ppm (s); Elemental analysis: calcd (%) for
C19H16N2OS: C 71.22, H 5.03, N 8.74, found: C 71.38, H 5.10, N 8.66.
3-(2-Phenyl-1,3-thiazol-4-yl)-1H-indole (6a): Orange solid (0.94 g,
68%): Rf =0.40 (CH2Cl2); mp: 210–2118C; 1H NMR (200 MHz,
[D6]DMSO): d=7.15 (t, 1H, J=7.1 Hz, H-5), 7.20 (t, 1H, J=7.1 Hz,
H-6), 7.44–7.61 (m, 4H, H-7, H-3’, H-4’ and H-5’), 7.84 (s, 1H, H-5’’),
8.00 (d, 1H, J=2.7 Hz, H-2), 8.07 (dd, 2H, J=7.9, 2.2 Hz, H-2’ and
H-6’), 8.21 (d, 1H, J=7.1 Hz, H-4), 11.5 ppm (bs, 1H, NH); 13C NMR
(50 MHz, [D6]DMSO): d=109.9 (d), 110.8 (s), 111.9 (d), 119.8 (d),
120.2 (d), 121.6 (d), 124.6 (s), 124.9 (d), 126.1 (2ꢂd), 129.2 (2ꢂd),
130.1 (d), 133.3 (s), 136.6 (s), 152.0 (s), 165.8 ppm (s); IR (KBr): n˜ =
3118 cmÀ1 (NH); Elemental analysis: calcd (%) for C17H12N2S: C
73.88, H 4.38, N 10.14, found: C 73.71, H 4.43, N 10.24.
3-[2-(4-Chlorophenyl)-1,3-thiazol-4-yl]-1H-indole (6g): Brown
solid (1.09 g, 70%): Rf =0.58 (CH2Cl2); mp: 215–2168C; 1H NMR
(200 MHz, [D6]DMSO): d=7.12 (t, 1H, J=7.0 Hz, H-5), 7.19 (t, 1H,
J=7.0 Hz, H-6), 7.47 (d,1H, J=7.0 Hz, H-7), 7.62 (d, 2H, J=8.7 Hz,
H-3’ and H-5’), 7.88 (s, 1H, H-5’’), 8.00 (d, 1H, J=2.6 Hz, H-2), 8.08
(d, 2H, J=8.7 Hz, H-2’ and H-6’), 8.21 (d, 1H, J=7.0 Hz, H-4),
11.5 ppm (d, 1H, J=2.6 Hz, NH); 13C NMR (50 MHz, [D6]DMSO): d=
110.4 (d), 110.6 (s), 111.9 (d), 119.8 (d), 120.2 (d), 121.6 (d), 124.6 (s),
125.0 (d), 127.7 (2ꢂd), 129.3 (2ꢂd), 132.1 (s), 134.5 (s), 136.5 (s),
152.1 (s), 164.4 ppm (s); IR (KBr): n˜ =3213 cmÀ1 (NH); Elemental
analysis: calcd (%) for C17H11ClN2S: C 65.70, H 3.57, N 9.01, found:
C, 65.55; H, 3.43; N, 9.27.
1-Methyl-3-(2-phenyl-1,3-thiazol-4-yl)-1H-indole (6b): Yellow
solid (0.95 g, 65%): Rf =0.87 (CH2Cl2); mp: 196–1978C; 1H NMR
(200 MHz, [D6]DMSO): d=3.88 (s, 3H, CH3), 7.20 (t, 1H, J=7.0 Hz,
H-5), 7.27 (t, 1H, J=7.0 Hz, H-6), 7.50–7.56 (m, 3H, H-3’, H-4’ and
H-5’), 7.83 (s, 1H, H-2), 7.99 (s, 1H, H-5’’), 8.04–8.08 ppm (m, 3H, H-
2’, H-7, H-6’), 8.22 (d, 1H, J=7.0 Hz, H-4); 13C NMR (50 MHz,
[D6]DMSO): d=32.2 (q), 99.5 (s), 110.0 (d), 110.2 (d), 120.0 (d), 120.3
(d), 121.7 (d), 124.9 (s), 126.1 (2ꢂd), 129.1 (d), 129.2 (2ꢂd), 130.1
(d), 133.2 (s), 137.0 (s), 151.5 (s), 165.9 ppm (s); Elemental analysis:
calcd (%) for C18H14N2S: C 74.45, H 4.86, N 9.65, found: C 74.53, H
4.96, N 9.48.
3-[2-(4-Chlorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-indole (6h):
White solid (1.24 g, 74%): Rf =0.84 (CH2Cl2); mp: 174–1758C;
1H NMR (200 MHz, [D6]DMSO): d=3.87 (s, 3H, CH3), 7.17–7.30 (m,
2H, H-5 and H-6), 7.53 (dd, 1H, J=6.9, 1.6 Hz, H-7), 7.61 (d, 1H, J=
8.5 Hz, H-3’ and H-5’), 7.85 (s, 1H, H-2), 8.00 (s, 1H, H-5’’), 8.07 (d,
2H, J=8.5 Hz, H-2’ and H-6’), 8.22 ppm (dd, 1H, J=6.9, 1.6 Hz, H-
4); 13C NMR (50 MHz, [D6]DMSO): d=32.6 (q), 109.8 (s), 110.2 (d),
110.4 (d), 120.0 (d), 120.3 (d), 121.7 (d), 124.9 (s), 127.2 (2ꢂd), 129.2
(d), 129.3 (2ꢂd), 132.0 (s), 134.6 (s), 137.0 (s), 151.7 (s), 164.5 ppm
(s); Elemental analysis: calcd (%) for C18H13ClN2S: C, 66.56; H, 4.03;
N, 8.62, found: C 66.77, H 4.15, N 8.43.
3-[2-(4-Methylphenyl)-1,3-thiazol-4-yl]-1H-indole (6c): Yellow
solid (0.87 g, 60%): Rf =0.50 (CH2Cl2); mp: 235–2368C; 1H NMR
(200 MHz, [D6]DMSO): d=2.39 (s, 3H, CH3), 7.14–7.19 (m, 2H, H-5
and H-6), 7.36 (d, 2H, J=8.0 Hz, H-3’ and H-5’), 7.44–7.48 (m, 1H,
H-7), 7.79 (s, 1H, H-2), 7.93–7.98 (m, 3H, H-2’, H-6’ and H-5’’), 8.18–
8.22 (m, 1H, H-4), 11.4 ppm (s, 1H, NH); 13C NMR (50 MHz,
[D6]DMSO): d=21.0 (q), 109.5 (d), 110.7 (s), 111.9 (d), 119.7 (d),
120.2 (d), 121.6 (d), 124.6 (s), 124.9 (d), 126.0 (2ꢂd), 129.7 (2ꢂd),
ChemMedChem 2011, 6, 1300 – 1309
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P. Diana et al.
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3-[2-(4-Bromophenyl)-1,3-thiazol-4-yl]-1H-indole (6i): Brown solid
(1.25 g, 70%): Rf =0.54 (CH2Cl2); mp 220–2218C; H NMR (200 MHz,
C16H10ClN3S: C 61.64, H 3.23, N 13.48, found: C 61.44, H 3.30, N
13.60.
1
[D6]DMSO): d=7.12–7.22 (m, 2H, H-5 and H-6), 7.48 (d, 1H, J=
6.9 Hz, H-7), 7.75 (d, 2H, J=8.5 Hz, H-3’ and H-5’), 7.87 (s,1H, H-2),
7.99 (s, 1H, H-5’’), 8.01 (d, 2H, J=8.5 Hz, H-2’ and H-6’), 8.21 (d,
1H, J=6.9 Hz, H-4), 11.5 ppm (s, 1H, NH); 13C NMR (50 MHz,
[D6]DMSO): d=110.4 (d), 110.6 (s), 111.9 (d), 119.8 (d), 120.2 (d),
121.6 (d), 123.3 (s), 124.6 (s), 125.0 (d), 127.9 (2ꢂd), 132.2 (2ꢂd),
132.4 (s), 136.6 (s), 152.2 (s), 164.5 ppm (s); IR (KBr): n˜ =3122 cmÀ1
(NH); Elemental analysis: calcd (%) for C17H11BrN2S: C 57.48, H 3.12,
N 7.89, found: C 57.71, H 3.26, N 7.68.
3-[2-(2-Chlorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azaindole
(7b): Yellow solid (1.19 g, 73%): Rf =0.64 (EtOAc); mp 258–2598C;
1H NMR (200 MHz, [D6]DMSO): d=3.97 (s, 3H, CH3), 7.42 (dd, 1H,
J=7.9, 5.1 Hz, H-5), 7.53–7.71 (m, 3H, H-4’, H-5’ and H-6’), 8.16 (s,
1H, H-2), 8.30 (s, 1H, H-5’’), 8.35–8.40 (m, 1H, H-3’), 8.48 (dd, 1H,
J=5.1, 1.3 Hz, H-6), 8.86 ppm (dd, 1H, J=7.9, 1.3 Hz, H-4); 13C NMR
(50 MHz, [D6]DMSO): d=31.9 (q), 109.2 (s), 113.7 (d), 116.3 (d),
119.2 (s), 127.8 (d), 129.9 (d), 130.6 (d), 130.7 (s), 130.8 (d), 131.1 (d),
131.2 (s), 131.9 (d), 140.0 (d), 144.5 (s), 148.9 (s), 161.8 ppm (s); Ele-
mental analysis: calcd (%) for C17H12ClN3S: C 62.67, H 3.71, N 12.90,
found: C 62.46, H 3.85, N 13.09.
3-[2-(4-Bromophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-indole (6j):
White solid (1.43 g, 82%): Rf =0.84 (CH2Cl2); mp: 185–1868C;
1H NMR (200 MHz, [D6]DMSO): d=3.87 (s, 3H, CH3), 7.16–7.30 (m,
2H, H-5 and H-6), 7.52 (dd, 1H, J=6.9, 1.5 Hz, H-7), 7.75 (d, 2H, J=
8.5 Hz, H-3’ and H-5’), 7.86 (s, 1H, H-2), 8.00 (s, 1H, H-5’’), 8.01 (d,
2H, J=8.5 Hz, H-2’ and H-6’), 8.21 ppm (dd, 1H, J=6.7, 1.6 Hz, H-
4); 13C NMR (50 MHz, [D6]DMSO): d=32.6 (q), 109.8 (s), 110.2 (d),
110.4 (d), 120.0 (d), 120.3 (d), 121.7 (d), 124.9 (s), 127.9 (2ꢂd), 129.2
(d), 132.2 (2ꢂd), 132.4 (s), 137.0 (s), 151.7 (s), 164.6 ppm (s); Ele-
mental analysis: calcd (%) for C18H13BrN2S: C 58.54, H 3.55, N 7.59,
found: C 58.75, H 3.64, N 7.38.
3-[2-(2-Fluorophenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7c): Yellow
solid (1.03 g, 70%): Rf =0.55 (EtOAc); mp: 2568C; 1H NMR
(200 MHz, [D6]DMSO): d=7.42–7.63 (m, 4H, H-3’, H-4’, H-5’ and H-
6’), 8.28 (s, 1H, H-5’’), 8.39 (s, 1H, H-2), 8.47 (dt, 1H, J=7.1, 4.5 Hz,
H-5), 8.56 (d, 1H, J=4.5 Hz, H-6), 9.17 ppm (d, 1H, J=7.1 Hz, H-4);
3
13C NMR (50 MHz, [D6]DMSO): d=110.9 (s), 114.1 (dd, JCF =8.6 Hz),
116.4 (dd, 2JCF =21 Hz), 116.3 (d), 120.4 (d, 2JCF =20 Hz), 121.0 (s),
4
3
125.2 (dd, JCF =3.2 Hz), 127.0 (d), 128.4 (d), 131.8 (dd, JCF =8.6 Hz),
135.5 (d), 136.9 (d), 141.5 (s), 148.7 (s), 158.8 (s), 159.3 ppm (d,
1JCF =251 Hz); IR (KBr): n˜ =3456 cmÀ1 (NH); Elemental analysis:
calcd (%) for C16H10FN3S: C 65.07, H 3.41, N 14.23, found: C 65.15, H
3.49, N 14.13.
3-[2-(4-Fluorophenyl)-1,3-thiazol-4-yl]-1H-indole (6k): White solid
(1.04 g, 70%): Rf =0.48 (CH2Cl2); mp: 209–2108C; 1H NMR
(200 MHz, [D6]DMSO) d: 7.12 (t, 1H, J=7.2 Hz, H-5), 7.17 (t, 1H, J=
7.2 Hz, H-6), 7.35–7.50 (m, 3H, H-3’, H-5’ and H-7), 7.83 (s, 1H, H-
5’’), 8.00 (d, 1H, J=2.6 Hz, H-2), 8.08–8.15 (m, 2H, H-2’ and H-6’),
3-[2-(2-Fluorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azaindole
(7d): Yellow solid (1.18 g, 76%): Rf =0.65 (EtOAc); mp: 257–2588C;
1H NMR (200 MHz, [D6]DMSO): d=3.98 (s, 3H, CH3), 7.40–7.65 (m,
4H, H-3’, H-4’, H-5’ and H-6’), 8.13 (s, 1H, H-5’’), 8.31 (s, 1H, H-2),
8.47 (dt, 1H, J=7.9, 5.3 Hz, H-5), 8.49 (dd, 1H, J=5.3, 1.3 Hz, H-6),
8.90 ppm (dd, 1H, J=7.9, 1.3 Hz, H-4); 13C NMR (50 MHz,
[D6]DMSO): d=18.5 (q), 109.3 (s), 113.1 (d), 113.2 (d), 116.2 (d),
8.22 (d, 1H, J=7.2 Hz, H-4), 11.5 (s, 1H, NH); 13C NMR (50 MHz,
2
[D6]DMSO): d=110.0 (d), 110.7 (s), 111.9 (d), 116.3 (2ꢂdd, JCF
=
22 Hz), 119.8 (d), 120.2 (d), 121.6 (d), 124.6 (s), 124.9 (d), 128.3 (2ꢂ
dd, 3JCF =8.6 Hz), 129.9 (d, 4JCF =3.1 Hz), 136.6 (s), 152.0 (s), 163.0
1
(d, JCF =247 Hz), 164.6 (s); IR (KBr): n˜ =3118 cmÀ1 (NH); Elemental
analysis: calcd (%) for C17H11FN2S: C 69.37, H 3.77, N 9.52, found: C
69.11, H 3.86, N 9.76.
2
4
116.4 (dd, JCF =19 Hz), 119.3 (s), 128.6 (dd, JCF =3.1 Hz), 120.4 (d,
2JCF =19 Hz), 128.9 (d), 125.2 (dd, JCF 8.7 Hz), 132.3 (d), 139.7 (dd,
3JCF =8.7 Hz), 146.6 (d, JCF =238 Hz), 156.8 (s), 158.7 (s), 158.8 ppm
3
3-[2-(4-Fluorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-indole
(6l):
1
White solid (1.01 g, 66%): Rf =0.70 (CH2Cl2); mp 151–1528C;
1H NMR (200 MHz, [D6]DMSO): d=3.87 (s, 3H, CH3), 7.20 (dt, 1H,
J=9.4, 1.3 Hz, H-5), 7.25 (dt, 1H, J=9.4, 1.3 Hz, H-6), 7.34–7.43 (m,
2H, H-3’ and H5’), 7.52 (dd, 1H, J=9.4, 1.3 Hz, H-4), 7.81 (s, 1H, H-
2), 7.99 (s, 1H, H-5’’), 8.07–8.14 (m, 2H, H-2’ and H-6’), 8.22 ppm
(dd 1H, J=9.4, 1.3 Hz, H-7); 13C NMR (50 MHz, [D6]DMSO): d=32.6
(q), 109.9 (s), 110.0 (d), 110.1 (d), 116.2 (2ꢂdd, 2JCF =22 Hz), 120.0
(s); Elemental analysis: calcd (%) for C17H12FN3S: C 66.00, H 3.91, N
13.58, found: C 66.21, H 4.06, N 13.37.
3-[2-(3-Methylphenyl-1,3-thiazol-4-yl)-1H-7-azaindole
(7e):
Yellow solid 0.97 g, 70%): Rf =0.61 (EtOAc); mp: 258–2598C;
1H NMR (200 MHz, [D6]DMSO): d=2.44 (s, 3H, CH3), 7.32–7.49 (m,
2H, H-4’ and H-6’),7.57 (dd, 1H, J=8.0, 5.4, Hz, H-5), 7.87–7.91 (m,
2H, H-2’ and H-5’), 8.12 (s,1H, H-2), 8.34 (s, 1H, H-5’’), 8.54 (dd, 1H,
J=5.4, 1.1 Hz, H-6), 9.11 (dd, 1H, J=6.8, 1.1 Hz, H-4), 12.9 ppm
(s,1H, NH); 13C NMR (50 MHz, [D6]DMSO): d=20.9 (q), 111.1 (s),
112.5 (d), 116.3 (d), 120.9 (s), 123.4 (d), 126.5 (d), 126.8 (d), 129.1
(d), 131.0 (d), 132.8 (s), 135.1 (d), 137.1 (Àd1), 138.6 (s), 141.8 (s), 149.5
3
(d), 120.3 (d), 121.7 (d), 124.9 (s), 128.3 (2ꢂdd, JCF =8.6 Hz), 129.1
1
(d), 129.9 (d, 4JCF =3.1 Hz), 137.0 (s), 151.5 (s), 163.1 (d, JCF
=
248 Hz), 165.6 ppm (s); Elemental analysis: calcd (%) for C18H13FN2S:
C 70.11, H 4.25, N 9.08, found: C 70.32, H 4.12, N 8.88.
General procedure for the preparation of 3-(2-phenyl-1,3-thia-
zol-4-yl)-1H-7-azaindoles (7a–t): A suspension of the proper thioa-
mide 8a–j (5 mmol) and 10a,b (5 mmol) in anhydrous EtOH
(20 mL) was heated under reflux for 30 min. The precipitate, ob-
tained after cooling, was filtered off, dried, and crystallized with
EtOH.
˜
(s), 166.8 ppm (s); IR (KBr): n=3089 cm (NH); Elemental analysis:
calcd (%) for C17H13N3S: C 70.08, H 4.50, N 14.42, found: C 70.29, H
4.62, N 14.21.
1-Methyl-3-[2-(3-methylphenyl-1,3-thiazol-4-yl)-1H-7-azaindole
(7 f): Yellow solid (1.15 g, 75%): Rf =0.70 (EtOAc); mp: 221–2228C;
1H NMR (200 MHz, [D6]DMSO): d=2.43 (s, 3H, CH3), 3.99 (s, 3H,
CH3), 7.31–7.48 (m, 3H, H-5, H-4’ and H-6’), 7.84–7.87 (m, 2H, H-2’
and H-5’), 7.99 (s,1H, H-2), 8.29 (s, 1H, H-5’’), 8.50 (dd, 1H, J=5.1,
1.2, Hz, H-6), 8.90 ppm (dd, 1H, J=7.9, 1.2 Hz, H-4); 13C NMR
(50 MHz, [D6]DMSO): d=20.9 (q), 21.1 (q), 109.5 (s), 111.7 (d), 116.2
(d), 119.5 (s), 123.4 (d), 126.5 (d), 129.1 (d), 129.9 (s), 130.0 (d), 131.0
(d), 132.5 (d), 132.9 (s), 138.6 (s), 139.4 (d), 149.7 (s), 166.7 ppm (s);
Elemental analysis: calcd (%) for C18H15N3S: C 70.79, H 4.95, N
13.76, found: C 70.55, H 4.87, N 13.93.
3-[2-(2-Chlorophenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7a): Yellow
solid (1.13 g, 72%): Rf =0.58 (EtOAc); mp: 247–2488C; 1H NMR
(200 MHz, [D6]DMSO): d=7.53–7.72 (m, 4H, H-5, H-4’, H-5’ and H-
6’), 8.30 (s, 1H, H-2), 8.37–8.43 (m, 2H, H-3’ and H.5’’), 8.54 (dd, 1H,
J=5.4, 1.1 Hz, H-6), 9.11 (dd, 1H, J=7.9, 1.1 Hz, H-4), 12.9 ppm
(s,1H, NH); 13C NMR (50 MHz, [D6]DMSO): d=110.7 (s), 114.5 (s),
116.3 (s), 120.7 (s), 126.9 (d), 127.8 (d), 130.7 (2ꢂd), 130.8 (d), 131.0
(d), 131.2 (d), 134.7 (d), 137.6 (d), 142.2 (s), 148.7 (s), 161.9 ppm (s);
IR (KBr): n˜ =3087 cmÀ1 (NH); Elemental analysis: calcd (%) for
1306
www.chemmedchem.org
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemMedChem 2011, 6, 1300 – 1309

Indole and Azaindole Antitumor Agents
3-[2-(3-Fluorophenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7g): Yellow
solid (1.04 g, 70%): Rf =0.56 (EtOAc); mp: 272–2738C; 1H NMR
(200 MHz, [D6]DMSO): d=7.34–7.94 (m, 5H, H-2’, H-4’, H-5, H-5’
and H-6’), 8.20 (s, 1H, H-5’’), 8.38 (s, 1H, H-2), 8.56 (d, 1H, J=
4.6 Hz, H-6), 9.15 (d, 1H, J=7.0 Hz, H-4), 12.94 ppm (s,1H, NH);
5.1 Hz, H-5), 7.95 (d, 2H, J=8.1 Hz, H-2’ and H-6’), 7.95 (s,1H, H-2),
8.28 (s, 1H, H-5’’), 8.48 (d, 1H, J=5.1 Hz, H-6), 8.88 ppm (d, 1H, J=
7.9 Hz, H-4); 13C NMR (50 MHz, [D6]DMSO): d=21.0 (q), 32.0 (q),
109.5 (s), 111.2 (d), 116.2 (d), 119.3 (s), 126.0 (2ꢂd), 129.8 (2ꢂd),
129.9 (d), 130.3 (s), 132.3 (d), 139.6 (d), 140.1 (s), 140.8 (s), 144.4 (s),
149.7 ppm (s) Elemental analysis: calcd (%) for C18H15N3S: C 70.79,
H 4.95, N 13.76, found: C 70.65, H 5.04, N 13.97.
2
13C NMR (50 MHz, [D6]DMSO): d=110.9 (s), 112.5 (dd, JCF =21 Hz),
113.4 (d), 116.4 (d), 117.0 (dd, 2JCF =21 Hz), 120.9 (s), 122.4 (dd,
3
4JCF =2.7 Hz), 127.4 (d), 131.4 (dd, 3JCF =8.4 Hz), 135.0 (d, JCF
=
=
3-[2-(4-Methoxyphenyl-1,3-thiazol-4-yl)-1H-7-azaindole
(7m):
1
8.4 Hz), 135.4 (d), 136.7 (d), 141.6 (s), 149.7 (s), 162.5 ppm (d, JCF
Yellow solid (1.10 g, 72%): Rf =0.56 (EtOAc); mp: 2338C; 1H NMR
(200 MHz, [D6]DMSO): d=3.85 (s, 3H, CH3), 7.11 (d, 2H, J=8.8 Hz,
H-3’ and H-5’), 7.52 (dd, 1H, J=7.9, 5.4 Hz, H-5), 8.01 (s, 1H, H-2),
8.03 (d, 2H, J=8.8 Hz, H-2’ and H-6’), 8.29 (s, 1H, H-5’’), 8.50 (d,
1H, J=5.4 Hz, H-6), 9.06 (d, 1H, J=7.9 Hz, H-4), 12.70 ppm (s,1H,
NH); 13C NMR (50 MHz, [D6]DMSO): d=55.4 (q), 110.9 (s), 111.3 (d),
114.6 (2ꢂd), 116.3 (d), 120.5 (s), 125.8 (s), 126.4 (d), 127.8 (2ꢂd),
134.9 (d), 137.9 (d), 142.9 (s), 149.5 (s), 160.9 (s), 166.6 ppm (s); IR
(KBr): n˜ =3062 cmÀ1 (NH); Elemental analysis: calcd (%) for
C17H13N3OS: C 66.43, H 4.26, N 13.67, found: C 66.51, H 4.33, N
13.59.
À1
˜
244 Hz), 165.1 (s); IR (KBr): n=3089 cm (NH); Elemental analysis:
calcd (%) for C16H10FN3S: C 65.07, H 3.41, N 14.23, found: C 65.29, H
3.52, N 13.96.
3-[2-(3-Fluorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azaindole
(7h): Yellow solid (1.20 g, 78%): Rf =0.63 (EtOAc); mp: 2748C;
1H NMR (200 MHz, [D6]DMSO): d=3.97 (s, 3H, CH3), 7.33–7.91 (m,
5H, H-2’, H-4’, H-5, H-5’ and H-6’), 8.06 (s, 1H, H-5’’), 8.31 (s, 1H, H-
2), 8.56 (dd, 1H, J=5.1, 1.2 Hz, H-6), 9.15 ppm (dd, 1H, J=7.9,
1.2 Hz, H-4); 13C NMR (50 MHz, [D6]DMSO): d=31.7 (q), 99.5 (s),
2
112.2 (dd, 2JCF =20 Hz), 112.4 (dd, 4JCF =2.6 Hz), 112.5 (dd, JCF
=
20 Hz), 116.3 (d), 116.8 (d), 118.6 (s), 122.4 (d), 129.7 (d), 131.4 (dd,
3-[2-(4-Methoxyphenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azain-
dole (7n): Yellow solid (1.31 g, 82%): Rf =0.62 (EtOAc); mp: 2518C;
1H NMR (200 MHz, [D6]DMSO): d=3.85 (s, 3H, CH3), 3.98 (s, 3H,
CH3), 7.10 (d, 2H, J=8.8 Hz, H-3’ and H-5’), 7.45 (dd, 1H, J=7.9,
5.2 Hz, H-5), 7.91 (s, 1H, H-2), 7.99 (d, 2H, J=8.8 Hz, H-2’ and H-6’),
8.28 (s, 1H, H-5’’), 8.51 (dd, 1H, J=5.2, 1.0, H-6), 8.91 ppm (dd, 1H,
J=7.9, 1.0 Hz, H-4); 13C NMR (50 MHz, [D6]DMSO): d=31.9 (q), 55.4
(q), 109.4 (s), 110.6 (d), 114.6 (2ꢂd), 116.2 (d), 119.1 (s), 125.8 (s),
127.7 (2ꢂd), 129.7 (d), 132.0 (d), 140.0 (d), 144.6 (s), 149.6 (s), 160.9
(s), 166.4 ppm (s); Elemental analysis: calcd (%) for C18H15N3OS: C
67.27, H 4.70, N 13.07, found: C 67.34, H 4.79, N 12.91.
3JCF =7.5 Hz), 135.1 (d, 3JCF =7.5 Hz), 138.6 (s), 140.7 (d), 145.3 (s),
1
150.3 (s), 162.5 ppm (d, JCF =242 Hz); Elemental analysis: calcd (%)
for C17H12FN3S: C 66.00, H 3.91, N 13.58, found C 66.26, H 4.04, N
13.41.
3-(2-Phenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7i): Yellow solid
(1.75 g, 70%): Rf =0.50 (EtOAc); mp: 2548C; 1H NMR (200 MHz,
[D6]DMSO): d=7.55–8.13 (m, 6H, H-2’, H-3’, H-4’, H-5, H-5’ and H-
6’), 8.15 (s, 1H, H-2), 8.37 (s, 1H, H-5’’), 8.56 (d, 1H, J=4.5 Hz, H-6),
9.15 (d, 1H, J=7.0 Hz, H-4), 12.9 ppm (s,1H, NH); 13C NMR
(50 MHz, [D6]DMSO): d=111.0 (s), 112.6 (d), 116.3 (d), 120.9 (s),
126.2 (2ꢂd), 126.8 (d), 129.3 (2ꢂd), 130.4 (d), 132.9 (s), 135.2 (d),
137.3 (d), 141.9 (s), 149.6 (s), 166.7 ppm (s); IR (KBr): n˜ =3089 cmÀ1
(NH); Elemental analysis: calcd (%) for C16H11N3S: C 69.29, H 4.00, N
15.15, found: C 69.40, H 4.09, N 14.98.
3-[2-(4-Chlorophenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7o): Yellow
solid (1.21 g, 78%): Rf =0.53 (EtOAc); mp: 2738C; 1H NMR
(200 MHz, [D6]DMSO): d=7.53 (dd, 1H, J=7.9, 5.4 Hz, H-5), 7.64 (d,
2H, J=8.5 Hz, H-3’ and H-5’), 8.10 (d, 2H, J=8.5 Hz, H-2’ and H-6’),
8.14 (s, 1H, H-2), 8.33 (s, 1H, H-5’’), 8.52 (d, 1H, J=5.4 Hz, H-6),
9.07 (d, 1H, J=7.9 Hz, H-4); 12.8 ppm (s,1H, NH); 13C NMR
(50 MHz, [D6]DMSO): d=110.7 (s), 112.8 (d), 116.3 (d), 120.4 (s),
123.2 (s), 126.7 (d), 127.8 (2ꢂd), 129.3 (2ꢂd), 131.7 (s), 134.8 (d),
137.9 (d), 142.6 (s), 150.0 (s), 165.3 ppm (s); IR (KBr): n˜ =3062 cmÀ1
(NH); Elemental analysis: calcd (%) for C16H10ClN3S: C 61.64, H 3.23,
N 13.48, found: C 61.70, H 3.27, N 13.42.
1-Methyl-3-(2-phenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7j): Yellow
solid (1.06 g, 73%): Rf =0.63 (EtOAc); mp: 231–2328C; 1H NMR
(200 MHz, [D6]DMSO): d=3.99 (s, 3H, CH3), 7.46 (dd, 1H, J=7.9,
5.2 Hz, H-5), 7.54–7.59 (m, 3H, H-3’, H-4’ and H-5’), 8.01 (s, 1H, H-2),
8.04–8.09 (m, 2H, H-2’ and H-6’), 8.30 (s, 1H, H-5’’), 8.50 (dd, 1H,
J=5.2, 1.1 Hz, H-6), 8.92 ppm (dd, 1H, J=7.9, 1.1 Hz, H-4); 13C NMR
(50 MHz, [D6]DMSO): d=32.2 (q), 109.6 (s), 116.2 (d), 111.9 (d),
119.6 (s), 126.1 (2ꢂd), 129.2 (2ꢂd), 130.0 (d), 130.3 (d), 132.8 (s),
132.9 (d), 139.3 (d), 143.9 (s), 149.7 (s), 166.5 ppm (s); Elemental
analysis: calcd (%) for C17H13N3S: C 70.08, H 4.50, N 14.42, found: C
70.33, H 4.62, N 14.18.
3-[2-(4-Chlorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azaindole
(7p): Yellow solid (1.41 g, 87%): Rf =0.66 (EtOAc); mp: 265–2668C;
1H NMR (200 MHz, [D6]DMSO): d=3.96 (s, 3H, CH3), 7.41 (dd, 1H,
J=7.9, 5.0 Hz, H-5), 7.61 (d, 2H, J=8.6 Hz, H-3’ and H-5’), 8.01 (s,
1H, H-2), 8.10 (d, 2H, J=8.6 Hz, H-2’ and H-6’), 8.27 (s, 1H, H-5’’),
8.47 (dd, 1H, J=5.0, 1.2 Hz, H-6), 8.84 ppm (dd, 1H, J=7.9, 1.2 Hz,
H-4); 13C NMR (50 MHz, [D6]DMSO): d=31.7 (q), 109.0 (s), 111.9 (d),
116.3 (d), 118.7 (s), 127.8 (2ꢂd), 129.3 (2ꢂd), 129.7 (d), 131.2 (d),
131.8 (s), 134.8 (s), 140.8 (d), 145.3 (s), 150.3 (s), 165.1 ppm (s); Ele-
mental analysis: calcd (%) for C17H12ClN3S: C 62.67, H 3.71, N 12.90,
found: C 62.38, H 3.83, N 12.67.
3-[2-(4-Methylphenyl-1,3-thiazol-4-yl)-1H-7-azaindole
(7k):
Yellow solid (1.03 g, 71%): Rf =0.54 (EtOAc); mp: 267–2688C;
1H NMR (200 MHz, [D6]DMSO): d=2.39 (s, 3H, CH3), 7.36 (d, 2H,
J=8.0 Hz, H-3’ and H-5’), 7.56 (dd, 1H, J=8.0, 5.5 Hz, H-5), 7.97 (d,
2H, J=8.0 Hz, H-2’ and H-6’), 8.08 (s, 1H, H-2), 8.33 (s, 1H, H-5’’),
8.53 (d, 1H, J=5.5 Hz, H-6), 9.11 (d, 1H, J=8.0 Hz, H-4), 12.80 ppm
(s, 1H, NH); 13C NMR (50 MHz, [D6]DMSO): d=21.0 (q), 111.0 (s),
112.0 (d), 116.3 (d), 120.7 (s), 126.1 (2ꢂd), 126.7 (d), 129.8 (2ꢂd),
130.3 (s), 134.5 (d), 137.4 (d), 140.2 (s), 142.1 (s), 149.5 (s),
166.8 ppm (s); IR (KBr): n˜ =3062 cmÀ1 (NH); Elemental analysis:
calcd (%) for C17H13N3S: C 70.08, H 4.50, N 14.42, found: C 70.29, H
4.64, N 14.19.
3-[2-(4-Bromophenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7q): Yellow
solid (1.48 g, 83%): Rf =0.59 (EtOAc); mp: 278–2798C; 1H NMR
(200 MHz, [D6]DMSO): d=7.55 (dd, 1H, J=7.9, 5.4 Hz, H-5), 7.75 (d,
2H, J=8.5 Hz, H-3’ and H-5’), 8.03 (d, 2H, J=8.5 Hz, H-2’ and H-6’),
8.15 (s, 1H, H-2), 8.33 (s, 1H, H-5’’), 8.53 (d, 1H, J=5.4 Hz, H-6),
9.08 (d, 1H, J=7.9 Hz, H-4), 12.8 ppm (s, 1H, NH); 13C NMR
(50 MHz, [D6]DMSO): d=110.8 (s), 112.9 (d), 126.3 (d), 120.6 (s),
123.6 (s), 126.8 (d), 128.0 (2ꢂd), 132.0 (s), 132.2 (2ꢂd), 134.6 (d),
137.7 (d), 142.4 (s), 149.9 (s), 165.4 ppm (s); IR (KBr): n˜ =2948 cmÀ1
1-Methyl-3-[2-(4-methylphenyl-1,3-thiazol-4-yl)-1H-7-azaindole
(7l): Yellow solid (1.18 g, 77%): Rf =0.67 (EtOAc); mp: 278–2798C;
1H NMR (200 MHz, [D6]DMSO): d=2.39 (s, 3H, CH3), 3.97 (s, 3H,
CH3), 7.36 (d, 2H, J=8.1 Hz, H-3’ and H-5’), 7.43 (dd, 1H, J=7.9,
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P. Diana et al.
MED
(NH); Elemental analysis: calcd (%) for C16H10BrN3S: C 53.95, H 2.83,
N 11.80, found: C 53.63, H 2.97, N 12.02.
treated with various concentrations of test derivatives (0.05–50 mm)
for 72 h. Control cells received vehicle alone (1% DMSO). All stud-
ies were performed in eight replicates and repeated at least three
times independently. At the end of drug exposure, the antiprolifer-
ative potential was determined with the sulforhodamine B (SRB)
protein staining method as previously reported.[16] Briefly, cells
were fixed with cold 50% trichloroacetic acid solution (Sigma Al-
drich) and stained with 0.4% SRB (Sigma Aldrich) dissolved in 1%
acetic acid (Sigma Aldrich) for 30 min. The plates were then
washed four times with 1% acetic acid to remove unbound stain,
air dried, and bound dye was dissolved by 10 mm Tris base
(pH 10.5). Optical density was read at 550 nm on a microplate
reader and the results were expressed as a percentage, relative to
DMSO-treated cells. Dose–response curves were created and IC50
values (that is, concentrations able to inhibit cell growth by 50%)
were determined graphically from the curve for each compound.
3-[2-(4-Bromophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azaindole
(7r): Yellow solid (1.59 g, 86%): Rf =0.69 (EtOAc); mp: 282–2838C;
1H NMR (200 MHz, [D6]DMSO): d=3.96 (s, 3H, CH3), 7.41 (dd, 1H,
J=7.9, 5.1 Hz, H-5), 7.74 (d, 2H, J=8.6 Hz, H-3’ and H-5’), 8.00 (d,
2H, J=8.6 Hz, H-2’ and H-6’), 8.02 (s, 1H, H-2), 8.27 (s, 1H, H-5’’),
8.47 (dd, 1H, J=5.1, 1.3 Hz, H-6), 8.84 ppm (dd, 1H, J=7.9, 1.3 Hz,
H-4); 13C NMR (50 MHz, [D6]DMSO): d=31.9 (q), 109.2 (s), 112.1 (d),
116.2 (d), 119.1 (s), 123.5 (s), 128.0 (2ꢂd), 129.9 (d), 131.9 (s), 132.1
(d), 132.2 (2ꢂd), 140.1 (d), 144.6 (s), 150.1 (s), 165.2 ppm (s); Ele-
mental analysis: calcd (%) for C17H12BrN3S: C 55.15, H 3.27, N 11.35,
found: C 55.34, H 3.33, N 11.07.
3-[2-(4-Fluorophenyl-1,3-thiazol-4-yl)-1H-7-azaindole (7s): Yellow
solid (1.19 g, 80%): Rf =0.57 (EtOAc); mp: 258–2598C; 1H NMR
(200 MHz, [D6]DMSO): d=7.36–7.45 (m, 2H, H-3’ and H-5’), 7.54
(dd, 1H, J=8.0, 5.4 Hz, H-5), 8.11 (s, 1H, H-2), 8.15–8.18 (m, 2H, H-
2’ and H-6’), 8.33 (s,1H, H-5’’), 8.52 (dd, 1H, J=5.4, 1.1 Hz, H-6),
In vitro kinase assays: CDK1, CDK5, and GSK3b kinase activity was
performed using the OmniaTM Ser/Thr Recombinant Kit (Invitrogen,
Carlsbad, CA) according to the manufacturer’s protocols. Briefly, in-
creasing concentrations of phenylthiazolyl-7-azaindoles 7l and 7j
(0.05–50 mm) were mixed to recombinant CDK1/cyclin B, or CDK5/
p25, or GSK3b (Invitrogen) in 1ꢂ kinase buffer containing S/T pep-
tide substrate, ATP, and dithiothreitol, and the kinase reaction was
performed at 308C for 60 min. The samples were transferred to a
96-well plate and incubated at RT for 20 min. Fluorescence prog-
ress curves were measured upon excitation at 360 nm and emis-
sion at 485 nm. IC50 values (inhibitor concentration at which
enzyme activity is reduced by 50%) were determined graphically
from the curve for each compound.
9.10 (dd, 1H, J=8.0, 1.1 Hz, H-4) 12.82 ppm (s, 1H, NH); 13C NMR
2
(50 MHz, [D6]DMSO): d=110.8 (s), 112.5 (d), 116.2 (2ꢂdd, JCF
=
22 Hz), 116.3 (d), 120.6 (s), 122.4 (d, 4JCF =3.0 Hz), 126.7 (d), 128.5
3
(2ꢂdd, JCF =8.4 Hz), 134.7 (d), 137.6 (d), 141.3 (s), 149.7 (s), 163.2
(d, 1JCF =248 Hz), 165.1 ppm (s); IR (KBr): n˜ =3099 cmÀ1 (NH); Ele-
mental analysis: calcd (%) for C16H10FN3S: C 65.05, H 3.41, N 14.23,
found: C 65.22, H 3.26, N 13.87.
3-[2-(4-Fluorophenyl)-1,3-thiazol-4-yl]-1-methyl-1H-7-azaindole
(7t): Yellow solid (1.31 g, 85%): Rf =0.60 (EtOAc); mp: 2618C;
1H NMR (200 MHz, [D6]DMSO): d=3.98 (s, 3H, CH3), 7.35–7.48 (m,
3H, H-3’, H-5 and H-5’), 7.99 (s, 1H, H-2), 8.10–8.14 (m, 2H, H-2’
and H-6’), 8.29 (s, 1H, H-5’’), 8.49 (dd, 1H, J=4.9, 1.1 Hz, H-6),
9.10 ppm (dd, 1H, J=8.0, 1.1 Hz, H-4); 13C NMR (50 MHz,
Cell-cycle phase distribution: Both adherent and floating cells were
fixed in 70% EtOH and incubated on ice for 30 min in staining so-
lution containing 50 mgmLÀ1 of propidium iodide, 50 mgmLÀ1 of
RNase, and 0.05% Nonidet P40 in PBS. Samples were analyzed
with a FACScan flow cytometer (Becton Dickinson, Sunnyvale, CA,
USA) with an excitation wavelength of 488 nm and an emission
wavelength of 585 nm. At least 30000 events were read and histo-
grams were analyzed using the CellQuest software according to
the Modfit model (Becton Dickinson).
[D6]DMSO): d=32.2 (q), 107.8 (s), 112.0 (d), 116.2 (d), 116.3 (dd,
3
2JCF =22 Hz), 117.9 (s), 127.8 (d, 4JCF =2.1 Hz), 128.3 (dd, JCF
=
1
8.7 Hz), 130.1 (d), 133.0 (d), 139.0 (d), 161.8 (d, JCF =248 Hz), 141.9
(s), 148.0 (s), 163.6 ppm (s); Elemental analysis: calcd (%) for
C17H12FN3S: C 66.00, H 3.91, N 13.58, found: C 66.09, H 3.82, N
13.43.
Statistical analysis: Statistical evaluation of data was performed
with a two-tailed Student’s t-test; p values <0.05 were considered
statistically significant.
Biological studies
Drugs: The phenylthiazolyl-7-azaindoles derivatives were prepared
as described above. Roscovitine was purchased from Calbiochem
(San Diego, CA, USA) and purvalanol A from Tocris (Bristol, UK). To
obtain a 1 mm stock solution of phenylthiazolyl-7-azaindoles, a var-
iable amount of a solution of 1% dimethyl sulfoxide (DMSO) made
in sterile water was added to each compound powdered stock and
the compound was completely dissolved, stored at À208C, and di-
luted in complete culture medium immediately before use.
Acknowledgements
This work was supported financially by the Ministero dell’Istru-
zione dell’Universitꢀ e della Ricerca and the Associazione Italiana
per la Ricerca sul Cancro.
Cell culture conditions: The Mycoplasma-free human pancreatic car-
cinoma (MiaPaCa-2) cell line was obtained from American Type
Culture Collection (Rockville, MD, USA). The Mycoplasma-free
human malignant peritoneal mesothelioma cell line (STO) was es-
tablished in our laboratory.[15] Cells were maintained in culture as a
monolayer in DMEM/F12 medium (Lonza Milano s.r.l, Treviglio,
Italy) supplemented with 10% heat-inactivated fetal bovine serum
in a humidified incubator at 378C under an atmosphere of 5%
CO2, 95% air.
Keywords: azaindoles · antitumor agents · indoles · kinases ·
nortopsentins
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Received: February 9, 2011
Revised: March 18, 2011
Published online on April 26, 2011
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ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemmedchem.org
1309