Antitumor activity and COMPARE analysis of bis-indole derivatives

Article abstract of DOI:10.1016/j.bmc.2010.03.063

This paper reports the synthesis of new derivatives (formed by two indole systems separated by a central moiety) analogous of potent antitumor agents previously described. The activity of the bis-indoles bearing a pyridine core confirms the good result described in the previous paper and compound 4c was chosen for the first in vivo experiment (Hollow Fiber Assay). COMPARE analysis and structure-activity relationships were also considered. Contrary to data reported by other Authors, no correlations were found between antitumor activity and NQO1 induction.

Full text of DOI:10.1016/j.bmc.2010.03.063

Bioorganic & Medicinal Chemistry 18 (2010) 3004–3011
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Antitumor activity and COMPARE analysis of bis-indole derivatives q
a
a
a
a
Aldo Andreani a, , Silvia Burnelli , Massimiliano Granaiola , Alberto Leoni , Alessandra Locatelli ,
Rita Morigi a, Mirella Rambaldi a, Lucilla Varoli a, Laura Landi b, Cecilia Prata b, Francesco Vieceli Dalla Sega b,
Cristiana Caliceti b, Robert H. Shoemaker c
*
a Dipartimento di Scienze Farmaceutiche, Università di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
b Dipartimento di Biochimica ‘G. Moruzzi’, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy
c Screening Technologies Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute at Frederick, Frederick, MD 21702, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
This paper reports the synthesis of new derivatives (formed by two indole systems separated by a central
moiety) analogous of potent antitumor agents previously described. The activity of the bis-indoles bear-
ing a pyridine core confirms the good result described in the previous paper and compound 4c was cho-
sen for the first in vivo experiment (Hollow Fiber Assay). COMPARE analysis and structure–activity
relationships were also considered. Contrary to data reported by other Authors, no correlations were
found between antitumor activity and NQO1 induction.
Received 3 November 2009
Revised 30 December 2009
Accepted 25 March 2010
Available online 29 March 2010
Keywords:
Indole
Ó 2010 Elsevier Ltd. All rights reserved.
Pyridine
Antitumor
Hollow fiber assay
COMPARE
NQO1
1. Introduction
none in the wings and with cores different from pyridine. The
antitumor activity of all the new compounds was evaluated accord-
In the first paper of this series2 we described the potent antitu-
mor activity of bis-indole derivatives where the core was formed
by a 2,6-disubstituted pyridine ring and the wings by a couple of
2-indolinones bearing different substituents at the benzene ring.
The most interesting compound was NSC 724440 which showed
ing to the protocols available at the National Cancer Institute,
Bethesda, MD (NCI). COMPARE analysis and structure–activity rela-
tionships were also considered. Furthermore, since a correlation has
been very recently suggested between NQO1 (NAD(P)H-quinone
oxidoreductase 1) induction and antiproliferative activity in a series
of benzylidene-indolin-2-ones,3 we studied the effect of some of
these antitumor compounds on NQO1 activity and viability in leu-
kemia cell lines.
GI50 1.2 lM and was tested in the Hollow Fiber Assay.
O
O
N
2. Results and discussion
2.1. Chemistry
N
N
H
H
This paper describes the design of new analogs (Schemes 1 and
2) of the most active bis-indoles previously described,2 with the
following rationale:
O
O
NSC 724440
(1) introduction of new substituents in the benzene rings of the
indolinone systems (compounds 4a–h).
Here, we report the synthesis of new analogs with different substit-
uents in the indolinones, with heterocycles different from indoli-
(2) Substitution of the indolinone systems with different het-
erocycles while maintaining the pyridine ring in the core
(compounds 4i and 6). In the course of the synthesis of com-
pound 4i, the monosubstituted derivative 5 was also isolated
and its antitumor activity was evaluated.
q
See Ref. 1.
* Corresponding author. Tel.: +39 051 2099714; fax: +39 051 2099734.
E-mail address: aldo.andreani@unibo.it (A. Andreani).
0968-0896/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2010.03.063

A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
3005
O
O
N
N
R
R
N
R1
R2
R1
R2
R4
R1
R4
N
R2
R3
R3
R3
O
O
4a-i
O
3
N
R
R4
O
N
1a-i
O
H
N
5
O
O
3
N
O
O
O
O
2
6
Comp.
Starting
material
R
R1
R2
R3
R4
4a
4b
4c
4d
4e
4f
1a
1b
1c
1d
1e
1f
H
H
H
H
H
I
H
H
H
H
H
H
H
F
OCH3
OCH3
H
OCH3
H
OCH3
H
OCH3
H
H
OCF3
H
Benzyl
H
H
H
4g
4h
4i
1g
1h
1i
H
H
H
H
SO2NH2
H
H
H
A
H
H
H
H
B
A = SO2-NH-p-C6H4-SO3H
B = condensed benzene ring
Scheme 1.
(3) Substitution of the core with systems different from pyridine
while maintaining the indolinone wings with substituents
which gave the best results in the previous paper, that is,
halogens and methoxy group.2 In details the core substitu-
tion concerns the introduction of:
methanol has been treated with pyridine-2,6-dicarbaldehyde 3 or
benzene-1,3-dicarbaldehyde 8, benzene-1,4-dicarbaldehyde 9, 4-
tert-butyl-2,6-diformylphenol 10, 1,10-phenanthroline-2,9-dicarb-
aldehyde 11, 2,5-dimethylpyrrole-3,4-dicarbaldehyde 12, 2,5-thio-
phenedicarbaldehyde 13, 6,60-dihydroxy-5,50-dimethoxy-[1,10-
biphenyl]-3,30-dicarbaldehyde 14 in the presence of piperidine or
a mixture of acetic acid/hydrochloric acid (see Schemes 1 and 2
and Table 1, methods 1 and 3). Only compound 4c has been pre-
pared in a mixture of acetic acid and anhydrous sodium acetate
(method 2), whereas compound 15j has been obtained from the
indolinone 1j and benzene-1,2-dicarbaldehyde 7 in the presence
of 4-toluenesulfonic acid (method 4).
- benzene ring: 15j, 16j, 17j and 16k
- substituted benzene ring: 18j and 18k
- phenanthroline: 19j,k
- pyrrole: 20j,l
- thiophene: 21j
- biphenyl: 22j.
For the synthesis of compound 4e, 6-trifluoromethoxyindolin-
2-one 1e was the starting indolinone and it was prepared by treat-
ing 6-trifluoromethoxyisatine with 98% hydrazine hydrate.
Most of the new derivatives (Schemes 1 and 2) have been pre-
pared with the previously published procedure:4,5,2 the appropri-
ate indolinone 1 (the 2-coumaranone 2 for compound 6), in

3006
A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
R1
7-14
R2
15-22
O
N
H
1j-l
j R1 = H R2 = OCH3
k R1 = Cl R2 = H
l R1 = H R2 = F
H
N
R2
N
H
O
R2
N
O
N
R1
R1
H
H
H
H
H
O
H
O
O
O
15j
16j-k
H
H
R2
N
R2
N
O
O
N
R1
R1
N
H
H
OH
H
H
H
O
H
O
O
O
17j
18j-k
H
H
O
O
N
N
H
N
N
H
H
H
O
O
R1
R2
N
R1
R2
N
H
H
R1
R1
R2
R2
N
H
20j, l
19j-k
H
N
H
O
O
N
H
H
O
O
H
H
S
N
H
H
N
O
O
O
O
O
O
OH
OH
22j
21j
Scheme 2.
For the synthesis of compound 4h, 4-{[(2-oxo-2,3-dihydro-1H-
indol-5-yl)sulfonyl]amino}benzenesulfonic acid 1h was the starting
indolinone and it was prepared by treating 2-oxoindoline-5-sulfo-
nyl chloride with 4-aminobenzenesulfonic acid in toluene.
According to the 1H NMR spectra, all the compounds were ob-
tained as pure E isomers, except 4b, 4i and 21j which contain also
a small amount of the Z isomer. The configuration was assigned by
means of NOE experiments: the compounds selected for this pur-
pose were 16j, 18j and 19j.
The spectrum of compound 16j shows that the geometrical con-
figuration of the two centers is the same, since the couple of NH
groups and the other couples of indole protons/substituents (ind-
4, ind-6, ind-7, OCH3-5) give a single signal. The irradiation of ind-
4 (6.99 ppm) produced NOE at OCH3 (3.52 ppm) and at the aromatic
protons (singlet 7.95 and doublet 7.81 ppm), whereas NOE was not
observed at the –CH@ proton; the irradiation of the aromatic singlet
at 7.95 produced NOE at 7.67 (–CH@) and at 6.99 ppm (ind-4). All
these data are in agreement with the E configuration.

A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
3007
Table 1
In compound 19j the peak at 8.99 ppm (ind-4) was irradiated
and only the expected NOE at 3.35 (OCH3) was observed. The lack
of any other effect (in particular with the –CH@ group) demon-
strates that even compound 19j belongs to the E configuration.
Compd
Formula
Mw
Method
Mp
4a
4b
4c
4d
4e
4f
4g
4h
4i
5
6
15j
16j
16k
17j
18j
18k
19j
19k
20j
20l
21j
22j
C23H13I2N3O2
C23H13F2N3O2
C29H27N3O8
C27H23N3O6
C23H13F6N3O4
C37H27N3O2
617.18
401.37
545.54
485.49
509.36
545.63
523.55
895.92
465.50
300.31
367.36
424.45
424.45
433.29
424.45
496.56
505.39
526.54
535.38
441.48
417.41
430.48
592.60
1
1
2
1
1
1
3
3
1
1
1
4
1
1
1
1
3
1
1
1
3
1
1
263–265 dec
310–313 dec
237–240 dec
298–307
325–328
195–200
310–314 dec
>330
2.2. Effects in cultured human tumor cell lines
As a preliminary test, the compounds were tested at a single high
concentration (10ꢀ5 M) in the full NCI 60 cell panel (NCI 60 cell one-
concentration screen). This panel is organized into subpanels repre-
senting leukemia, melanoma and cancers of lung, colon, kidney,
ovary, breast, prostate and central nervous system. Only compounds
with pre-determined threshold inhibition criteria in a minimum
number of cell lines progress to the full five-concentration assay.
These criteria were selected to efficiently capture compounds with
anti-proliferative activity based on careful analysis of historical
DTP screening data. The One-concentration data is a mean graph
of the percent growth of treated cells (unpublished results).
All but two of the compounds tested were subjected to the full
five-concentration assay. They were dissolved in DMSO and evalu-
ated using five concentrations at 10-fold dilutions, the highest
being 10ꢀ4 M. Table 2 shows the results obtained (vincristine is re-
ported for comparison purposes), expressed at three assay end-
points: the 50% growth inhibitory power (GI50), the cytostatic
effect (TGI = total growth inhibition) and the cytotoxic effect
C23H17N5O6S2
C35H25N5O12S4.CH3COOH
C31H19N3O2
>330
C19H12N2O2
C23H13NO4
C26H20N2O4
C26H20N2O4
C24H14Cl2N2O2
C26H20N2O4
250–255 dec
220–222
258–260 dec
259–262
>330
327–330
220–224
310–315
250–253
>330
C30H28N2O5
C28H22Cl2N2O3
C32H22N4O4
C30H16Cl2N4O2
C26H23N3O4
C24H17F2N3O2
C24H18N2O4S
C34H28N2O8
240–245 dec
244–247
>330
195–199
Also the spectra of compounds 18j and 19j show that the
geometrical configuration of the two centers is the same. For com-
pound 18j, the first NOE analysis was devoted to the identification
of the aromatic and –CH@ protons. The irradiation of the C(CH3)3
groups (1.31 ppm) produced NOE at 7.71 ppm (peak which was as-
signed to the aromatic hydrogens of the core). NOE was produced
also at 6.99 ppm (ind-4) and at 3.58 ppm (OCH3). The irradiation of
ind-4 at 6.99 ppm produced the expected NOE at the aromatic
hydrogens (7.71 ppm) but not at the methine bridge, whereas
the irradiation at 9.87 ppm (OH) gave NOE at 7.72 ppm (–CH@).
These measures are in agreement with the E configuration.
(LC50). The compounds showing GI50 >20 lM (6, 17j, 20j and 21j)
are not reported. For some derivatives the five-concentration test
was repeated and no significant differences were found; in this
case the data reported in Table 2 are the mean values between
the two experiments.
The activity of the bis-indoles bearing a pyridine core confirms
the good result described in the previous paper.2 Six of the eleven
compounds prepared (4a–f) were retested and submitted to BEC
(Biological Evaluation Committee) for a possible future develop-
ment. Further studies continued at the NCI where the maximum
tolerated dose (MTD) was determined for compounds 4c, and it
Table 2
Sixty cell panel (growth inhibition, cytostatic and cytotoxic activity of the selected compounds expressed as micromolar concentration)
a
Comp
Modes
Leukemia
NSCLC
Colon
CNS
Melanoma
Ovarian
Renal
Prostate
Breast
MGMIDb
4a
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
0.9
30.9
—
0.8
9.8
—
0.2
2.8
67.6
0.4
8.7
64.6
0.2
8.9
—
0.3
5.4
—
1.5
10.0
77.6
2.5
7.6
—
5.4
—
1.0
11.5
—
1.3
5.0
21.9
2.0
10.2
41.7
0.3
1.5
33.1
0.9
18.6
85.1
0.4
0.5
1.9
7.6
0.7
3.3
13.8
0.2
0.5
7.2
0.5
1.9
22.4
0.2
0.5
2.0
1.2
4.0
13.8
1.1
5.7
32.4
0.3
0.8
3.2
0.7
3.6
21.9
0.3
0.8
2.6
1.9
1.0
3.2
13.5
0.9
2.8
8.3
0.2
0.5
2.7
0.7
2.2
13.5
0.4
1.1
5.7
1.1
5.6
22.4
1.6
8.5
44.7
0.3
0.8
5.7
0.8
11.2
27.5
0.4
2.5
12.3
1.8
13.8
33.1
19.0
56.2
91.2
8.7
30.9
72.4
14.1
—
0.9
2.6
8.3
1.1
3.8
14.8
0.3
0.7
4.5
0.7
2.5
18.2
0.3
0.7
2.9
0.6
2.2
24.0
1.4
12.9
36.3
0.3
1.0
16.6
0.5
3.4
25.1
0.1
0.3
3.2
1.4
19.5
—
21.9
81.3
—
0.8
4.4
21.9
0.8
10.0
34.7
0.2
1.5
24.6
0.7
17.4
60.3
0.3
0.9
4.4
17.4
1.1
6.2
27.5
0.2
1.0
11.0
0.7
5.7
32.4
0.3
4b
4c
4d
4e
4f
4i
1.9
15.5
6.3
2.0
15.8
0.7
1.3
7.6
1.3
0.6
5.5
0.7
5.2
1.4
43.6
74.1
24.0
57.5
89.1
14.4
37.1
85.1
14.1
87.1
3.0
7.6
11.2
44.7
17.0
41.7
79.4
10.7
26.9
74.1
21.4
79.4
2.5
11.5
79.4
17.8
69.2
97.7
6.2
45.7
79.4
7.8
—
1.2
5.0
—
12.3
45.7
14.1
43.6
85.1
9.1
31.6
81.3
11.7
87.1
1.7
18.6
14.4
44.7
83.2
9.5
44.7
83.2
7.8
35.5
15.8
49.0
85.1
11.2
33.9
91.2
14.1
72.4
1.4
20.9
13.8
38.0
77.6
11.5
35.5
72.4
13.8
91.2
1.2
5
5.7
33.1
97.7
14.4
58.9
1.7
LC50
GI50
TGI
GI50
TGI
15j
16j
87.1
1.7
7.4
2.1
6.3
95.5
11.0
85.1
4.3
29.5
2.9
30.2
6.2
79.4
4.1
25.7
6.0
64.6
LC50
83.2
(continued on next page)

3008
A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
Table 2 (continued)
a
Comp
Modes
Leukemia
NSCLC
Colon
CNS
Melanoma
Ovarian
Renal
Prostate
Breast
MGMIDb
16k
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
GI50
TGI
1.3
9.8
27.5
3.9
43.6
—
2.8
46.8
—
4.2
20.4
42.7
8.7
32.4
69.2
3.5
15.1
64.6
3.2
28.2
75.9
25.7
79.4
—
2.6
14.8
33.1
6.3
19.9
53.7
2.2
6.2
21.9
2.8
1.7
13.5
38.9
4.8
21.4
66.1
2.3
11.0
58.9
3.8
3.2
16.6
34.7
4.4
13.2
39.8
2.9
9.3
36.3
3.2
11.5
74.1
13.2
42.7
61.7
5.1
18.2
52.5
10.7
93.3
0.2
2.7
14.4
41.7
5.9
25.1
61.7
2.2
15.8
44.7
5.5
58.9
—
2.3
9.3
36.3
7.2
22.4
61.7
3.6
15.8
56.2
3.3
19.5
97.7
9.5
58.9
97.7
9.1
32.4
75.9
20.9
95.5
0.3
1.5
16.2
50.1
4.8
24.5
72.4
2.2
10.2
72.4
3.7
36.3
—
2.4
13.2
42.7
5.5
31.6
63.1
2.4
11.5
67.6
3.9
2.4
13.8
37.1
5.7
24.5
63.1
2.7
13.2
52.5
3.5
32.4
91.2
8.1
46.8
85.1
5.6
19.9
58.9
12.6
93.3
0.2
18j
18k
19j
3.0
60.3
—
16.2
—
3.9
—
—
7.4
75.9
19k
20l
1.1
30.2
—
2.4
9.1
37.1
6.9
89.1
0.1
6.2
3.8
14.4
70.8
93.3
4.9
22.4
70.8
13.8
—
30.9
79.4
5.0
17.0
53.7
10.5
75.9
0.1
34.7
77.6
3.4
13.2
46.8
6.8
87.1
0.1
6.3
30.9
70.8
8.1
25.7
72.4
15.1
—
31.6
79.4
7.9
20.4
44.7
10.5
—
7.8
25.1
74.1
21.9
95.5
0.2
22j
Vincristine sulfatec
0.3
19.9
0.1
6.3
0.3
7.9
15.8
15.8
4.0
7.9
19.9
10.0
a
Highest concn = 100
l
M except 16k (50.1
l
M): only modes showing a value <100
lM are reported.
b
Mean graph midpoint, that is, the mean concentration for all cell lines.
c
Highest concn = 10ꢀ3 M.
was found 100 mg/kg. Compound 4c was then chosen for the first
in vivo experiment, that is, the Hollow Fiber Assay.6 It was sub-
jected to four experiments against a panel of three tumor cell lines
each consisting of the breast, non-small cell lung, colon, ovarian,
CNS and melanoma cell lines. Under the experimental conditions
employed, the activity of compound 4c was not considered high
enough for the subsequent preclinical studies.
Good results were obtained also with other structures: when
the core is a benzene ring, the compound with the wings in the
meta position (16j) was more active than the analogs ortho (15j)
and para (17j). Between the two derivatives where the benzene
ring is substituted (18j,k), compound 18k was the most active of
this subset of core-modified derivatives and was submitted to BEC.
A particular mention is due to the phenanthroline core (19j,k)
considering potency and toxicity; in fact they showed a great dif-
ference between GI50 and LC50. Compound 19k, which was also
selective towards leukemias, was retested and then submitted to
BEC.
2.3. Structure–activity relationships
2.3.1. Wing modification
The introduction of a benzyl group in the indolinone NH group
gave the derivative 4f (mean GI50 = 1.3
l
M) which was not more
2.4. COMPARE analysis
active than its parent compound described in the previous paper2
showing mean GI50 = 0.5
tive towards leukemias.
The substitution of indolinone with coumaranone (6) led to loss
of activity. The same happened with benzoindolinone (4i) even
though the selectivity for leukemias was maintained.
l
M but 4f was less toxic and more selec-
First of all we defined the level of effect (GI50, TGI, LC50) most
useful for COMPARE analysis. LC50 was selected since it was
achieved in many cell lines and seemed to provide the most consis-
tent patterns of activity. MATRIX COMPARE identifies compounds
with most closely related patterns in the NCI-60 (Table S4). The
LC50 data provided the most useful information and defined a
sub-set of seven compounds with a highly coherent pattern of cell
killing: 4a, 4b, 4c, 4d, 4f, 18k, 19k (Table S5).
Then we selected a prototype compound to run MOLECULAR
TARGETS COMPARE (on basal expression array data and other
characterized potential targets) to probe mechanism. Compound
4b was selected based on strength of association with the other
top six compounds in this series and with a closely related analog
(with Cl in place of F) previously shown to have in vivo activity in
the hollow fiber tumor model.2
No very strong mechanistic leads were apparent for 4b from the
expression array COMPAREs. The strongest negative COMPARE re-
sult indicated that CLK4a (cyclin dependent kinase-like 4) expres-
sion is inversely correlated, that is, cell lines with low levels are
highly sensitive to the cell killing effects of the compound and vice
versa. The other highest ranked array results did not seem to com-
plement this result. No compelling correlations or patterns were
apparent from COMPARE against other molecular targets. The
same analyses were also run using the average pattern for 4a. Once
again, strong COMPAREs were not observed against the basal
expression arrays. The CLK4 negative COMPARE result was not
As far as the substituents at the indolinone system are con-
cerned, the introduction of sulfur containing groups (4g,h) was
detrimental whereas for the halogens the activity increased with
the following pattern: F, I, Cl: mean GI50 values were 1.1 (4b), 0.9
(4a) and 0.5 l
M2, respectively.
Increase of activity seems also connected to the number of
methoxy groups: compounds with one, two and three methoxy
groups were prepared and mean GI50 values were 1.2,2 0.7,
0.2 lM: the compound bearing three methoxy groups (4c) is the
most active of all the compounds so far prepared, including those
described in the previous paper.2
Compound 4e bearing a trifluoromethoxy group, showed a high
level of activity (mean GI50 0.3 lM) and was selective towards
prostate tumors (GI50 0.1 lM).
2.3.2. Core modification
The substitution of the pyridine core with a thiophene ring (21j)
led to loss of activity; better results were obtained with the intro-
duction of a 2,5-dimethylpyrrole ring (20j,l): in particular the com-
pound bearing a fluorine atom on the indolinone wings (20l) was
more active than the analog bearing a methoxy group (20j).

A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
3009
replicated with this compound’s data. However, CCND1 (cyclin D1)
molecular target levels were the top negative correlation in the
characterized target database, supporting the notion that down-
regulation of CCND1 sensitizes cells to the killing effect of the drug.
2-Coumaranone 2, pyridine-2,6-dicarbaldehyde 3, benzene-1,2-
dicarbaldehyde (phthaldialdehyde) 7, benzene-1,3-dicarbaldehyde
(isophthaldehyde) 8, benzene-1,4-dicarbaldehyde (terephthalalde-
hyde) 9, 4-tert-butyl-2,6-diformylphenol 10, 1,10-phenanthroline-
2,9-dicarbaldehyde 11,21 2,5-dimethylpyrrole-3,4-dicarbaldehyde
12,22 2,5-thiophenedicarbaldehyde 13, 6,60-dihydroxy-5,50-dime-
thoxy-[1,10-biphenyl]-3,30-dicarbaldehyde 14 are commercially
available or have been prepared as described in the literature.
2.5. NQO1 activation in leukemia cell lines
Compounds 4c, 4e and 4f were among the most active of the
series in leukemia cells (mean GI50 0.2, 0.2 and 0.3 lM, respec-
3.1.1. Synthesis of 6-trifluoromethoxyindolin-2-one (1e)
6-Trifluoromethoxyisatine (20 mmol), prepared as described in
the literature,23 was treated with 98% hydrazine hydrate (10 mL).
After 1 h reflux, water was added (50 mL) and reflux was main-
tained for one additional hour. The reaction mixture was then
cooled and acidified with 2 N hydrochloric acid. The expected ind-
olinone was crystallized from ethanol with a yield of 60%.
Mw 217.15; mp 140 °C; IR: 3135, 1721, 1634, 902; 1H NMR: 3.49
(2H, s, CH2), 6.74 (1H, s, ind-7), 6.88 (1H, d, ind-4/5, J = 8.1), 7.29
(1H, d, ind-4/5, J = 8.1), 10.56 (1H, s, NH). Anal. (C9H6F3NO2) C, H, N.
tively). Taking into account that a correlation has been recently
suggested between antitumor activity and NQO1 induction in a
series of benzylidene-indolin-2-ones3 we decided to investigate
whether NQO1 activation might be a possible mechanism of action
for compounds 4c, 4e and 4f. Therefore, three human leukemia cell
lines (M07e, B1647 and HEL) and non transformed cells (HUVEC)
were incubated with these compounds at different concentrations
(0.1–10 l
M) or with the known NQO1 inducer sulforaphane,7 as
positive control, for 24–48 h. Then, NQO1 activity was assayed.8
Meanwhile, the effect of compounds on cell proliferation was eval-
uated with the 2-day MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide] assay, which was also previously
used to determine IC50 values for each cell line. The MTT assay con-
3.1.2. Synthesis of 4-{[(2-oxo-2,3-dihydro-1H-indol-5-yl)sulfo-
nyl]amino}benzenesulfonic acid (1h)
2-Oxoindoline-5-sulfonyl chloride24 (40 mmol) was dissolved
in toluene (50 mL) and refluxed for 6 h with 40 mmol of 4-amino-
benzenesulfonic acid. After cooling, the resulting precipitate was
collected by filtration with a yield of 98% and used as such without
further purification.
firmed the antiproliferative activity of 4c (IC50 = 1–2
lM), 4e
(IC50 = 3–5 M), and 4f (IC50 = 3–10 M) in leukemia cells. Figure
l
l
S1 shows NQO1 activation in M07e cells, representative of the
three human leukemia cell lines under investigation. Cells were
pre-treated with 5
different concentrations. Compounds 4c and 4e resulted to be toxic
also in HUVEC cells (IC50 <5 M). Sulforaphane induced NQO1
lM sulforaphane and the three compounds at
Mw 368.39; mp 260 °C; dec IR: 3385, 2646, 1713, 1613, 1034. 1H
NMR: 3.50 (2H, s, CH2), 6.77 (1H, dd, ind-6, J = 7.5, J = 1.5), 7.34 (2H,
dd, ar, J = 6.6, J = 2), 7.40 (2H, br, NHSO2+SO3H), 7.45 (1H, d, ind-7,
J = 7.5), 7.46 (1H, d, ind-4, J = 1.5), 7.71 (2H, dd, ar, J = 6.6, J = 2),
10.46 (1H, s, NH). Anal. (C14H12N2O6S2) C, H, N.
l
activity in both normal and leukemia cells. On the other hand com-
pounds 4c, 4e and 4f caused a slight NQO1 activation in HUVEC in a
concentration range up to 5
kemia cells, compound 4f at 0.5
l
M (not shown). Interestingly in leu-
M concentration caused a strong
l
3.1.3. Synthesis of compounds 4a–i, 5, 6 and 15–22
Four different methods were employed according to the substit-
uents in the indole system (Table 1).
activation of NQO1 and behaved as antiproliferative in a dose
dependent manner. Conversely it was less toxic in HUVEC cells
(IC50 >20 lM).
These results suggest that NQO1 activation by compound 4f
may contribute to its antiproliferative effect in some leukemia cells
but they do not support the reported assumption.3
COMPARE analysis did not show any connection between NQO1
expression levels and the pattern of activity in the NCI 60 cell
lines.9,10
3.1.3.1. Method 12 (compounds 4a,b,d–f,i, 5, 6, 16j,k, 17j, 18j,
19j,k, 20j, 21j and 22j). Compound 1 (or 2, 10 mmol) was dis-
solved in methanol and treated with the appropriate aldehyde
(5 mmol) and piperidine (2 mL). The reaction mixture was refluxed
for 3–5 h (according to a TLC test), cooled and, if necessary, concen-
trated at reduced pressure. The yellow to orange precipitate thus
formed was collected by filtration with a yield of 20% for com-
pounds 5, 18j and 22j, 70–80% for compounds 6, 16j,k, 17j, 19k
and 21j, and 40–50% for the others. The compounds were subjected
to biological tests after crystallization from ethanol.
3. Experimental section
3.1. General
Data for 4a. IR: 3232, 1701, 1163, 1117, 764. 1H NMR: 6.89 (2H,
d, ind-7, J = 7.6), 7.00 (2H, t, ind-6, J = 7.6), 7.52 (2H, d, ind-5,
J = 7.6), 7.89 (1H, t, py-4, J = 8), 8.41 (2H, d, py-3+5, J = 8), 8.72
(2H, s, –CH@), 10.79 (2H, broad, NH). Anal. (C23H13I2N3O2) C, H, N.
Data for 4b. IR: 3175, 1716, 1623, 1142, 1086. 1H NMR: 6.26
(2H, td, ind-6, J = 9, J = 2.4), 6.61 (2H, dd, ind-5, J = 9, J = 2.4), 7.69
(2H, s, –CH@), 7.92 (2H, d, py-3+5, J = 7.8), 8.09 (1H, t, py-4,
J = 7.8), 8.20 (2H, dd, ind-7, J = 9, J = 9), 10.81 (2H, broad, NH). Anal.
(C23H13F2N3O2) C, H, N.
The melting points are uncorrected. All the compounds pre-
pared have a purity of at least 95% as determined by combustion
analysis (Table S2). Bakerflex plates (silica gel IB2-F) were used
for TLC: the eluent was petroleum ether/acetone in various propor-
tions. Kieselgel 60 was used for column chromatography; the elu-
ent was
a mixture of petroleum ether/acetone in various
proportions. The IR spectra were recorded in Nujol on a Nicolet
Avatar 320 E.S.P.; mmax is expressed in cmꢀ1. The 1H NMR spectra
were recorded in (CD3)2SO on a Varian Gemini (300 MHz); the
chemical shift (referenced to solvent signal) is expressed in d
(ppm) and J in hertz; abbreviations: ar = aromatic, ind = indole,
py = pyridine, pyr = pyrrole, tio = thiophene.
All the starting indolinones 1, except 6-trifluoromethoxyindo-
lin-2-one (1e) and 4-{[(2-oxo-2,3-dihydro-1H-indol-5-yl)sulfo-
nyl]amino}benzenesulfonic acid (1h), are described in the
literature: 1a,11 1b,12 1c,13 1d,14 1f,15 1g,16 1i,17 1j,18 1k19 and
1l.20
Data for 4d. IR: 3176, 1701, 1271, 1168, 779. 1H NMR: 3.78 (6H,
s, OCH3), 3.92 (6H, s, OCH3), 6.64 (2H, d, ind, J = 9), 6.97 (2H, d, ind,
J = 9), 7.88 (1H, t, py-4, J = 7.4), 8.05 (2H, s, –CH@), 8.65 (2H, d, py-
3+5, J = 7.4), 10.75 (2H, s, NH). Anal. (C27H23N3O6) C, H, N.
Data for 4e. IR: 2919, 1716, 1619, 1143, 794. 1H NMR: 6.30 (2H,
dd, ind-5, J = 8.4, J = 2.4), 6.69 (2H, d, ind-7, J = 2.4), 7.77 (2H, s, –
CH@), 7.97 (2H, d, py-3+5, J = 7.5), 8.13 (1H, t, py-4, J = 7.5), 8.19
(2H, d, ind-4, J = 8.4), 10.82 (2H, s, NH). Anal. (C23H13F6N3O4) C,
H, N.

3010
A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
Data for 4f. IR: 3334, 1696, 1609, 1096, 748. 1H NMR: 5.02 (4H,
lected by filtration and purified by column chromatography with a
s, CH2), 6.52 (2H, t, ind-5/6, J = 7.5), 6.89 (2H, d, ind-4/7, J = 7.5),
7.10 (2H, t, ind-5/6, J = 7.5), 7.31 (10H, m, ar), 7.90 (2H, s, –CH@),
8.10 (2H, d, ind-4/7, J = 7.5), 8.16 (1H, t, py-4, J = 7.8), 8.24 (2H, d,
py-3+5, J = 7.8). Anal. (C37H27N3O2) C, H, N.
yield of 20%.
Data for 4c. IR: 3247, 1706, 1629, 1137, 994. 1H NMR: 3.72 (6H,
s, OCH3), 3.83 (6H, s, OCH3), 3.99 (6H, s, OCH3), 6.29 (2H, s, ind-7),
7.86 (3H, t, py-4+CH@, J = 8), 8.59 (2H, d, py-3+5, J = 8), 10.58 (2H,
s, NH). Anal. (C29H27N3O8) C, H, N.
Data for 4i. IR: 3165, 3052, 1706, 1619, 811. 1H NMR: 7.07 (2H,
d, ar, J = 8.7), 7.55 (6H, m, ar), 7.81 (2H, s, –CH@), 7.94 (2H, m, ar),
8.13 (3H, m, ar), 8.40 (2H, d, ar, J = 8.7), 11.43 (2H, s, NH). Anal.
(C31H19N3O2) C, H, N.
3.1.3.3. Method 32 (compounds 4g,h, 18k and 20l). The appro-
priate aldehyde (10 mmol) was dissolved in acetic acid (50 mL)
and treated with the appropriate indolinone 1 (20 mmol) and
37% hydrochloric acid (1 mL). The reaction mixture was refluxed
for 3–5 h (according to a TLC test) and cooled. The yellow to orange
precipitates thus formed were collected by filtration with a yield of
40%. Compound 4h was isolated as acetate. The compounds were
subjected to biological tests after purification by column chroma-
tography (yield 18–25%).
Data for 5. IR: 3158, 1707, 1619, 1224, 814. 1H NMR: 7.54 (3H,
m, ar), 7.71 (1H, s, –CH@), 7.93 (1H, m, ar), 8.02 (1H, m, ar), 8.19
(3H, m, py), 9.25 (1H, d, ar, J = 8.4), 10.24 (1H, s, CHO), 11.44 (1H,
s, NH). Anal. (C19H12N2O2) C, H, N.
Data for 6. IR: 1787, 1609, 1230, 1076, 738. 1H NMR: 6.71 (2H,
td, ar, J = 8, J = 1.7), 7.20 (2H, dd, ar, J = 8, J = 1.7), 7.27 (2H, td, ar,
J = 8, J = 1.7), 8.00 (2H, s, –CH@), 8.09 (2H, dd, ar, J = 8, J = 1.7),
8.21 (3H, m, py-3,4,5). Anal. (C23H13NO4) C, H, N.
Data for 4g. IR: 3329, 1721, 1609, 1153, 784. 1H NMR: 6.80 (4H,
broad, NH2), 6.87 (2H, d, ind-7, J = 8.2), 7.52 (2H, dd, ind-6, J = 8.2,
J = 1.7), 7.78 (2H, s, –CH@), 7.96 (2H, d, py-3+5, J = 8), 8.12 (1H, t,
py-4, J = 8), 8.71 (2H, d, ind-4, J = 1.7), 10.91 (2H, s, NH). Anal.
(C23H17N5O6S2) C, H, N.
Data for 16j. IR: 3189, 1714, 1203, 1037, 810. 1H NMR: 3.52 (6H,
s, OCH3), 6.78 (2H, d, ind-7, J = 8.8), 6.84 (2H, dd, ind-6, J = 8.8,
J = 1.9), 6.99 (2H, d, ind-4, J = 1.9), 7.67 (2H, s, –CH@), 7.70 (1H, t,
ar, J = 7.8), 7.81 (2H, d, ar, J = 7.8), 7.95 (1H, s, ar), 10.43 (2H, s,
NH). Anal. (C26H20N2O4) C, H, N.
Data for 4h. IR: 3200–2600, 1711, 1603, 1030, 830. 1H NMR:
1.90 (3H, s, CH3COO), 5.00 (5H, br, SO3H+NHSO2+ex), 6.91 (2H, d,
ind-7, J = 8.1), 7.30 (4H, d, ar, J = 8.4), 7.67 (2H, dd, ind-6, J = 8.1,
J = 1.5), 7.70 (4H, d, ar, J = 8.4), 8.11 (2H, d, ind-4, J = 1.5), 8.24
(2H, s, –CH@), 8.56 (2H, d, py-3+5, J = 8), 8.76 (1H, t, py-4, J = 8),
11.48 (2H, s, NH). Anal. (C37H29N5O14S4) C, H, N.
Data for 16k. IR: 3170, 3073, 1716, 1173, 753. 1H NMR: 6.83
(2H, d, ind-7, J = 7.4), 7.04 (2H, d, ind-5, J = 7.4), 7.25 (2H, t, ind-
6, J = 7.4), 7.51 (1H, t, ar, J = 7.2), 8.29 (2H, d, ar, J = 7.2), 8.45 (2H,
s, –CH@), 8.56 (1H, s, ar), 10. 87 (2H, s, NH). Anal. (C24H14Cl2N2O2)
C, H, N.
Data for 17j. IR: 3411, 3176, 1685, 1609, 840. 1H NMR: 3.64 (6H,
s, OCH3), 6.80 (2H, d, ind-7, J = 8.5), 6.87 (2H, dd, ind-6, J = 8.5,
J = 2), 7.17 (2H, d, ind-4, J = 2), 7.66 (2H, s, –CH@), 7.88 (4H, s,
ar), 10.45 (2H, s, NH). Anal. (C26H20N2O4) C, H, N.
Datafor18k. IR:3165, 1690, 1573, 1240, 717. 1HNMR:1.31(9H, s,
C(CH3)3), 6.85 (2H, d, ind-5/7, J = 7.8), 7.03 (2H, d, ind-5/7, J = 7.8),
7.22 (2H, t, ind-6, J = 7.8), 8.39 (2H, s, ar), 8.70 (2H, s, –CH@), 10.00
(1H, s, OH), 10.80 (2H, s, NH). Anal. (C28H22Cl2N2O3) C, H, N.
Data for 20l. IR: 3211, 1701, 1609, 1173, 779. 1H NMR: 2.18 (6H, s,
CH3), 6.74 (2H, dd, ind-6, J = 9, J = 4.6), 6.80 (2H, dd, ind-4, J = 9,
J = 2.7), 6.90 (2H, dt, ind-5, J = 9, J = 2.7), 7.39 (2H, s, –CH@), 10.40
(2H, s, NH-ind), 11.86 (1H, s, NH-pyr). Anal. (C24H17F2N3O2) C, H, N.
Data for 18j. IR: 3600–3100, 1701, 1619, 1209, 723. 1H NMR:
1.31 (9H, s, C(CH3)3), 3.58 (6H, s, OCH3), 6.79 (2H, d, ind-7,
J = 8.5), 6.85 (2H, dd, ind-6, J = 8.5, J = 2.5), 6.99 (2H, d, ind-4,
J = 2.5), 7.71 (2H, s, ar), 7.72 (2H, s, –CH@), 9.87 (1H, s, OH),
10.40 (2H, s, NH). Anal. (C30H28N2O5) C, H, N.
Data for 19j. IR: 3160, 1712, 1209, 1035, 851. 1H NMR: 3.35 (6H,
s, OCH3), 6.50 (2H, d, ind-7, J = 8.4), 6.54 (2H, dd, ind-6, J = 8.4,
J = 2.4), 7.82 (2H, s, –CH@), 8.07 (2H, s, ar), 8.20 (2H, d, ar,
J = 8.4), 8.61 (2H, d, ar, J = 8.4), 8.99 (2H, d, ind-4, J = 2.4), 10.29
(2H, s, NH). Anal. (C32H22N4O4) C, H, N.
3.1.3.4. Method 4 (compound 15j). Benzene-1,2-dicarbaldehyde
7 (10 mmol) was dissolved in toluene (5 mL) and treated with
the indolinone 1j (20 mmol) in the presence of 4-toluenesulfonic
acid (0.5 mmol). The reaction mixture was refluxed for 3–6 h
(according to a TLC test) and after cooling the solvent was removed
under reduced pressure. The residue was crystallized from ethanol
with a yield of 30%.
Data for 19k. IR: 3170, 1706, 1235, 1163, 758. 1H NMR: 6.86
(2H, d, ind-5/7, J = 7.8), 7.08 (2H, d, ind-5/7, J = 7.8), 7.30 (2H, t,
ind-6, J = 7.8), 8.06 (2H, s, –CH@), 8.50 (2H, d, ar, J = 8.5), 8.61
(2H, s, ar), 8.66 (2H, d, ar, J = 8.5), 10.95 (2H, s, NH). Anal.
(C30H16Cl2N4O2) C, H, N.
Data for 15j. IR: 3500–3100, 1716, 1697, 1204. 1H NMR: 3.51
(6H, s, OCH3), 6.65 (2H, d, ind-4, J = 2.4), 6.73 (2H, d, ind-7,
J = 8.6), 6.79 (2H, dd, ind-6, J = 8.6, J = 2.4), 7.62 (2H, s, –CH@),
7.66 (2H, m, ar), 7.78 (2H, m, ar), 10.42 (2H, s, NH). Anal.
(C26H20N2O4) C, H, N.
Data for 20j. IR: 3237, 1686, 1614, 1199, 1030. 1H NMR: 2.15
(6H, s, CH3), 3.46 (6H, s, OCH3), 6.69 (6H, m, ind), 7.36 (2H, s, –
CH@), 10.19 (2H, s, NH-ind), 11.68 (1H, s, NH-pyr). Anal.
(C26H23N3O4) C, H, N.
3.2. Biology
Data for 21j. IR: 3200, 1711, 1593, 1153, 723. 1H NMR: 3.77 (6H,
s, OCH3), 6.79 (4H, m, ind-4+7), 7.42 (2H, dd, ind-6, J = 11.8, J = 2.2), 7.84 (1H, d,
tio, J = 4.6), 7.90 (1H, d, tio, J = 4.6), 8.21 (2H, s, –CH@), 10.45 (2H, s,
NH). Anal. (C24H18N2O4S) C, H, N.
3.2.1. In vitro growth inhibition and cytotoxicity
The screening is a two-stage process,25 beginning with the eval-
uation of all compounds against the 60 cell lines at a single concen-
tration of 10ꢀ5 M. Compounds which exhibit significant growth
inhibition are evaluated against the 60 cell panel at five concentra-
tion levels by the NCI according to standard procedures (http://
dtp.nci.nih.gov/branches/btb/ivclsp.html).
Data for 22j. IR: 3334, 1690, 1593, 1045, 815. 1H NMR: 3.52 (3H,
s, OCH3), 3.75 (3H, s, OCH3), 3.90 (6H, s, OCH3), 6.77 (2H, s, ar), 7.29
(2H, m, ar), 7.37 (2H, dd, ind-6, J = 5, J = 1.8), 7.59 (2H, d, ind-7,
J = 5), 7.74 (2H, s, –CH@), 8.80 (2H, d, ind-4, J = 1.8), 9.35 (2H,
broad, OH), 10.31 (2H, s, NH). Anal. (C34H28N2O8) C, H, N.
3.2.2. Methodology of acute toxicity and hollow fiber assay
3.1.3.2. Method 2 (compound 4c). Pyridine-2,6-dicarbaldehyde 3
(15 mmol) was treated with 30 mmol of the indolinone 1c,
30 mmol of anhydrous sodium acetate and 130 mL of acetic acid.
The reaction mixture was refluxed for 3–6 h (according to a TLC
test), acetic acid was removed under reduced pressure and the res-
idue was treated with ice water. The resulting precipitate was col-
See Supplementary data.
3.2.3. Compare
COMPARE analyses26 were performed using publically available
programs at the Developmental Therapeutics Program website
(http://dtp.nci.nih.gov).

A. Andreani et al. / Bioorg. Med. Chem. 18 (2010) 3004–3011
3011
Rambaldi, M.; Varoli, L.; Calonghi, N.; Cappadone, C.; Voltattorni, M.;
Zini, M.; Stefanelli, C.; Masotti, L.; Shoemaker, R. H. J. Med. Chem. 2008,
51, 7508.
3.2.4. NQO1 activity and MTT cell proliferation assays
NQO1 activity was determined essentially as described in the
literature.8 In brief, cells were pretreated for 24–48 h with com-
pound dissolved in DMSO (<0.1% final concentration), plated in
96-well plates and incubated for 20 min with a solution containing
0.8% digitonin and 2 mM EDTA (pH 7.8) prior to adding the reac-
tion mixture (0.025 mM Tris–HCl, 0.67 mg/mL bovin serum albu-
2. Andreani, A.; Burnelli, S.; Granaiola, M.; Leoni, A.; Locatelli, A.; Morigi, R.;
Rambaldi, M.; Varoli, L.; Landi, L.; Prata, C.; Berridge, M. V.; Grasso, C.;
Fiebig, H.-H.; Kelter, G.; Burger, A. M.; Kunkel, M. W. J. Med. Chem. 2008,
51, 4563.
3. Zhang, W.; Go, M.-L. Bioorg. Med. Chem. 2009, 17, 2077.
4. Andreani, A.; Rambaldi, M.; Leoni, A.; Locatelli, A.; Bossa, R.;
Chiericozzi, M.; Dambrosio, M.; Galatulas, I. Eur. J. Med. Chem. 1993,
28, 653.
5. Andreani, A.; Leoni, A.; Locatelli, A.; Morigi, R.; Chiericozzi, M.; Fraccari, A.;
Galatulas, I. Anticancer Res. 1998, 18, 3407.
6. Hollingshead, M.; Alley, M. C.; Camalier, R. F.; Abbott, B. J.; Mayo, J. G.;
Malspeis, L.; Grever, M. R. Life Sci. 1995, 57, 131.
7. Fahey, J. W.; Talalay, P. Food Chem. Toxicol. 1999, 37, 973.
8. Prochaska, H. J.; Santamaria, A. B. Anal. Biochem. 1988, 169, 328.
9. Kelland, L. R.; Sharp, S. Y.; Rogers, P. M.; Myers, T. G.; Workman, P. J. Natl. Cancer
Inst. 1999, 91, 1940.
10. Tudor, G.; Alley, M.; Nelson, C. M.; Huang, R.; Covell, D. G.; Gutierrez, P.;
Sausville, E. A. Anti-Cancer Drugs 2005, 16, 381.
11. Hardegger, H.; Corrodi, H. Helv. Chim. Acta 1956, 39, 514.
12. Clark, R. D.; Muchowski, J. M.; Fisher, L. E.; Flippin, L. A.; Repke, D. B.; Souchet,
M. Synthesis 1991, 10, 871.
min, 0.01% Tween-20, 5
30
M NADP+, 2 U/mL yeast glucose 6-phosphate dehydrogenase,
0.3 mg/mL MTT, 50 M menadione). The reaction was arrested
lM FAD, 1 mM glucose 6-phosphate,
l
l
after 5 min by the addition of a stop solution (0.3 mM dicumarol
in 0.5% DMSO and 5 mM potassium phosphate, pH 7.4) and the
blue color generated by the reaction was measured at 595 nm in
a multiwell plate reader (Wallac Victor2, Perkin–Elmer). Absor-
bance values were normalized on protein concentration. MTT
reduction was measured following incubation of cells with each
compound for 24–48 h.
Acknowledgement
13. Sakai, S.; Aimi, N.; Kubo, A.; Kitagawa, M.; Hanasawa, M.; Katano, K.;
Yamaguchi, K.; Haginiwa, J. Chem. Pharm. Bull. 1975, 23, 2805.
14. Mehta, L. K.; Parrick, J.; Payne, F. J. Chem. Res. (S) 1998, 190.
15. Crestini, C.; Saladino, R. Synth. Commun. 1994, 24, 2835.
16. Lai, J. Y. Q.; Cox, P. J.; Patel, R.; Sadiq, S.; Aldous, D. J.; Thurairatnam,
S.; Smith, K.; Wheeler, D.; Jagpal, S.; Parveen, S.; Fenton, G.; Harrison, T.
K. P.; McCarthy, C.; Bamborough, P. Bioorg. Med. Chem. Lett. 2003, 13,
3111.
We are grateful to the National Cancer Institute (Bethesda, MD)
for the anticancer tests.
Supplementary data
17. Mayer, F.; Oppenheimer, T. Chem. Ber. 1918, 51, 1239.
18. Koelsch, C. F. J. Am. Chem. Soc. 1944, 66, 2019.
19. Romeo, A.; Corrodi, H.; Hardegger, E. Helv. Chim. Acta 1955, 38, 463.
20. Zakrzewska, A.; Kolehmainen, E.; Osmialowski, B.; Gawinecki, R. J. Fluorine
Chem. 2001, 111, 1.
21. Angeloff, A.; Daran, J.-C.; Bernadou, J.; Meunier, B. Eur. J. Inorg. Chem. 2000, 9,
1985.
22. Ghigi, E.; Drusiani, A. Atti Accad. Sci, Ist. Bologna, Classe Sci. Fis. 1957, 11, 14;
Chem. Abstr. 1958, 11818a.
23. Lackey, K.; Besterman, J. M.; Fletcher, W.; Leitner, P.; Morton, B.; Sternbach, D.
D. J. Med. Chem. 1995, 38, 906.
24. Barlaam, B.; Bird, T. G.; Lambert-van der Brempt, C.; Campbell, D.; Foster, S. J.;
Maciewicz, R. J. Med. Chem. 1999, 42, 4890.
Synthesis of the compounds not reported here. NSC numbers
(Table S1), analytical data (elemental analyses) Table S2, LC50 ma-
trix COMPARE results (Table S3), LC50 matrix COMPARE results for
the most closely related compounds (Table S4), methodology of
acute toxicity, methodology of the Hollow Fiber Assay, effect of sul-
foraphane and compounds 4c, 4e and 4f on NQO1 activity in M07e
leukemia cell line (Fig. S1). Supplementary data associated with
this article can be found, in the online version, at doi:10.1016/
j.bmc.2010.03.063.
25. Monks, A.; Scudiero, D.; Skehan, P.; Shoemaker, R.; Paull, K.; Vistica, D.; Hose,
C.; Langley, J.; Cronise, P.; Vaigro-Wolff, A., et al J. Natl. Cancer Inst. 1991, 83,
757.
References and notes
26. Paull, K. D.; Shoemaker, R. H.; Hodes, L.; Monks, A.; Scudiero, D. A.;
Rubinstein, L.; Plowman, J.; Boyd, M. R. J. Natl. Cancer Inst. 1989, 81,
1088.
1. Potential antitumor agents. 45. For part 44, see the following: Andreani,
A.; Burnelli, S.; Granaiola, M.; Leoni, A.; Locatelli, A.; Morigi, R.;