Nucleophilic substitutions in the isoindole series as a valuable tool to synthesize derivatives with antitumor activity

Article abstract of DOI:10.1016/j.tet.2011.01.056

A novel synthetic approach to the synthesis of 3-substituted isoindoles through nucleophilic substitution of 3-halo derivatives by charged carbon, and neutral nitrogen, oxygen, and sulfur nucleophiles, assisted by a 1-acyl group, is reported. Aryl-thio-isoindoles, obtained through a direct nucleophilic substitution with sulfur nucleophiles, showed cytotoxic activity, with GI ₅₀ values from micromolar to sub-micromolar concentrations, against the total number of cell lines investigated.

Full text of DOI:10.1016/j.tet.2011.01.056

Tetrahedron 67 (2011) 2072e2080
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Nucleophilic substitutions in the isoindole series as a valuable tool to synthesize
derivatives with antitumor activity
*
Patrizia Diana , Annamaria Martorana, Paola Barraja, Alessandra Montalbano, Anna Carbone,
Girolamo Cirrincione
ꢀ
Dipartimento Scienze e Tecnologie Molecolari e Biomolecolari - Sezione Chimica Farmaceutica e Biologica, Universita degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
A novel synthetic approach to the synthesis of 3-substituted isoindoles through nucleophilic substitution
of 3-halo derivatives by charged carbon, and neutral nitrogen, oxygen, and sulfur nucleophiles, assisted
by a 1-acyl group, is reported. Aryl-thio-isoindoles, obtained through a direct nucleophilic substitution
with sulfur nucleophiles, showed cytotoxic activity, with GI50 values from micromolar to sub-micromolar
concentrations, against the total number of cell lines investigated.
Received 3 November 2010
Received in revised form 31 December 2010
Accepted 18 January 2011
Available online 25 January 2011
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
Isoindoles
Nucleophilic substitutions
Antitumor activity
Docking
Colchicine analogues
1. Introduction
We have reported direct aromatic nucleophilic substitutions on
halogenated pyrroles4 and more recently on indoles;5 such re-
Isoindoles appeared late on the chemical scene. Early attempts
to prepare isoindole or its simple derivatives were unsuccessful and
these compounds did not become known until 1951 when Wittig
obtained 2-methylisoindole.1 Isoindoles are very unstable and
easily undergo autoxidation and self-condensation reactions.
However, N-substituted isoindoles are generally more stable than
N-unsubstituted compounds.
The chemistry of isoindoles is characterized by their strong
tendency to undergo ready electrophilic substitution at the five-
membered ring, due to their high p-electron density, preferentially
actions proved to be good methods to functionalize these
cessive heterocycles.
p-ex-
Thus, considering our interest in the isoindole system, and
hoping to get a useful tool to introduce a variety of functional
groups into the isoindole moiety, we decided to perform nucleo-
philic substitutions on 3-haloisoindoles, bearing suitable sub-
stituents on position 1, and, if possible, to compare their reactivity
with those of the pyrrole and indole ring systems.
This study was further encouraged by the interesting antitumor
activity of several compounds containing the isoindole moiety,6e11
and by the potent antiproliferative activity of arylthioindoles.12
In this paper we describe the reactivity of 3-halo-2H-isoindoles
toward charged carbon, and neutral nitrogen, oxygen, and sulfur
nucleophiles. We also report the antitumor activity of arylth-
ioisoindoles obtained through a direct nucleophilic substitution
with sulfur nucleophiles.
at the C-1 (C-3) position.1 On the contrary, very few examples of
nucleophilic reactions in the isoindole series have been reported.
In fact, direct nucleophilic substitution in the isoindole series
involved replacement of an ethoxy group, bound to the position 1 of
an isoindolenine structure, by primary aromatic amines, hetero-
cyclic amines, benzylamines, hydrazines, and hydroxylamines.2 The
sole example of halogen replacement from an isoindole system was
observed, only very recently, in the case of the reaction of 1,1,3-
trichloro-1H-isoindole with hydrazines to give 1,3-disubstituted
1H-isoindoles.3
2. Results and discussions
2.1. Chemistry
We selected 3-halo-2H-isoindoles 5e8 as substrates to perform
nucleophilic substitutions. Such compounds were synthesized
according to the synthesis reported for derivatives 5 and 7.13 Thus,
* Corresponding author. Tel.: þ39 091 23896815; fax: þ39 091 23860854; e-mail
address: diana@unipa.it (P. Diana).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.01.056

P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
2073
treatment of phthalimidine 1 with 2 M equivalents of the Vilsmeier
reagent, obtained by reaction of POX3 (X¼Cl, Br) with dime-
thylformamide (DMF) or dimethylacetamide (DMA), gave the iso-
indolenine derivatives 2e4 (55e91%) as shown Scheme 1.
Instead, from the reaction of 3-bromo-1-carboxaldehyde-iso-
indole 7 and amines it was possible to isolate the direct nucleo-
philic substitution products 21e25 (Method B) in excellent yields
(80e100%).
1-Acetyl-3-chloro-2-methyl-isoindole 8 provided the nucleo-
philic substitution product 28, in moderate yield (41%), only when
the nucleophile pyrrolidine was used as a solvent (Method D).
Reaction of 3-halo-isoindoles 5 and 7 with 4-methoxyphenol
furnished the 1-carboxaldehyde-3-(4-methoxyphenoxy)-2H-iso-
indole 29 in poor yields, 8% (Method A) and 15% (Method C), re-
spectively. The same direct nucleophilic product was obtained from
the same halo-isoindoles, under microwave irradiation (Method C),
in 35 and 42% yields, respectively.
O
X
1) POX 3/DCM;
2) DMF or DMA
NH
N
CH3
CH3
C
N
R
1
2 R=H, X=Cl
3 R=CH3, X=Cl
4 R=H, X=Br
Nucleophilic reactions of 3-halo-isoindoles 5 and 7 with charged
nucleophiles (malononitrile and ethyl cyanoacetate salts and NaCN),
in DMF as a solvent (Method A), did not provide the nucleophilic
substitution products probably because of the poor solubility of the
nucleophiles in the reaction solvent. Instead 1-acetyl-3-chloro-2-
methyl-isoindole 8 furnished the substitution product 33, in good
yield (70%) when NaCN was used as nucleophile. When substrates 5
and 7 were reacted with malononitrile and ethyl cyanoacetate salts
in ethanol (Method B), the substitution products 30 and 31 were
obtained in 40e51% yields. The same reactions carried out under
microwave irradiation (Method C) gave compounds 30 and 31 with
mixed results. In the attempt to improve the yields of these com-
pounds, and considering that in the indole series the best results in
the nucleophilic substitution reactions were obtained under phase
transfer catalysis, substrate 5 was reacted by heating at 60 ꢀC
a mixture of an excess of the above mentioned nucleophile and 18-
crown-6 as phase transfer catalyst (Method E). This method gave
derivatives 30 and 31 in lower yields (15%).
NaOH/EtOH
X
Cl
NCH3
CH3I/K2CO3
Acetone
NH
R=CH3, X=Cl
C R
C
O
CH3
O
8
5 R=H, X=Cl
6 R=CH3, X=Cl
7 R=H, X=Br
Scheme 1. Synthesis of 3-halo-2H-isoindoles 5e8.
Basic hydrolysis of the latter furnished the isoindoles 5e7 in good
yields (74e86%). 1-Acetyl-3-chloro-2H-isoindole 6 was converted
into the corresponding N-methyl derivative 8 using potassium car-
bonate and methyl iodide in anhydrous acetone (50%) (Scheme 1).
Our first attempts at nucleophilic reactions, were carried out by
heating under reflux a mixture of halo-isoindoles in DMF, an excess
of the nucleophile and, in the case of arylthioles, phenols, and
amines, a stoichiometric amount of triethylamine (TEA) in order to
neutralize the halogenidric acid formed (Method A).
Thus, under such conditions, 3-chloro-isoindoles 5 and 6 reac-
ted with arylthioles to afford compounds 9e16 in good yields
(52e80%). When the same sulfur nucleophiles were reacted with 3-
bromo-isoindole 7, the corresponding direct substitution products
9e12 were obtained in poor yields (10e25%). Instead, surprisingly,
the N-substituted 3-chloro-isoindole 8 did not provide the nucle-
ophilic substitution products (Scheme 2 and Table 1).
When 3-halo-isoindoles 7 and 8 were reacted with sulfur nu-
cleophiles, using ethanol as solvent and a stoichiometric amount of
TEA (Method B), the direct nucleophilic substitution products 9e12
and 17e20, respectively, were obtained in good to excellent yields
(57e99%).
Moreover, 1-carboxaldehyde-3-halo-isoindoles 5 and 7 reacted
with an excess of arylthioles and a stoichiometric amount of TEA
under microwave irradiation (Method C) to afford compounds
9e12 in higher yield (65e85%) in a much shorter time (5 min).
Surprisingly, when 1-acetyl-3-chloro-isoindole 6 was reacted un-
der the same reaction conditions (Method C), derivatives 13e16
were obtained in lower yields (30e37%) (Table 1).
Reaction of 1-acetyl-2-methyl-3-chloro-isoindole 8 with malo-
nonitrile gave the substitution product 32 in moderate yields (30%)
(Method B). The yield of this compound did not improve by using
methods C (20%) and E (16%).
Thus, as in the case of pyrroles and indoles, isoindoles can also
be functionalized through nucleophilic replacement of halogens
assisted by a 1-acyl group. However, although some reactions did
not fulfill these expectations, probably due to the instability of the
products under the reaction conditions, it is possible to outline
some reactivity features of the isoindole system. Chloro derivatives
reacted well in an aprotic dipolar solvent (DMF), whereas the
bromo derivatives gave best results in ethanol, a highly solvating
solvent. In contrast with the pyrrole series, in which nucleophilic
substitutions take place only on the N-methyl derivatives, iso-
indoles resemble the indoles in which N-unsubstituted derivatives
are more reactive than the corresponding N-methyl compounds. In
contrast to halo-indoles, which did not react with charged carbon
nucleophiles, replacement of halogen by cyanide and methylene
active compounds was observed in isoindole series.
2.2. Anticancer activity
The potent antitumor activity showed by arylthioindoles en-
couraged us to evaluate the aryl-thio-isoindoles 9e20 for such
a biological property. Arylthioindoles are potent tubulin assembly
inhibitors and bind the colchicine site. They show antitumor ac-
tivity comparable with those of colchicines and combretastatin
A-4.12
All of the isolated aryl-thio-isoindoles 9e20 were submitted to
the National Cancer Institute (Bethesda MD) and five of them (9,10,
13, 14, and 17) were pre-screened, at one dose concentration
(10ꢁ5 M), in a panel of approximately 60 tumor cell lines that have
grouped in disease sub-panels including leukemia, non-small-cell
lung, colon, central nervous system, melanoma, ovarian, renal,
prostate, and breast tumors cell lines.
Reaction of 1-carboxaldehyde-3-chloro-isoindole
5
with
substituted amines (Method A), gave compounds 21e25 in good
yields (50e70%). Conduction of the reaction under microwave ir-
radiation did not lead to any improvement providing the sub-
stitution products 21e25 in 55e71% (Method C). Whereas when
ethanol was used as solvent (Method B), only products 21 and 22
were isolated (89 and 64% yields, respectively).
1-Acetyl-3-chloro-isoindole 6 only reacted with benzylamine
and pyrrolidine in ethanol, (Method B), to give the nucleophilic
substitution products 26 and 27, respectively, in low yields (9e33%).

2074
P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
OC6H4-4-OCH3
NH
NR2R3
NR1
SAr
NR1
C H
ArNHR2R3
C R
O
C
O
R
ArSH
O
29
9
R=R1=H, Ar=C6H5
21 R=R1=R2=H, R3=CH2-C6H4-4-OCH3
22 R=R1=R2=H, R3=CH2-C6H4-4-CH3
23 R=R1=R2=H, R3=CH2-C6H5
24 R=R1=H, R2=CH3, R3=CH2-C6H5
25 R=R1=H, R2-R3=(CH2)4
10 R=R1=H, Ar=C6H4-4-OCH3
11 R=R1=H, Ar=C6H4-4-CH3
12 R=R1=H, Ar=C6H4-3-OCH3
13 R=CH3, R1=H; Ar=C6H5
4-OCH3-C6H4OH
X
14 R=CH3, R1=H; Ar=C6H4-4-OCH3
15 R=CH3, R1=H; Ar=C6H4-4-CH3
16 R=CH3, R1=H; Ar=C6H4-3-OCH3
17 R=R1=CH3, Ar=C6H5
18 R=R1=CH3, Ar=C6H4-4-OCH3
19 R=R1=CH3, Ar=C6H4-4-CH3
20 R=R1=CH3, Ar=C6H4-3-OCH3
26 R=CH3, R1=R2=H, R3=CH2-C6H5
27 R=CH3, R1=H, R2-R3=(CH2)4
28 R=R1=CH3, R2-R3=(CH2)4
NR1
C R
O
5 R=R1=H, X=Cl; 6 R=CH3, R1= H, X=Cl
7 R=R1=H, X=Br; 8 R=R1=CH3, X=Cl
CNCH2CO2Et
NaCN
CNCH2CN
CH(CN)CO2Et
NH
CN
CH(CN)2
NR1
NCH3
C H
O
C
O
CH3
C R
O
33
31
30 R=R1=H;
32 R=R1=CH3
Scheme 2. Reactivity of 1-halo-2H-isoindoles 5e8 toward charged carbon, and neutral nitrogen, oxygen, and sulfur nucleophiles.
Compounds 10 and 14 were further selected for full evaluation
at five concentration levels (10ꢁ4e10ꢁ8 M).
the treatment of human diseases.14,15 Most of the antimitotic drugs
in clinical use bind at the three major binding sites of tubulin: the
vinca, taxane, and colchicine sites.16 Combretastatin A-4 (CA-4)
strongly inhibits the tubulin assembly by binding to the colchicines
site and prevents tubulin polymerization.17
The antitumor activity of compounds was given by three pa-
rameters for each cell line; pGI50 value (GI50 is the molar concen-
tration of the compound that inhibits 50% net cell growth), pTGI
value (TGI is the molar concentration of the compound leading to
total inhibition of net cell growth), and pLC50 value (LC50 is the
molar concentration of the compound that induces 50% net cell
death). An evaluation of the data reported in the Tables 2 and 3
revealed that compounds 10,14 were cytotoxic showing GI50
values against the total number of cell lines investigated from mi-
cromolar to sub-micromolar concentrations.
Moreover, positive TGI (98e100%) and LC50 (63e75%) values
were observed with respect to a good number of cell lines. In par-
ticular aryl-thio-isoindoles 10,14 were selective with respect to the
colon, renal, and leukemia sub-panels.
The most sensitive cell lines resulted COLO 205 (pGI50 6.76 and
6.18, respectively) of colon cancer sub-panel, A498 (pGI50 6.58 and
5.46, respectively) of renal cancer sub-panel, and SR (pGI50 5.87
and 5.78, respectively) of leukemia sub-panel (Table 3). Derivative 10
also showed selectivity with respect to MOLT-4, (pGI50 5.88) of leu-
kemia sub-panel, and MDA-MB-468 (pGI50 5.85) ofbreastcancer sub-
panel (Table 3).
Docking studies were performed to investigate the binding
ability of the aryl-thio-isoindoles to the colchicines binding site.
Isoindole 14 was docked inside the colchicine binding site of
tubulin (PBD code 1SA0),18 using GLIDE software XP mode default
parameters.19 To validate the use of GLIDE, the docking studies
were performed on the reference compounds DAMAecolchicine
and combretastatin A-4 (CA-4). Such studies showed that com-
pound 14 overlaps well with the CA-4 in the crystallized protein
complex. Derivative 14 established hydrogen bond between the C-3
acetyl moiety of isoindole ring and Ser 178, the C-4 methoxy group
of phenyl ring is in close proximity to Cys 241, a key residue for the
binding and biological activity of many colchicine analogues.13
Hydrophobic contacts (Ala 180, Leu 255 and Leu 248) stabilize
the binding of the isoindole 14 to the protein (Figs. 1 and 2).
It is our intention to carry out biological studies in order to verify
if the aryl-thio-isoindoles act as antimitotic agents.
3. Experimental section
3.1. General
2.3. Docking
€
Microtubules are a component of the mitotic spindle, and they
are essential for many cellular processes. Compounds that are able
to interfere with the microtubule equilibrium in cells are useful in
All melting points were taken on a BuchieTottoli capillary ap-
paratus and are uncorrected; IR spectra were determined in bro-
moformwith a JascoFT/IR 5300 spectrophotometer;1Hand 13CNMR

P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
2075
Table 1
Direct nucleophilic substitution products of 1-substituted-3-halo-isoindoles
Table 3
Inhibition of in vitro cancer cell lines by compounds 10 and 14a
a
Substrate
Nucleophile
Product
Method (%Yield)
Cell line
pGI50
A
B
C
D
E
10
14
5
7
5
7
5
7
5
7
6
6
6
6
8
8
8
8
5
7
5
7
5
7
5
7
5
7
6
6
8
5
7
5
7
5
7
8
8
HSeC6H5
HSeC6H5
9
9
52
10
73
19
63
25
60
13
53
72
72
80
0
0
0
0
60
0
60
0
53
0
50
0
70
0
d
66
d
57
d
75
d
67
d
d
d
d
99
70
98
80
89
100
64
98
0
96
0
80
0
99
9
33
0
d
15
40
51
40
40
30
d
81
85
80
70
65
82
75
78
30
31
37
36
d
d
d
d
66
d
55
d
50
d
51
d
71
d
d
d
0
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
41
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
d
15
d
15
d
16
d
Leukemia
CCRF-CEM
HL-60(TB)
K-562
MOLT-4
RPMI-8226
SR
5.25
5.29
5.67
5.88
5.15
5.78
4.84
4.82
5.58
HSeC6H4-4eOMe
HSeC6H4-4eOMe
HSeC6H4-4eMe
HSeC6H4-4eMe
HSeC6H4-3eOMe
HSeC6H4-3eOMe
HSeC6H5
HSeC6H4-4eOMe
HSeC6H4-4eMe
HSeC6H4-3eOMe
HSeC6H5
HSeC6H4-4eOMe
HSeC6H4-4eMe
HSeC6H4-3eOMe
H2NeCH2eC6H4-4-OMe
H2NeCH2eC6H4e4-OMe
H2NeCH2eC6H4-4eMe
H2NeCH2eC6H4-4eMe
H2NeCH2eC6H5
H2NeCH2eC6H5
H2Ne(CH3)eCH2eC6H5
H2Ne(CH3)eCH2eC6H5
Pyrrolidine
10
10
11
11
12
12
13
14
15
16
17
18
19
20
21
21
22
22
23
23
24
24
25
25
26
27
28
29
29
30
30
31
31
32
33
4.96
5.87
Non-small cell lung cancer
A549/ATCC
EKVX
HOP-62
HOP-92
NCI-H226
NCI-H23
NCI-322M
NCI-H460
NCI-H522
4.88
5.26
4.81
5.26
5.58
4.85
5.09
5.53
4.85
5.40
5.09
4.90
5.62
5.25
4.83
4.88
5.13
4.99
Colon cancer
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
6.18
5.26
4.90
4.94
5.40
5.44
5.43
6.76
4.92
4.92
4.94
4.81
5.19
4.90
Pyrrolidine
H2NeCH2eC6H5
Pyrrolidine
0
0
0
8
0
0
0
0
Pyrrolidine
CNC cancer
SF-268
SF-295
SF-539
SNB-19
SNB-75
U251
HOeC6H4-4eOMe
HOeC6H4-4eOMe
CNeCH2eCN
35
42
70
40
20
30
28
d
4.83
5.04
4.96
5.32
4.92
4.91
4.89
4.94
4.84
4.94
4.97
4.92
CNeCH2eCN
CNeCH2eCO2Et
CNeCH2eCO2Et
CNeCH2eCN
0
0
70
NaCN
Melanoma
LOX IMVI
MALME-3M
M14
MDA-MB-435
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
Methods: A (Nu/DMF and TEA in the cases of thiols, 4-methoxyphenol and amines,
reflux, 0.5e2 h), B (Nu/EtOH and TEA in the cases of thiols, 4-methoxyphenol and
amines, 50 ꢀC, 6e23 h), C (Nu/DMF and TEA in the cases of thiols, 4-methoxyphenol
and amines, 150 W, 150 ꢀC, 5 min), D (Nu, reflux, 30 h), E (Nu/KOH/18-crown-6
ether/CH3CN, 60 ꢀC, 8e10 h).
4.91
4.85
4.91
5.57
4.87
4.82
4.89
4.70
4.96
4.93
4.75
4.93
5.56
4.89
4.87
4.90
4.82
4.99
Table 2
Overview of the results of the in vitro antitumor screening for compounds 10 and 14a
10
No.e
Nf
Range
MG_MIDg
b
Ovarian cancer
IGROV1
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
NCI/ADR-RES
SK-OV-3
pGI50
60
60
60
60
59
38
4.65e6.18
4.08e5.22
4.01e4.57
5.13
4.58
4.15
pTGIc
pLC50
4.86
4.93
4.65
5.22
4.85
4.94
5.30
4.93
4.91
4.88
4.76
4.78
4.93
5.75
d
14
No.
60
60
60
N
Range
MG_MID
5.08
4.60
pGI50
pTGI
pLC50
60
60
45
4.75e6.76
4.27e6.40
4.01e6.04
4.18
a
Data obtained from the NCI’s in vitro disease-oriented human tumor cells
Renal cancer
786e0
A498
screen.
b
c
d
e
f
4.92
5.46
4.83
4.78
4.97
4.83
4.97
5.29
4.78
6.58
4.78
5.54
4.87
4.96
4.82
5.23
pGI50 is the ꢁlog of the molar concentration that inhibits 50% net cell growth.
pTGI is the ꢁlog of the molar concentration giving total growth inhibition.
pLC50 is the ꢁlog of the molar concentration leading to 50% net cell death.
No. is the number of the cell lines investigated.
ACHN
CAKI-1
RXF 393
SN12C
TK-10
UO-31
N is the number of cell lines giving positive pGI50, pTGI, and pLC50
.
g
MG_MID¼mean graph midpoint¼arithmetical mean value for all tested cancer
cell lines. If the indicated effect was not attainable within the used concentration
interval, the highest tested concentration was used for the calculation.
Prostate cancer
PC-3
DU-145
spectra were measured at 200 and 50.3 MHz, respectively, in DMSO-
d6 or CDCl3 solution, using a Bruker Avance II series 200 MHz
spectrometer (TMS as internal reference). Column chromatography
was performed with Merck silica gel 230e400 mesh ASTM or with
4.88
5.20
4.95
4.80
Breast cancer
MCF7
4.89
4.91
€
Buchi Sepacore chromatography module (prepacked cartridge sys-
(continued on next page)
tem). Elemental analyses (C, H, N) were performed with a VARIO EL

2076
P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
Table 3 (continued )
3.1.1. 2,3-Dihydro-1H-isoindol-1-one (1). This compound was pre-
a
pared from phthalimide according to the procedure of von Dobe-
Cell line
pGI50
neck et al.13 Yield 80%. Mp 150e151 ꢀC (lit. mp 148e150 ꢀC).
10
14
MDA-MB-231/ATCC
HS 578T
BT-549
T-47D
MDA-MB-468
4.87
5.19
5.69
5.04
5.85
4.94
4.96
5.50
5.08
5.41
3.1.2. 1-(3-Halo-1H-isoindol-1-ylidene)-N,N-dialkylmethan
amine
(2e4). A solution of POCl3 or POBr3 (30 mmol) in anhydrous DCM
(7 mL) was added dropwise to DMF or DMA (30 mmol) in anhy-
drous DCM (15 mL) at 0 ꢀC. The mixture was stirred for 30 min at
room temperature. Then, a solution of 1H-isoindolinone 1 (2 g,
15 mmol) in anhydrous DCM (75 mL) was added to the mixture, at
a
Data obtained from the NCI’s in vitro disease-oriented human tumor cells
screen.
0
ꢀC. Subsequently, the reaction mixture was heated at reflux for
5 h, and then after cooling, the solvent was removed at reduced
pressure. Ice-water was added, and the mixture was neutralized
with NaOH 5 M. The precipitate was filtered out, washed with
water and dried. The residue was recrystallized from MeOH/H2O
(1:1) to give the following compounds.
3.1.3. 1-(3-Chloro-1H-isoindol-1-ylidene)-N,N-dimethyl methanam
ine (2). Yield (2.29 g, 74%) as cream solid, mp 108e110 ꢀC. IR: 1635
(CN) cmꢁ1. 1H NMR CDCl3:
d
3.46 (br s, 6H, 2ꢂCH3), 7.15 (s, 1H, CH),
7.23 (t, J¼8.2 Hz, 1H, H-5), 7.29 (t, J¼8.2 Hz, 1H, H-6), 7.56 (d,
J¼8.2 Hz, 1H, H-4), 7.61 (d, J¼8.2 Hz, 1H, H-7). 13C NMR CDCl3:
d 41.2
(q) 46.7 (q), 116.0 (d), 119.6 (d), 122.2 (s), 122.9 (d), 126.0 (d), 129.9
(s), 138.7(d), 140.9 (s), 142.9 (s). Anal. Calcd for C11H11ClN2: C, 65.93;
H, 5.36; N, 13.55. Found: C, 65.76; H, 5.60; N, 13.49.
3.1.4. 1-(3-Chloro-1H-isoindol-1-ylidene)-N,N-dimethyl ethanamine
(3). Yield (1.82 g, 55%) as cream solid, mp 110e112 ꢀC. IR: 1566 (CN)
cmꢁ1. 1H NMR DMSO-d6:
d
2.69 (s, 3H, CH3), 3.49 (br s, 6H, 2ꢂCH3),
7.15 (t, J¼8.0 Hz,1H, H-5), 7.29 (t, J¼8.0 Hz,1H, H-6), 7.51 (d, J¼8.0 Hz,
1H, H-4), 7.83 (d, J¼8.0 Hz, 1H, H-7). 13C NMR DMSO-d6:
d 19.4 (q),
44.1 (qꢂ2),113.7 (s),118.6 (d),120.4 (d),121.4 (d),122.5 (s),125.2 (d),
129.2 (s), 137.5 (s), 156.4 (s). Anal. Calcd for C12H13ClN2: C, 65.31; H,
5.94; N, 10.52. Found: C, 65.22; H, 6.03; N 10.27.
Fig. 1. The structure of 14 (green) and DAMAecolchicine (purple) docked into the
colchicines binding site of tubulin.
3.1.5. 1-(3-Bromo-1H-isoindol-1-ylidene)-N,N-dimethyl methanam
ine (4). Yield (3.43 g, 91%) as cream solid, mp 136e137 ꢀC. IR: 1635
(CN)cmꢁ1.1HNMR DMSO-d6:
d 3.35 (s, 3H,CH3), 3.63(s, 3H,CH3), 7.17
(t, J¼7.8 Hz,1H, H-5), 7.30 (t, J¼7.8 Hz,1H, H-6), 7.44 (d, J¼7.8 Hz,1H,
H-4), 7.86 (d, J¼7.8 Hz, 1H, H-7), 7.93 (s, 1H, CH). 13C NMR DMSO-d6:
d
40.1 (q), 46.2 (q) 116.6 (d), 119.0 (d), 122.3 (d), 122.9 (s), 125.3 (d),
128.8 (s), 130.6 (s), 140.2 (s), 141.6 (d). Anal. Calcd for C11H11BrN2: C,
52.61; H, 4.42; N, 11.16. Found: C, 52.44; H, 4.71; N, 11.01.
3.2. General procedure for the preparation of 1-substituted-
3-halo-2H-isoindoles (5e7)
A solution of proper 3-halo-isoindolylidene 2e4 (5 mmol),
NaOH (4 M, 5 mL), and ethanol (65 mL) was heated at reflux for 3 h.
After cooling, the solvent was evaporated at reduced pressure and
the reaction residue was neutralized with HCl (3 M). The resulting
precipitated was filtered off, washed with water, and dried over
P2O5. The crude residue was recrystallized from MeOH/H2O (1:3) to
give the following compounds.
3.2.1. 1-Carboxaldehyde-3-chloro-2H-isoindole (5). Yield (0.77 g,
86%) as white solid, mp 126e127 ꢀC. IR: 3436 (NH), 1606 (CO) cmꢁ1
.
1H NMR DMSO-d6:
H-6), 7.65 (d, J¼7.7 Hz, 1H, H-4), 8.13 (d, J¼7.7 Hz, 1H, H-7), 9.82 (br
s,1H, CHO),14.30 (br s,1H, NH). 13C NMR DMSO-d6:
118.3 (s), 118.9
d
7.25 (t, J¼7.7 Hz, 1H, H-5), 7.41 (t, J¼7.7 Hz, 1H,
Fig. 2. The structure of 14 (green) and CA-4 (purple) docked into the colchicines
binding site of tubulin.
d
(s), 119.0 (dꢂ2), 121.2 (s), 122.4 (s), 123.6 (d), 127.3 (d), 174.1 (d).
Anal. Calcd for C9H6ClNO: C, 60.19; H, 3.37; N, 7.80. Found: C, 60.48;
H, 3.13; N, 7.62.
III elemental analyzers. Microwave experiments were carried out
using a CEM Discover LabmateTM microwave apparatus.
Elemental analyses were within 0.4% of the theoretical values
and were performed with a VARIO EL III elemental analyzer.
3.2.2. 1-Acetyl-3-chloro-2H-isoindole (6). Yield (0.72 g, 74%) as
white solid, mp 159e160 ꢀC. IR: 3320 (NH),1624 (CO) cmꢁ1. 1H NMR

P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
2077
DMSO-d6:
J¼8.7 Hz, 1H, H-6), 7.61 (d, J¼8.7 Hz, 1H, H-4), 8.07 (d, J¼8.7 Hz, 1H,
H-7), 13.90 (br s, 1H, NH). 13C NMR DMSO-d6:
118.8 (d), 120.5 (s), 120.6 (d), 122.0 (s), 122.7 (d), 126.7 (d), 184.2 (s).
Anal. Calcd for C10H8ClNO: C, 62.03; H, 4.16; N, 7.23. Found: C,
62.38; H, 4.31; N, 7.41.
d
2.57 (s, 3H, CH3) 7.18 (t, J¼8.7 Hz, 1H, H-5), 7.35 (t,
KOH (6 mmol) and dibenzo 18-crown-6 ether (0.09 g, 0.3 mmol)
and stirred at room temperature for 30 min. The proper 1-
substituted-3-halo-isoindoles 5,8 was added (10 mmol), and the
reaction mixture was heated at 60 ꢀC for 8e10 h 1 M hydrochloric
acid was added and the solid was filtered off, dried, and purified by
chromatography column.
d
27.5 (q), 113.8 (sꢂ2)
3.2.3. 3-Bromo-1-carboxaldehyde-2H-isoindole (7). Yield (0.94 ꢁg1,
3.3.1. 1-Carboxaldehyde-3-(phenylsulfanyl)-2H-isoindole (9). Chro
matographic column (9:1 DCM/ethylacetate). From 1-carbox-
84%) as white solid, mp 110e111 ꢀC. IR: 3077 (NH), 1600 (CO) cm
.
1H NMR DMSO-d6:
H-6), 7.57 (d, J¼7.8 Hz, 1H, H-4), 8.13 (d, J¼7.8 Hz, 1H, H-7), 9.82 (br
s, 1H, CHO),13.77 (br s, 1H, NH). 13C NMR DMSO-d6:
118.1 (s), 118.6
d
7.25 (t, J¼7.8 Hz, 1H, H-5), 7.39 (t, J¼7.8 Hz, 1H,
aldehyde-3-chloro-2H-isoindole 5 cream crystals, yield 52%
(Method A: reflux for 30 min), 81% (Method C: 150 W; 150 ꢀC;
5 min); from 3-bromo-1-carboxaldehyde-2H-isoindole 7 cream
crystals, yield 10% (Method A: reflux for 30 min), 66% (Method B:
50 ꢀC for 20 h), 85% (Method C: 150 W; 150 ꢀC; 5 min). Mp
d
(s), 119.0 (s), 119.7 (d), 123.6 (dꢂ2), 125.1 (s), 127.0 (d), 174.3 (d).
Anal. Calcd for C9H6BrNO: C, 48.25; H, 2.70; N, 6.25. Found: C,
48.55; H, 2.43; N, 6.01.
145e147 ꢀC. IR: 3379 (NH), 1632 (CO) cmꢁ1 1H NMR DMSO-d6:
.
d
7.15e7.34 (m, 6H, H-5, C6H5) 7.40 (t, J¼7.9 Hz, 1H, H-6), 7.67 (d,
J¼7.9 Hz, 1H, H-4), 8.21 (d, J¼7.9 Hz, 1H, H-7), 9.97 (s, 1H, CHO),
14.40 (br s, 1H, NH). 13C NMR DMSO-d6:
118.4 (s), 119.8 (d), 124.1
(d), 124.7 (s), 126.5 (d), 126.6 (d), 127.6 (dꢂ2), 129.0 (s), 129.2 (dꢂ3),
135.7 (s), 143.8 (s), 176.7 (d). Anal. Calcd for C15H11NOS: C, 71.12; H,
4.38; N, 5.53. Found: C, 71.42; H, 4.27; N, 5.19.
3.2.4. 1-Acetyl-3-chloro-2-methyl-2H-isoindole (8). A solution of 1-
acetyl-3-chloro-2H-isoindole 6 (1.16 g, 6 mmol) in anhydrous ace-
tone (30 mL) was treated with finely powdered anhydrous K2CO3
(1.12 g, 8.16 mmol). The resulting suspension was stirred vigorously
for 4 h under nitrogen atmosphere. Iodomethane (1.02 mL,
16.32 mmol) was then added, and stirring was continued for 16 h.
The suspension was filtered off and the crude solid washed with
acetone (3ꢂ10 mL). The filtrate was evaporated to a solid residue
that was stirred in 25 mL of H2O. The solid was collected by fil-
tration, dried over P2O5, and purified by column chromatography,
eluting with dichloromethane, to give the title compound 8 (0.62 g,
50%) as white solid.
d
3.3.2. 1-Carboxaldehyde-3-[(4-methoxyphenyl)sulfanyl]-2H-iso-
indole (10). Chromatographic column (8:2 DCM/ethylacetate).
From 1-carboxaldehyde-3-chloro-2H-isoindole 5 cream needles,
yield 73% (Method A: reflux for 30 min), 80% (Method C: 150 W;
150 ꢀC; 5 min); from 3-bromo-1-carboxaldehyde-2H-isoindole 7
cream needles, yield 19% (Method A: reflux for 30 min), 57%
(Method B: 50 ꢀC for 16 h), 70% (Method C: 150ꢁW1 ; 150 ꢀC; 5 min).
Mp 93e94 ꢀC. IR: 1622 (CO) cmꢁ1. 1H NMR CDCl3:
d 2.69 (s, 3H,
CH3), 4.24 (s, 3H, CH3), 7.14 (t, J¼8.7 Hz,1H, H-5), 7.32 (t, J¼8.7 Hz,1H,
Mp 154e156 ꢀC. IR: 3436 (NH), 1610 (CO) cm 1H NMR CDCl3:
.
H-6), 7.61 (d, J¼8.7 Hz, 1H, H-4), 7.81 (d, J¼8.7 Hz,1H, H-7). 13C NMR
d
3.72 (s, 3H, CH3) 6.79 (d, J¼8.7 Hz, 2H, H-30, H-50), 7.20 (t, J¼7.4 Hz,
CDCl3:
d
30.6 (q), 35.5 (q),119.3 (d),119.8 (d),120.5 (s),120.8 (s),121.7
1H, H-5), 7.26 (t, J¼7.4 Hz, 1H, H-6), 7.35 (d, J¼8.7 z, H-20, 2H, H-60),
(s),122.3 (d),127.0 (d),128.2 (s),185.6 (s). Anal. Calcd for C11H10ClNO:
C, 63.52; H, 4.85; N, 6.75. Found: C, 63.39; H, 5.06; N, 6.52.
7.40 (d, J¼7.4 Hz, 1H, H-4), 7.72 (d, J¼7.4 Hz, 1H, H-7), 7.90e7.94 (br
s, 1H, NH), 9.70 (s, 1H, CHO). 13C NMR CDCl3:
d 55.4 (q), 115.2 (s),
115.3 (dꢂ2), 117.5 (s), 117.6 (d), 119.0 (s), 121.1 (d), 123.9 (d), 125.2
(s), 127.9 (dꢂ2), 132.7 (s), 133.6 (d), 160.1 (s), 172.4 (d). Anal. Calcd
for C16H13NO2S: C, 67.82; H, 4.62; N, 4.94. Found: C, 68.08; H, 4.79;
N, 4.70.
3.3. General procedure for the preparation of 3-substituted
isoindoles (9e33)
Method A: To a solution of 1-substituted-3-halo-isoindoles 5e8
(3 mmol) in anhydrous DMF (20 mL), TEA (0.42 mL, 3 mmol), and
the proper nucleophile (6 mmol) were added. The reaction mixture
was heated under reflux (0.5e2 h), and then after cooling, poured
into ice-water. The resulting precipitate was collected by filtration,
dried, and purified by chromatography column.
Method B: To a solution of 1-substituted-3-halo-isoindoles 7,8
(3 mmol) in anhydrous ethanol (30 mL), TEA (0.42 mL, 3 mmol),
and the proper nucleophile (6 mmol) were added. The reaction
mixture was heated at 50 ꢀC (6e23 h). After cooling, the solvent
was evaporated and the solid residue was stirred in water (25 mL).
The resulting precipitate was filtered, dried and purified by chro-
matography column.
3.3.3. 1-Carboxaldehyde-3-[(4-methylphenyl)sulfanyl]-2H-isoindole
(11). Chromatographic column (9:1 DCM/ethylacetate). From 1-
carboxaldehyde-3-chloro-2H-isoindole 5 cream needles, yield 63%
(Method A: reflux for 30 min), 65% (Method C: 150 W; 150 ꢀC;
5 min); from 3-bromo-1-carboxaldehyde-2H-isoindole 7 cream
needles, yield 25% (Method A: reflux for 30 min), 75% (Method B:
50 ꢀC for 18 h), 82% (Method C: 150 W; 150 ꢀC; 5 min). Mp
174e175 ꢀC. IR: 3386 (NH), 1653 (CO) cmꢁ1 1H NMR DMSO-d6:
.
d
2.22 (s, 3H, CH3), 7.12 (br s, 4H, C6H4), 7.23 (t, J¼8.0 Hz, 1H, H-5),
7.38 (t, J¼8.0 Hz, 1H, H-6), 7.65 (d, J¼8.0 Hz, 1H, H-4), 8.18 (d,
J¼8.0 Hz, 1H, H-7), 9.93 (s, 1H, CHO) 14.41 (br s, 1H, NH). 13C NMR
DMSO-d6: d 20.4 (q),119.7 (s), 119.8 (d),123.9 (d), 124.3 (s),124.4 (s),
Method C: To a solution of 1-substituted-3-chloro-isoindoles 5,6
(3 mmol) in anhydrous DMF (20 mL), TEA (0.42 mL, 3 mmol), and
the proper nucleophile (6 mmol) were added. The reaction mixture
was heated by microwave irradiation using a Discovery Cem Re-
actor (150 W; 150 ꢀC; 5 min), and then after cooling, poured into
ice-water. The resulting precipitate was collected by filtration,
dried, and purified by chromatography column.
Method D: A solution of 1-acetyl3-chloro-2-methyl-isoindole 8
(3 mmol) was heated under reflux for 24 h with an excess of pyr-
rolidine (30 mmol). The reaction mixture was heated at 50 ꢀC
(30 h). After cooling, the solvent was evaporated and the solid
residue was stirred in water (25 mL). The resulting precipitate was
filtered, dried and purified by chromatography column.
126.5 (d), 128.4 (dꢂ2), 128.9 (s), 129.9 (d), 130.0 (dꢂ2), 131.7 (s),
136.5 (s), 176.5 (d). Anal. Calcd for C16H13NOS: C, 71.88; H, 4.90; N,
5.24. Found: C, 71.60; H, 4.87; N, 5.52.
3.3.4. 1-Carboxaldehyde-3-[(3-methoxyphenyl)sulfanyl]-2H-iso-
indole (12). Chromatographic column (DCM). From 1-carbox-
aldehyde-3-chloro-2H-isoindole
5 cream crystals, yield 60%
(Method A: reflux for 45 min), 75% (Method C: 150 W; 150 ꢀC;
5 min); from 3-bromo-1-carboxaldehyde-2H-isoindole 7 cream
crystals, yield 13% (Method A: reflux for 30 min), 67% (Method B:
50 ꢀC for 20 h), 78% (Method C: 150 W; 150 ꢀC; 5 min). Mp
144e145 ꢀC. IR: 3387 (NH), 1629 (CO) cmꢁ1 1H NMR DMSO-d6:
.
d
3.69 (s, 3H, CH3), 6.65 (d, J¼8.1 Hz,1H, H-40), 6.74 (s,1H, H-20), 6.79
Method E: A solution of the proper nucleophile (6 mmol) in
anhydrous acetonitrile (20 mL) was treated with finely powdered
(d, J¼8.1 Hz, 1H, H-60), 7.11 (t, J¼8.1 Hz, 1H, H-50), 7.29 (t, J¼8.1 Hz,
1H, H-5), 7.40 (t, J¼8.1 Hz 1H, H-6), 7.68 (d, J¼8.1 Hz, 1H, H-4), 8.20

2078
P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
(d, J¼8.1 Hz, 1H, H-7), 9.96 (br s, 1H, CHO), 14.30 (br s, 1H, NH). 13
C
129.3 (dꢂ2), 129.8 (s), 135.9 (s), 187.0 (s). Anal. Calcd for C17H15NOS:
NMR DMSO-d6:
d
55.1 (q), 112.0 (d), 113.1 (d), 119.5 (d), 119.7 (d),
C, 72.57; H, 5.37; N, 4.98. Found: C, 72.80; H, 5.27; N, 4.66.
124.1 (d), 124.7 (sꢂ2), 126.5 (d), 129.2 (s), 130.3 (dꢂ2), 137.0 (sꢂ2),
159.7 (s), 176.7 (d). Anal. Calcd for C16H13NO2S: C, 67.82; H, 4.62; N,
4.94. Found: C, 67.54; H, 4.49; N, 5.10.
3.3.10. 1-Acetyl-3-[(4-methoxyphenyl)sulfanyl]-2-methyl-2H-iso-
indole (18). Chromatographic column (DCM). Cream needles, yield
70% (Method B: 50 ꢀC for 20 h). Mp 85e86 ꢀC. IR: 1626 (CO) cmꢁ1
.
3.3.5. 1-Acetyl-3-(phenylsulfanyl)-2H-isoindole (13). Chromatograp
hic column (98:2 DCM/ethylacetate). Cream crystals, yield 53%
(Method A: reflux for 1 h), 30% (Method C: 150 W; 150 ꢀC; 5 min).
Mp 145e147 ꢀC. IR: 3382 (NH), 1724 (CO) cmꢁ1. 1H NMR DMSO-d6:
1H NMR CDCl3:
d 2.76 (s, 3H, CH3), 3.73 (s, 3H, CH3), 4.31 (s, 3H,
CH3), 6.74 (d, 2H, J¼8.7 Hz, H-30, H-50), 7.04 (d, J¼8.7 Hz, 2H, H-20, H-
60), 7.20 (t, J¼7.7 Hz, 1H, H-5), 7.35 (t, J¼7.7 Hz, 1H, H-6), 7.87 (d,
J¼7.7 Hz, 1H, H-4), 7.91 (d, J¼7.7 Hz, 1H, H-7). 13C NMR CDCl3:
d 30.9
d
2.63 (s, 3H, CH3), 7.10 (d, J¼7.8 Hz, 2H, H-20, H-60) 7.20e7.34 (m,
(q), 36.2 (q), 55.4 (q),115.1 (d), 118.2 (s), 120.0 (dꢂ2),120.9 (d),123.0
(d), 125.8 (s), 126.4 (dꢂ2), 128.3 (s), 129.5 (s), 130.1 (d), 148.5 (s),
159.8 (s), 194.2 (s). Anal. Calcd for C18H17NO2S: C, 69.43; H, 5.50; N,
4.50. Found: C, 69.18; H, 5.55; N, 4.63.
4H, H-5, H-30, H-50, H40), 7.34 (t, J¼8.8 Hz, 1H, H-6), 7.64 (d,
J¼8.8 Hz, 1H, H-4), 8.19 (d, J¼8.8 Hz, 1H, H-7), 13.93 (br s, 1H, NH).
13C NMR DMSO-d6:
d 27.6 (q), 114.9 (s), 119.6 (d), 121.2 (d), 123.4 (d),
124.2 (s), 126.0 (d), 126.1 (d), 126.2 (s), 126.9 (dꢂ2), 129.3 (dꢂ2),
129.4 (s), 136.5 (s), 185.8 (s). Anal. Calcd for C16H13NOS: C, 71.88; H,
4.90; N, 5.24. Found: C, 72.11; H, 4.79; N, 4.98.
3.3.11. 1-Acetyl-2-methyl-3-[(4-methylphenyl)sulfanyl]-2H-isoindole
(19). Chromatographic column (DCM). Cream crystals, yield 98%
(Method B: 50 ꢀC for 18 h). Mp 107e108 ꢀC. IR: 1624 (CO) cmꢁ1. 1H
3.3.6. 1-Acetyl-3-[(4-methoxyphenyl)sulfanyl]-2H-isoindole
(14). Chromatographic column (DCM). Cream crystals, yield 72%
(Method A: reflux for 1 h), 31% (Method C: 150 W; 150 ꢀC; 5 min).
Mp 112e114 ꢀC. IR: 3403 (NH), 1701 (CO) cmꢁ1. 1H NMR DMSO-d6:
NMR CDCl3: d 2.26 (s, 3H, CH3), 2.78 (s, 3H, CH3), 4.30 (s, 3H, CH3),
6.88e7.03 (m, 4H, H-20, H-30, H-50, H-60), 7.20 (t, J¼8.4 Hz, 1H, H-5),
7.36 (t, J¼8.4 Hz, 1H, H-6), 7.85 (d, J¼8.4 Hz, 1H, H-4), 7.93 (d,
J¼8.4 Hz,1H, H-7). 13C NMR CDCl3:
d 20.9 (q), 31.0 (q), 36.1 (q),120.0
d
2.60 (s, 3H, CH3), 3.69 (s, 3H, CH3) 6.87 (d, J¼8.8 Hz, 2H, H-30, H-50)
(d), 120.8 (d), 123.0 (d), 123.2 (s), 124.6 (s), 126.4 (d), 127.4 (dꢂ2),
128.2 (s), 130.1 (dꢂ2), 133.9 (s), 136.5 (s), 138.8 (s), 187.0 (s). Anal.
Calcd for C18H17NOS: C, 73.19; H, 5.80; N, 4.74. Found: C, 73.34; H,
5.77; N, 4.56.
7.17 (t, J¼7.9 Hz, 1H, H-5), 7.27 (d, J¼8.8 Hz, 2H, H-20, H-60), 7.31 (t,
J¼7.9 Hz, 1H, H-6), 7.69 (d, J¼7.9 Hz, 1H, H-4), 8.14 (d, J¼7.9 Hz, 1H,
H-7) 13.82 (br s, 1H, NH). 13C NMR DMSO-d6:
d 27.6 (q), 55.0 (q),
115.0 (dꢂ2), 117.6 (s), 119.8 (d), 121.0 (d), 123.1 (d), 123.6 (s), 125.9
(s), 126.0 (d), 127.0 (s), 128.8 (s), 130.9 (dꢂ2), 158.6 (s), 185.8 (s).
Anal. Calcd for C17H15NO2S: C, 68.66; H, 5.08; N, 4.71. Found: C,
68.93; H, 5.21; N, 4.39.
3.3.12. 1-Acetyl-3-[(3-methoxyphenyl)sulfanyl]-2-methyl-2H-iso-
indole (20). Chromatographic column (DCM). Cream solid, yield
80% (Method B: 50 ꢀC for 20 h). Mp 84e85 ꢀC. IR: 1626 (CO) cmꢁ1
.
1H NMR CDCl3:
d 2.75 (s, 3H, CH3), 3.66 (s, 3H, CH3), 4.27 (s, 3H,
3.3.7. 1-Acetyl-3-[(4-methylphenyl)sulfanyl]-2H-isoindole
(15). Chromatographic column (DCM). Cream crystals, yield 72%
(Method A: reflux for 1 h), 37% (Method C: 150 W; 150 ꢀC; 5 min).
CH3), 6.46e6.50 (m, 2H, H-20, H-40), 6.64 (d, J¼7.8 Hz, 1H, H-60), 7.07
(t, J¼8.0 Hz, 1H, H-5), 7.17 (t, J¼8.0 Hz, 1H, H-6), 7.33 (t, J¼7.8 Hz, 1H,
H-50), 7.80 (d, J¼8.0 Hz, 1H, H-4), 7.90 (d, J¼8.0 Hz, 1H, H-7). 13C
Mp 129e131 ꢀC. IR: 3382 (NH), 1655 (CO) cmꢁ1
.
1H NMR DMSO-
NMR CDCl3: d 31.0 (q), 36.0 (q), 55.2 (q),111.5 (d),112.6 (d), 118.9 (d),
d6:
d
2.21 (s, 3H, CH3), 2.62 (s, 3H, CH3), 7.07e7.12 (m, 4H, C6H4),
120.0 (d), 120.6 (d), 121.5 (s), 123.1 (d), 124.7 (s), 126.3 (d), 128.1 (s),
128.9 (s), 130.1 (d), 137.2 (s), 160.1 (s), 187.0 (s). Anal. Calcd for
C18H17NO2S: C, 69.43; H, 5.50; N, 4.50. Found: C, 69.71; H, 5.45; N,
4.22.
7.18 (t, J¼8.5 Hz, 1H, H-5), 7.34 (t, J¼8.5 Hz, 1H, H-6), 7.65 (d,
J¼8.5 Hz, 1H, H-4), 8.19 (d, J¼8.5 Hz, 1H, H-7), 13.89 (br s, 1H, NH).
13C NMR DMSO-d6:
d 20.4 (q), 27.6 (q), 117.0 (s), 119.7 (d), 121.1
(d), 123.3 (d), 124.0 (s), 126.0 (d), 127.1 (s), 127.8 (dꢂ2), 129.2 (s),
129.9 (dꢂ2), 132.7 (s), 136.0 (s), 185.7 (s). Anal. Calcd for
C17H15NOS: C, 72.57; H, 5.37; N, 4.98. Found: C, 72.41; H, 5.61; N,
5.23.
3.3.13. 1-Carboxaldehyde-3-[(4-methoxybenzyl)amino]-2H-isoindole
(21). Chromatographic column (DCM). From 1-carboxaldehyde-3-
chloro-2H-isoindole 5 brown solid, yield 60% (Method A: reflux for
1 h), 89% (Method B: 50 ꢀC for 9 h), 66% (Method C: 150 W; 150 ꢀC;
5 min); from 3-bromo-1-carboxaldehyde-2H-isoindole 7 brown
solid,100% (Method B: 50 ꢀC for 9 h). Mp 140e141 ꢀC. IR: 3376 (NH),
3.3.8. 1-Acetyl-3-[(3-methoxyphenyl)sulfanyl]-2H-isoindole
(16). Chromatographic column (DCM). Cream crystals, yield 80%
(Method A: reflux for 1.5 h), 36% (Method C: 150 W; 150 ꢀC;
3190 (NH), 1650 (CO) cmꢁ1. 1H NMR DMSO-d6:
d 3.73 (s, 3H, CH3),
5 min). Mp 102e105 ꢀC. IR: 3380 (NH), 1645 (CO) cmꢁ1
.
1H NMR
4.50 (s, 2H, CH2), 6.93 (d, J¼8.4 Hz, 2H, H-30, H-50), 7.13 (t, J¼6.9 Hz,
1H, H-5), 7.26 (t, J¼6.9 Hz, 1H, H-6), 7.31 (d, J¼8.4 Hz, 2H, H-20, H-
60), 7.49 (d, J¼6.9 Hz, 1H, H-4), 7.78 (d, J¼6.9 Hz, 1H, H-7), 8.00 (s,
1H, NH), 8.07 (s, 1H, CHO), 9.16 (s, 1H, NH). 13C NMR DMSO-d6:
DMSO-d6:
d
2.63 (s, 3H, CH3), 3.68 (s, 3H, CH3), 6.63 (d, J¼8.3 Hz,
1H, H-40), 6.70 (s, 1H, H-20), 6.75 (d, J¼8.3 Hz, 1H, H-60), 7.15e7.24
(m, 2H, H-50, H-5), 7.35 (t, J¼8.3 Hz, 1H, H-6), 7.66 (d, J¼8.3 Hz,
1H, H-4), 8.20 (d, J¼8.3 Hz, 1H, H-7), 13.93 (br s, 1H, NH). 13C NMR
d
51.7 (t), 55.0 (q), 113.8 (dꢂ2), 116.7 (d), 118.7 (d), 121.8 (s), 122.6
DMSO-d6:
d
27.6 (q), 55.1 (q), 111.6 (d), 112.8 (d), 114.8 (s), 119.1
(d), 125.9 (d), 128.8 (dꢂ2), 129.2 (s), 129.5 (s), 130.9 (s), 138.7 (s),
142.6 (d), 157.1 (s). Anal. Calcd for C17H16N2O2: C, 72.84; H, 5.75; N,
9.99. Found: C, 72.51; H, 5.88; N, 10.06.
(d), 119.6 (d), 121.2 (d), 123.5 (d), 124.3 (s), 126.0 (d), 127.0 (s),
129.5 (s), 130.2 (d), 137.9 (s), 159.7 (s), 185.9 (s). Anal. Calcd for
C17H15NO2S: C, 68.66; H, 5.08; N, 4.71. Found: C, 68.93; H, 5.18; N,
4.37.
3.3.14. 1-Carboxaldehyde-3-[(4-methylbenzyl)amino]-2H-isoindole
(22). Chromatographic column (DCM). From 1-carboxaldehyde-3-
chloro-2H-isoindole 5 brown solid, yield 60% (Method A: reflux for
1.5 h), 64% (Method B: 50 ꢀC for 10 h), 55% (Method C: 150 W;
150 ꢀC; 5 min); from 3-bromo-1-carboxaldehyde-2H-isoindole 7
brown solid, 98% (Method B: 50 ꢀC for 10 h). Mp 67e69 ꢀC. IR: 3376
3.3.9. 1-Acetyl-2-methyl-3-(phenylsulfanyl)-2H-isoindole
(17). Chromatographic column (DCM). Cream solid, yield 99%
(Method B: 50 ꢀC for 18 h). Mp 95e96 ꢀC. IR: 1626 (CO) cmꢁ1. 1H
NMR CDCl3:
d
2.74 (s, 3H, CH3), 4.26 (s, 3H, CH3), 6.92 (d, J¼6.8 Hz,
2H, H-20, H-60), 7.08e7.20 (m, 4H, H-5, H-30, H-40, H-50), 7.32 (t,
J¼8.7 Hz, 1H, H-6), 7.80 (d, J¼8.7 Hz, 1H, H-4), 7.89 (d, J¼8.7 Hz, 1H,
(NH), 3189 (NH), 1650 (CO) cmꢁ1. 1H NMR DMSO-d6:
d 2.28 (s, 3H,
CH3), 4.50 (s, 2H, CH2), 7.11e7.30 (m, 6H, H-5, H-6, H-20, H-30, H-50,
H-60), 7.42 (d, J¼7.4 Hz, 1H, H-4), 7.78 (d, J¼7.4 Hz, 1H, H-7), 8.03 (s,
1H, NH), 8.10 (s, 1H, CHO), 9.33 (br s, 1H, NH). 13C NMR DMSO-d6:
H-7). 13C NMR CDCl3:
d 31.0 (q), 36.0 (q), 120.0 (d), 120.7 (d), 121.8
(s), 123.1 (d), 124.6 (s), 126.2 (d), 126.3 (d), 126.7 (dꢂ2), 128.1 (s),

P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
2079
d
20.7 (q), 51.3 (t), 116.7 (d), 119.4 (d), 122.3 (d), 123.9 (s), 126.0 (d),
H-7) 14.4 (br s, 1H, NH). 13C NMR DMSO-d6:
d
19.9 (q), 23.8 (t), 25.6
127.4 (dꢂ2), 127.9 (s), 129.1 (dꢂ2), 131.9 (s), 135.9 (s), 136.5 (s), 138.5
(s), 143.0 (d). Anal. Calcd for C17H16N2O: C, 77.25; H, 6.10; N, 10.60.
Found: C, 77.49; H, 6.13; N, 10.31.
(t), 51.1 (t), 54.5 (t), 89.5 (s), 107.5 (s), 118.6 (d), 120.2 (s), 120.3 (d),
121.4 (d), 125.1 (d), 129.2 (s), 153.5 (s). Anal. Calcd for C14H16N2O: C,
73.66; H, 7.06; N, 12.27. Found: C, 73.44; H, 7.16; N, 12.50.
3.3.15. 3-(Benzylamino)-1-carboxaldehyde-2H-isoindole (23). Chro
matographic column (DCM). From 1-carboxaldehyde-3-chloro-2H-
isoindole 5 brown solid, yield 53% (Method A: reflux for 1.5 h), 50%
(Method C: 150 W; 150 ꢀC; 5 min); from 3-bromo-1-carbox-
aldehyde-2H-isoindole 7 brown solid, 96% (Method B: 50 ꢀC for
18 h). Mp 111e112 ꢀC. IR: 3377 (NH), 3195 (NH), 1650 (CO) cmꢁ1. 1H
3.3.20. 1-Acetyl-1-methyl-3-pyrrolidin-1-yl-2H-isoindole (28). Chro
matographic column (95:5 DCM/ethylacetate). Cream solid, yield
41% (Method D: reflux for 30 h). Mp 75e78 ꢀC. IR: 1685 (CO) cmꢁ1
.
1H NMR CDCl3:
d 1.26 (s, 3H, CH3) 1.74e1.81 (m, 4H, CH2), 2.54e2.66
(m, 2H, CH2), 2.72e2.89 (m, 2H, CH2), 3.13 (s, 3H, CH3), 7.45 (t,
J¼6.5 Hz, 1H, H-5), 7.47e7.55 (m, 2H, H-6, H-4), 7.81 (d, J¼6.5 Hz,
NMR DMSO-d6:
d
4.57 (d, J¼4.8 Hz, 2H, CH2), 7.14 (t, J¼7.3 Hz,1H, H-
1H, H-7). 13C NMR CDCl3:
123.2 (d), 123.3 (d), 128.8 (d), 130.9 (s), 131.2 (d), 132.9 (s), 133.9 (s),
143.1 (s), 167.7 (s). Anal. Calcd for C15H18N2O: C, 74.35; H, 7.49; N,
11.56. Found: C, 74.54; H, 7.52; N, 11.35.
d
24.3 (tꢂ2), 29.7 (q), 46.8 (tꢂ2), 76.5 (q),
5), 7.24e7.39 (m, 6H, C6H5, H-6), 7.50 (d, J¼7.3 Hz, 1H, H-4), 7.79 (d,
J¼7.3 Hz,1H, H-7), 8.03 (s,1H, NH), 8.10 (s,1H, CHO), 9.35 (t, J¼4.8 Hz,
1H, NH). 13C NMR DMSO-d6:
d 51.4 (t), 116.8 (d), 118.7 (d), 121.9 (s),
122.3 (d), 126.0 (d), 127.2 (d), 127.4 (dꢂ2), 128.5 (dꢂ2), 129.6 (s),
138.7 (s), 139.0 (s), 139.6 (s), 142.8 (d). Anal. Calcd for C16H14N2O: C,
76.78; H, 5.64; N, 11.19. Found: C, 76.92; H, 5.69; N, 10.97.
3.3.21. 1-Carboxaldehyde-3-(4-methoxyphenoxy)-2H-isoindole
(29). Chromatographic column (98:2 DCM/ethylacetate). From 1-
carboxaldehyde-3-chloro-2H-isoindole 5 white solid, yield 8%
(Method A: reflux for 10 h), 35% (Method C: 150 W; 150 ꢀC; 5 min);
from 3-bromo-1-carboxaldehyde-2H-isoindole 7 white solid, 15%
(Method B: 50 ꢀC for 16 h). Mp 133e135 ꢀC. IR: 3415 (NH),1644 (CO)
3.3.16. 3-[Benzyl(methyl)amino]-1-carboxaldehyde-2H-isoindole
(24). Chromatographic column (DCM). From 1-carboxaldehyde-3-
chloro-2H-isoindole 5 brown solid, yield 50% (Method A: reflux for
1.5 h), 51% (Method C: 150 W; 150 ꢀC; 5 min); from 3-bromo-1-car-
boxaldehyde-2H-isoindole 7 brown solid, 80% (Method B: 50 ꢀC for
23 h). Mp 105e106 ꢀC. IR: 3376 (NH),1633 (CO) cmꢁ1.1H NMR DMSO-
cmꢁ1. 1H NMR DMSO-d6:
d
3.33 (s, 3H, CH3), 7.56 (t, J¼7.8 Hz, 1H, H-
5), 7.64 (t, J¼7.8 Hz, 1H, H-6), 7.74 (d, J¼7.8 Hz, 2H, H-30, H-50), 7.86
(d, J¼7.8 Hz, 2H, H-20, H-60), 7.90 (br s, 1H, CHO), 8.63 (d, J¼7.8 Hz,
1H, H-4), 8.93 (d, J¼7.8 Hz, 1H, H-7), 11.31 (br s, 1H, NH). 13C NMR
d6:
d
3.62 (s, 3H, CH3), 4.79 (s, 2H, CH2), 7.20 (t, J¼7.6 Hz,1H, H-5), 7.34
(t, J¼7.6 Hz,1H, H-6), 7.35e7.40 (m, 5H, C6H5), 7.54 (d, J¼7.6 Hz,1H, H-
DMSO-d6: d 40.6 (q), 120.3 (s), 120.7 (d), 123.3 (d), 123.4 (d), 124.2
4), 7.96 (d, J¼7.6 Hz,1H, H-7), 8.03 (br s,1H, NH), 8.24 (s,1H, CHO).13C
(s), 127.9 (dꢂ2), 128.3 (d), 129.4 (s), 129.7 (dꢂ2), 130.1 (s), 131.3 (d),
133.2 (d), 136.4 (s), 136.7 (s), 169.6 (d). Anal. Calcd for C16H13NO3: C,
71.90; H, 4.90; N, 5.24. Found: C, 71.69; H, 4.83; N, 5.48.
NMR DMSO-d6: d 38.2 (q), 61.2 (t), 117.1 (d), 118.5 (d),122.7 (d), 123.5
(s), 125.8 (d), 127.7 (dꢂ2), 127.8 (d), 128.8 (dꢂ2), 130.3 (s), 131.1 (s),
136.3 (s), 140.6 (s), 141.1 (d). Anal. Calcd for C17H16N2O: C, 77.25; H,
6.10; N, 10.60. Found: C, 77.53; H, 6.22; N, 10.34.
3.3.22. 2-(1-Carboxaldehyde-2H-isoindole-3-yl)-malono-nitrile
(30). Chromatographic column (DCM). From 1-carboxaldehyde-3-
chloro-2H-isoindole 5 brown solid, yield 40% (Method B: 50 ꢀC for
12 h), 70% (Method C: 150 W; 150 ꢀC; 5 min), 15% (Method E: reflux
for 8 h); from 3-bromo-1-carboxaldehyde-2H-isoindole 7 brown
solid, 51% (Method B: 50 ꢀC for 8 h), 40% (Method C: 150 W; 150 ꢀC;
5 min). Mp 155e158 ꢀC. IR: 3221 (NH), 2204 (CN), 2208 (CN), 1628
3.3.17. 1-Carboxaldehyde-3-pyrrolidin-1-yl-2H-isoindole (25). Chr
omatographic column (DCM). From 1-carboxaldehyde-3-chloro-
2H-isoindole 5 brown needles, yield 70% (Method A: reflux for 2 h),
71% (Method C: 150 W; 150 ꢀC; 5 min); from 3-bromo-1-carbox-
aldehyde-2H-isoindole 7 brown needles, 99% (Method B: 50 ꢀC for
6 h). Mp 108e109 ꢀC. IR 3391 (NH), 1631 (CO) cmꢁ1. 1H NMR DMSO-
(CO) cmꢁ1. 1H NMR DMSO-d6:
d
4.45 (s,1H, CH), 7.34 (t, J¼7.8 Hz,1H,
d6:
d
1.90 (q, J¼6.4 Hz, 2H, CH2), 2.01 (q, J¼6.4 Hz, 2H, CH2), 3.78 (t,
H-5), 7.50 (t, J¼7.8 Hz,1H, H-6), 7.70 (d, J¼7.8 Hz,1H, H-4), 8.02 (br s,
J¼6.4 Hz, 2H, CH2), 3.92 (t, J¼6.4 Hz, 2H, CH2), 7.16 (t, J¼7.6 Hz, 1H,
H-5), 7.29 (t, J¼7.6 Hz, 1H, H-6), 7.51 (d, J¼7.6 Hz, 1H, H-4), 7.87 (d,
J¼7.6 Hz, 1H, H-7), 8.14 (s, 1H, CHO), 14.40 (br s, 1H, NH). 13C NMR
1H, CHO), 8.17 (d, J¼7.8 Hz, 1H, H-7), 10.25 (br s, 1H, NH). 13C NMR
DMSO-d6:
d
60.0 (d), 117.0 (s), 117.8 (s), 118.7 (s), 119.8 (dꢂ2), 120.3
(s), 124.5 (s), 124.8 (d), 126.3 (s), 128.5 (d), 140.1 (d). Anal. Calcd for
C12H7N3O: C, 68.89; H, 3.37; N, 20.09. Found: C, 68.66; H, 3.40; N,
20.28.
DMSO-d6:
d 24.2 (t), 25.5 (t), 50.8 (t), 53.9 (t), 116.8 (d), 118.9 (d),
122.3 (d), 123.9 (s), 125.2 (d), 129.4 (s), 131.0 (s), 138.1 (d), 139.5 (s).
Anal. Calcd for C13H14N2O: C, 72.87; H, 6.59; N, 13.07. Found: C,
72.58; H, 6.63; N, 13.27.
3.3.23. Ethyl 2-cyano-2-(1-carboxaldehyde-2H-isoindole-3-yl)-ace-
tate (31). Chromatographic column (DCM). From 1-carbox-
aldehyde-3-chloro-2H-isoindole 5 cream solid, yield 40% (Method
B: 50 ꢀC for 20 h), 20% (Method C: 150 W; 150 ꢀC; 5 min), 15%
(Method E: reflux for 10 h); from 3-bromo-1-carboxaldehyde-2H-
isoindole 7 cream solid, 40% (Method B: 50 ꢀC for 20 h), 30%
(Method C: 150 W; 150 ꢀC; 5 min). Mp 127e128 ꢀC. IR: 3373 (NH),
3.3.18. 3-(Benzylamino)-1-acetyl-2H-isoindole (26). Chromatograp
hic column (98:2 DCM/ethylacetate). Brown solid, yield 9% (Method
ꢀ
B: 50 C for 19 h). Mp 101e103 ꢀC. IR: 3357 (NH), 3193 (NH), 1597
(CO) cmꢁ1. 1H NMR DMSO-d6:
d
2.53 (s, 3H, CH3), 4.66 (d, J¼6.6 Hz,
2H, CH2), 7.13 (t, J¼7.6 Hz, 1H, H-5), 7.25e7.38 (m, 6H, H-6, C6H5),
7.54 (d, J¼7.6 Hz, 1H, H-4), 7.77 (d, J¼7.6 Hz, 1H, H-7), 8.30 (br s, 1H,
2204 (CN), 1674 (CO), 1618 (CO) cmꢁ1. 1H NMR DMSO-d6:
d 1.29 (t,
NH), 9.24 (br s, 1H, NH). 13C NMR DMSO-d6:
d
14.8 (q), 45.7 (t), 119.2
J¼7.4 Hz, 3H, CH3), 2.50 (s, 1H, CH), 4.25 (q, J¼7.4 Hz, 2H, CH2), 7.33
(t, J¼8.1 Hz,1H, H-5), 7.47 (t, J¼8.1 Hz,1H, H-6), 7.70 (d, J¼8.1 Hz,1H,
H-4), 8.17 (s, 1H, CHO), 8.31 (d, J¼8.1 Hz, 1H, H-7), 10.75 (br s, 1H,
(d), 119.3 (d), 121.4 (d), 123.2 (s), 126.1 (d), 126.9 (dꢂ2), 127.1 (d),
128.6 (dꢂ2), 134.5 (s), 135.8 (s), 136.7 (s), 139.0 (s), 156.0 (s). Anal.
Calcd for C17H16N2O: C, 77.25; H, 6.10; N, 10.60. Found: C, 77.40; H,
6.14; N, 10.46.
NH). 13C NMR DMSO-d6:
d 13.8 (q), 61.9 (t), 85.2 (s), 115.0 (s), 117.1
(s), 119.7 (dꢂ2), 121.1 (s), 121.4 (d), 124.3 (s), 124.5 (d), 127.7 (d),
138.3 (d), 164.3 (s). Anal. Calcd for C14H12N2O3: C, 65.62; H, 4.72; N,
10.93. Found: C, 65.81; H, 4.75; N, 10.73.
3.3.19. 1-Acetyl-3-pyrrolidin-1-yl-2H-isoindole (27). Chromatogra
phic column (DCM). Cream needles, yield 33% (MethodꢁB1: 50 ꢀC for
18 h). Mp 168e169 ꢀC. IR 3391 (NH), 1645 (CO) cm
.
1H NMR
3.3.24. 2-(1-Acetyl-1-methyl-2H-isoindole-3-yl)-malono-nitrile
(32). Chromatographic column (DCM). Brown solid, yield 30%
(Method B: 50 ꢀC for 20 h), 28% (Method C: 150 W; 150 ꢀC; 5 min),
16% (Method E: reflux for 10 h). Mp 103e104 ꢀC. IR: 2193 (CN), 1624
DMSO-d6:
d
1.79e2.01 (m, 4H, CH2ꢂ2), 2.73 (s, 3H, CH3), 3.79 (br s,
2H, CH2), 4.10 (br s, 2H, CH2), 7.14 (t, J¼8.2 Hz, 1H, H-5), 7.28 (t,
J¼8.2 Hz, 1H, H-6), 7.56 (d, J¼8.2 Hz, 1H, H-4), 7.85 (d, J¼8.2 Hz, 1H,

2080
P. Diana et al. / Tetrahedron 67 (2011) 2072e2080
(CO) cmꢁ1. 1H NMR CDCl3:
d
1.96 (s, 3H, CH3) 3.17 (s, 3H, CH3), 4.92
stitute (Bethesda, MD) for the antitumor tests reported in this
paper.
(s, 1H, CH), 7.45 (d, J¼6.6 Hz, 1H, H-4), 7.50e7.58 (m, 2H, H-6, H-5),
7.87 (d, J¼6.6 Hz, 1H, H-7). 13C NMR CDCl3:
d 24.1 (q), 28.9 (q), 72.1
(d), 122.5 (d), 123.2 (s), 124.1 (d), 129.5 (d), 132.0 (s), 132.2 (d), 134.0
(s), 138.5 (sꢂ2), 169.1 (s), 204.4 (s). Anal. Calcd for C14H11N3O: C,
70.87; H, 4.67; N, 17.71. Found: C, 70.67; H, 4.74; N, 17.85.
Supplementary data
Supplementary data associated with this article can be found in
the online version, at doi:10.1016/j.tet.2011.01.056.
3.3.25. 1-Acetyl-3-cyano-2-methyl-2H-isoindole (33). Chromatogra
phic column (DCM). White solid, yield 70% (Method A: reflux for
5 h), 10% (Method B: 50 ꢀC for 20 h). Mp 118e119 ꢀC. IR: 2212 (CN),
References and notes
1649 (CO) cmꢁ1. 1H NMR CDCl3:
d 2.79 (s, 3H, CH3) 4.34 (s, 3H, CH3),
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7.32 (t, J¼8.1 Hz, 1H, H-5), 7.40 (t, J¼8.1 Hz, 1H, H-6), 7.75 (d,
J¼8.1 Hz, 1H, H-4), 7.95 (d, J¼8.1 Hz, 1H, H-7). 13C NMR CDCl3:
d 31.1
(q), 38.1 (q), 104.6 (s), 112.4 (s), 118.9 (d), 120.4 (d), 125.3 (d), 125.5
(s),126.6 (d),129.4 (s), 133.8 (s), 188.1 (s). Anal. Calcd for C12H10N2O:
C, 72.71; H, 5.08; N, 14.13. Found: C, 72.86; H, 5.15; N, 13.98.
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The reported 3D structure of two tubulin dimers cocrystalized
with stathmin-like domain and N-deacetyl-N-(2-mercaptoacetyl)-
colchicine (DAMAecolchicine), was downloaded from the PDB data
bank (http://www.rcsb.org/pdb; PDB code: 1SA0).18 All docking
runs were performed into the colchicine binding site of the tubulin,
using GLIDE 15 software,19 with its XP mode default parameters.
GLIDE output consists of a score named GSCORE, where a more
negative value indicates a higher binding affinity. To validate the
use of GLIDE program, the docking studies were performed on the
reference compounds colchicine and combrestatin A-4. GLIDE
successfully reproduced the binding conformations reported in
literature with acceptable root-mean-square deviation (RMSD) of
atom coordinates.
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Acknowledgements
17. Jordan, M. A.; Wilson, L. Nat. Rev. Cancer 2004, 4, 253e265.
18. Ravelli, R. B.; Gigant, B.; Curmi, P. A.; Jourdan, I.; Lachkar, S.; Sobel, A.; Knossow,
M. Nature 2004, 428, 198e202.
This work was financially supported by Ministero dell’Istruzione
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€
dell’Universita e della Ricerca. We thank the National Cancer In-
19. 15 GLIDE Version 4.5, Prime, Version 1.6; Schrodinger LLC: New York, NY, 2007.