Parallel synthesis of O-phenoxyethyl and O-adamantyl N-acyl thiocarbamates endowed with antiproliferative activity

Article abstract of DOI:10.1002/ardp.200800212

In order to further explore the antiproliferative properties of O-phenoxyethyl and O-adamantyl acylthiocarbamates (ATCs), a series of 14 derivatives was prepared by a parallel adaptation of a highly convergent one-pot three-step procedure. Ten acylthiocar

Full text of DOI:10.1002/ardp.200800212

344
Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
Full Paper
Parallel Synthesis of O-Phenoxyethyl and O-Adamantyl N-acyl
Thiocarbamates Endowed with Antiproliferative Activity
Andrea Spallarossa, Sara Cesarini, Silvia Schenone, and Angelo Ranise
Dipartimento di Scienze Farmaceutiche, Universitꢀ di Genova, Genova, Italy
In order to further explore the antiproliferative properties of O-phenoxyethyl and O-adamantyl
acylthiocarbamates (ATCs), a series of 14 derivatives was prepared by a parallel adaptation of a
highly convergent one-pot three-step procedure. Ten acylthiocarbamates were selected by the
National Cancer Institute drug evaluation program and screened against a panel of 55 to 58 cell
lines derived from nine different types of human cancers. In general, the tested compounds
showed a widespread micromolar activity with some specificity against leukemia, renal UO-31,
central nervous system (CNS) SNB-75, and non-small cell lung HOP-92 cancer cell lines. Bioinfor-
matic COMPARE analyses were carried out to identify possible mechanism(s) of action for acylth-
iocarbamate antiproliferative activity.
Keywords: N-Acylthiocarbamates / Antiproliferative agents / Parallel synthesis /
Received: November 21, 2008; accepted: February 12, 2009
DOI 10.1002/ardp.200800212
Introduction
According to the degree of substitution at the thiocarba-
mic nitrogen atom, thiocarbamates can be distinguished
into primary, secondary, and tertiary compounds [1]. Sec-
ondary acylthiocarbamates (i.e. secondary thiocarba-
mates bearing an acyl substituent at the thiocarbamic
nitrogen, Fig. 1) have been widely studied for their physi-
cochemical properties [1–4] and biological activities
including elastase inhibition [5], anti-inflammatory [6],
antiproliferative [7], antibacterial [7], and fungicidal [7]
effects (Fig. 1). Conversely, a limited number of works
were focussed on tertiary acylthiocarbamates (herein-
after, ATCs) [8–11] which turned out to be novel and
potent anti-HIV-1 agents (Fig.1). Despite these data, the
Figure 1. Selected secondary and tertiary acylthiocarbamates
(ATCs) endowed with biological activities.
biological potential of this chemical class still remains
largely unexplored.
As part of our synthetic program directed toward the
development of new HIV-1 non-nucleoside reverse tran-
scriptase inhibitors, the O-phenoxyethyl ATCs I-VII and
their O-adamantyl analogue VIII (Fig. 2) had revealed
moderate cytotoxicity against MT-4 lymphoblastoid T
cells [9]. In order to further investigate the antiprolifera-
tive properties of ATCs, we planned the synthesis of new
Correspondence: Dr. Andrea Spallarossa, Dipartimento di Scienze
Farmaceutiche, Universitꢀ di Genova, Viale Benedetto XV 3, I-16132
Genova, Italy.
E-mail: andrea.spallarossa@unige.it
Fax: +39 010 353 8358
Abbreviation: Pearson correlation coefficient (PCC); tertiary acylthiocar-
bamates (ATCs)
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
Acylthiocarbamates as Antiproliferative Agents
345
Table 1. Physical and chemical data of ATC 1–14.
Compound
R
(Het)ArCO
Cryst. solvent(s)a) M.p. (8C)
Yield (%)
Formula
1b)
2
phenoxyethyl
phenoxyethyl
phenoxyethyl
phenoxyethyl
adamantyl
adamantyl
adamantyl
adamantyl
adamantyl
adamantyl
adamantyl
adamantyl
adamantyl
adamantyl
4-chlorobenzoyl
4-methoxybenzoyl
2-furoyl
DE
DE-P
DE
101–103c)
70–72
76c)
91
C22H18ClNO3S
C23H21NO4S
C20H17NO3S
C20H17NO3S2
C26H27NO4S
C24H24N2O4S
C24H24ClNO2S
C24H23Cl2NO2S
C24H23Cl2NO2S
C27H31NO5S
C30H29NO2S
C28H27NO2S
C22H23NO3S
C22H23NO2S2
3b)
4b)
5
98–99d)
84d)
87e)
53
2-thenoyl
DE
91–92e)
2-acetoxybenzoyl
3-nitrobenzoyl
4-chlorobenzoyl
3,4-dichlorobenzoyl
3,5-dichlorobenzoyl
3,4,5-trimethoxybenzoyl DE-M
1,1'-biphenyl-4-carbonyl DM-M
1-naphthoyl
2-furoyl
DE-M
DE-M
DM-M
DE-M
DE-M
144–145
157–158
164–166
128–130
154–155
101–102
182–184
167–169
132–134f)
163–164
6
7
8
9
10
11
12
13b)
14
55
59
48
54
56
52
DE-M
DE-M
DE-M
62
60f)
56
2-thenoyl
a)
Crystallization solvent(s): DE = diethyl ether, DM = dichloromethane, M = methanol, P = petroleum ether.
Compounds 1, 3, 4, and 13 are identical to II, VI, VII, and VIII (Fig: 2), respectively.
Lit. [11]: m.p.: 101–1038C, yield: 74%.
Lit. [11]: m.p.: 98–998C, yield: 85%.
Lit. [11]: m.p.: 91–928C, yield: 85%.
b)
c)
d)
e)
f)
Lit. [11]: m.p.: 133-1348C, yield: 58%.
Reaction conditions: (a) NaH (1 eq.), dry DMF, 908C (for S1: dry toluene, rt), 30 min; (b) C6H5-NCS (1 eq.), 908C (for B1: rt), 30 min; (c) dry pyridine (large excess), (Het)ArCOCl
(1.2 eq.), rt, 6 h, then 558C, 1 h (for 1 – 4: 1.1 eq, rt, 6 h). The structures of alcohols ROH (A1, 2) and acyl chlorides (Het)ArCOCl (C1 – 11) are listed in Fig. 2.
Scheme 1. Synthesis of the title compounds.
biphenyl-carbonyl, 1-naphtoyl, 2-furoyl, and 2-thenoyl)
whereas the N-phenyl group was kept constant. The O-
adamantyl analogues were privileged according to the
well-known antitumor properties of some adamantane
derivatives [12–17]. To allow rapid analoguing, a parallel
synthetic method was set up. Among the prepared com-
pounds, ATCs 1–4, 7–10, 13, and 14 (Table 1) were
selected by the National Cancer Institute (NCI; Bethesda,
MD, USA) for antiproliferative testing against a panel of
cell lines extracted from nine different human tumors.
Figure 2. ATC-hit compounds [11]: chemical structure and cyto-
toxicity against MT-4 lymphoblastoid T cells.
Results and discussion
O-phenoxyethyl 2 (Table 1) and O-adamantyl derivatives
5–12, 14 (Table 1). The structure-activity relationship Chemistry
(SAR) strategy was focussed on the variation of the acyl ATCs 1–14 were prepared by a parallel adaptation of the
moiety (mono-, di-, and tri-substituted benzoyl groups, previously reported one-pot three-step protocol [9]. As
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

346
A. Spallarossa et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
different reactivity of key-intermediates S and B towards
phenylisothiocyanate and acyl chloride building blocks,
respectively, different reaction conditions were adopted
for the synthesis of O-phenoxyethyl and O-adamantyl
ATCs (see Experimental, Section 4). The work-up simply
required quenching with water, extraction, and filtra-
tion; all derivatives were purified by crystallization from
the proper solvent or solvent mixtures (Table 1).
To properly evaluate the parallel procedure, II, VI, VII,
and VIII (Fig. 1) previously prepared by a “one-at-a-time”
method [9], were re-synthesized using the parallel variant
(compounds 1, 3, 4, and 13 in Table 1). The quality of the
products (in terms of yield and purity) was not influenced
by the parallelization of the synthetic procedure. The
overall yields ranged from 46% to 91% (see Table 1).
Biological data
ATCs 1–14 (Table 1) were submitted to the NCI develop-
mental therapeutics program for antiproliferative test-
ing against 55 to 58 cell lines isolated from nine different
human tumors; the ten derivatives reported in Tables 2,
3, and 4 were selected and screened by NCI. The results
are expressed as GI50 (measure of the growth inhibitory
power), TGI (measure of the cytostatic activity), and LC50
(measure of the cytocidal effect). Table 2 summarizes the
number of cell lines against which each compound was
screened (55 – 58), the number of lines against which it
gave a positive (inferior to 100 lM) GI50, TGI, or LC50 value
and the corresponding concentration range. The GI50 val-
ues of the ten molecules are reported in Tables 3 and 4.
Figure 3. Synthetic building blocks.
shown in Scheme 1, the starting alcohols A1, 2 (Fig. 3a)
were converted into the corresponding alcoholates S1, 2
using sodium hydride in anhydrous aprotic solvents (tol-
uene or DMF) and condensed in situ with phenylisothio-
cyanate. The thiocarbamic intermediates B1, 2 were acy-
lated by acyl chlorides C1 – 11 (Fig. 3c) in the presence of
pyridine to afford the desired products. To obviate the
Table 2. Anticancer activity of 1, 2, 3, 4, 7, 8, 9, 10, 13, and 14a).
Compound
Investigated
Number (No) of human tumor cell linesb) Giving positive GI50, TGI and LC50
GI50 (lM)c)
TGI (lM)d)
LC50 (lM)e)
No
Range
No
Range
No
Range
1
2
3
4
7
8
9
10
13
14
56
57
56
56
56
55
55
56
58
58
56
55
56
56
55
54
55
56
58
58
0.19 – 46.9
0.05 – 88.4
13.8 – 32.2
17.0 – 58.6
16.2 – 99.8
2.8 – 93.2
5.2 – 75.2
2.7 – 66.0
13.7 – 48.5
15.3 – 85.7
52
13
55
45
6
11
9
18
29
14
3.12 – 94.0
32
1
36
13
1
4
2
5
5
54.5 – 97.3
98.6
29.9 – 98.5
28.2 – 90.2
33.3 – 96.5
31.2 – 89.7
14.4 – 98.5
35.4 – 84.5
21.8 – 92.5
32.4 – 98.7
33.8 – 92.9
54.5 – 95.9
64.6 – 99.7
58.2
47.9 – 82.2
67.3 – 89.4
67.1 – 98.9
63.7 – 91.0
64.3 – 96.2
3
a)
Data obtained from NCI's in-vitro disease-oriented human tumor cell lines screen.
b)
The table shows the number of cell lines against which each compound was screened, the number of lines against which it gave
a positive GI50, or TGI, or LC50 value (a100 lM) and the corresponding concentration range.
Compound concentration that produces 50% growth inhibition.
Compound concentration that produces total growth inhibition.
Compound concentration that produces 50% cytocidal effect.
c)
d)
e)
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
Acylthiocarbamates as Antiproliferative Agents
347
Table 3. Cytotoxicity of 1, 2, 3, 4, 7, 8, 9, 10, 13, and 14 against human cultured cell lines of leukemia, non-small cell lung cancer
(NSCLC), colon cancer, CNS cancer, and melanoma.
Panel
Compounds GI50 (lM)a)
Cell Lines
1
2
3
4
7
8
9
10
13
14
Leukemia
CCRF-CEM
HL-60(TB)
K-562
MOLT-4
RPMI-8226
SR
13.7
18.6
30.4
22.4
18.1
–
14.9
20.2
23.8
19.7
14.6
–
20.1
24.3
28.4
23.8
19.8
–
27.6
27.6
36.1
27.4
20.9
–
16.2
17.0
29.8
26.8
–
2.8
5.2
24.4
–
–
–
2.9
16.9
19.3
28.7
24.4
–
15.3
25.0
26.8
26.1
–
15.8
17.1
–
–
–
9.7
2.7
2.8
–
–
–
43.0
25.7
25.2
NSCLC
A549/ATCC
EKVX
HOP-62
16.3
20.1
23.0
3.3
31.1
31.7
71.2
20.1
–
32.4
53.4
34.1
23.7
30.8
22.1
16.2
14.8
–
21.3
22.4
21.9
17.1
28.1
29.5
28.3
18.8
–
20.7
36.3
34.8
22.9
31.9
26.6
45.5
34.0
30.9
35.7
43.0
30.0
21.1
32.2
20.8
44.6
31.9
31.2
28.9
40.2
37.8
13.2
42.7
21.8
42.7
29.0
35.5
36.1
45.8
35.4
16.0
26.0
14.8
43.6
21.0
21.5
28.0
32.6
27.1
4.0
32.2
18.8
28.3
19.5
27.2
27.8
29.7
30.8
19.9
32.8
17.8
47.7
24.8
33.3
30.2
35.8
33.3
17.2
HOP-92
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
–
18.1
21.4
23.2
19.1
Colon Cancer
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
19.9
19.5
16.2
19.3
17.6
19.1
19.1
30.5
34.5
29.1
44.1
40.4
31.3
50.0
21.0
21.0
17.3
22.3
19.2
19.5
20.5
24.8
24.7
19.4
27.4
34.1
26.0
25.5
16.8
31.6
33.5
34.6
32.3
39.1
34.4
15.9
43.2
24.8
33.3
29.6
33.7
35.2
18.6
33.8
28.1
34.6
39.4
40.2
39.5
16.4
23.4
16.1
26.6
17.7
26.5
22.7
16.5
25.1
19.9
28.2
33.5
31.2
29.0
17.8
32.6
22.2
29.8
31.8
31.9
40.8
CNS Cancer
SF-268
SF-295
SF-539
SNB-19
SNB-75
U251
25.1
27.6
18.9
19.2
–
43.9
29.2
40.2
83.8
1.6
18.0
16.2
22.8
26.7
–
34.1
26.6
34.3
29.4
24.3
21.4
43.3
36.8
30.7
29.6
42.8
30.2
40.3
36.2
36.6
33.4
93.4
34.6
52.9
34.5
40.0
45.6
61.0
33.0
35.7
22.1
31.3
34.6
66.0
19.0
32.9
27.7
20.2
34.7
48.5
23.3
37.5
27.9
34.5
33.7
85.7
29.1
16.2
46.1
16.5
Melanoma
LOX IMVI
MALME-3M
M14
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
17.4
29.0
16.1
22.1
15.8
–
52.0
28.4
43.2
22.9
> 100
–
19.3
19.9
19.6
19.6
18.2
–
17.1
31.3
17.0
21.3
24.8
–
–
–
–
–
26.6
26.8
21.0
21.2
37.9
17.7
30.9
23.4
22.5
43.2
19.2
18.2
54.8
22.1
39.5
25.6
54.3
33.9
30.2
> 100
32.0
46.6
40.6
34.9
20.8
20.0
44.5
19.5
41.3
25.0
49.7
22.7
19.3
59.4
28.3
43.2
32.6
29.1
18.9
15.2
30.4
16.1
26.3
22.1
18.7
16.3
34.8
48.0
17.9
16.6
29.4
18.2
a)
Growth inhibition (GI50); GI50 values lower than 10.0 lM are reported in bold.
As shown in Table 2, most of the ATCs showed antipro-
The average GI50 values reported in Fig. 4 indicate that
liferative activity against the majority of the cell lines the phenoxyethyl derivatives 1–4 showed a widespread
investigated (54 to 58 out of 55 to 58), but only O-phen- activity in the micromolar concentration range against
oxyethyl derivatives 1, 3, and 4 demonstrated cytostatic all the considered cancer subpanels. Nevertheless,
properties at micromolar concentrations in a good num- enhanced potencies were detected against specific cell
ber of cell lines (45 to 55) and cytocidal properties in 13 lines (Tables 3 and 4). Thus, ATC 1 (4-chlorobenzoyl)
to 36 cell lines.
emerged as particularly effective against HOP-92 non-
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

348
A. Spallarossa et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
Table 4. Cytotoxicity of 1, 2, 3, 4, 7, 8, 9, 10, 13, and 14 against human cultured cell lines of ovarian, renal, prostate, and breast
cancers.
Panel
Compounds GI50 (lM)a)
Cell Lines
1
2
3
4
7
8
9
10
13
14
Ovarian Cancer
IGROV1
OVAR-3
OVAR-4
OVAR-5
16.9
17.2
18.6
17.0
20.3
36.1
> 100
38.0
24.6
88.4
52.2
52.7
17.7
16.5
20.1
19.2
19.8
21.8
25.4
21.0
29.8
28.4
25.5
30.4
–
–
–
–
–
–
44.6
39.5
45.6
39.2
53.1
39.5
38.2
18.8
41.5
36.7
45.3
46.7
46.3
41.6
32.5
28.1
29.2
26.5
27.0
25.7
28.0
36.1
39.7
31.2
23.4
34.6
35.0
29.4
31.8
28.4
OVAR-8
SK-OV-3
Renal Cancer
786-0
A498
18.7
14.9
20.3
17.4
18.6
19.3
29.4
47.9
18.4
44.8
47.0
26.5
43.7
60.9
0.046
19.7
16.0
23.0
18.7
13.8
19.5
20.9
15.7
25.2
25.5
27.7
27.2
23.6
22.1
41.0
–
29.6
64.7
34.8
35.3
99.8
45.1
37.1
27.0
30.3
37.1
34.8
29.9
> 100
26.8
66.9
21.1
32.8
34.9
33.2
42.1
41.2
36.5
53.4
25.1
25.6
25.0
29.6
31.3
32.7
28.7
42.7
19.1
31.2
23.3
27.1
33.3
13.7
27.8
42.3
24.9
35.4
33.2
33.0
28.3
62.2
27.0
43.9
18.7
ACHN
CAKI-1
RXF 393
SN12C
TK-10
UO-31
0.186
Prostate Cancer
PC-3
DU-145
21.1
17.3
35.4
37.1
24.1
20.3
24.7
28.6
34.0
76.4
39.9
83.1
35.1
75.2
22.6
58.9
20.5
52.9
22.8
84.7
Breast Cancer
MCF7
NCI/ADR-RES
MDA-MB-231/ATCC
HS 578T
MDA-MB-435
MDA-N
BT-549
16.1
23.9
23.1
46.9
17.0
16.6
20.2
20.0
41.9
37.1
86.1
65.1
31.7
35.1
49.9
19.9
20.7
25.7
16.4
32.2
16.2
18.9
23.0
20.5
20.2
21.0
24.3
58.6
17.0
17.2
20.8
35.8
33.2
36.5
29.4
39.9
43.8
49.6
43.1
54.4
28.0
30.1
38.2
41.3
30.2
32.7
35.9
54.6
30.1
37.3
38.6
48.9
42.2
31.8
50.2
61.2
29.4
22.7
33.4
27.4
29.5
25.1
32.9
43.2
26.3
28.6
31.8
32.6
28.9
29.4
34.5
47.3
30.7
29.6
30.0
32.0
29.8
31.4
35.3
76.7
T-47D
a)
Growth inhibition (GI50); GI50 values lower than 10.0 lM are reported in bold.
small cell lung (GI50 = 3.3 lM) and UO-31 (GI50 = 0.186 lM) ities against CCRF-CEM leukemia cell line (GI50 values:
renal cancer cell lines; 2 (4-methoxybenzoyl) showed 2.8 lM and 5.9 lM, respectively, Table 3)
high sensitivity against leukemia (average GI50
18.6 lM), renal (UO-31 cell line, GI50 = 46 nM), and CNS ence the antiproliferative activity, even though a general
(SNB-75 cell line GI50 = 1.6 lM) cancers. structure-activity trend cannot be identified: the most
=
The nature of the acyl moiety seems to slightly influ-
In general, the O-adamantyl analogues 7–10, 13, 14 effective ATCs (1, 3, 4, and 10) carried acyl moieties with
were endowed with a reduced antiproliferative activity different electronic and steric properties (4-chloroben-
in comparison with their corresponding phenoxyethyl zoyl, 3,4,5-trimethoxybenzoyl or heteroaroyl groups).
analogues (in particular, compare the MG_MID values for
In order to shed some light on the mechanism of
7 and 1, 13 and 3, 14, and 4) but they showed a higher action of the title compounds, a COMPARE analysis [18–
degree of specificity against leukemia (Fig. 4). ATC 10 24] was performed on ATCs 1–4, 7–10, 13, and 14. This
(3,4,5-trimethoxybenzoyl) resulted to be the most active bioinformatic tool correlates the antiproliferative pro-
adamantyl congener and emerged effective against all files of two agents calculating a Pearson correlation coef-
leukemia cell lines in the 2.7 to 9.7 lM concentration ficient (PCC). A high PCC suggests that the two molecules
range. Furthermore, this compound significantly inhib- share a similar antiproliferative mechanism. Matrix
ited the growth of non-small cell lung cancer NCI-H522 COMPARE was used to determine the pair-wise correla-
cell line (GI50 = 4.0 lM, Table 3). ATC 8 (3,4-dichloroben- tion of the cell response pattern (GI50 end point) for every
zoyl) and 9 (3,5-chlorobenzoyl) showed interesting activ- combination of two compounds in the set of the ten ATCs
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
Acylthiocarbamates as Antiproliferative Agents
349
For each compound, the average GI50 concentration (in lM) has been calculated for both each tumor subpanel and all cell lines (Mean Graph Midpoint, MG_MID). The so
obtained values were converted in the corresponding 1/GI50 and plotted. The symbol code is the following: MG_MID; Leukemia; NSCLC; Colon Cancer; CNS Cancer;
Melanoma; Ovarian Cancer; Renal Cancer; Prostate Cancer; Breast Cancer.
Figure 4. Mean Growth Inhibition (GI50) values of ATCs 1–4, 7–10, 13, and 14.
Table 5. Results of a matrix COMPARE analysis of ATCs 1–4, 7–10, 13, and 14a).
Cpd.
14
13
10
9
8
7
4
3
2
1
2
3
4
7
8
9
10
13
0.238 (54) 0.146 (54)
0.103 (55) 0.096 (55)
–0.042 (54) 0.206 (54)
0.285 (54) 0.318 (54)
0.708 (56) 0.391 (56)
0.809 (55) 0.497 (55)
0.791 (55) 0.723 (55)
0.651 (56) 0.519 (56)
0.660 (58)
0.041 (53) 0.209 (51)
0.140 (54) 0.207 (52)
–0.156 (53) 0.085 (51)
0.035 (53) 0.276 (51)
0.587 (56) 0.688 (54)
0.824 (55) 0.874 (54)
0.895 (54)
0.172 (52)
0.107 (53)
–0.100 (52) –0.286 (53) 0.481 (55)
0.157 (52) –0.004 (53)
0.698 (55)
0.129 (53) 0.543 (55)
0.186 (54) 0.119 (56)
0.371 (56)
0.187 (56)
0.840 (56)
a)
The Pearson correlation coefficient (PCC) calculated from a matrix COMPARE analysis is given. Numbers in brackets correspond
to the number of cell lines that were used for calculation. The data considered significant (p a 0.01) are shown in bold. The dis-
tinct p values were calculated from the PCCs and the number of cell lines by StaTable vers.1.0.2 (Cytel Software, Cambridge, MA,
USA).
screened. Correlations could not be detected when the O- with the alkylating agent cisplatin (correlation coeffi-
phenoxyethyl and O-adamantyl subgroups were com- cients: 0.739 and 0.807, respectively) and the O-adaman-
pared (Table 5). In contrast, within each subgroup a high tyl ATC 10 with the antimitotic compound S-trityl-L-cys-
pattern consistency was found: four out of six possible teine (PCC = 0.702). These activities may be related to the
correlations were found significant (p a 0.01) within the electrophilic nature of the acylthiocarbamic group and
phenoxyethyl subgroup, and all 15 correlations in the its ability to interact with different cellular substrates
adamantyl subgroup were considered significant. These according to the steric and electronic properties of the
observations suggest that both compound classes repre- ATC O- and N-substituents.
sent groups of antiproliferative agents with different but
characteristic mechanism(s) of action. To further investi-
gate this aspect, the individual 1–4, 7–10, 13, and 14
screening results at the GI50 end point were used as
Conclusions
probes to search the NCI standard agent compound set The SAR extension studies on the new ATCs confirmed
containing 171 agents with confirmed mechanism(s) of the antiproliferative properties of the series. In the NCI
action. The only significant (p a 0.01) correlations screening, ATCs 1–4, 7–10, 13, and 14 exhibited a wide-
obtained involved the O-phenoxyethyl derivatives 1 and 2 spread antiproliferative activity at micromolar concen-
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

350
A. Spallarossa et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
(ppm) units relative to the internal standard tetramethylsilane,
and the splitting patterns were described as follows: s (singlet), t
(triplet) and m (multiplet). The first order values reported for
coupling constants J were given in Hz. Elemental analyses were
performed by an EA1110 Elemental Analyser (Fison-Instru-
ments, Milan, Italy); all compounds were analyzed for C, H, N
and S and the analytical results were within l 0.4% of the theo-
retical values.
trations. The antitumor effect was, on average, higher
within the O-phenoxyethyl series but the O-adamantyl
derivatives showed higher selectivity. The nature of the
acyl moiety appeared to slightly affect the ATC antiproli-
ferative activity. COMPARE computational analyses pro-
vided indications about the possible mechanism(s) of
action of the title compounds. The elucidation of the bio-
logical target(s) to which the ATC antiproliferative activ-
ity is related and the improvement of the anticancer
properties will be the objective for future studies.
Parallel synthesis of O-(2-phenoxyethyl)
[(hetero)aroyl](phenyl)thiocarbamates 1–4
A 60% sodium hydride dispersion in mineral oil (0.40 g,
10 mmol) was added in a single portion at 208C to each num-
bered reaction tube of a 12-Carousel Reaction StationTM, contain-
ing a stirred solution of 2-phenoxyethanol (1.254 mL, 10 mmol)
in dry toluene (15 mL). After stirring for 30 min, phenyl isothio-
cyanate (1.194 mL, 10 mmol) was added to each reaction mix-
ture, which was then stirred for 30 min at rt. Then, dry pyridine
(5 mL) and the suitable acyl chloride (11 mmol) were added suc-
cessively, each one in one portion. After stirring at 208C for 6 h,
water (25 mL) was added into each tube. The contents of the
tubes were then transferred into a set of separating funnels.
More water (125 mL) was added into each funnel. After parallel
extraction with diethyl ether (40 mL6 3), the combined extracts
of each reaction were washed with water (30 mL6 2), 2 M HCl
(30 mL62), 1 M NaHCO3 (30 mL), brine (30 mL), dried over anhy-
drous Na2SO4, and filtered in parallel through pads of Florisil1
(diameter 562 cm) by an in-house device. Parallel evaporating
in vacuo using an EvaposelTM apparatus gave residues which were
purified by crystallization from the suitable solvent (mixture).
The IR and 1H-NMR spectra for O-(2-Phenoxyethyl) 4-chloroben-
zoyl(phenyl)thiocarbamate 1, O-(2-phenoxyethyl) 2-furoyl(phe-
nyl)thiocarbamate 3, O-(2-phenoxyethyl) phenyl(thien-2-ylcarbo-
nyl)thiocarbamate 4 are consistent with literature data [9].
The authors are very grateful to Dr. V. L. Narayanan, Chief of
Drug Synthesis and Chemistry branch, National Cancer Insti-
tute (Bethesda, MD, USA) for the in-vitro evaluation of anti-
cancer activity. This work was supported by MURST – Minis-
tero dell' Universitꢀ e della Ricerca Scientifica e Tecnologica
(Cofinanziamento Nazionale), CNR (Consiglio Nazionale delle
Ricerche, Rome), and Ministero Italiano della Salute – Istituto
Superiore di Sanitꢁ (grant n8 40D.46). Fondazione Carige is
gratefully acknowledged for financially supporting S.C. The
authors thank Mr. O. Gagliardo for the microanalyses, Mr. F.
Tuberoni, Dr. C. Rossi and Dr. R. Raggio for the IR and NMR
spectra.
The authors have declared no conflict of interest.
Experimental
Chemistry
O-(2-Phenoxyethyl) 4-
All building blocks used are commercially available. Alcohols (1-
adamantanol, and 2-phenoxyethanol), phenylisothiocyanate,
acyl chlorides, and 60% sodium hydride dispersion in mineral
oil were purchased by Chiminord and Aldrich Chemical, Milan
(Italy). Solvents were reagent grade. DMF was dried on molecular
sieves (5 ꢀ 1/1699 inch pellets). Unless otherwise stated, all com-
mercial reagents were used without further purification.
Organic solutions were dried over anhydrous sodium sulphate.
Thin layer chromatography (TLC) system for routine monitoring
the course of reactions and confirming the purity of analytical
samples employed aluminium-backed silica gel plates (Merck
DC-Alufolien, Kieselgel 60 F254; Merck, Germany): CHCl3 was used
as developing solvent and detection of spots was made by UV
light and / or by iodine vapours. The parallel solution phase
chemistry was performed by using a Carousel-12 Reaction Sta-
tionTM (Radleys Discovery Technologies, Italian distributor: Step-
Bio, Bologna, Italy). The evaporation of solutions was performed
in parallel with an EvaposelTM apparatus (Radleys Discovery Tech-
nologies, Italian distributor: StepBio) operating at reduced pres-
sure of about 15–20 Torr. Yields were not optimized. Melting
points were determined on a Fisher-Johns apparatus (Fischer-Sci-
entific, Pittsburgh, PA, USA) and are uncorrected. IR spectra
were recorded on a Perkin Elmer 398 spectrometer (Perkin
Elmer, USA) as KBr discs. 1H-NMR spectra (200 MHz) were
recorded in CDCl3 on a Varian Gemini 200 instrument (Varian
Inc., Palo Alto, CA, USA). Chemical shifts were reported in d
methoxybenzoyl(phenyl)thiocarbamate 2
IR (KBr) cm– 1 1685; 1H-NMR (CDCl3) d: 3.77 (s, 3H, methoxy), 3.92
(t, J = 5 Hz, 2H, CH2/b-H phenoxyethyl), 4.78 (t, J = 5 Hz, 2H, CH2/a-
H phenoxyethyl), 6.60-8.10 (m, 14H, arom H). Anal. Calcd. for
C23H21NO4S: C, 67.79; H, 5.19; N, 3.44; S, 7.87. Found: C, 67.59; H,
5.32; N, 3.23; S, 7.98.
Parallel synthesis of O-1-adamantyl
[(hetero)aroyl](phenyl)thiocarbamates 5–14
A 60% sodium hydride dispersion in mineral oil (0.40 g,
10 mmol) was added in a single portion at 208C to each num-
bered reaction tube of a 12-Carousel Reaction StationTM, contain-
ing a stirred solution of 1-adamantanol (1.522 g, 10 mmol) in
dry DMF (25 mL). After stirring for 30 min at 908C, phenyl iso-
thiocyanate (1.194 mL, 10 mmol) was added to each reaction
mixture, which was then stirred for 30 min at 908C. After cool-
ing to 208C, dry pyridine (5 mL) and the suitable acyl chloride
(12 mmol) were added successively, each one in one portion. The
resulting mixtures were stirred at 208C for 6 h, and then at 558C
for 1 h. After cooling to 208C and addition of water (25 mL) into
each vessel, the contents of the tubes were then transferred into
a set of separating funnels. More water (125 mL) was added into
each funnel. After parallel extraction with dichloromethane
(40 mL 6 3), the combined extracts of each reaction were washed
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
Acylthiocarbamates as Antiproliferative Agents
351
with water (30 mL 6 5), dried over anhydrous Na2SO4, and fil-
tered in parallel through pads of Florisil1 (diameter 5 6 2 cm) by
an in-house device. Parallel in-vacuo evaporation (EvaposelTM
apparatus) gave residues which were purified by crystallization
from the suitable solvent mixture. The elemental analysis as
well as the IR and1H-NMR spectra for 13 are consistent with liter-
ature data [9].
C28H27NO2S: C, 76.16; H, 6.16; N, 3.17; S, 7.26. Found: C, 76.41; H,
6.18; N, 2.99; S, 7.36.
O-1-Adamantyl 2-furoyl(phenyl)thiocarbamate 13 [9] and
O-1-Adamantyl phenyl(2-thenoyl)thiocarbamate 14
IR (KBr) cm– 1 1680; 1H-NMR (CDCl3) d: 1.48–1.97 (m, 6H, 3 CH2),
2.01–2.48 (m, 9H, 3 CH2 and 3 CH), 6.85–8.10 (m, 8H, 5 arom H,
3H, thioph). Anal. Calcd. for C22H23NO2S2: C, 66.47; H, 5.83; N,
3.52; S, 16.13. Found: C, 66.65; H, 6.02; N, 3.45; S, 15.97.
O-1-Adamantyl 2-acetoxybenzoyl(phenyl)thiocarbamate
5
IR (KBr) cm– 1 1765; 1H-NMR (CDCl3) d: 1.14–1.75 (m, 6H, 3 CH2),
1.84–2.14 (m, 9H, 3 CH2 and 3 CH), 2.44 (s, 3H, acetyl), 7.01–7.94
(m, 9H, arom H). Anal. Calcd. for C26H27NO4S: C, 69.46; H, 6.05; N,
3.12; S, 7.13. Found: C, 69.56; H, 6.13; N, 3.05; S, 7.25.
Pharmacology
Evaluation of anticancer activity
The NCI high-flux anticancer drug screen [21, 24, 25] utilized a
panel of 60 human tumor cell lines in culture derived from nine
cancer types (lung, colon, CNS, ovarian, renal, prostate, and
breast cancer, leukemia and melanoma). The compounds were
tested at ten-fold dilutions of five concentrations ranging from
10– 4 to 10 – 8 M. According to the NCI protocol, cell lines were
exposed to test agents in 96-well plates for the last 48 of a 72 h
incubation and a sulforhodamine B (SRB) protein assay was used
to estimate cell viability or growth. For each compound, the
drug concentration required to produce 50% (GI50) and total
(TGI) growth inhibition, and 50% cytocidal effect (LC50) were
obtained for 56 to 58 cell lines. Values were calculated for each
of these parameters if the level activity was reached; if the effect
was not reached or was exceeded, the value is expressed as
greater or lesser than the maximum or minimum concentration
tested.
O-1-Adamantyl 3-nitrobenzoyl(phenyl)thiocarbamate 6
IR (KBr) cm– 1 1685; 1H-NMR (CDCl3) d: 1.41–1.75 (m, 6H, 3 CH2),
1.93–2.25 (m, 9H, 3 CH2 and 3 CH), 7.23–8.81 (m, 9H, arom H).
Anal. Calcd. for C24H24N2O4S: C, 66.04; H, 5.54; N, 6.42; S, 7.34.
Found: C, 66.00; H, 5.54; N, 6.49; S, 7.60.
O-1-Adamantyl 4-chlorobenzoyl(phenyl)thiocarbamate 7
IR (KBr) cm– 1 1690; 1H-NMR (CDCl3) d: 1.42–1.71 (m, 6H, 3 CH2),
1.90–2.33 (m, 9H, 3 CH2 and 3 CH), 7.20–8.06 (m, 9H, arom H).
Anal. Calcd. for C24H24ClNO2S: C, 67.67; H, 5.68; N, 3.29; S, 7.53.
Found: C, 67.95; H, 5.70; N, 3.40; S, 7.31.
O-1-Adamantyl 3,4-
dichlorobenzoyl(phenyl)thiocarbamate 8
IR (KBr) cm– 1 1690; 1H-NMR (CDCl3) d: 1.40–1.80 (m, 6H, 3 CH2),
1.90-2.48 (m, 9H, 3 CH2 and 3 CH), 7.16–8.05 (m, 8H, arom H).
Anal. Calcd. for C24H23Cl2NO2S: C, 62.61; H, 5.04; N, 3.04; S, 6.96.
Found: C, 62.43; H, 4.99; N, 3.15; S, 7.07.
References
[1] W. Walter, K. D. Bode, Angew. Chem. Int. Ed Engl. 1967, 6,
281–293, and references therein.
[2] J. M. Quante, R. A. Hoke, P. D. Mize, D. L. Woodard, O. L.
Willner (Becton, Dickinson and Company). US Patent,
5516902, 1996 [Chem. Abstr. 1996, 125, 50759z].
O-1-Adamantyl 3,5-
dichlorobenzoyl(phenyl)thiocarbamate 9
IR (KBr) cm– 1 1685; 1H-NMR (CDCl3) d: 1.32–1.78 (m, 6H, 3 CH2),
1.92–2.32 (m, 9H, 3 CH2 and 3 CH), 7.12–7.85 (m, 8H, arom H).
Anal. Calcd. for C24H23Cl2NO2S: C, 62.61; H, 5.04; N, 3.04; S, 6.96.
Found: C, 62.52; H, 5.07; N, 3.07; S, 6.72.
[3] A. M. Plutin, M. Suarez, E. Ochoa, T. Machado, et al., Tetra-
hedron 2005, 61, 5812–5817.
[4] H. Arslan, U. Flꢁrke, N. Kꢂlcꢂ, Spectrochim. Acta A Mol. Bio-
mol. Spectrosc. 2007, 67, 936–943.
[5] G. A. Digenis, N. P. Rodis (University of Kentucky Research
Foundation). US Patent, 5539123. 1996 [Chem. Abstr. 1996,
125, 167993n].
O-1-Adamantyl 3,4,5-
trimethoxybenzoyl(phenyl)thiocarbamate 10
IR (KBr) cm– 1 1690; 1H-NMR (CDCl3) d: 1.45–1.80 (m, 6H, 3 CH2),
1.80–2.30 (m, 9H, 3 CH2 and 3 CH), 3.94 (s, 9H, 3 CH3O), 7.14–
7.64 (m, 7H, arom H). Anal. Calcd. for C27H31NO5S: C, 67.34; H,
6.49; N, 2.91; S, 6.66. Found: C, 67.22; H, 6.54; N, 3.07; S, 6.55.
[6] N. S. Ramazonov, V. N. Syrov, S. Yu, Chem. Nat. Compd.
2006, 42, 558–561.
[7] P. Kutschy, M. Suchy, A. Andreani, M. Dzurilla, et al., Tetra-
hedron 2002, 58, 9029–9039.
O-1-Adamantyl 1,1'-biphenyl-4-
[8] http://www.rsc.org/Publishing/Journals/P1/article.asp?doi=
P19950000369. M. Sakamoto, M. Yoshiaki, M. Takahashi,
T. Fujita, S. Watanabe, J. Chem. Soc. Perkin Trans. 1, 1995, 4,
373–377.
ylcarbonyl(phenyl)thiocarbamate 11
IR (KBr) cm– 1 1685; 1H-NMR (CDCl3) d: 1.41–1.79 (m, 6H, 3 CH2),
1.93–2.31 (m, 9H, 3 CH2 and 3 CH), 7.05–8.20 (m, 14H, arom H).
Anal. Calcd. for C30H29NO2S: C, 77.06; H, 6.25; N, 3.00; S, 6.86.
Found: C, 77.30; H, 6.36; N, 3.10; S, 6.51.
[9] A. Ranise, A. Spallarossa, S. Schenone, O. Bruno, et al., J.
Med. Chem. 2003, 46, 768–781.
[10] Mugnoli, A. Borassi, A. Spallarossa, S. Cesarini, Acta Crystal-
logr. C 2006, 62, 315–317.
O-1-Adamantyl 1-naphthoyl(phenyl)thiocarbamate 12
IR (KBr) cm– 1 1690; 1H-NMR (CDCl3) d: 1.42–2.13 (m, 15H, 6 CH2
and 3 CH), 7.03–8.60 (m, 12H, arom H). Anal. Calcd. for
[11] A. Spallarossa, S. Cesarini, A. Ranise, S. Schenone, et al.,
Eur. J. Med. Chem. 2008. DOI: 10.1016/j.ejmech.2008.10.032.
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

352
A. Spallarossa et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 344–352
[12] J. J. Wang, C. W. Chi, S. Y. Lin, Y. T. Chern, Anticancer Res.
1997, 17, 3473–3477.
[19] K. D. Paull, R. H. Shoemaker, L. Hodes, A. Monks, et al., J.
Natl. Cancer Inst. 1989, 81, 1088–1092.
[20] R. Bai, K. D. Paull, C. L. Herald, G. R. Pettit, E. Hamel, J. Biol.
Chem. 1991, 266, 15882–15889.
[13] J. J. Wang, S. S. Wang, C. F. Lee, M. A. Chung, Y. T. Chern,
Chemotherapy 1997, 43, 182–189.
[21] A. Monks, D. Scudiero, P. Skehan, R. Shoemaker, et al., J.
Natl. Cancer Inst. 1991, 83, 757–766.
[14] J. J. Wang, T. Y. Liu, P. H. Yin, C. W. Wu, et al., Anticancer
Res. 2000, 20, 3067–3073.
[22] K. D. Paull, C. M. Lin, L. Malspeis, E. Hammel, Cancer Res.
1992, 52, 3892–3900.
[15] L. Hareng, W. Lasek, T. Switaj, J. Sienko, et al., Anticancer
Res. 2006, 26, 1209–1215.
[23] M. R. Boyd, K. D. Paull, L. R. Rubinstein in Cytotoxic Anti-
cancer Drugs: Models and Concepts for Drug Discovery and
Development (Eds.: F. A. Vleriote, T. H. Corbett, L. H. Baker),
Kluwer Academic, Hingham, MA, USA, 1992, pp 11–34.
[16] M. I. Dawson, Z. Xia, G. Liu, M. Ye, et al., J. Med. Chem. 2007,
50, 2622–2639.
[17] P. Lorenzo, R. Alvarez, M. A. Ortiz, S. Alvarez, et al., J. Med.
Chem. 2008, 51, 5431–5440.
[24] J. N. Weinstein, T. G. Myers, P. M. O'Connor, S. H. Friend, et
al., Science 1997, 275, 343–349.
[18] M. R. Boyd in Cancer: Principles and Practice of Oncology
(Eds.: V. T. J. DeVita, S. Hellman, S. A. Rosenberg), Lippin-
cott, Philadelphia, PA, USA, 1989, Vol. 3, pp 1–12.
[25] M. R. Grever, S. A. Schepartz, B. Chabner, Semin. Oncol.
1992, 19, 622–638.
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com