Synthesis and structure evaluation of new complex butylarylpiperazin-1-yl derivatives

Article abstract of DOI:10.1007/s00044-013-0740-z

A series of arylpiperazine derivatives of 1,16-diphenyl-19-azahexacyclo- [14.5.1.0^2,15.0^3,8.0^9,14.0^17,21] docosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,22-trione and 4,10-diphenyl-1H,2H,3H, 5H-indeno[1,2-f]isoindole-1,3,5-trione was synthesized. The pharmacological profile of compound 4 at the 5-HT_1A receptor was measured by binding assay. The title compounds were tested in cell-based assay against the human immunodeficiency virus type-1. The X-ray crystallographic studies of derivatives 2, 6, 7, 11, 19, and 20 were presented.

Full text of DOI:10.1007/s00044-013-0740-z

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2014) 23:1519–1536
DOI 10.1007/s00044-013-0740-z
ORIGINAL RESEARCH
Synthesis and structure evaluation of new complex
butylarylpiperazin-1-yl derivatives
•
Daniel Szulczyk Anna Bielenica Michał A. Dobrowolski
•
•
•
Łukasz Dobrzycki Mariola Krawiecka Bozena Kuran
•
•
_
Marta Struga
Received: 21 March 2013 / Accepted: 17 August 2013 / Published online: 3 September 2013
Ó The Author(s) 2013. This article is published with open access at Springerlink.com
´
´
Abstract A series of arylpiperazine derivatives of 1,
16-diphenyl-19-azahexacyclo-[14.5.1.02,15.03,8.09,14.017,21
(Gonzalez-Gomez et al., 2003) and a1-adrenergic receptors
(Prandi et al., 2012).
]
docosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,22-trione and
4,10-diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-
trione was synthesized. The pharmacological profile of
compound 4 at the 5-HT1A receptor was measured by
binding assay. The title compounds were tested in cell-
based assay against the human immunodeficiency virus
type-1. The X-ray crystallographic studies of derivatives 2,
6, 7, 11, 19, and 20 were presented.
Using quantitative structure–activity relationship analysis,
the ‘‘rule of five’’ scheme was worked out for orally admin-
istrated drugs (Lipinski et al., 1997; Kerns and Di, 2008).
According to authors, the drugs that cross the blood–brain
barrier are those of molecular mass lower than 450 u and of
theoretical partition coefficient n-octanol/water (logP) being
in the range of 1–4 or logD7.4 1–3. The biological barrier
permeability is also determined by the following important
parameters: numbers of hydrogen bond donors and acceptors
in the potential medicine’s structure (HBD maximum 4 and
HBA less than 6), polar surface area (PSA) correlated with
Keywords 5-HT1A receptor Á Arylpiperazines Á
X-ray crystallography Á Diels–Alder reaction
2
˚
them [expected value is less than 60–70 A (Oprea, 2002)], as
well as compound’s solubility (logS greater than 60 lg/cm3).
Proper drug permeability makes it possible to cross the barrier
and to reach the regions of a drug’s action.
Introduction
The literature survey shows that many ligands of serotonin
5-HT1A, 5-HT2A, and 5-HT7 receptors contain a flexible
hydrocarbon chain of different lengths, attached to an
arylpiperazine moiety that is the pharmacophore group
(Fig. 1) (Lewgowd et al., 2011; Czopek et al., 2010; Bo-
jarski, 2006; Leopoldo, 2004). The pharmacophore group
is recognized not only by metabotropic serotonin receptor
binding sites, but also by those of D2-dopaminergic
In last two decades, a number of binding modes of long-
chain arylpiperazine derivatives to 5-HT1A (Lewgowd et al.,
2011; Nowak et al., 2006), 5-HT2A (Klabunde and Evers,
2005; Bronowska et al., 2001), and 5-HT7 (Kim et al., 2012;
´
´
Lopez-Rodrıguez et al., 2003) receptors have been proposed.
The ionic interaction between the protonated nitrogen of the
piperazine ring of a ligand and Asp3.32 residue of the
receptor (Nowak et al., 2006; Vermeulen et al., 2003; Roth
et al., 1997) constituted a main essential interaction. The
hydrophobic terminal imide or amide group, the hydrocar-
bon linker, and an aromatic ring bound to the piperazine
moiety are placed in a hydrophobic pocket composed of
aromatic and/or aliphatic amino acids side chains (Kim et al.,
2012; Varin et al., 2010; Lepailleur et al., 2005). The flexible
chain of N-(4-arylpiperazin-1-yl-alkyl)substituted deriva-
tives can adopt one of the two main conformations: extended
or bent. The results of geometry optimization (Lewgowd
et al., 2011) proved that conformers with extended spacer are
D. Szulczyk Á A. Bielenica (&) Á M. Krawiecka Á B. Kuran Á
M. Struga
Department of Medical Chemistry, Faculty of Medicine, Medical
University of Warsaw, Oczki 3 Street, 02-007 Warsaw, Poland
e-mail: abielenica@wum.edu.pl
M. A. Dobrowolski Á Ł. Dobrzycki
Faculty of Chemistry, University of Warsaw, Pasteura 1 Street,
02-093 Warsaw, Poland
123

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Med Chem Res (2014) 23:1519–1536
Fig. 1 Some representative
5-HT1A receptor ligands
N
N
O
N
O
N
N
H3CO
Buspirone
O
N
N
N
NAN-190
O
H3CO
N
O
N
O
N
BMY-7378
preferred in a solution, whereas in vacuum bent geometries
predominate. Theoretical calculations determine minimum
energy for extended linker conformations also in solid state
and for complexes with a receptor (Siracusa et al., 2008).
According to pharmacophore model of the 5-HT1A receptor
(Chilmonczyk et al., 1997; Bronowska et al., 2001), a folded
conformer promotes high affinity for the 5-HT1A receptor. It
is known that ligand binding can lead to a change in the
conformation of the receptor protein, however, also in the
ligand itself (Sylte et al., 2001). In addition, the role of the
solvent molecules is quite difficult to explain—they can take
part in a ligand—receptor H-bond formation, be involved in
the process of a receptor activation or influence entropy
effects (Pardo et al., 2007).
spectrometer, operating at 300 MHz (1H NMR) and 75 MHz
(13C NMR). The chemical shift values are expressed in ppm
relative to TMS as an internal standard. Mass spectral elec-
trospray ionization (ESI) measurements were carried out on
a Mariner Perspective—Biosystem instrument with TOF
detector. The spectra were obtained in the positive ion mode
with a declustering potential 140–300 V. Elemental analyses
were recorded on a CHN model 2400 Perkin-Elmer. TLC
was carried out using silicagel 60 F254 with layer thickness of
0.25 mm (Merck) and the results were visualized using UV
lamp at 254 nm. Column chromatography was carried out
using silica gel 60 (200–400 mesh, Merck) and chloroform/
methanol (19.5:0.5 vol) mixture as eluent.
This paper reports synthesis and biological activity of
compounds purposely designed to combine the bulky hydro-
phobic imide ring with alkyl linker bearing different substit-
uents. The collected group of arylpiperazine derivatives can
be used for further investigations concerning ligand-5-HT
receptor interactions. For this reason X-ray crystallographic
studies of derivatives 2, 6, 7, 11, 19, and 20 were described.
The molecular descriptors for selected arylpiperazine deriv-
atives were presented. The pharmacological profile of the
compound 4 was evaluated for its affinity to the 5-HT1A
receptor. It was reported, that cytotoxicity of aromatic, high-
volume arylpiperazine derivatives is low (Filosa et al., 2007;
Ananda Kumar et al., 2009), and they act as anti-HIV-1 agents
(Yang et al., 2010), cytotoxicity and anti-HIV activity of
selected derivatives were examined.
1,16-Diphenyl-19-azahexacyclo
[14.5.1.02,15.03,8.09,14.017,21]docosa-
2,3,5,7,8,9,11,13,14-nonaene-18,20,22-trione (1)
The mixture of 2.14 g (0.004 mol) of 1,3-diphenyl-2H-
cyclopenta[l]phenanthren-2-one (‘‘Phencyclone’’) was
suspended in 75 ml of benzene and 0.48 g (0.005 mol) of
maleimide was added. After refluxing time of 8 h the
residue was evaporated, and the residue was purified by
column chromatography (chloroform:methanol 9.5:0.5
vol). The combined fractions were condensed to dryness to
give 1.86 g (87 %) of (1), m.p. 327–328 °C. 1H NMR
(DMSO-d6) d (ppm): 11.04 (s, 1H, NH), 8.85 (d, 2H,
CHarom., J = 8.4 Hz), 8.24 (d, 2H, CHarom., J = 7.8 Hz),
7.73 (t, 2H, CHarom., J = 7.2 Hz), 7.59–7.51 (m, 4H,
CHarom.), 7.41 (t, 2H, CHarom., J = 7.5 Hz), 7.22 (t, 2H,
CHarom., J = 7.8 Hz), 7.14 (d, 2H, CHarom., J = 7.8 Hz),
7.04 (d, 2H, CHarom., J = 5.7 Hz), 4.65 (s, 2H, CH). 13C
NMR (DMSO-d6) d (ppm): 197.12, 173.09, 173.05,
134.03, 133.98, 133.48, 133.22, 133.76 (2C), 132.37,
132.12, 132.09, 132.06, 132.00, 131.83, 131.62, 131.47,
130.49, 130.21, 129.75, 129.68 (2C), 128.63, 128.54,
127.96, 126.84, 126.78, 122.35, 122.31, 63.65, 63.59,
45.25, 45.20. Anal. Calcd. for C33H21NO3: C, 82.45; H,
4.38; N, 2.92. Found: C, 82.40; H, 3.00; N, 4.40.
Materials and methods
Chemistry
All chemicals and solvents were purchased from Aldrich.
Melting points were determined on an Electrothermal Dig-
ital Melting Point Apparatus and are uncorrected. The NMR
spectra were recorded on a Bruker AVANCE DMX400
123

Med Chem Res (2014) 23:1519–1536
1521
19-(4-Bromobutyl)-1,16-diphenyl-19-azahexacyclo-
[14.5.1.02,15.03,8.09,14.017,21]-docosa-2,3,5,7,8,9,11,13,
14-nonaene-18,20,22-trione (2)
7.36–7.14 (m, 4H, CHarom.), 7.05 (d, 2H, CHarom.
,
J = 9.3 Hz), 6.75 (d, 1H, CHarom., J = 8.7 Hz), 6.60 (d–d,
1H, CHarom., J1 = 5.1 Hz, J2 = 5.4 Hz), 4.67 (s, 2H, CH),
3.78 (s, 1H, CH2), 3.31–2.72 (m, 3H, CH2), 3.05 (s, 1H,
CH2), 2.92 (s, 1H, CH2), 2.05 (t, 4H, CH2, J = 2.1 Hz),
1.44 (t, 2H, CH2, J = 7.2 Hz), 1.24–1.22 (m, 1H, CH2),
0.88–0.83 (m, 1H, CH2), 0.33–0.23 (m, 2H, CH2). 13C
NMR (DMSO-d6) d (ppm): 197.17, 173.08, 173.02,
157.48, 147.68, 137.35, 134.24, 133.73, 133.68, 133.35,
133.30, 132.12 (3C), 132.07, 132.02, 132.00, 131.87,
131.69, 131.51, 130.31, 130.12, 129.99, 129.84, 129.73,
128.47, 128.32, 127.77, 126.58, 126.49, 122.41, 122.19,
119.83, 108.92, 63.75, 63.72, 50.87, 50.43, 48.58, 48.49,
45.34, 45.32, 44.86, 32.69, 28.81, 28.73. ESI MS: m/
z = 697.1 [M?H]? (100 %).
A mixture of imide (1) (1.41 g, 0.003 mol), 1,4-dibromo-
butane (0.7 ml, 0.006 mol), anhydrous K2CO3 (1.39 g),
and catalytic amount of KI were refluxed in acetonitrile for
24 h. Then the solvent was removed on a rotary evaporator
and the oily residue was purified by column chromatog-
raphy (chloroform:methanol 9.5:0.5 vol). The combined
fractions were condensed to dryness to give 1.36 g (86 %)
1
of (2), m.p. 286–289 °C. H NMR (DMSO-d6) d (ppm):
8.84 (d, 2H, CHarom., J = 9.0 Hz), 8.27 (d, 2H, CHarom.
,
J = 8.4 Hz), 7.75 (t, 2H, CHarom., J = 8.1 Hz), 7.59–7.52
(m, 4H, CHarom.), 7.43 (t, 2H, CHarom., J = 8.7 Hz),
7.25–7.14 (m, 4H, CHarom.), 7.01 (d, 2H, CHarom.
,
J = 7.5 Hz), 4.61 (s, 2H, CH), 2.87–2.78 (m, 2H, CH2),
2.11–2.07 (m, 2H, CH2), 1.24–1.21 (m, 2H, CH2),
0.49–0.43 (m, 2H, CH2). 13C NMR (DMSO-d6) d (ppm):
197.09, 173.12, 173.01, 134.11, 133.88, 133.51 (2C),
133.28, 133.39, 132.32, 132.17, 132.04, 132.00, 131.90,
131.87, 131.65, 131.36, 130.27, 130.19, 129.83, 129.69,
129.66, 128.52, 128.47, 127.89, 126.72, 126.68, 122.33,
122.30, 63.68, 63.61, 45.31, 45.28, 44.89, 32.79, 28.74,
28.53. ESI MS: m/z = 638.0 [M?H]? (100 %).
19-(4-(4-(2-(Methyloxy)phenyl)piperazin-1-yl)butyl)-
1,16-diphenyl-19-azahexa-cyclo[14.5.1.02,15.03,8.09,14
.017,21]docosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,
22-trione (4)
1
Yield: 71 %, m.p. 197–200 °C. H NMR (DMSO-d6) d
(ppm): 8.83 (d, 2H, CHarom., J = 8.4 Hz), 8.27 (d, 2H,
CHarom., J = 7.8 Hz), 7.74 (t, 2H, CHarom., J = 7.8 Hz),
7.58–7.52 (m, 4H, CHarom.), 7.42 (t, 2H, CHarom.
,
J = 7.5 Hz), 7.24–7.14 (m, 4H, CHarom.), 7.10 (d, 2H,
CHarom., J = 8.7 Hz), 6.92–6.83 (m, 4H, CHarom.), 4.68 (s,
2H, CH), 3.75 (s, 3H, OCH3), 2.78–2.72 (m, 7H, CH2),
2.17–2.12 (m, 4H, CH2), 1.44 (t, 3H, CH2, J = 7.2 Hz),
1.23–1.16 (m, 1H, CH2), 1.05 (t, 1H, CH2, J = 6.9 Hz).
13C NMR (DMSO-d6) d (ppm): 197.14, 173.11, 173.09,
157.44, 147.52, 142.74, 137.31, 134.27, 133.79, 133.66,
133.31 (2C), 133.30, 132.16 (2C), 132.03, 132.01, 131.96,
131.83, 131.68, 131.57, 130.34, 130.05, 129.94, 129.81,
129.78, 128.44, 128.29, 127.68, 126.53, 126.47, 122.46,
122.21, 119.80, 108.87, 63.74, 63.71, 55.12, 50.85, 50.46,
48.53, 48.47, 45.35, 45.31, 44.88, 32.67, 28.78, 28.74. ESI
MS: m/z = 726.1 [M?H]? (100 %).
General method for the preparation of arylpiperazine
derivatives of 19-(4-bromobutyl)-1,16-diphenyl-19-
azahexacyclo[14.5.1.02,15.03,8.09,14.017,21]docosa-2,3,
5,7,8,9,11,13,14-nonaene-18,20,22-trione (3–9)
A mixture of derivative (2) (0.3 g, 0.002 mol) and the
corresponding amine (0.004 mol), anhydrous K2CO3
(0.3 g), and catalytic amount of KI were refluxed in ace-
tonitrile for 30 h. Then the mixture was filtered off and the
solvent was evaporated. The gray residue was purified by
column chromatography (chloroform:methanol 9.5:0.5 vol)
and/or crystallized from methanol. Obtained compounds
were converted into their hydrochlorides. The solid product
was dissolved in methanol saturated with gaseous HCl. The
hydrochloride was precipitated by addition of diethyl ether.
The crude product was crystallized from an appropriate
solvent.
1,16-Diphenyl-19-(4-(4-phenylpiperazin-1-yl)butyl)-
19-azahexacyclo-[14.5.1.02,15.03,8.09,14.017,21]docosa-
2,3,5,7,8,9,11,13,14-nonaene-18,20,22-trione (5)
1
1,16-Diphenyl-19-(4-(4-pyridin-2-ylpiperazin-1-yl)
butyl)-19-azahexacyclo-[14.5.1.02,15.03,8.09,14
.017,21]docosa-2,3,5,7,8,9,11,13,14-nonaene-18,
20,22-trione (3)
Yield: 69 %, m.p. 202–203 °C. H NMR (DMSO-d6) d
(ppm): 8.71 (d, 2H, CHarom., J = 8.1 Hz), 8.31 (d, 2H,
CHarom.
, J = 8.1 Hz), 7.62–7.69 (m, 2H, CHarom.),
7.64–7.48 (m, 7H, CHarom.), 7.45–7.37 (m, 3H, CHarom.),
7.22–7.14 (m, 6H, CHarom.), 7.08–7.04 (m, 1H, CHarom.),
4.48 (s, 2H, CH), 3.51–3.42 (m, 4H, CH2), 3.27–3.23 (m,
3H, CH2), 3.13–2.95 (m, 4H, CH2), 2.63–2.61 (m, 2H,
CH2), 2.35–2.29 (m, 3H, CH2). 13C NMR (DMSO-d6) d
(ppm): 197.23, 173.17, 173.09, 157.53, 147.75, 137.42,
1
Yield: 67 %, m.p. 200–203 °C. H NMR (DMSO-d6) d
(ppm): 8.81 (d, 2H, CHarom., J = 8.7 Hz), 8.27 (d, 2H,
CHarom., J = 8.1 Hz), 8.09–8.06 (m, 1H, CHarom.), 7.74 (t,
2H, CHarom., J = 7.8 Hz), 7.57–7.40 (m, 7H, CHarom.),
123

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Med Chem Res (2014) 23:1519–1536
19-(4-(4-(4-Acetylphenyl)piperazin-1-yl)butyl)-1,
134.33, 133.82, 133.79, 133.41, 133.32, 132.17, 132.11,
132.06, 132.03, 131.92, 131.77 (2C), 131.58, 130.43,
130.18, 129.98, 129.89, 129.78 (2C), 128.51, 128.39,
127.81, 126.62, 126.53, 122.48, 122.22, 119.86, 115.37,
115.29, 63.81, 63.78, 50.90, 50.62, 48.64, 48.54, 45.48,
45.46, 44.93, 32.70, 28.84, 28.77. ESI MS: m/z = 696.2
[M?H]? (100 %).
16-diphenyl-19-azahexacyclo-[14.5.1.02,15.03,8
.09,14.017,21]docosa-2,3,5,7,8,9,11,13,14-nonaene-
18,20,22-trione (8)
1
Yield: 77 %, m.p. 202–204 °C. H NMR (DMSO-d6) d
(ppm): 8.82 (d, 2H, CHarom., J = 8.1 Hz), 8.28 (d, 2H,
CHarom., J = 7.8 Hz), 7.80–7.72 (m, 4H, CHarom.), 7.54 (t,
2H, CHarom.
J = 7.5 Hz), 7.22 (t, 2H, CHarom., J = 7.8 Hz), 7.15 (d,
2H, CHarom. J = 7.8 Hz), 7.03 (d, 2H, CHarom.
,
J = 7.2 Hz), 7.42 (t, 2H, CHarom.,
19-(4-(4-(4-Chlorophenyl)piperazin-1-yl)butyl)-1,
16-diphenyl-19-azahexacyclo-[14.5.1.02,15.03,8.09,14
.017,21]docosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,
22-trione (6)
,
,
J = 8.1 Hz), 6.92 (d, 2H, CHarom., J = 9.3 Hz), 4.68 (s,
2H, CH), 3.52–3.44 (m, 4H, CH2), 3.16 (t, 4H, CH2,
J = 4.2 Hz), 2.77 (t, 2H, CH2, J = 6.9 Hz), 2.44 (s, 3H,
COCH3), 2.10–2.07 (m, 4H, CH2), 1.46 (t, 2H, CH2,
J = 6.9 Hz). 13C NMR (DMSO-d6) d (ppm): 197.23,
186.59, 173.39, 173.37, 157.51, 147.59, 137.62, 134.57,
133.89, 133.85, 133.69, 133.57, 132.55, 132.34, 132.17,
132.11, 131.92, 131.85, 131.69, 131.57, 130.46, 130.38,
129.90, 129.83, 129.77, 129.72, 128.59, 128.30, 127.75,
126.61, 126.54, 122.47, 122.26, 119.82, 115.36, 115.34,
63.85, 63.82, 50.78, 50.68, 48.61, 48.59, 45.47, 45.44,
44.92, 32.77, 28.90, 28.83, 26.82. ESI MS: m/z = 738.6
[M?H]? (100 %).
1
Yield: 92 %, m.p. 220–221 °C. H NMR (DMSO-d6) d
(ppm): 8.15 (d, 2H, CHarom., J = 8.4 Hz), 8.27 (d, 2H,
CHarom., J = 7.5 Hz), 7.74 (t, 2H, CHarom., J = 7.8 Hz),
7.57–7.52 (m, 4H, CHarom.), 7.42 (t, 2H, CHarom.
,
J = 7.5 Hz), 7.24–7.13 (m, 6H, CHarom.), 7.02 (d, 2H,
CHarom., J = 8.7 Hz), 6.88 (d, 2H, CHarom., J = 9.3 Hz),
4.67 (s, 2H, CH), 3.49–3.43 (m, 4H, CH2), 3.28–3.20 (m,
3H, CH2), 3.15–2.99 (m, 4H, CH2), 2.69–2.59 (m, 2H,
CH2), 2.37–2.30 (m, 3H, CH2). 13C NMR (DMSO-d6) d
(ppm): 197.21, 173.11, 173.06, 157.50, 147.74, 137.41,
134.36, 133.81, 133.78, 133.43, 133.33, 132.15, 132.12,
132.07, 132.04, 131.95, 131.72, 131.68, 131.56, 130.46,
130.12, 129.97, 129.84, 129.73 (2C), 128.59, 128.37,
127.85, 126.65, 126.54, 122.47, 122.25, 119.83, 115.39,
115.28, 63.80, 63.76, 50.91, 50.67, 48.68, 48.57, 45.42,
45.40, 44.96, 32.75, 28.86, 28.73. ESI MS: m/z = 730.1
[M?H]? (100 %).
1,16-Diphenyl-19-(4-(4-(2-(trifluoromethyl)phenyl)
piperazin-1-yl)butyl)-19-azahexa-cyclo
[14.5.1.02,15.03,8.09,14.017,21]docosa-2,3,5,7,8,9,
11,13,14-nonaene-18,20,22-trione (9)
1
Yield: 84 %, m.p. 211–212 °C. H NMR (DMSO-d6) d
(ppm): 8.78 (d, 2H, CHarom., J = 8.4 Hz), 8.30 (d, 2H,
CHarom., J = 7.8 Hz), 7.74 (t, 2H, CHarom., J = 6.3 Hz),
19-(4-(4-(2-Fluorophenyl)piperazin-1-yl)butyl)-1,
16-diphenyl-19-azahexacyclo-[14.5.1.02,15.03,8.09,14
.017,21]docosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,
22-trione (7)
7.69–7.60 (m, 3H, CHarom.), 7.54 (t, 3H, CHarom.
,
J = 6.3 Hz), 7.48–7.40 (m, 4H, CHarom.), 7.18–7.14 (m,
2H, CHarom.), 4.48 (s, 2H, CH), 3.95–3.91 (m, 3H, CH2),
3.61–3.37 (m, 10H, CH2), 3.22–3.17 (m, 3H, CH2),
3.01–2.92 (m, 4H, CH2). 13C NMR (DMSO-d6) d (ppm):
197.19, 173.12, 173.05, 157.51, 147.74, 137.40, 134.36,
133.88, 133.77, 133.43, 133.37, 132.15, 132.10, 132.04,
132.01, 131.99, 131.78 (2C), 131.54, 130.48, 130.13,
129.92, 129.86, 129.71 (2C), 128.53, 128.37, 127.86,
126.66, 126.51, 123.92, 122.45, 122.18, 119.83, 115.34,
115.28, 63.80, 63.78, 61.17, 50.92, 50.68, 48.62, 48.59,
45.44, 45.41, 44.97, 32.76, 31.28, 28.87, 28.73. ESI MS: m/
z = 792.2 [M?H]? (100 %).
1
Yield: 87 %, m.p. 205–207 °C. H NMR (DMSO-d6) d
(ppm): 8.83 (d, 2H, CHarom., J = 8.4 Hz), 8.28 (d, 2H,
CHarom., J = 7.2 Hz), 7.74 (t, 2H, CHarom., J = 7.2 Hz),
7.58–7.52 (m, 4H, CHarom.), 7.42 (t, 2H, CHarom.
,
J = 7.8 Hz), 7.24–7.14 (m, 4H, CHarom.), 7.10–6.95 (m,
6H, CHarom.), 4.68 (s, 2H, CH), 3.39–3.36 (m, 2H, CH2),
3.11–3.07 (m, 2H, CH2), 3.03–2.93 (m, 4H, CH2),
2.73–2.71 (m, 4H, CH2), 2.14–2.10 (m, 4H, CH2). 13C
NMR (DMSO-d6) d (ppm): 197.20, 173.41, 173.35,
157.56, 147.54, 137.61, 134.41, 133.87, 133.79, 133.54,
133.49, 132.28, 132.17, 132.08, 132.02, 131.90, 131.76,
131.61, 131.55, 130.40, 130.17, 129.93, 129.82, 129.73,
129.70, 128.53, 128.34, 127.82, 126.69, 126.51, 122.48,
122.23, 119.88, 115.33, 115.27, 63.81, 63.74, 50.98, 50.63,
48.62, 48.54, 45.43, 45.41, 44.96, 32.72, 28.82, 28.79. ESI
MS: m/z = 714.2 [M?H]? (100 %).
10-Diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-
1,3,5-trione (10)
The mixture of 2.06 g (0.006 mol) of 1,3-diphenylcyclo-
penta[a]indene-2,8-dione (‘‘Indanocyclone’’) was sus-
pended in 75 ml of benzene and 0.65 g (0.006 mol) of
123

Med Chem Res (2014) 23:1519–1536
1523
4,10-Diphenyl-2-[4-(4-phenylpiperazin-1-yl)butyl]-
maleimide was added. After refluxing time of 16 h the
yellow residue was evaporated. Next it was purified by
column chromatography (chloroform:methanol 9.5:0.5
vol). The combined fractions were condensed to dryness to
1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-trione (12)
1
Yield: 87 %, m.p. 231–232 °C. H NMR (DMSO-d6) d
(ppm): 7.61 (t, 3H, CHarom., J = 3.6 Hz), 7.56–7.44 (m,
8H, CHarom.), 7.40–7.31 (m, 2H, CHarom.), 7.28–7.23 (m,
2H, CHarom.), 6.98 (d, 2H, CHarom., J = 8.1 Hz), 6.86 (t,
1
give 1.50 g (73 %) of (10), m.p. 223–225 °C. H NMR
(CDCl3) d (ppm): 7.60 (d, 2H, CHarom., J = 2.7 Hz),
7.59–7.58 (m, 2H, CHarom.), 7.52 (d, 2H, CHarom.
,
1H, CHarom.
,
J = 7.2 Hz), 6.23 (d, 1H, CHarom.,
J = 2.1 Hz), 7.51–7.49 (m, 2H, CHarom.), 7.45 (d, 2H,
CHarom., J = 2.1 Hz), 7.44–7.40 (m, 4H, CHarom.). 13C
NMR (CDCl3) d (ppm): 190.91, 165.89, 165.73, 149.69,
141.97, 139.37, 135.58, 135.52, 135.14, 134.81, 134.24,
131.59, 130.57, 130.54, 129.87, 129.34, 129.28 (2C),
129.09 (3C), 128.59 (2C), 127.91 (2C), 124.59, 124.54.
ESI MS: m/z = 424.1 [M?Na]? (100 %).
J = 6.6 Hz), 3.76 (d, 2H, CH2, J = 11.4 Hz), 3.49–3.42
(m, 4H, CH2), 3.15–3.02 (m, 6H, CH2), 1.72–1.69 (m, 2H,
CH2), 1.57–1.52 (m, 3H, CH2). 13C NMR (CDCl3) d
(ppm): 190.32, 165.58, 165.37, 149.52, 148.83, 141.58,
137.54, 135.13, 134.77, 134.39, 134.12, 133.94, 132.22,
130.47, 129.63 (2C), 129.41 (4C), 128.85 (2C), 128.49
(4C), 128.36 (2C), 127.24 (3C), 124.11, 123.53, 57.84,
57.65, 50.97, 50.86, 36.63, 34.50, 29.57, 26.48. ESI MS: m/
z = 618.4 [M?H]? (100 %).
2-(4-Bromobutyl)-4,10-diphenyl-1H,2H,3H,5H-
indeno[1,2-f]isoindole-1,3,5-trione (11)
4,10-Diphenyl-2-{4-[4-(pyridin-2-yl)piperazin-1-
yl]butyl}-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,
3,5-trione (13)
A mixture of imide (10) (2.64 g, 0.006 mol), 1,4-dibro-
mobutane (1.5 ml, 0.012 mol), anhydrous K2CO3 (2.51 g),
and catalytic amount of KI were refluxed in acetonitrile for
14 h. Then the solvent was removed on a rotary evaporator
and the dark yellow solid residue was purified by column
chromatography (chloroform:methanol 9.5:0.5 vol). The
combined fractions were condensed to dryness to give
2.44 g (92 %) of (11), m.p. 241–242 °C. 1H NMR (CDCl3)
d (ppm): 7.63–7.59 (m, 3H, CHarom.), 7.56–7.55 (m, 2H,
CHarom.), 7.53–7.50 (m, 4H, CHarom.), 7.48–7.41 (m, 5H,
CHarom.), 3.72 (q, 2H, CH2, J = 7.2 Hz), 3.54 (t, 2H, CH2,
J = 6.9 Hz), 3.35 (t, 2H, CH2, J = 6.3 Hz), 1.26–1.21 (m,
2H, CH2). 13C NMR (CDCl3) d (ppm): 190.21, 165.67,
165.49, 148.11, 141.34, 137.49, 135.09, 134.80, 134.26,
134.04, 133.87, 132.08, 130.52, 129.75, 129.37 (3C),
128.79 (3C), 128.51 (2C), 128.17, 127.14 (2C), 124.03,
123.48, 36.63, 34.50, 29.57, 26.48. ESI MS: m/z = 560.1
[M?Na]? (100 %).
1
Yield: 90 %, m.p. 219–220 °C. H NMR (DMSO-d6) d
(ppm): 8.14 (d, 1H, CHarom., J = 3.9 Hz), 7.82–7.74 (m,
1H, CHarom.), 7.61 (t, 3H, CHarom., J = 3.6 Hz), 7.56–7.48
(m, 8H, CHarom.), 7.40–7.31 (m, 2H, CHarom.), 7.19–7.02
(m, 1H, CHarom.), 6.84 (t, 1H, CHarom., J = 6.0 Hz), 6.23
(d, 1H, CHarom.
, J = 6.9 Hz), 4.37 (d, 2H, CH2,
J = 15.0 Hz), 3.52–3.31 (m, 6H, CH2), 3.06–2.99 (m, 4H,
CH2), 1.68–1.67 (m, 2H, CH2), 1.56–1.55 (m, 2H, CH2).
13C NMR (CDCl3) d (ppm): 190.02, 165.63, 165.27,
153.84, 147.79, 141.44, 137.41, 135.58, 134.62, 134.29,
134.07, 133.68, 132.15, 130.32, 129.46 (2C), 129.39 (3C),
128.69 (2C), 128.38 (3C), 128.28, 128.20 (2C), 127.17
(3C), 124.46, 123.74, 52.35, 51.98, 48.79, 58.23, 36.96,
34.86, 27.62, 26.13. ESI MS: m/z = 619.4 [M?H]?
(100 %).
General method for the preparation of arylpiperazine
derivatives of 2-(4-bromobutyl)-4,10-diphenyl-1H,
2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-trione (12–19)
4,10-Diphenyl-2-[4-(4-{2-[2-(trifluoromethyl)
phenyl]ethyl}piperazin-1-yl)butyl]-1H,2H,3H,5H-
indeno[1,2-f]isoindole-1,3,5-trione (14)
A mixture of derivative (11) (0.3 g, 0.0005 mol) and the
corresponding amine (0.001 mol), anhydrous K2CO3
(0.3 g), and catalytic amount of KI were refluxed in ace-
tonitrile for 30 h. Then the mixture was filtered off and the
solvent was evaporated. The yellow residue was purified by
column chromatography (chloroform:methanol 9.5:0.5 vol)
and/or crystallized from methanol. Obtained compounds
were converted into their hydrochlorides. The solid product
was dissolved in methanol saturated with gaseous HCl. The
hydrochloride was precipitated by addition of diethyl ether.
The crude product was crystallized from appropriate
solvent.
1
Yield: 91 %, m.p. 232–233 °C. H NMR (DMSO-d6) d
(ppm): 7.46–7.65 (m, 2H, CHarom.), 7.62–7.60 (m, 4H,
CHarom.), 7.56–7.44 (m, 9H, CHarom.), 7.41–7.30 (m, 2H,
CHarom.), 6.23 (d, 1H, CHarom., J = 6.6 Hz), 3.46–3.37 (m,
4H, CH2), 3.34–3.09 (m, 14H, CH2), 1.66–1.65 (m, 2H,
CH2), 1.57–1.55 (m, 2H, CH2). 13C NMR (CDCl3) d
(ppm): 190.18, 166.94, 166.57, 149.97, 148.22, 142.53,
137.16, 135.86, 134.51, 134.72, 134.58, 134.02 (2C),
132.48, 131.30, 129.64 (2C), 129.58 (3C), 129.48, 128.91
(2C), 128.75 (3C), 128.59, 128.27 (2C), 127.85 (2C),
127.03, 124.59, 123.61, 123.00, 59.89, 55.12, 55.01, 50.79,
123

1524
Med Chem Res (2014) 23:1519–1536
50.83, 36.74, 34.95, 32.73, 29.48, 26.17. ESI MS: m/
z = 714.3 [M?H]? (100 %).
133.91, 132.27 (2C), 130.39 (2C), 129.79 (2C), 129.51
(3C), 128.88 (3C), 128.68 (3C), 128.02 (2C), 127.57 (2C),
124.69, 123.24, 57.49, 57.33, 50.17, 50.06, 36.94, 34.42,
29.96, 26.76. ESI MS: m/z = 652.4 [M?H]? (100 %).
2-{4-[4-(2-Fluorophenyl)piperazin-1-yl]butyl}-4,10-
diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-
trione (15)
2-{4-[4-(2-Chlorophenyl)piperazin-1-yl]butyl}-4,10-
diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-
trione (18)
1
Yield: 88 %, m.p. 245–247 °C. H NMR (DMSO-d6) d
(ppm): 7.61 (t, 3H, CHarom., J = 3.9 Hz), 7.56–7.44 (m,
8H, CHarom.), 7.41–7.30 (m, 2H, CHarom.), 7.21–7.00 (m,
4H, CHarom.), 6.23 (d, 1H, CHarom., J = 7.8 Hz), 3.50–3.37
(m, 8H, CH2), 3.21–3.08 (m, 4H, CH2), 1.70–1.68 (m, 2H,
CH2), 1.58–1.53 (m, 2H, CH2). 13C NMR (CDCl3) d
(ppm): 191.47, 166.12, 165.97, 149.48, 148.57, 141.72,
137.16, 135.69, 134.38, 134.21, 134.09, 133.92, 132.46,
130.85 (2C), 129.36 (2C), 129.29 (3C), 128.63 (2C),
128.52 (3C), 128.47 (2C), 127.69 (4C), 124.82, 123.96,
57.06, 56.93, 50.46, 50.27, 36.12, 34.98, 29.58, 26.02. ESI
MS: m/z = 636.4 [M?H]? (100 %).
1
Yield: 75 %, m.p. 235–237 °C. H NMR (DMSO-d6) d
(ppm): 7.60 (t, 3H, CHarom., J = 3.6 Hz), 7.56–7.55 (m,
1H, CHarom.), 7.53–7.48 (m, 2H, CHarom.), 7.47–7.44 (m,
6H, CHarom.), 7.40–7.31 (m, 3H, CHarom.), 7.20–7.08 (m,
2H, CHarom.), 6.23 (d, 1H, CHarom., J = 7.8 Hz), 3.51–3.28
(m, 6H, CH2), 3.19–3.07 (m, 6H, CH2), 1.70–1.68 (m, 2H,
CH2), 1.58–1.53 (m, 6H, CH2). 13C NMR (CDCl3) d
(ppm): 190.30, 165.71, 165.49, 149.83, 148.79, 141.26,
137.44, 135.86, 134.92, 134.77, 134.51, 133.34 (2C),
132.58 (2C), 130.93 (2C), 129.81 (2C), 129.79 (2C),
128.73 (3C), 128.52 (3C), 128.39 (2C), 127.04 (2C),
124.82, 123.17, 58.14, 58.07, 52.58, 52.47, 35.97, 34.06,
29.74, 26.11. ESI MS: m/z = 652.4 [M?H]? (100 %).
2-{4-[4-(4-Fluorophenyl)piperazin-1-yl]butyl}-4,10-
diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-
trione (16)
Synthesis of 2-{4-[4-(2-metoxyphenyl)piperazin-1-
yl]butyl}-4,10-diphenyl-1H,2H,3H,5H-indeno[1,2-
f]isoindole-1,3,5-trione (19)
1
Yield: 93 %, m.p. 241–242 °C. H NMR (DMSO-d6) d
(ppm): 7.61 (t, 3H, CHarom., J = 3.9 Hz), 7.56–7.53 (m,
1H, CHarom.), 7.51–7.48 (m, 3H, CHarom.), 7.47–7.46 (m,
5H, CHarom.), 7.41–7.30 (m, 2H, CHarom.), 7.13–7.07 (m,
2H, CHarom.), 7.03–6.98 (m, 2H, CHarom.), 3.67 (d, 2H,
CH2, J = 9.0 Hz), 3.47–3.42 (m, 4H, CH2), 3.06 (d, 6H,
CH2, J = 8.4 Hz), 1.69–1.68 (m, 2H, CH2), 1.57–1.54 (m,
2H, CH2). 13C NMR (CDCl3) d (ppm): 191.19, 166.58,
165.74, 149.53, 148.82, 141.13, 137.64, 135.97, 134.27,
134.09, 134.01, 133.84, 132.16, 130.76 (2C), 129.94 (3C),
129.59 (2C), 128.89 (3C), 128.72 (3C), 128.11 (2C),
127.75 (3C), 125.49, 123.52, 57.68, 57.51, 50.94, 50.00,
36.81, 34.86, 29.37, 26.97. ESI MS: m/z = 636.4 [M?H]?
(100 %).
1
Yield: 79 %, m.p. 245–246 °C. H NMR (DMSO-d6) d
(ppm): 7.61 (t, 3H, CHarom., J = 3.6 Hz), 7.56–7.44 (m,
8H, CHarom.), 7.41–7.31 (m, 2H, CHarom.), 7.05–6.87 (m,
4H, CHarom.), 6.23 (d, 1H, CHarom., J = 6.9 Hz), 3.79 (s,
3H, OCH3), 3.47–3.44 (m, 6H, CH2), 3.07–2.97 (m, 6H,
CH2), 1.69–1.67 (m, 2H, CH2), 1.59–1.52 (m, 2H, CH2).
13C NMR (CDCl3) d (ppm): 192.35, 165.07, 164.79,
149.81, 148.96, 141.13, 137.77, 135.42, 134.37, 134.26,
134.08, 133.11 (2C), 132.66 (2C), 130.72 (3C), 129.86,
129.72 (2C), 128.91 (3C), 128.54 (2C), 128.21 (3C),
127.75 (2C), 124.11, 123.59, 62.00, 58.84, 58.71, 52.97,
52.84, 35.06, 34.26, 29.59, 26.91. ESI MS: m/z = 648.3
[M?H]? (100 %).
2-{4-[4-(4-Chlorophenyl)piperazin-1-yl]butyl}-4,10-
diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-
trione (17)
3-{4-[4-(2-Metoxyphenyl)piperazin-1-yl]butyl}3-
azatricyclo[7.3.1.05,13]trideca-(12),5,7,9(13),10-
pentaene-2,4-dione (20) was obtained according
to method presented previously (Hackling et al., 2003)
1
Yield: 82 %, m.p. 248–249 °C. H NMR (DMSO-d6) d
(ppm): 7.61 (t, 3H, CHarom., J = 3.6 Hz), 7.56–7.53 (m,
1H, CHarom.), 7.51–7.48 (m, 2H, CHarom.), 7.47–7.45 (m,
5H, CHarom.), 7.40–7.30 (m, 2H, CHarom.), 7.31–7.27 (m,
2H, CHarom.), 7.00 (d, 2H, CHarom., J = 9.0 Hz), 6.23 (d,
1H, CHarom., J = 7.5 Hz), 3.77 (d, 2H, CH2, J = 10.8 Hz),
3.49–3.72 (m, 4H, CH2), 3.07–3.01 (m, 6H, CH2),
1.68–1.66 (m, 2H, CH2), 1.57–1.52 (m, 2H, CH2). 13C
NMR (CDCl3) d (ppm): 190.64, 165.27, 165.11, 149.82,
148.56, 141.93, 137.14, 135.70, 134.31, 134.27, 134.03,
1
Yield: 63 %, m.p. 279–282 °C. H NMR (DMSO-d6) d
(ppm): 8.59–8.48 (d, 2H, CHarom., J = 8.1 Hz), 8.11 (d,
2H, CHarom.
,
J = 7.8 Hz), 7.64 (t, 2H, CHarom.,
J = 7.6 Hz), 7.08–6.76 (m, 4H, CHarom.) 4.56–4.17 (m,
2H, CH2), 3.87 (s, 3H, OCH3), 3,41–2.98 (m, 5H, CH2),
2.93–2.32 (m, 5H, CH2), 2.04–1.42 (m, 4H, CH2). 13C
123

Med Chem Res (2014) 23:1519–1536
1525
Cytotoxicity assays
NMR (CDCl3) d (ppm): 165.72, 159.08, 158.97, 140.62,
134.22, 134.17, 134.09, 133.74, 132.25, 130.14, 129.64,
129.53, 128.47, 128.38, 128.09, 127.48, 124.02, 123.61,
61.13, 60.95, 57.53, 51.27, 51.13, 41.37, 41.29, 26.96,
26.87. ESI MS: m/z = 344.6 [M?H]? (100 %).
Cytotoxicity assays were run in parallel with antiviral
assays.
Exponentially growing MT-4 cells were seeded at an
initial density of 1 9 105 cells/ml in 96-well plates in
RPMI-1640 medium, supplemented with 10 % fetal bovine
serum (FBS), 100 units/ml penicillin G, and 100 lg/ml
streptomycin. Cell cultures were then incubated at 37 °C in
a humidified 5 % CO2 atmosphere in the absence or pres-
ence of serial dilutions of test compounds. Cell viability
was determined after 96 h at 37 °C by the 3-(4,5-dimeth-
ylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT)
method (Pauwels et al., 1988).
Biological assays
Cell-based assays
Cell-based assays were performed at Dipartimento di Sci-
`
enze e Tecnologie Biomediche, Universita di Cagliari,
Monserrato, Italy.
Test compounds
Antiviral assays
Compounds were dissolved in DMSO at 100 mM and then
diluted in culture medium.
Compound’s activity against HIV-1 was based on inhibi-
tion of virus-induced cytopathogenicity in MT-4 cell
acutely infected with a multiplicity of infection (m.o.i.) of
0.01. In brief, 50 ll of RPMI containing 1 9 104 MT-4
cells were added to each well of flat-bottom microtitre
trays, containing 50 ll of RPMI with or without serial
dilutions of test compounds. Then, 20 ll of a HIV-1 sus-
pension containing 100 CCID50 was added. After a 4-day
incubation at 37 °C, cell viability was determined by the
MTT method (Pauwels et al., 1988).
Cells and viruses
Cell line and viruses were purchased from the American Type
Culture Collection (ATCC). The absence of mycoplasma
contamination was checked periodically by the Hoechst stain-
ing method. Cell line supporting the multiplication of human
immunodeficiency virus type-1 (HIV-1) was the CD4? human
T-cells containing an integrated HTLV-1 genome (MT-4).
H
N
O
O
O
O NH
O
O
O N
O
Br
Br(CH2)4Br
O
2
1
O
O N
O
N
N
R
HN
N R
3-9
F3C
F
O
O
N
Cl
R:
3
4
5
6
7
8
9
Scheme 1 Synthesis of butylarylpiperazinyl derivatives of 1,16-diphenyl-19-azahexacyclo[14.5.1.02,15.03,8.09,14.017,21]docosa-2,3,5,7,8,9,11,
13,14-nonaene-18,20,22-trione (1)
123

1526
Med Chem Res (2014) 23:1519–1536
H
N
Br
O
O
O
O
Br(CH2)4Br
NH
O
O
N
O
O
O
O
11
10
N
R
N
O
N
R
HN
N
O
O
12-19
F3C
F
O
Cl
N
F
Cl
R:
12
13
14
15
16
17
18
19
Scheme 2 1,3-Diphenylcyclopenta[a]indene-2,8-dione as starting material for new synthetic route of complex arylpiperazines
1997) The refinement was based on F2 for all reflections
In vitro ligand binding assays
except for those with very negative F2. The weighted R factor,
wR, and all goodness-of-fit S values are based on F2. The non-
Ligand studies with native 5-HT1A receptor were con-
ducted according to the methods previously described
hydrogen atoms were refined anisotropically. The hydrogen
atoms were located from a difference map and were refined
isotropically. The atomic scattering factors were taken from
the International Tables (Wilson, 1992). Crystallographic data
for the structures have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication
no. CCDC 913714-913719. Copy of the data can be obtained
on application to CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (email: deposit@ccdc.cam.ac.uk).
(Lewgowd et al., 2011).
X-ray structure determination
Suitable crystals were mounted for measurements. The X-ray
measurements were performed at 100(2) K on a KUMA CCD
k-axis diffractometer with graphite-monochromated Mo Ka
˚
radiation (0.71073 A). The crystals were positioned at
62.25 mmfrom the KM4CCD camera. The data were corrected
for Lorentz and polarization effects, additionally absorption
corrections were applied. Data reduction and analysis were
carried out with the Kuma Diffraction (Wrocław, Poland)
programmes (Oxford Diffraction CrysAlis CCD and CrysAlis
RED, 2001). The structures were solved by direct methods
(Sheldrick, 1990) and refined by using SHELXL (Sheldrick,
X-ray crystal data for 2
C37H28BrNO3, monoclinic space group P21/c: a = 15.7066
˚
(8), b = 7.9750(4), c = 23.0807(12) A, b = 100.366(4);
3
V = 2843.9(3) A , Z = 4, Dcalcd = 1.435 g/cm3; l =
˚
1.485 mm-1; F(000) = 1264. A total of 21,137 reflections
O
O
O
N
O
O
Br
N
N
N
Br(CH2)4Br
HN
N
NH
O
O
O
20
Scheme 3 Synthesis of 3-{4-[4-(2-metoxyphenyl)piperazin-1-yl]butyl}3-azatricyclo[7.3.1.05,13]trideca-(12),5,7,9(13),10-pentaene-2,4-dione
(20)
123

Med Chem Res (2014) 23:1519–1536
1527
X-ray crystal data for 7
Table 1 Cytotoxicity and anti-HIV-1 activity of compounds 3, 6–10,
and 12–19
C47H40FN3O3, monoclinic space group P21/n: a = 11.8103
˚
Compounds
MT-4
CCa50
HIV-1IIIB
ECb50
(4), b = 23.4267(5), c = 13.2359(3) A, b = 96.196(2);
3
V = 3640.67(17) A , Z = 4, Dcalcd = 1.302 g/cm3; l =
˚
3
90
[90
0.085 mm-1; F(000) = 1504. A total of 27,438 reflections
were integrated in the h-range of 2.8°–25.0° of which 6,394
were unique, leaving an overall R-merge of 0.0104. For
solution and refinement, 6,394 were considered as unique
after merging for Fourier. The final agreement factors were
R1 = 0.0323 for 5,658 reflections with F [ 4r(F);
R1 = 0.0365 and wR2 = 0.1276 for all the 6,394 data;
GOF = 1.144. The residual electron density in the final
difference Fourier does not show any feature above
6
[100
[100
[100
20
[100
[100
[100
[20
7
8
9
10
9
[9
12
[100
[100
9
[100
[100
[9
13
14
-3
-3
15
[100
[100
[100
[100
[100
45
[100
[100
[100
[100
[100
0.002
˚
0.24 e A and below -0.2 e A
˚
.
16
17
X-ray crystal data for 11
18
19
C31H22BrNO3, monoclinic space group P21: a = 9.3851
˚
Efavirenz
(7), b = 23.3058(14), c = 11.4605(7) A, b = 106.711(7);
3
V = 2400.9(3) A , Z = 4, Dcalcd = 1.484 g/cm3; l =
˚
a
Compound concentration (lM) required to reduce the viability of
mock-infected MT-4 cells by 50 %, as determined by the MTT
method
1.747 mm-1; F(000) = 1,096. A total of 9,877 reflections
were integrated in the h-range of 2.86°–26.0° of which
6,914 were unique, leaving an overall R-merge of 0.0318.
For solution and refinement, 4,835 were considered as
unique after merging for Fourier. The final agreement
factors were R1 = 0.0633 for 4,665 reflections with
F [ 4r(F); R1 = 0.1047 and wR2 = 0.1518 for all the
6,914 data; GOF = 1.049. The residual electron density in
the final difference Fourier does not show any feature
b
Compound concentration (lM) required to achieve 50 % protection
of MT-4 cells from the HIV-1-induced cytopathogenicity, as deter-
mined by the MTT method
were integrated in the h-range of 2.71°–25.0° of which
5,007 were unique, leaving an overall R-merge of 0.041. For
solution and refinement, 5,007 were considered as unique
after merging for Fourier. The final agreement factors were
R1 = 0.028 for 3,431 reflections with F [ 4r(F);
R1 = 0.0501 and wR2 = 0.0553 for all the 5,007 data;
GOF = 0.864. The residual electron density in the final
difference Fourier does not show any feature above 0.33 e
-3
-3
˚
above 1.05 e A and below -0.96 e A
˚
.
X-ray crystal data for 19
C41H36Cl2N3O3, triclinic space group P-1: a = 11.4607(3),
˚
b = 12.0127(3), c = 13.7081(4) A, a = 97.455(2), b =
-3
-3
˚
A
˚
and below -0.32 e A
3
˚
.
103.874(2), c = 105.357(2); V = 1728.71(8) A , Z = 2,
Dcalcd = 1.337 g/cm3; l = 0.234 mm-1; F(000) = 728. A
total of 19,541 reflections were integrated in the h-range of
3.01°–25.0° of which 6,084 were unique, leaving an overall
R-merge of 0.0173. For solution and refinement, 6,084
were considered as unique after merging for Fourier. The
final agreement factors were R1 = 0.0351 for 4,789 reflec-
tions with F [ 4r(F); R1 = 0.0471 and wR2 = 0.0956 for
all the 6,084 data; GOF = 1.077. The residual electron
density in the final difference Fourier does not show any
X-ray crystal data for 6
C47H40ClN3O3, monoclinic space group P21/n: a = 11.8478
˚
(9), b = 23.8155(18), c = 13.0659(10) A, b = 101.732(6);
V = 3609.7(5) A , Z = 4, Dcalcd = 1.344 g/cm3; l =
3
˚
0.155 mm-1; F(000) = 1536. A total of 27,540 reflections
were integrated in the h-range of 2.72°–25.0° of which
6,356 were unique, leaving an overall R-merge of 0.0653.
For solution and refinement, 6,348 were considered as
unique after merging for Fourier. The final agreement
factors were R1 = 0.0339 for 2,916 reflections with
F [ 4r(F); R1 = 0.0935 and wR2 = 0.1195 for all the
6348 data; GOF = 0.854. The residual electron density in
the final difference Fourier does not show any feature
-3
-3
˚
feature above 0.29 e A and below -0.25 e A
˚
.
X-ray crystal data for 20
C27H30ClN3O3, triclinic space group P-1: a = 7.66540
˚
(10), b = 10.3318(2), c = 16.0440(3) A, a = 96.0230
3
-3
-3
˚
˚
above 0.22 e A and below -0.22 e A
˚
(10), b = 93.910(2), c = 106.740(2); V = 1203.60(4) A ,
.
123

1528
Med Chem Res (2014) 23:1519–1536
Z = 2, Dcalcd = 1.324 g/cm3; l = 0.193 mm-1; F(000) =
508. A total of 13,968 reflections were integrated in the h-
range of 2.94°–25.0° of which 4,235 were unique, leaving
an overall R-merge of 0.0149. For solution and refine-
ment, 4,235 were considered as unique after merging for
Fourier. The final agreement factors were R1 = 0.0267 for
3,532 reflections with F [ 4r(F); R1 = 0.0327 and
wR2 = 0.0758 for all the 4,235 data; GOF = 1.068. The
residual electron density in the final difference Fourier
commercially available 1,3-diphenyl-2H-cyclopenta[l]phe-
nanthren-2-one (‘‘Phencyclone’’) and maleimide were
condensed in Diels–Alder reaction, and toluene was used
as a solvent. After addition of 1,4-dibromobutane, 1,
16-diphenyl-19-azahexacyclo[14.5.1.02,15.03,8.09,14.017,21
]
docosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,22-trione was
obtained (1). Finally, synthesized 19-(4-bromobutyl)-1,16-
diphenyl-19-azahexacyclo-[14.5.1.02,15.03,8.09,14.017,21]do-
cosa-2,3,5,7,8,9,11,13,14-nonaene-18,20,22-trione (2) was
used to obtain seven new complex arylpiperazines (3–9).
In the second synthetic path (Scheme 2), ‘‘Indanocy-
clone’’ and maleimide were refluxed to give 4,10-diphenyl-
-3
˚
does not show any feature above 0.27 e A and below
-3
˚
-0.21 e A
.
1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-trione
(10).
Results and discussion
This step of synthesis shows different approaches (de-
carbonylation) of the condensation reaction between dienes
and dienophiles.
Chemistry
The 2-(4-bromobutyl)-4,10-diphenyl-1H,2H,3H,5H-indeno
[1,2-f]isoindole-1,3,5-trione (11) was obtained by conden-
sation of 1,4-dibromobutane with above-mentioned com-
plex imide in acetonitrile used as a solvent. The final step
was to synthesize arylpiperazine derivatives by refluxing
Synthesis of N-butylarylpiperazinyl derivatives
Two synthetic lines of N-substituted arylpiperazine deriv-
atives were prepared. In the first path (Scheme 1),
Fig. 2 Crystal structures of 2,
6, and 7. Thermal ellipsoids
drawn at 50 % probability level
123

Med Chem Res (2014) 23:1519–1536
1529
affinity) investigations (Scheme 3), however, the X-ray
crystal analysis of the compound has not been published
yet.
All obtained compounds were purified by flash chro-
matography. Elemental analysis, mass spectrometry, 1H
NMR and 13C NMR spectra confirmed the identity of the
products. For compounds 2 and 11, also for hydrochlorides
of 6, 7, 19, and 20 X-ray analyses were done.
Biology
Cytotoxicity and anti HIV-1 activity
Title compounds were tested in cell-based assay against the
human immunodeficiency virus type-1 (HIV-1), using Ef-
avirenz as reference inhibitor. The cytotoxicity was eval-
uated in parallel with the antiviral activity.
None of tested compounds showed selective antiviral
activity against HIV-1. However compounds 10 and 14
turned out cytotoxic for exponentially growing MT4 cells
in the low micromolar range (CC50 = 9 lM) (Table 1).
X-ray structural analyses
The crystal structures have been determined for three
‘‘phencyclone’’ derivatives 2, 6, and 7. Their main skeleton
resembles buspirone, but have more bulky maleimide
fragment and in the case of 2 there is no piperazine moiety
(n-butyl chain is terminated by bromine atom). In struc-
tures 6 and 7, the aromatic fragment (p-chlorophenyl and
o-fluorophenyl, respectively) is different from 2-pirymidi-
nyl substituent in buspirone.
In all of these structures phenanthrene moiety forms a
kind of ‘‘roof’’ over n-butyl chain, and phenyl rings are
situated like ‘‘wings’’ directed outside (Fig. 2). In structures
6 and 7, the piperazine moiety adopts chair conformation.
All compounds crystallize in monoclinic system without
solvent with one molecule in an asymmetric unit. Unit cell
contains 4 molecules related by inversion center (Fig. 3).
The crystal structure of 2 is stabilized by two kinds of short
interactions between C–HÁÁÁO and C–HÁÁÁBr (Fig. 4). In 6
there are three types of C–HÁÁÁO contacts. The oxygen atom
from maleimide moiety contacts with piperazine and phen-
anthrene fragments. Second one interacts with phenyl ring
(Fig. 5).Thestructureof7 showssimilarC–HÁÁÁO interactions
and there is an additional short C–HÁÁÁF contact (Fig. 6).
Two crystal structures based on ‘‘Indanocyclone’’ 11
and 19 are disordered. Compound 11 crystallizes without
solvent in monoclinic P21 space group with two mole-
cules in an asymmetric unit. The structure is a racemic
twin in which one molecule is disordered. The disorder
occurs in the n-butyl chain together with bromine atom
and in the first phenyl ring of Indanocyclone. Two side
Fig. 3 Crystal packing of 2, 6, and 7
corresponding piperazines with 2-(4-bromobutyl)-4,10-
diphenyl-1H,2H,3H,5H-indeno[1,2-f]isoindole-1,3,5-trione
(11). Crude products (12–19) were purified and their
hydrochlorides were made.
In addition, the synthesis of 3-{4-[4-(2-metoxyphenyl)
piperazin-1-yl]butyl}3-azatricyclo-[7.3.1.05,13]trideca(12),
5,7,9(13),10-pentaene-2,4-dione (20) was carried out. The
compound was the subject of previous biological (5-HTR
123

1530
Med Chem Res (2014) 23:1519–1536
phenyl rings are almost coplanar, the angle between
mean best planes is 3.5°. There are three types of C–
HÁÁÁO interactions between maleimide oxygens and the n-
butyl chain, as well as the side phenyl ring, and between
oxygen from Indanocyclone moiety and the side phenyl
ring (Fig. 7).
molecule in an asymmetric unit. Disorder occurs in first
Indanocyclone phenyl ring and gives rise to pÁÁÁp stacking
between disordered benzene and maleimide rings. Two
side phenyl rings are tilted with respect to each other by
24.8° (Fig. 8). The n-butyl chain adopts cis conformation
with dihedral angle N1-C28-C29-C30 equal to 55.6.
The structure is stabilized by a set of N?HÁÁÁCl- bonds
between piperazine and chloride anions. There are two
Compound 19 crystallizes as a hydrochloride with one
molecule of water in triclinic P-1 space group with one
Fig. 4 Short intermolecular
contacts in crystal structure of 2
Fig. 5 Short intermolecular contacts in crystal structure of 6
123

Med Chem Res (2014) 23:1519–1536
1531
Fig. 6 Short intermolecular contacts in crystal structure of 7
Fig. 7 Crystal packing and
short intermolecular contacts in
crystal structure of 11
123

1532
Med Chem Res (2014) 23:1519–1536
Fig. 8 Crystal packing of 19.
Disordered phenyl ring showing
pÁÁÁp stacking with maleimide
ring
Fig. 9 Short intermolecular
contacts in crystal structure of
19
types of interactions between oxygens from maleimide
moiety and C–H from butyl chain and Indanocyclone
phenyl ring. Water molecule forms C–HÁÁÁO bonds with
piperazine and Indanocyclone phenyl ring. There are also
O–HÁÁÁCl- interactions (Fig. 9).
Compound 20, an analog of NAN-190, crystallizes in
triclinic P-1 space group as a hydrochloride with one
molecule in an asymmetric unit. The imide moiety is
almost planar. The piperazine ring adopts chair confor-
mation (Fig. 10). The crystal structure forms layers
123

Med Chem Res (2014) 23:1519–1536
1533
Fig. 10 Crystal structure of 20.
Thermal ellipsoids drawn at
50 % probability level
Fig. 11 Crystal packing of 20.
View along a axis
123

1534
Med Chem Res (2014) 23:1519–1536
Fig. 12 Short intermolecular
contacts in crystal structure of
20
along
a axis comprising of alternating molecules
˚
Table 2 Selected intramolecular distances (A) for arylpiperazine
derivatives 6, 7, 19, and 20
(Fig. 11). The structure is stabilized by N?HÁÁÁCl-
hydrogen bonds. In addition there are short contacts
between chloride anion and C–H from the methoxy
group, the butyl chain and the piperazine moiety. There
are also interactions between oxygens from the imide
fragment with C–H from piperazine and the methoxy-
phenyl ring (Fig. 12).
6
7
19
20
CentroidÁÁÁO(1)
N(1)ÁÁÁO(1)
CentroidÁÁÁN(1)
10.78
5.78
5.69
10.7
8.13
4.06
5.67
11.89
6.66
5.68
5.78
5.71
Conclusions
Compounds 6, 7, 19, and 20 fit well to the three-point
pharmacophore model for 5-HT1A receptor ligands (Chil-
monczyk et al., 1997). Apart from an aromatic ring and the
basic nitrogen of piperazine, localized in the distance of
˚
5.2–5.7 A from a centroid, authors have found the third
point essential for a ligand–receptor interaction—the car-
˚
bonyl oxygen, expected in the distance of 7.07 A from the
˚
center of an aromatic ring and 4.3 A from N4 piperazine
atom. Intramolecular distances measured for a set of
5-HT1A receptor ligands by Chilmonczyk et al. were in the
˚
˚
range of 7.93–12.37 A (CentroidÁÁÁO(1)), 3.95–7.16 A
(N(1)ÁÁÁO(1)), and 5.15–
˚
5.64 A (CentroidÁÁÁN(1)).
˚
Fig. 13 Molecular geometric parameters (in A) observed in solid
state for the derivative 20
The values calculated for new arylpiperazine derivatives
(6, 7, 19, and 20) are in agreement with the presented three-
point pharmacophore model (Table 2, Fig. 13). The dis-
tance between the center of the phenyl group and the imide
could serve as potential 5-HT1A receptor ligands. They also
prove that similar molecular values can be estimated for
the derivative 4. Although it is an exception from ‘‘the rule
of five,’’ because of its high molecular weight, volume and
logP, and low solubility logS (Table 3), the compound 4
possess moderate activity to the 5-HT1A receptor.
˚
oxygen (O1) is in the range of 8,13–11,89 A. The mea-
sured distance of the protonated nitrogen (N1) and O1 atom
˚
is in the range of 4.06–6.66 A. The value of centroid –N1
˚
length is in a narrow range between 5.67 and 5.71 A.
Presented results suggest that compounds 6, 7, 19, and 20
123

Med Chem Res (2014) 23:1519–1536
1535
Table 3 Molecular descriptors calculated for representative 5-HT1A receptor ligands and for selected synthesized derivatives (drug likeness
prediction done via http://molsoft.com/mprop/)
2
PSA (A )
3
Volume (A )
˚
˚
Compound
Molecular
weight (u)
Number
of HBA
Number
of HBD
logP
logS [log
(moles/l]
Buspirone
385.25
385.24
393.21
725.33
729.28
713.31
651.23
443.22
5
4
4
5
4
4
4
4
0
0
0
0
0
0
0
0
2.09
3.14
3.08
6.82
7.91
7.33
7.74
4.25
-1.89
-3.12
-4.16
-10.82
-11.22
-11.12
-10.79
-5.74
56.28
46.42
44.93
58.07
49.46
49.96
49.75
44.30
421.63
428.35
415.76
758.15
769.80
758.17
646.73
466.09
BMY-7378
NAN-190
4
6
7
19
20
Synthesis and antiproliferative properties of N3/8-disubstituted
3,8-diazabicyclo[3.2.1]octane analogues of 3,8-bis[2-(3,4,5-tri-
Structural data obtained for a set of long-chain aryl-
piperazine derivatives can serve for further investigations
concerning ligands activity to metabotropic 5-HT
receptors.
methoxyphenyl)pyridin-4-yl]methyl-piperazine. Eur
Chem 42:293–306
J
Med
´
´
´
Gonzalez-Gomez JC, Santana L, Uriarte E, Brea J, Villazon M, Loza
MI, De Luca M, Rivas ME, Montenegro GY, Fontenla JA (2003)
New arylpiperazine derivatives with high affinity for alpha1A,
D2 and 5-HT2A receptors. Bioorg Med Chem Lett 13:175–178
Acknowledgments Authors are grateful to Professor Paolo La Colla
(Universita di Cagliari, Monserrato, Italy) for performing cytotoxicity
and HIV-1 activity screenings, and Professor Andrzej Bojarski
¨
Hackling A, Ghosh R, Perachon S, Mann A, Holtje HD, Wermuth
CG, Schwartz JC, Sippl W, Sokoloff P, Stark H (2003) N-
(omega-(4-(2-methoxyphenyl)piperazin-1-yl)alkyl)carboxamides
as dopamine D2 and D3 receptor ligands. J Med Chem 46:
3883–3899
´
(Institute of Pharmacology, Polish Academy of Science, Krakow,
Poland) for 5-HT1A affinity investigation.
Conflict of interest None.
Kerns EH, Di L (2008) Drug-like properties: concepts structure
design and methods: from ADME to toxicity optimization.
Academic Press, Amsterdam
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HT7 selectivity. Bioorg Med Chem 20:1139–1148
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Creative Commons Attribution License which permits any use, dis-
tribution, and reproduction in any medium, provided the original
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