Synthesis and antiproliferative action of a novel series of maprotiline analogues

Article abstract of DOI:10.1016/j.ejmech.2013.10.076

The synthesis of a diverse library of compounds structurally related to maprotiline, a norepinephrine reuptake transporter (NET) selective antidepressant which has recently been identified as a novel in vitro antiproliferative agent against Burkitt's lymp

Full text of DOI:10.1016/j.ejmech.2013.10.076

European Journal of Medicinal Chemistry 71 (2014) 333e353
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and antiproliferative action of a novel series of maprotiline
analogues
a
b
,
a
b
c
b
*
Y.M. McNamara , S.A. Bright , A.J. Byrne , S.M. Cloonan , T. McCabe , D.C. Williams ,
M.J. Meegan
a
a
School of Pharmacy & Pharmaceutical Sciences, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
b
c
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 8 August 2013
Received in revised form
The synthesis of a diverse library of compounds structurally related to maprotiline, a norepinephrine
reuptake transporter (NET) selective antidepressant which has recently been identified as a novel in vitro
antiproliferative agent against Burkitt’s lymphoma (BL) cell lines is reported. A series of 9,10-dihydro-
29 October 2013
9,10-ethanoanthracenes were synthesised with modifications to the bridge of the dihydroethanoan-
Accepted 30 October 2013
thracene structure and with alterations to the basic side chain. A number of compounds were found to
reduce cell viability to a greater extent than maprotiline in BL cell lines. In addition a related series of
novel 9-substituted anthracene compounds were investigated as intermediates in the synthesis of 9,10-
dihydro-9,10-ethanoanthracenes. These compounds proved the most active from the screen and were
found to exert a potent caspase-dependant apoptotic effect in the BL cell lines, while having minimal
effect on the viability of peripheral blood mononuclear cells (PBMCs). Compounds also displayed activity
in multi-drug resistant (MDR) cells.
Available online 9 November 2013
Keywords:
Maprotiline
Multidrug resistance
Burkitt’s lymphoma
Ethanoanthracenes
Ó 2013 Elsevier Masson SAS. All rights reserved.
1. Introduction
prednisone (CHOP) and more recently rituximab, a monoclonal
antibody which targets the CD20 antigen on the surface of malig-
Burkitt’s lymphoma (BL) is a rare but aggressive B-cell malig-
nancy that was first documented in 1958 by Dennis Burkitt [1].
There are three main forms of BL, the sporadic form found in
developed countries, the more common endemic form found in the
malarial belt of equatorial Africa and an HIV-associated form [2,3].
BL is the most frequent childhood cancer in equatorial Africa while
in developed countries, the sporadic form accounts for 1e2% of
adult lymphomas. The disease can manifest as tumours in the jaw
and facial bones, kidneys, ovaries and abdomen. Endemic BL is
usually associated with the oncogenic EpsteineBarr virus (EBV)
nant and normal B-lymphocytes. Rituximab, in conjunction with
chemotherapeutic drugs such as vincristine, doxorubicin, metho-
trexate and cyclophosphamide can allow up to 60% survival rates in
children [6,7]. However, due to a growing incidence of HIV-
associated BL and increased resistance to treatments there is a vi-
tal need to develop more potent, selective and economical treat-
ments for this disease.
Antidepressants are a class of compounds used to treat the
symptoms of depression [8,9] which target the monoamine trans-
porters: NET, serotonin reuptake transporter (SERT) and dopamine
reuptake transporter (DAT) by mimicking the effects of naturally
occurring neurotransmitters. Different types of antidepressants
vary in their affinities for different transporters. Recent discoveries
of the presence of these transporters in some malignancies [10]
originally led to the study of monoamine transporter ligands as
pro-apoptotic agents including citalopram, fluoxetine, tricyclic
antidepressants (TCA) imipramine and clomipramine [11e15] and
amphetamine related compounds such as MDMA (ecstasy) and
fenfluramine. BL cells have also been shown to overexpress the
monoamine transporters SERT and NET to various degrees.
[2,3]. EBV acts to interrupt cellular pathways that regulate cell
proliferation and prevent apoptosis of the cell. In this way, EBV
maintains proliferation of the tumour cells [4,5].
BL malignancies proliferate rapidly and as such require intensive
combination chemotherapy treatments including a combination of
cyclophosphamide, doxorubicin, vincristine (oncovin) and
*
Corresponding author.
E-mail address: brights@tcd.ie (S.A. Bright).
0223-5234/$ e see front matter Ó 2013 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2013.10.076

334
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
However their involvement in the antiproliferative effect of
monoamine transporter ligands has been disputed and is unlikely
to play an important role [16].
Maprotiline is an atypical antidepressant compound, charac-
terised by its tetracyclic structure and secondary amine side chain.
Maprotiline was first patented in 1969 by Wilhelm and Schmidt
and a subsequent publication reported its synthesis [17]. Maproti-
line selectively targets NET over SERT and DAT transporters [18]
the ability of these compounds to inhibit anti-MDR activity in a
leukaemic MDR cell line [24].
Based on this evidence, it was decided to design a library of
analogues related in structure to maprotiline 1 (Fig. 1), with mod-
ifications to both the bridgehead of the 9,10-dihydro-9,10-
ethanoanthracene structure and to the C-9 substituent. These
compounds were then evaluated in a series of malignant cell lines
including BL cell lines, MUTU-I and DG-75 cell lines, and MDR cells
overexpressing P-gp and BCRP proteins, in order to investigate the
structureeactivity relationships of these maprotiline analogues and
to attempt to improve potency.
(
norepinephrine selective reuptake inhibitor, NSRI) but is also
known to have moderate effects on -noradrenergic receptors,
adrenergic and muscarinic receptors and histaminic receptors
19,20]. Side effects from the use of maprotiline include seizures,
b
a-
[
drowsiness, sweating, headaches, arrhythmia and memory
impairment [19]. Although maprotiline is not used clinically as an
antidepressant due to the emergence of more efficient drugs such
as selective serotonin reuptake inhibitors (SSRI), other effects of
maprotiline have recently been discovered.
Previous research from our groups identified the antidepressant
maprotiline (Fig. 1) as a potential antiproliferative agent against BL
cell lines, in particular, the resistant lymphoma cell line DG-75 had
an EC50 value in the low micromolar range following a treatment
time of 72 h with maprotiline [16,21]. It was found that maprotiline
2. Chemistry
In the present work, modifications of the dihydroethanoan-
thracene bridgehead structure and also to the C-9 basic substitu-
ent of the maprotiline were investigated to produce a varied
library of compounds for evaluation. Synthesis of novel maproti-
line analogues was achieved as illustrated in Schemes 1e4. The
initial approach required formation of the dihydroethanoan-
thracene and dihydroethenoanthracene structures from an
anthracene precursor, by way of a DielseAlder reaction, to give
products with varied functional groups on the bridgehead (Series
1 and 2). An alternative route involved building the basic side
chain from anthraldehyde, followed by a DielseAlder reaction to
form the bridged dihydroethanoanthracene structure (Series 4). A
further series of related anthracene compounds were also pre-
pared to allow the effects of the presence or absence of the
ethylene bridge on the biochemical activity of the products to be
assessed (Series 3).
(
and the SSRI fluoxetine) induce Type II autophagic cell death in the
resistant DG-75 cell line [21]. This antiproliferative effect was not
observed for other NSRIs nisoxetine and reboxetine and is thought
to occur independently of the NET transporter. Also, when the
normal activity of the transporters was blocked with nisoxetine, the
autophagic death induced by maprotiline was not prevented [16].
Maprotiline-induced anti-multi-drug resistance (MDR) effects in
both cancer cell lines and the malarial strain Plasmodium falciparum
have recently been reported [22,23]. MDR is a major problem in drug
treatment of all cancers. Proteins such as P-glycoprotein (P-gp) and
breast cancer resistant protein (BCRP) are drug efflux pumps
commonly overexpressed in many cancers and are responsible for
eliminating therapeutic drugs from a target cancer cell. Maprotiline
has previously been shown to sensitise resistant malarial strains and
resistant cancer cell lines overexpressing P-gp towards anti-malarial
and chemotherapeutic drugs [24,25]. A study on strains of
P. falciparum known to be resistant and sensitive to the anti-malarial
drug chloroquine found several functional moieties of 9,10-dihydro-
2.1. Series 1
9,10-Dihydro-9,10-ethanoanthracenes 2 and 3 were obtained
via a DielseAlder reaction of the diene anthracene with diethyl
fumarate and ethyl acrylate [27]. Esters 2 and 3 were then hydro-
lysed to give the corresponding carboxylic acids 4 and 5 which were
then coupled to a series amines (EDCI/HOBt) to provide the 11-
substituted- and 11,12-disubstituted-dihydroethanoanthracene
1
amides (6e20) (Scheme 1). In the H NMR spectrum of 7, the alkyl
9
,10-ethanoanthracene compounds including aromatic groups, the
protons H11 and H12 appear as a singlet at d 4.30 ppm, integrating
nature of a basic side chain and a cationic charge were important for
an anti-MDR effect. It was found that most of the successful com-
pounds contained amine substituted ethanoanthracene structures
compared to compounds which contained amide side chains which
were not as potent [25,26]. The anti-MDReffect is thought to have an
inhibitory effect on the P-gp mediated efflux pump but the exact
mechanism of activity is unknown. Further studies demonstrated
for two protons. Interestingly, the alkyl protons H9 and H11 do not
show coupling to each other to give the expected doublet, perhaps a
result of a small dihedral angle calculated as 65.9 [28]. Instead,
ꢀ
both signals appear as singlets; however, the HeH COSY spectrum
indicates the presence of coupling interaction between the two
protons. This small angle would predict a small coupling constant
1
of approximately <1.0 Hz, which was not observed in the H NMR
spectrum. The appearance of protons H9 and H11 as singlets in the
1
H NMR spectrum is in agreement with literature reports of related
9
,10-dihydroethanoanthracene compounds [24,25].
The H NMR spectrum for the novel amide 9 shows the dia-
1
stereotopic methylene protons H12
signals at 1.95 ppm and 2.15 ppm. The signal at
appears as a multiplet, while the signal at 1.95 ppm (H12
resonates with coupling to the diastereotopic H12
(J ¼ 11.9 Hz).
Cis coupling with H11 (J ¼ 17.8 Hz) and coupling to H10
J ¼ 2.5 Hz) is also clearly seen in the HeH COSY spectrum. A
multiplet at 2.96 ppm represents the alkyl proton H11 due to the
interaction with both diastereotopic H12 protons and H9. H10 is
found as a singlet at 4.89 ppm. Interestingly, even though
coupling was observed for H12
a
and H12
b
resonating as two
d
d
d
2.15 ppm
d
a
)
b
(
d
d
a
with H10 (J ¼ 2.5 Hz), this is not
N
H
obvious from its singlet signal. Similarly, H9, which is further
downfield than H10 due to its relative proximity in space to the
amide group, does not show any coupling to H11, as it resonates as
Fig. 1. Maprotiline 1.

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
335
O
O
O
OH
OH
(b)
(e)
R
R
R
(a)
2
R = CO Et
R = H
4 R = CO
5 R = H
2
H
36 R = CH
37 R = H
OH
2
2
3
(g)
(
c)
R2
N
O
R2
CN
N
R3
R3
R1
(d)
R1
40
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
R = CONR R , R = R = CH
1 2 3 2 3 3
2
2
2
2
2
2
2
2
2
3
3
1 R = CH NR R , R = R = CH
1
2
2
3
2
3
3
R = CONR R , R = R = CH CH
2 R = CH NR R , R = R = CH CH
3
1
2
3
2
3
2
3
1
2
2
3
2
3
2
R = CONR R , R = R = -(C H10)-
3 R = H, R = R = CH
1
2
3
2
3
5
1
2
3
3
R = H, R = R = CH
4 R = H, R = R = (C H10)-
1
2
3
3
1
2
3
5
0 R = H, R = R = -(C H10)-
5 R = H, R = R = -(C H )NCH
1
2
3
5
1
2
3
4
8
3
1 R = H, R = R = -(C H )NCH
6 R = H, R = R = -(C H )-
1
2
3
4
8
3
1
2
3
4
8
2 R = H, R = R = (C H )-
7 R = H, R = CH , R = C H
1
2
3
4
8
1
2
3
3
6
11
3 R = H, R = CH , R = C H
8 R = R = H, R = CH CH
3
1
2
3
3
6
11
1
2
3
2
4 R = R = H, R = CH CH
3
9 R = H, R = R = -(C H OC H )-
1
2
3
2
1
2
3
2
4
2
4
5 R = H, R = R = -(C H OC H )-
0 R = R = H, R = C H
1
2
3
2
4
2
4
1
2
3
6
5
6 R = H, R = R = (C H )NCO C(CH )
1 R = H, R = R = (C H )N(C H )Cl
1
2
3
4
8
2
3 3
1
2
3
2
4
6
4
7 R = R = H, R = C H
5
1
2
3
6
8 R = H, R = R = (C H )N(C H )Cl
1
2
3
2
4
6
4
9 R = R = H, R = CH(COOCH )(CH C H OH)
1
2
3
3
2
6
4
0 R = R = H, R = HC(CO CH )CH CH(CH )
1
2
3
2
3
2
3
2
O
O
N
N
CO C(CH )
N
NH
N
NH
2
3 3
(f)
(d)
16
34
35
R
R
O
O
O
O
O
OH
NH
NH
(
b)
1
9 R = 4-C H OH
32 R = 4-C
33 R = CH(CH )
3 2
6 4
H OH
6
4
20 R = CH(CH3)2
ꢀ
Scheme 1. Reagents and conditions: (a) EtO
2
CeCH]CHeCO
2
Et, or CH
2
ꢀ
]CHeCO
2
Et, AlCl
3
, rt, 18e24 h; (b) KOH, EtOH, reflux, 3 h; (c) EDCI, HOBt, Et
3
N, NHR
1
R
2
, 0 C, 18e24 h; (d)
ꢀ
ꢀ
LiAlH , THF, rt, 18e24 h; (e) LiAlH , THF, reflux, 3 h; (f) TFA, CH
4
4
2
Cl
2
, 0 e23 C, 6 h; (g) CH
2
]CHCN, hydroquinone, microwave irradiation, 200 C, 10 min.
ꢀ
a singlet at
d
4.51 ppm. However, the HeH COSY clearly demon-
(Fig. 2A), and the value of 63.11 previously reported for the
diester 2 [29].
strates the interaction of both H10 and H9 with and H12 and H11
protons respectively.
The amines 21e31 were obtained by reduction of the corre-
The X-ray crystal structure of the novel compound 9 was ob-
tained (Fig. 2B) and confirmed the trans configuration of the
compound. The three six membered rings adopt a boat confor-
mation, as previously observed for related 9,10-dihydro-9,10-
ethano- and etheno-anthracenes [29]. The out-of-plane angle be-
tween the two aromatic rings for compound 9 was determined to
4
sponding amides with LiAlH in moderate yields. The amino acid
ester coupled compounds 19 and 20 were subsequently converted
to their corresponding amino acids 32 and 33 by base hydrolysis.
Deprotection of 16 with TFA afforded piperazine 34, which was
reduced to afford the amine 35 (Scheme 1). The acids 4 and 5 were
also reduced to the alcohols 36 and 37 respectively. Compound 40
was obtained by reaction of anthracene with acrylonitrile under
microwave conditions.
ꢀ
ꢀ
be 55.20 , compared with the dihedral angle of 54.91 observed
for the 11,12-bis-disubstituted 6 determined in the present work

336
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
ꢀ
Scheme 2. Reagents and conditions: (a) ethyl propiolate, hydroquinone, microwave irradiation, 160 C, 45 min; (b) 5 M KOH, EtOH, reflux, 3 h; (c) EDCI, HOBt, NEt
3
, NHR
2
, CH
2
Cl
2
,
ꢀ
ꢀ
18e24 h; (d) LiAlH
4
, THF, 18e24 h; (e) dimethyl acetylenedicarboxylate, sealed tube, 120 C, 24 h; (f) Dimethyl acetylenedicarboxylate, microwave irradiation, 160 C, 45 min.
2.2. Series 2
dihydroethanoanthracene analogues when initially evaluated in BL
cell lines (see Biochemical evaluation).
9
,10-Ethenoanthracene compounds 38 and 39 were obtained as
previously reported [30,31] by reaction of anthracene with the
dienophiles dimethyl acetylene dicarboxylate and ethyl propiolate
respectively using both conventional sealed tube and/or microwave
methods [32,33]. Compound 39 was hydrolysed to the acid 41,
which was then coupled with the amines piperidine and N-methyl-
N-cyclohexylamine to afford the novel amides 42 and 43 respec-
2
.3. Series 3
The preparation of a related series of substituted anthracenes
was next investigated (Scheme 3). Following successful modification
of the anthraldehyde 46, a DielseAlder reaction allowed construc-
tion of the bridgeddihydroethanoanthracene structures (Scheme 4).
Anthraldehyde 46 was reacted with carbethoxymethylene triphe-
nylphosphorane to afford 47 in high yield as the E-isomer (Scheme
4
tively. Subsequent reduction with LiAlH afforded the corre-
sponding amines 44 and 45 (Scheme 2). These compounds were
prepared to investigate the effect of the alkene structure on the
bridgehead of the dihydroethenoanthracene structure. The specific
amines used, N-methyl-N-cyclohexylamine and piperidine, were
chosen due to the positive result obtained from their corresponding
3
), identified due to the characteristic coupling constant
(
J ¼ 16.0 Hz) [34]. The alkenes 48 and 49 were similarly obtained on
reaction of anthraldehyde with the appropriate ylides. The ester 47
was then hydrolysed in basic conditions to produce the
Scheme 3. Reagents and conditions: (a) CH
h; (d) NaCNBH , CH OH, CH NH HCl, pH 5e6, 72 h, rt; (e) CH
, 110 C, 24 h, sealed tube; (i) CNCH CO
3
NO
2
, CH
3
CO
2
H, cyclohexylamine, 6 h, reflux; (b) NO
2
C
6
H
4
CH
2
PPH
3
Br, NaH, THF, 12 h, reflux; (c) CH
3
CH
2
OCOCHPPh
3
, CH
2
Cl
2
, reflux 6e
, 18 h, rt;
7
3
ꢀ
3
3
2
3
CH
2 3
OCOCHPPh , CH
2
Cl
2
, reflux 6e7 h; (f) 5 M KOH, EtOH, 3 h, reflux; (g) EDCI, HOBt, NEt
3
, NHR
1
2
R , CH
2
Cl
2
ꢀ
(
h) CH
3
NH
2
2
2
H, morpholine, DMF, reflux, 7 h; (j) CNCH
2
CO
2
H, morpholine, DMF, 90 C, 1 h.

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
337
ꢀ
Scheme 4. Reagents and conditions: (a) dimethyl acetylenedicarboxylate, microwave irradiation, 160 C, 45 min; (b) CH
2
]CHCO
2
H, xylene, CH
3
CO
2
H, microwave irradiation,
ꢀ
ꢀ
ꢀ
250 C, 10 min; (c) NH(CH
3
)(C
6
H
11), EDCI, HOBt, CH
2
Cl
2
, 0 C to rt, 24 h; (d) CH
2
]CHCN, hydroquinone, sealed tube, 130 C, 24 h; (e) NH
2
OH$HCl, pyridine, EtOH, reflux, 3 h; (f)
/Pd, ethyl acetate, 48 h, rt.
RCOCl, Et N, CH Cl , reflux, 3 h; (g) NaCNBH
3
2
2
3
, CH NH
3
2
.HCl, CH
3
OH, rt, 72 h; (h) HCl/CHCl
3
, 10 min, rt; (i) CH OH, 4 weeks; (j) NaBH , MeOH, rt, 2 h; (k) H
3
4
2
corresponding acid 50 [34]. A series of novel amides (51e57) were
obtained from the acid 50 in a coupling reaction with a variety of
amines, while the N-methylamide 58 was obtained by heating 47
compound 63 indicated the exclusive formation of the ortho
adduct, attributed to the stabilising overlap of molecular orbitals
from carbonyl and nitrile groups [37]. Surprisingly, the X-ray crystal
structure obtained by XRD was not as expected for 63 as initially
indicated by NMR, IR and mass spectrometry. Instead of an alde-
hyde group at the C-9 position of the dihydroethanoanthracene
ꢀ
with methylamine (2 M in THF) in a sealed tube at 110 C for 24 h
(Scheme 3).
The generation of a ketone functional group in compound 48
0
allowed progression to compound 59 via a reductive amination re-
action with methylamine hydrochloride and NaCNBH . A Knoeve-
structure, a methyl hemiacetal structure 63 is present as shown in
3
Fig. 2C. The three six membered rings are seen to adopt a boat
conformation [29]. The out-of-plane dihedral angle between the
nagel reaction was next used to obtain the nitrile 60 by treatment of
0
ꢀ
anthraldehyde with cyanoacetic acid while the alternative product
two aromatic rings for compound 63 was determined to be 56.60 .
ꢀ
0
6
1 was isolated on reaction at 90 C for 1 h [35]. The nitrostyrene 62
It was demonstrated that this novel acetal structure (63 ) was
was obtained from 9-anthraldehyde and nitromethane in a Henrye
Knoevenagel reaction in 66% yield [36] (Scheme 3).
formed during the slow crystallisation of 63 from methanol and is
reversible. The structure of compound 63 was confirmed by high
0
resolution mass spectrometry of the crystal which detected a mo-
þ
2
.4. Series 4
lecular ion of 292.1329, [M þ H] (molecular formula C19
H18NO
2
requires 292.1338). An IR spectrum also identified absorption bands
ꢁ ꢁ1
1
These dihydroethanoanthracene compounds contain sub-
at 2238 cm and 3448 cm , corresponding to a nitrile and a hy-
1
0
stituents at both the bridgehead C-9 and the bridge C-11
positions (Scheme 4). Reaction of anthranaldehyde with the dien-
ophile acrylonitrile under microwave conditions at 160 C afforded
droxyl group respectively. A H NMR spectrum of 63 could not be
obtained as a shift in equilibrium towards formation of the alde-
hyde 63 was observed. The dimethylacetal of 63 had been previ-
ously reported [38]. The adducts 64 [39] and 65 [37,40] were
obtained on reaction of anthranaldehyde with dimethylacetylene
ꢀ
the adduct 63 in 70% yield (compared with 48% yield after 24 h at
ꢀ
1
130 C under conventional conditions). H NMR spectroscopy for

338
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
0
Fig. 2. Ortep representation of the X-ray crystal structure of (A) 6, (B) 9 and (C) 63 (acetal) with the thermal ellipsoids set at 30% probability.

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
339
dicarboxylate and acrylic acid respectively. Compound 65 was
coupled to N-methyl-N-cyclohexylamine using HOBt and ECDI, to
afford the amine 66, Scheme 4.
demonstrated compound 29 to be the most potent compound of
this series with EC50 values of 23.5 M in MUTU-I cells and 8.8
in DG-75 cells; other active compounds from this series included
22, 24 and 27 (EC50 values of 65.0, 65.6, 23.0 M, and 51.8, 69.9,
35.5 M in MUTU-I and DG-75 cells respectively). Other com-
pounds were not active (23, 28, 30, 31: EC50 > 100 M). Impor-
m
mM
The ortho adducts 67, 68 and 69 were isolated in high yields, by
reaction of the anthracenes 47, 58 and 60 respectively with acryloni-
m
m
ꢀ
trile, at high pressure in a sealed tube at 130 C, using catalytic
m
amounts of hydroquinone as an inhibitor. Reduction (H
alkenes 67, 68and69afforded products 70, 71 and 72 respectively. The
alcohol 73 was obtained from 63 via NaBH reduction while reductive
amination of 63 with NaCNBH and methylamine led to the formation
of 74 in high yield (87%). Esterification of the alcohol 73 afforded the
esters 76 and 77, while the carbamate products 78, 79 and 80 were
similarly obtained from the oxime 75 in high yields (Scheme 4).
2
/Pd) of the
tantly, these results show that compounds with an amide group
(4e6, 11, 20, 32, 33) or nitrile (40) at C-11, do not possess any
antiproliferative effect. This is consistent with a previous report
that a series of 9,10-dihydro-9,10-ethanoanthracenes with amine
groups were much more active than their amide analogues at
reducing efflux of rhodamine through the P-gp efflux pump, in an
4
3
MDR leukaemia cell line (EC50 range of 0.25
mMe970 mM) [24].
9,10-Dihydro-9,10-ethenoanthracene compounds (38, 39, 44,
3
. Results and discussion
45), Series 2, Scheme 2 were similarly evaluated for their anti-
proliferative effects using an Alamar Blue dye. Compound 45 was
found to exhibit a potent antiproliferative effect on the DG-75 cell
3.1. Biochemical evaluation
line with an EC50 value of 10.2 mM while other similar compounds
The library of synthesised 9,10-dihydroanthracene and 9-
anthracenyl compounds was evaluated for antiproliferative activ-
ity on the BL cell lines MUTU-I (chemosensitive cell line) and DG-75
(38, 39, 44) had no effect. This antiproliferative effect was found to
be much more potent than the effect of 24 (which is the saturated
analogue of 45) (EC50: 70
strongest antiproliferative effect in the MUTU-I cell line with an
EC50 value of 31.5 M. In contrast, the unsaturated dihy-
mM). Compound 45 also displayed the
(
chemoresistant cell line). Antiproliferative activity was measured
with an Alamar Blue dye which is used to determine the percentage
of cell viability when treated with a test sample. The BL cell lines
were chosen for evaluation as previous results from our group have
shown maprotiline to reduce viability in such cell lines. Cells were
treated over a range of concentrations for each compound for 24 h
m
droethenoanthracene compound 44 displayed a weaker anti-
proliferative effect than the corresponding saturated compound 27
(EC50: 73.3
m
M versus 23
mM) on the MUTU-I cell line. Compounds
38 and 39 (EC50 > 100
mM) were found to have no effect on either of
(
MUTU-I) and 72 h (DG-75) (Table 1).
the BL cell lines, while their saturated analogues 2 and 3 displayed
The results for selected dihydroethanoanthracene ester, car-
moderate to weak antiproliferative effects on the MUTU-I cell line
boxylic acid, carboxyamide and nitrile compounds in Series 1,
Scheme 1 (2e20, 32e33, 40), showed that compounds 2, 3 and 19
displayed anti-proliferative effects in MUTU-I cells following 24 h
(EC50 values of 89 mM and 55 mM respectively), suggesting that the
double bond accounts for the lack of activity of 38 and 39.
For the 9,11-disubstituted-9,10-dihydro-9,10-ethanoanthracene
compounds evaluated (63, 66e80), Series 4, Scheme 4, the dieth-
ylcarbamate compound 79 was found to be the most effective
compound for inducing an antiproliferative effect in the resistant
treatment with EC50 values of 89.4e55.4
mM. All other dihy-
droethanoanthracene carboxyamide compounds were found to
have no effect on the MUTU-I cell line (4, 5, 6, 7, 11, 20, 32, 33:
EC50 > 100
9 was the only compound in this series that exhibited a toxic effect
on the drug resistant DG-75 cell line with an EC50 value of 54.6 M.
m
M). Despite their activity in MUTU-I cells, compound
DG-75 cell line with an EC50 value of 3.1
potent than the EC50 value of maprotiline determined in the pre-
sent study (37.5 M). The benzoyl oxime derivative 80 was also
found to weakly inhibit proliferation of the DG-75 cell line with an
mM. This value is more
1
m
m
Results for selected 9,10-dihydro-9,10-ethanoanthracene
methanamine compounds (22e31), Series 1, Scheme 1,
EC50 value of 95.3
mM after treatment for 72 h.
Table 1
The antiproliferative effects of maprotiline analogues on BL cell lines.
Compound
MUTU-I (24 h)
EC50
DG-75 (72 h)
EC50
Compound
MUTU-I (24 h)
DG-75 (72 h)
EC50
EC50
Maprotiline
1
2
3
1
2
2
2
2
44
45
47
48
15.8
89.4
55.4
63.0
65.0
65.6
23.0
23.5
73.3
31.5
27.1
21.8
8.8
37.5
>100
>100
54.6
51.8
69.9
35.5
8.8
>100
10.2
>100
7.6
>100
>100
9.3
>100
32.5
9-Substituted anthracenes
(Series 3)
55
56
57
58
59
60
62
63
66
67
70
75
76
77
78
79
80
7.6
5.4
62.1
11.6
9,10-Dihydro-9,10-ethanoanthracenes
(
Series 1)
38.5
62.5
62.9
21.2
3.0
31.7
40.6
45.6
29.3
20.4
12.8
24.5
34.6
28.4
80.5
>100
>100
>100
>100
1.5
>100
>100
>100
>100
>100
>100
>100
>100
3.1
9
2
4
7
9
9,11-Disubstituted-9,10-dihydro-9,
10-ethanoanthracene (Series 4)
9
9
,10-Dihydro-9,10-etheneoanthracenes
Series 2)
-Substituted anthracenes
Series 3)
(
(
49
51
52
53
54
24.9
21.5
1.9
18.7
95.3
EC50 values were estimated from log-concentration sigmoidal doseeresponse curves where the cytotoxic potency of each compound was evaluated with an Alamar Blue assay.
Experiments were performed in triplicate on three independent days using four test compound concentrations. Data were subjected to non-linear regression analysis using a
sigmoidal dose response (Hill slope ¼ 1) using GRAPHPAD Prism4 software (Graphpad software Inc., San Diego, CA). Miconazole (10
mM) was used as a positive control and
resulted in >90% cytotoxicity to all cell lines. Of the compounds selected for biological screening, data are only shown for those compounds which exhibited activity (EC50
value <100) in at least 1 of the BL cell lines.

340
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
The acetate ester 76 was found to have the most potent effect on
the MUTU-I cell line with an EC50 value of 12.8 M. The oxime 75
was also found to display a slightly less potent antiproliferative
effect, with an EC50 value of 20.4 M. Interestingly, the effect of the
acetoxyimino compound 78 on the viability of MUTU-I cells is
much less potent than either 75 or 76 (EC50: 34.6 M). Compound
9, contains an ethylamide group and was also found to have a
investigation based on their antiproliferative effects and analysis of
m
their drug-like (Lipinski) properties [42] from a Tier-1 profiling
together with predictions of permeability, metabolic stability,
bloodebrain barrier partition, plasma protein binding and human
intestinal absorptionproperties (see Supplementary data). The most
active 9,10-dihydro-9,10-ethanoanthracene, 79, and 9-anthracenyl
m
m
7
compounds (53, 55, 56, 62) were evaluated at 10 mM over a 24 h
moderate effect on the MUTU-I cell line with an EC50 value of 28.4.
All other 11-cyano-dihydroethanoanthracene compounds evalu-
ated were found to have only weak antiproliferative effects on the
treatment time in MUTU-I, DG-75 and PBMC cells (Fig. 3A). Only
compound 62 significantly reduced the viability of PBMCs.
Compared to PBMCs, compounds 55 and 79 had a more potent effect
on the malignant cell lines, while compounds 56 and the positive
control vinblastine significantly reduced the cell viability of BL cell
lines but did not significantly reduce the cell viability of PBMCs. This
suggests that the 9-substituted anthracene compounds exert a
selectively toxic effect on BL cell lines.
Designing drugs that can induce programmed cell death (PCD),
namely apoptosis, of a cancer cell, whilst ignoring the ‘normal’ cells
of the body is imperative to the future development of safe effective
anticancer agents. In order to investigate the possible apoptotic
effect of this subset of potent compounds, PI FACS analysis was
MUTU-I cell line (EC50 values > 80
ester compound 70 has a more effective antiproliferative activity
than its unsaturated analogue 67 (EC50 value of 29.3 M versus
5.6 M respectively), possibly due to the restricted conformation
of the unsaturated ester 67 (compounds 68, 69, 71, 73, 74 had no
effect on either the DG-75 or MUTU-I cell line (EC50 > 100 M)).
mM). Interestingly the saturated
m
4
m
m
However, by far the most potent group of compounds syn-
thesised were the 9-substituted anthracenyl compounds 47e49,
51e60 and 62 (Series 3, Scheme 3) with antiproliferative activities
in the low micromolar range in the BL cell lines. Compound 53 was
found to exert the most potent antiproliferative effect on the
carried out at 10 mM in the MUTU-I cell line. The MUTU-I cell line
MUTU-I cell line, with an EC50 value of 1.9
related 55 and 56 also displayed potent activities with EC50 values
of 7.6 M and 5.4 M, respectively. The nitrostyrene compounds 49
and 62 also exhibited potent antiproliferative effects with
approximate EC50 values of 8.8 M and 3.0 M respectively. Most of
m
M. The structurally
was chosen for this study because these cells tend to die by classical
apoptosis. This is in contrast to the chemoresistant DG-75 cell line
which is more likely to die by the autophagic route of PCD [21].
m
m
Vinblastine (10
52.89 ꢂ 5.1% of cells in the pre-G
FACS analysis determined that compounds 56 and 62 had
phase of the cell
mM) was used as
a positive control with
m
m
1
phase of the cell cycle, after 24 h.
the remaining anthracene related compounds were found to have
antiproliferative activities in the low micromolar range, with EC50
54.70 ꢂ 4.9% and 31.43 ꢂ 4.1% of cells in the pre-G
1
values in the range of 18.7e38.5
played only moderate effects on the MUTU-I cell line (EC50: 62.5
and 62.9 M). Interestingly, both 58 and 59 have secondary N-
mM. Compounds 58 and 59 dis-
cycle respectively (Fig. 3B), indicating that they are inducing sig-
nificant apoptosis in the MUTU-I cell line. Compound 53 was found
m
to have an average of 15.44 ꢂ 5.8% of cells in the pre-G
indicating the formation of apoptotic cells. Compounds 55 and 79
did not induce apoptosis in the MUTU-I cell line at 10 M.
1
phase, again
methylamine groups compared to the other, more potent com-
pounds, which for the most part have tertiary amine groups, which
may be influencing their relative potencies on the MUTU-I cell line.
The lead compound maprotiline 1 also contains a secondary
amine and was found to be less potent than a number of the 9-
anthracenyl compounds (49, 53, 55, 56, 62) in this cell line.
Several of the 9-substituted anthracene compounds displayed
potent antiproliferative activity on the resistant DG-75 cell line. The
nitrostyrene 62 compound, displayed the most potent activity for
m
Apoptosis is an energy-dependant process which involves acti-
vation of specific caspases and a complex cascade of biochemical
signalling events to allow the cell to die. The apoptotic cell exhibits
several structural and biochemical modifications including protein
cleavage, DNA fragmentation, membrane disruption and caspase
activation [43]. As activation of caspases is one of the hallmarks for
apoptosis, it was decided to carry out caspase activation experi-
ments in order to confirm the results from the FACS analysis. Cas-
pases 3 and 7 are two of ten major caspases identified and are
categorised as effectors or executioner caspases [43]. Caspase 3/7
activity was assessed using the Apotox-Glo Triplex assay, results
showed that compounds 53, 56 and 62 all significantly activate
caspases 3 and 7, compared to the untreated control, consistent with
the results of the FACS analysis, suggesting that these compounds do
in fact induce apoptosis in the MUTU-I cell line (Fig. 3C). In contrast
55 and 79 do not seem to induce caspase activation in this cell line,
again, consistent with results from the FACS analysis suggesting that
these compounds do not have an apoptotic effect.
the DG-75 cell line with an EC50 value of 1.5 mM. The potent anti-
proliferative effect of compound 62 on BL cell lines further suggests
nitrostyrene based compounds as potential lead compounds in the
development of new anticancer agents [41]. The styrene 49 was
found to have no effect on the viability of DG-75 cells (>50% cell
viability at 100 mM), compared to the nitrostyrene 62, which dis-
played the most potent effect against the DG-75 cell line. Struc-
turally related piperazines 55 and 56 were also found to induce a
significant antiproliferative effect, with EC50 values of 62.1
m
M and
M. It is noteworthy that both of these potent compounds (55,
6) contain N-substituted piperazine groups, and while they
11.6
m
5
exhibit a potent toxic effect the BL cell lines, the structurally similar
piperazine compound, 57, was found to have no antiproliferative
effect on the DG-75 cell line and only a moderate effect on the
3.3. Multi-drug resistance activity of maprotiline analogues
MUTU-I cell line (38.5
DG-75 cells. However, the N,N-diethylamide 52 displayed a signif-
icant effect after 72 h (EC50: 9.3 M), while the pyrrolidine 54
induced an EC50 value of 32.5 M.
m
M). The amides 51 and 53 were inactive in
9,10-Dihydro-9,10-ethanoanthracenes have been previously
evaluated by Alibert et al. and were found to decrease the multi-drug
resistance of a leukaemia cell line via possible inhibition of the P-gp
efflux pump, allowing increased cellular accumulation of rhoda-
mine [24]. As a number of the novel dihydroethanoanthracenes
evaluated in the present study were found to have antiproliferative
m
m
3.2. Investigations into the effects of 9,10-dihydro-9,10-
ethanoanthracenes and 9-anthracenyl compounds on peripheral
blood mononuclear cells and apoptosis
effects at low mM concentrations, it was of interest to this study to
determine if these compounds (27, 66), and the cohort of com-
pounds tested above, could demonstrate an ability to overcome
MDR. For this, normal (parental) HL-60 cells and HL-60 cells over-
expressing the drug efflux pumps P-gp and BCRP were acquired [44].
Representative 9,10-dihydro-9,10-ethanoanthracenes and 9-
anthracenyl compounds were chosen for further biochemical

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
341
Fig. 3. Investigations into the effects of analogue compounds on PBMCs, apoptosis and caspase activation. A) The effect of each compound at 10
mM on the viability of the MUTU-I,
DG-75 and PBMC cells was analysed. Compounds were evaluated using the Alamar Blue cell viability assay in three independent experiments. Compounds were screened for the
induction of B) programmed cell death or apoptosis by FACS analysis and C) caspase activation. D) Compounds 53, 55, 62, 66 and 79. Statistical analysis was performed using a
Student’s t-test, *p < 0.05; **p < 0.01; ***p < 0.001.
Parental HL-60 cells were sensitive to both paclitaxel (taxol, a
microtubule stabiliser) and SN-38 (a topoisomerase I inhibitor),
common chemotherapeutics (Fig. 4A). HL-60 P-gp cells are resistant
to taxol (but not SN-38) and this resistance can be overcome by
administration of the P-gp inhibitor verapamil (Fig. 4A&B). Likewise,
HL-60 BCRP are resistant to SN-38 (but not taxol), this resistance can
be reversed by administration of the BCRP inhibitor KO143
to maprotiline. Biochemical evaluation of these analogues revealed
a number of compounds that displayed potent antiproliferative
effects and induced apoptosis and caspase activation in BL cell lines.
Many of these compounds were more potent than maprotiline. A
representative group of compounds were evaluated in PBMCs and
it was revealed that many of the compounds had no effect on their
viability, implying that these maprotiline analogues are selectively
toxic to BL cell lines. Three of these compounds 56, 62 and 66 also
displayed the ability to overcome chemotherapeutic resistance due
to drug efflux pumps. However, the significant antiproliferative and
apoptotic effects of compound 56 on BL cell lines, together with a
lack of toxicity against normal PBMCs suggests this nitrostyrene
based compound as a potential lead compound in the development
of new anticancer agents and warrants further investigation [41].
These results also demonstrate the importance of defining struc-
tureeactivity relationships for novel compounds.
(Fig. 4A&C). All three cell lines were treated with the selected
compounds and evaluated for apoptotic effects. Results showed that
compounds 56, 62 and 66 induced apoptosis in all 3 HL-60 cell lines.
These results suggest that these particular maprotiline analogues
are not substrates for drug efflux pumps. Compound 53, which
induced the lowest level of apoptosis in the MUTU-I cell line,
showed minimal activity in parental HL-60 cells, whilst compounds
27, 55 and 79 displayed no activity in any of the cell lines (Fig. 4D).
4
. Conclusion
5. Experimental section
Previous research identified the NSRI maprotiline as a pro-
autophagic antiproliferative agent in BL cell lines [16,21]. Based
on this evidence, diverse library of 9,10-dihydro-9,10-
5.1. Chemistry: experimental methods
a
ethanoanthracenes, 9,10-dihydro-9,10-ethenoanthracenes and
related anthracenes was synthesised that were related in structure
All reagents were commercially available and were used
without further purification unless otherwise indicated.

342
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
Fig. 4. Selective compounds induce apoptosis in MDR cells. (A) Parental HL-60 cells are sensitive to both taxol and SN-38 while drug-resistant cells are resistant to either (B) taxol
P-gp-expressing MDR cells) or (C) SN-38 (BCRP-expressing cells). (D) Maprotiline and analogues 56, 62 and 66 show activity in parental and drug-resistant HL-60 cells. Statistical
(
analysis was performed using a Student’s t-test, *p < 0.05; **p < 0.01; ***p < 0.001.
Tetrahydrofuran (THF) was distilled immediately prior to use from
Na/benzophenone under a slight positive pressure of nitrogen,
toluene was dried by distillation from sodium and stored on acti-
Samples were detected using a wavelength of 254 nm. All samples
were analyzed using acetonitrile (70%)/water (30%) over 10 min
and a flow rate of 1 mL/min.
ꢀ
vated molecular sieves (4 A) and dichloromethane was dried by
The following compounds were prepared as previously re-
ported: trans-11,12-diethoxycarbonyl-9,10-dihydro-9,10-ethanoan
thracene (2) [45], 11-ethoxycarbonyl-9,10-dihydro-9,10-ethanoan
thracene (3) [46], trans-11,12-dihydroxycarbonyl-9,10-dihydro-
9,10-ethanoanthracene (4) [29], 11-hydroxycarbonyl-9,10-dihydro-
distillation from calcium hydride prior to use. Uncorrected melting
points were measured on a Gallenkamp apparatus. IR spectra were
recorded as thin films on NaCl plates or as KBr discs on a Perkine
1
13
Elmer Paragon 100 FT-IR spectrometer. H and C NMR spectra
ꢀ
0
0
were obtained on a Bruker Avance DPX 400 instrument at 20 C,
9,10-ethanoanthracene (5) [47], trans-11,12-(N,N,N ,N -tetra-
methyl)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxyami
de (6) [29], 9,10-dihydro-N-methylpiperazinyl-9,10-ethanoanthra
cene-11-carboxyamide (11) [48], 9,10-dihydro-11-N-ethylamino-
9,10-ethanoanthracene-11-carboxyamide (14) [49], 9,10-dihydro
morpholinyl-9,10-ethanoanthracene-11-carboxyamide (15) [50],
4
00.13 MHz for 1H spectra, 100.61 MHz for C spectra, in either
13
3 3 3 3
CDCl , CD COCD or CD OD (internal standard tetramethylsilane).
Low resolution mass spectra were run on a Hewlett-Packard 5973
MSD GCeMS system in an electron impact mode, while high res-
olution accurate mass determinations for all final target com-
pounds were obtained on a Micromass Time of Flight mass
spectrometer (TOF) equipped with electrospray ionization (ES)
interface operated in the positive ion mode at the High Resolution
Mass Spectrometry Laboratory by Dr. Martin Feeney in the School
of Chemistry, Trinity College Dublin. Thin layer chromatography
was performed using Merck Silica gel 60 TLC aluminium sheets
with fluorescent indicator visualizing with UV light at 254 nm.
Flash chromatography was carried out using standard silica gel 60
0
0
trans-9,10-dihydro-N, N, N , N -tetramethyl-9,10-ethanoanthra
cene-11,12-dimethan amine (21) [29], 9,10-dihydro-N-piperidinyl-
9,10-ethanoanthracene-11-methanamine (24) [51], 9,10-dihydro-
N-methylpiperazinyl-9,10-ethanoanthracene-11-methanamine
(25) [51], 9,10-dihydromorpholinyl-9,10-ethanoanthracene-11-
methanamine (29) [50], 9,10-dimethyl-9,10-dihydro-9,10-etheno
anthracene-11,12-dicarboxylate (38) [30], 9,10-dihydro-9,10-
ethenoanthracene-11-ethylcarboxylate (39) [31], 9,10-dihydro-
9,10-ethanoanthracene-11-carbonitrile (40) [52], 9,10-dihydro-
9,10-ethenoanthracene-11-carboxylic acid (41) [29], 3-(9-anthra-
cenyl)acrylic acid ethyl ester (47) [34], (E)-4-(9-anthracenyl)but-3-
en-2-one (48) [53], 3-(9-anthracenyl)acrylic acid (50) [34], 3-(9-
anthracenyl)acrylonitrile (60) [36], (E)-9-(2-nitrovinyl)anthracene
(62) [36], 9-formyl-9,10-dihydro-11-cyano-9,10-ethanoanthracene
(63) [54], dimethyl-9-formyl-9,10-dihydro-9,10-ethenoanthra
cene-11,12-dicarboxylate (64) [39], 9-formyl-9,10-dihydro-9,10-
ethanoanthracene-11-carboxylic acid (65) [37,40] 9-((E)-(hydrox-
yimino)methyl)-9,10-dihydro-9,10-ethanoanthracene-11-
(
230e400 mesh) obtained from Merck. All products isolated were
homogeneous on TLC. The purity of the tested compounds was
determined by high-performance liquid chromatography (HPLC) or
combustion analysis and unless otherwise stated, the purity level
was ꢃ95%. Elemental analyses were performed on an Exetor
Analytical CE4400 CHN analyser in the microanalysis laboratory,
Department of Chemistry, University College Dublin. Analytical
HPLC was performed using a Waters 2487 Dual Wavelength
Absorbance detector, a Waters 1525 binary HPLC pump and a
Waters 717plus Autosampler. The column used was a Varian Pursuit
XRs C18 reverse phase 150 ꢄ 4.6 mm chromatography column.
carbonitrile (75) [32].

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
343
5.1.1. General procedure 1: preparation of amides
purified by flash column chromatography over silica gel (eluent:
To a solution of the appropriate acid (10 mmol) in dry DCM at
C were added HOBt (36 mmol), EDCI (36 mmol) and triethyl-
2:1, hexane/ethyl acetate) to afford a colourless powder (70%). M.p.
ꢀ
ꢀ
ꢁ1 1
0
138e140 C. IR
(6H, br m, CH
), 2.00 (1H, ddd, J ¼ 18.0 Hz, J ¼ 11.0 Hz, J ¼ 2.4 Hz,
H12 ), 2.11 (1H, m, H12
), 2.95 (1H, ddd, J ¼ 16.0 Hz, J ¼ 10.0 Hz,
J ¼ 2.4 Hz, H11), 3.46 (4H, br s, CH ), 4.37 (1H, s, H10), 4.48 (1H, s,
H9), 7.11 (4H, m, ArH), 7.31 (4H, m, ArH). C NMR (ppm) (CDCl
24.51 (C12), 41.63 (C10), 42.00 (CH ), 43.98 (C9), 44.40 (CH ), 46.39
(C11), 47.10 (CH ), 47.25 (CH ), 122.43, 122.94, 123.48, 125.53,
3
nmax (KBr) 1672 (C]O) cm . H NMR d (CDCl ) 1.58
amine (4.4 mmol). The reaction mixture was stirred for 10 min
before adding the appropriate amine (36 mmol). This solution was
stirred overnight at room temperature. The solvent was then
evaporated and water (50 mL) was added and the product extracted
with DCM (3 ꢄ 50 mL). The combined organic layers were washed
2
a
b
2
13
3
)
2
2
with brine (3 ꢄ 50 mL) and dried over anhydrous Mg
2
SO
4
. The
2
2
solvent was evaporated in vacuo to afford the amide.
125.57, 125.78, 125.89 (ArCH), 133.37, 134.59, 140.45, 143.64 (C
4
),
þ
171.58. HRMS (ESI) calculated for C21
H23NONa: [M þ Na]
0 0
.1.1.1. trans-11,12-(N,N,N ,N -Tetraethyl)-9,10-dihydro-9,10-
5
340.1677: found 340.1673.
ethanoanthracene-11,12-dicarboxyamide (7).
trans-11,12-Dihydroxycarbonyl-9,10-dihydro-9,10-
5.1.1.5. 9,10-Dihydro-11-pyrrolidinyl-9,10-ethanoanthracene-11-
ethanoanthracene (4) (1.70 mmol, 0.50 g) was treated with dime-
thylamine hydrochloride (6.12 mmol, 0.25 g) according to general
procedure 1 above. The product was then purified using flash col-
carboxyamide (12).
11-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
(1.8 mmol, 0.50 g) was reacted with pyrrolidine (3.24 mmol, 0.23 g)
according to general procedure 1 above. The product was then
purified by flash column chromatography over silica gel (eluent:
2:1, hexane/ethyl acetate) to afford a colourless powder (58%). M.p.
(5)
umn chromatography over silica gel (5% MeOH/DCM) to afford the
ꢀ
product as colourless crystals (75%). M.p. 120e123 C. IR
n
max (KBr)
),
, H9/
H10), 4.30 (2H, s, H11/H12), 7.12e7.19 (8H, m, ArH). C NMR (ppm)
CDCl ) 12.76, 14.52 (CH ), 39.93, 41.63 (CH ), 44.65 (C11/C12),
7.95 (C9/C10), 122.05, 124.61, 125.65, 125.80 (ArCH), 139.49, 142.27
), 170.83 (C]O). HRMS (ESI) calculated for
ꢁ
1 1
1636 (C]O) cm . H NMR
d
(CDCl
3
) 1.08 (6H, t, J ¼ 7.0 Hz, CH
3
ꢀ
ꢁ1 1
1
.23 (6H, t, J ¼ 7.0 Hz, CH ), 3.08 (2H, m, CH
3
2
), 3.41 (8H, m, CH
2
74e75 C. IR
(2H, br s, CH
(1H, ddd, J ¼ 16.0 Hz, J ¼ 10.0 Hz, J ¼ 2.4 Hz, H11), 3.41 (4H, br s,
CH ), 4.38 (1H, s, H9), 4.52 (1H, s, H10), 7.12 (4H, m, ArH), 7.27 (4H,
m, ArH). C NMR (ppm) (CDCl
(C12), 43.05 (C9), 43.59 (C10), 45.50 (CH
n
max (KBr) 1643 (C]O) cm . H NMR
d
(CDCl
3
) 1.67
), 2.87
1
3
2
), 1.98 (3H, br m, CH , H12 ), 2.09 (1H, m, H12
2
a
b
(
3
3
2
4
2
13
(
[
C
M
4
C
26
H
33
N
2
O
2
:
3
) 23.76 (CH
2
), 25.87 (CH
2
), 31.30
), 46.10 (C11), 122.13,
þ
þ H] 405.2549: found 405.2542.
2
122.62, 123.24, 125.23, 125.29, 125.46, 125.53 (ArCH), 143.25, 143.40
þ
5
.1.1. 2. trans-11,12-N -Piperidinyl-9,10-dihydro-9,10-
(C
4
), 171.68 (C]O). HRMS (ESI) calculated for C21
H
21NO: [M þ Na]
ethanoanthracene-11,12-dicarboxyamide (8).
326.1521: found 326.1512.
trans-11,12-Dihydroxycarbonyl-9,10-dihydro-9,10-
ethanoanthracene (4) (1.7 mmol, 0.50 g) was treated with piperi-
dine (6.12 mmol, 0.52 g) according to general procedure 1 above.
The product was then purified using flash column chromatography
over silica gel (5% MeOH/DCM) to afford the product as colourless
5.1.1.6. 9,10-Dihydro-11-N-methyl-N-cyclohexanyl-9,10-
ethanoanthracene-11-carboxyamide (13).
11-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
(5)
(1.8 mmol, 0.50 g) was reacted with N-methyl-N-cyclohexylamine
(3.24 mmol, 0.36 g) according to general procedure 1 above. The
product was then purified by flash column chromatography over
ꢀ
ꢁ1 1
crystals (89%). M.p. 144e145 C. IR
NMR (CDCl ) 1.53 (12H, m, CH ), 3.42 (2H, H9), 3.57 (4H, m, CH
.76 (4H, m, CH ), 4.32 (2H, s, H11), 7.12 (4H, m, ArH), 7.21 (2H, d,
J ¼ 8.0 Hz, ArH), 7.32 (2H, d, J ¼ 8.0 Hz, ArH). C NMR (ppm) (CDCl
4.27, 25.45, 26.57, 42.93, 44.53 (CH ), 46.35 (C9), 47.45 (C11),
n
max (KBr) 1623 (C]O) cm . H
d
3
2
2
),
3
2
silica gel (eluent: 2:1, hexane/ethyl acetate) to afford a colourless
13
ꢀ
3
)
powder (94%). M.p. 70e74 C. IR
H) cm . H NMR
n
max (KBr) 1640 (C]O), 2927 (Ce
), 1.98 (1H, m,
), 2.72 (1H, br s, NCH), 2.88 (1H, br s, NCH),
2.97 (1H, m, H11), 4.37 (1H, s, H10), 4.85 (1H, s, H9), 7.11 (4H, m,
ꢁ1 1
2
2
3 2
d (CDCl ) 1.28e1.92 (10H, m, 5CH
1
22.32, 124.41, 125.81, 139.59, 142.01 (ArCH), 169.83 (C]O). HRMS
H12 ), 2.15 (1H, m, H12
a
b
þ
(
ESI) calculated for C28
H
32
N
2
O
2
Na: [M þ Na] 451.2361: found
13
4
51.2357.
ArH), 7.29 (2H, m, ArH), 7.35 (2H, dd, J ¼ 3.5 Hz, J ¼ 8.0 Hz, ArH).
NMR (ppm) (CDCl ) 25.32, 25.63, 25.82, 25.97 (CH ), 27.70 (CH),
29.20 (CH ), 29.86 (C12), 31.04, 31.26, 32.32, 32.66 (CH ), 42.29
(C11), 44.15 (C10), 46.98 (C9), 143.83, 140.72 (C
C
3
2
5
.1.1.3. 9,10-Dihydro-N,N-dimethylamino-9,10-ethanoanthracene-
3
2
1
1
(
(
1-carboxyamide (9).
1-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
1.8 mmol, 0.50 g) was reacted with dimethylamine hydrochloride
3.24 mmol, 0.26 g) according to general procedure 1 above. The
4
), 173.00 (C]O).
þ
(5)
HRMS (ESI) calculated for C24
H27NONa: 368.1990 [M þ Na]: found
368.1974.
product was then purified by flash column chromatography over
5.1.1.7. tert-Butyl-4-(9,10-dihydro-9,10-ethanoanthracene-11-
silica gel (eluent: 85:15, hexane/ethyl acetate) to afford the product
carbonyl)piperazine-1-carboxylamide (16).
ꢁ1 1
as a colourless semi-solid (78%). IR
NMR (CDCl
) 1.95 (1H, ddd, J ¼ 17.8 Hz, J ¼ 11.9 Hz, J ¼ 2.5 Hz,
H12 ), 2.15 (1H, m, H12 ), 2.86 (3H, s, CH ), 2.96 (1H, m, H11), 3.02
3H, s, CH ), 4.89 (1H, s, H10), 4.51 (1H, s, H9), 7.13 (4H, m, ArH), 7.25
3H, m, ArH), 7.39 (1H, m, ArH). C NMR (ppm) (CDCl
5.34 (CH ), 36.48 (CH ), 41.40 (C10), 43.61 (C9), 46.31 (C10), 122.17,
22.68, 123.27, 125.25, 125.30, 125.66 (ArCH), 140.14, 143.30 (C ),
20NO: [M þ H]
nmax (film) 1655 (C]O) cm
H
11-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
(5)
t
d
3
(0.3 mmol, 0.08 g) was reacted with 1- Boc-piperazine (0.5 mmol,
0.11 g) according to general procedure 1 above. The product was
then purified by flash column chromatography over silica gel
(eluent: 2:1, hexane/ethyl acetate) to afford a colourless powder
a
b
3
(
(
3
13
3
2
) 31.79 (CH ),
ꢀ
ꢁ1 1
3
3
3
(85%). M.p. 192e195 C. IR
n
max (KBr) 1630 (C]O) cm . H NMR
), 1.96 (1H, dd, J ¼ 5.0 Hz, J ¼ 10.7 Hz,
), 2.94 (1H, m, H11), 3.39 (8H, br m, CH
1
4
d
(CDCl
3
) 1.48 (9H, s, 3 ꢄ CH
3
þ
173.00 (C]O). HRMS (ESI) calculated for C19
H
H12
a
), 2.13 (1H, m, H12
b
2
278.1545: found 278.1539.
piperazine), 4.38 (1H, s, H10), 4.47 (1H, s, H9), 7.12 (4H, m, ArH), 7.14
13
(
3H, m, ArH), 7.40 (1H, d, J ¼ 3.34 Hz, ArH). C NMR (ppm) (CDCl
27.92 (CH ), 32.02 (C12), 41.32 (C10), 43.51 (C11), 44.73 (CH
piperazine), 46.35 (C9), 79.90 (C
125.34, 125.37, 125.43, 125.59, 125.66 (ArCH), 139.91, 142.91, 143.10,
3
)
5
.1.1.4. 9,10-Dihydro-11-piperidinyl-9,10-ethanoanthracene-11-
3
2
t
carboxyamide (10).
1-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
1.8 mmol, 0.50 g) was reacted with piperidine (3.24 mmol, 0.28 g)
according to general procedure 1 above. The product was then
4
O Bu), 122.26, 122.71, 123.27,
1
(5)
t
(
143.14 (C
calculated for C26
4
), 154.11 (C]O Bu), 171.83 (C]O amide). HRMS (ESI)
þ
3
H N
2
O
3
Na: [M þ Na] 441.2154: found 441.2148.

344
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
5
.1.1.8. 9,10-Dihydro-11-N-anilinyl-9,10-ethanoanthracene-11-
silica gel (2:1, hexane/ethyl acetate) to afford a colourless powder
ꢀ
carboxyamide (17).
(55%). M.p. 143e144 C. IR
n
max (KBr) 1648 (C]O), 1748 (C]O),
(CDCl
) 0.90 (6H, d, J ¼ 8.0 Hz), 1.33 (1H,
), 1.98 (1H, m, H11), 2.14 (1H, m, H11), 2.82
(1H, ddd, J ¼ 2.0 Hz, J ¼ 5.0 Hz, J ¼ 16.0 Hz, H12), 3.73 (3H, s, OCH ),
4.41 (1H, s, H10), 4.52 (1H, m, NHCH), 4.61 (1H, s, H9), 5.44 (1H, d,
ꢁ1 1
11-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
(5)
3288 (NH) cm . H NMR
m, CH), 1.50 (2H, m, CH
d
3
(
1.8 mmol, 0.50 g) was reacted with aniline (3.24 mmol, 0.31 g)
2
according to general procedure 1 above. The product was then
purified by flash column chromatography over silica gel (eluent:
3
13
2
2
:1, hexane/ethyl acetate) to afford a colourless powder (60%). M.p.
J ¼ 8.0 Hz, NH), 7.13 (4H, m, ArH), 7.33 (4H, m, ArH). C NMR (ppm)
(CDCl ) 21.42, 22.32 (CH ), 24.24 (C16), 41.04 (C14), 43.35 (C11),
45.21 (C9), 46.98 (C10), 50.10 (C13), 51.79 (OCH ), 122.88, 123.01,
123.16, 124.93, 124.97, 125.43, 125.69, 125.97 (ArCH), 139.28, 142.35,
ꢀ
ꢁ1 1
30e232 C. IR
n
max (KBr) 1660 (C]O) cm . H NMR
), 2.07 (1H, m, H12
1H, ddd, J ¼ 14.9 Hz, J ¼ 9.9 Hz, J ¼ 2.5 Hz, H11), 4.43 (1H, s, H10),
.69 (1H, s, H9), 6.99e7.16 (4H, m, ArH), 7.24e7.41 (4H, m, ArH),
d
(CDCl
3
) 1.80
3
3
(
(
1H, ddd, J ¼ 14.5, J ¼ 12.4, J ¼ 2.9 Hz, H12
a
b
), 2.87
3
4
142.82, 143.32 (C
4
), 172.88, 173.18 (C]O). HRMS (ESI) calculated for
13
þ
7
4
1
.49 (2H, d, J ¼ 7.5 Hz, ArH). C NMR (ppm) (CDCl
2.89 (C11), 44.85 (C10), 47.45 (C9), 119.22 (C15), 122.95, 123.43,
24.69, 125.28, 125.58 (ArCH), 128.62 (C15), 139.45, 140.03, 143.32
3
) 29.69 (CH
2
),
C
24
H
27NO
3
: [M þ H] 378.2070: found 378.2053.
5.1.1.12. 9,10-Dihydro-11-piperazinyl-9,10-ethanoanthracene-11-
(
C
C
4
), 143.97 (NH), 170.89 (C]O). HRMS (ESI) calculated for
carboxyamide (34). To a solution of tert-butyl-4-(9,10-dihydro-9,10-
þ
23
H19NONa: [M þ Na] 348.1364: found 348.1362.
ethanoanthracene-11-carbonyl)piperazine-1-carboxylate
(16)
(
0.095 mmol, 0.04 g) in DCM (3 mL) was added trifluoroacetic acid
ꢀ
ꢀ
5
.1.1.9. 9,10-Dihydro-11-4-(4-chlorophenyl)piperazinyl-9,10-
(0.956
m
mol, 0.11 mg) at 0 C. The solutionwas stirred at 23 C for 6 h.
ethanoanthracene-11-carboxyamide (18).
1-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
1.8 mmol, 0.50 g) was reacted with 4-(4-chlorophenyl)-piperazine
3.24 mmol, 0.64 g) according to general procedure 1 above. The
product was then purified by flash column chromatography over
silica gel (eluent: 95%, DCM/MeOH) to afford a colourless powder
After this time the solution was diluted with DCM (10 mL) and
basified by the slow addition of aq. satd. NaHCO . The aqueous layer
was extracted with ethyl acetate, dried over anhydrous Na SO and
1
(
(
(5)
3
2
4
the solvent removed in vacuo. The resulting residue required no
further purification and the product was isolated as a pale solid
ꢀ
ꢁ1 1
(80%). M.p. 130e133 C. IR
(CDCl ) 1.26 (1H, m, H11), 1.97 (1H, m, H12
2.91e3.60 (8H, 3 ꢄ br s, CH piperazine), 4.38 (1H, s, H10), 4.46 (1H, s,
H9), 7.16 (4H, m, ArH), 7.26 (3H, m, ArH), 7.40 (1H, d, J ¼ 7.6 Hz, ArH).
n
max (KBr) 1668 (C]O) cm . H NMR
ꢀ
ꢁ1 1
.
(
d
87%). M.p. 111e113 C. IR
(CDCl
) 1.98 (1H, ddd, J ¼ 17.7 Hz, J ¼ 11.9 Hz, J ¼ 2.5 Hz, H12
1H, m, H12
), 2.99 (1H, ddd, J ¼ 16.3 Hz, J ¼ 10.2 Hz, J ¼ 2.1, H11), 3.00,
.69 (8H, 2br m, CH ), 4.39 (1H, s, H10), 4.50 (1H, s, H9), 6.86 (2H, d,
n
max (KBr) 1648 (C]O) cm
H NMR
d
3
a
), 2.13 (1H, m, H12 ),
b
3
a
), 2.01
2
(
3
b
13
2
C NMR (ppm) (CDCl
3
) 31.95 (C12), 41.15 (C10), 43.49 (C11), 46.30
13
J ¼ 1.9 Hz, H15), 7.14e7.38 (10H, 2m, ArH, H16). C NMR (ppm)
(C9), 122.27, 122.72, 123.29, 125.34, 125.38, 125.45, 125.28, 125.67
(
(
1
CDCl
C11), 49.05, 49.50, 53.06 (CH
25.37,125.39,125.47,125.62,125.69,128.69 (ArCH),139.95 (C
3
) 32.03 (CH
2
C12), 41.26 (C9), 43.56 (C10), 45.00 (CH
),117.43,122.30,122.74,122.74,123.31,
CeN),
2
), 46.40
(ArCH), 139.88142.89, 143.11, 143.15 (C
4
), 171.68 (C]O). HRMS (ESI)
þ
2
calculated for C21
H
23
N
2
O: [M þ H] 319.1810: found 319.1800.
4
1
42.9, 143.14, 143.23 149.05 (CeCl), 171.65 (C]O). HRMS (ESI)
5.1.2. General procedure 2: preparation of amines
The appropriate amide (1 mmol) was added slowly to a slurry of
4 2
LiAlH (8 mmol) in dry THF. The solution was stirred overnight. H O
þ
calculated for C27
25 2
H N OClNa: [M þ Na] 451.1553: found 451.1541.
5
.1.1.10. Methyl 2-(9,10-dihydro-9,10-ethanoanthracene-11-
(2 mL) was added slowly to quench the reaction. The suspension
was filtered over Celite. Diethyl ether (50 mL) was added to the
solution and extracted with 2 N HCl (3 ꢄ 20 mL). The aqueous phase
was basified and extracted with EtOAc (3 ꢄ 20 mL). The solution
carboxamido)-3-(4-hydroxyphenyl)
propanoate
(19).
(5)
11-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
(
1.12 mmol, 0.31 g) and DL-tyrosine methyl ester (2.2 mmol, 0.51 g)
were reacted together according to general procedure 1 above. No
2 4
was dried over anhydrous Mg SO . The solvent was evaporated in
further purification was required. The product was obtained as pale
vacuo to give the product.
ꢀ
crystals (73%). M.p. 102e104 C. IR
n
max (KBr) 1745 (CH
3
OC]O),
ꢁ1
1
0
0
1
H12
2
3
4
614 (NHC]O), 3320 (OH) cm . H NMR
d
(CDCl ) 1.71 (1H, m,
3
5.1. 2.1. trans-9,10-Dihydro-N, N, N , N -tetraethyl-9,10-
*
*
a
), 1.86 (1H, m, H12
.73 (2H, m, CH
), 2.78 (1H, d, J ¼ 5.6 Hz, H11), 3.03 (2H, m, CH
.83 (3H, s, CH
a
), 2.08 (1H, m, 12
b
), 2.20 (1H, m, H12
b
),
),
ethanoanthracene-11,12-dimethanamine (22).
*
0
0
2
2
trans-11,12-N,N,N ,N -Tetraethyl-9,10-dihydro-9,10-
*
3
), 4.33 (1H, s, H10), 4.37 (1H, s, H10), 4.47 (1, s, H9),
.58 (1H, s, H9), 4.67 (1H, dd J ¼ 16.0 Hz, J ¼ 7.0 Hz, H13), 4.76 (1H,
ethanoanthracene-11,12-dicarboxyamide (7) (1 mmol, 0.4 g) was
added to LiAlH according to general procedure 2 above. No further
4
purification was required. The resulting residue required no further
purification and the product was isolated as a brown solid (35%).
*
*
*
dd, J ¼ 14.2 Hz, J ¼ 5.4 Hz, H13), 5.72 (1H, d, J ¼ 7.6 Hz, NH), 5.77
*
(
1H, dd, J ¼ 7.6 Hz, NH), 6.69 (2H, m, ArH phenol), 6.77 (2H, d,
13
ꢀ
ꢁ1 1
J ¼ 8.0 Hz, ArH phenol), 7.17 (4H, m, ArH), 7.31 (4H, m, ArH).
C
*
M.p. 60e64 C. IR
NMR (CDCl
) 0.98 (12H, t, J ¼ 7.0 Hz, 4CH
C12), 1.94 (2H, dd, J ¼ 9.5 Hz, J ¼ 12.5 Hz, C13), 2.05 (2H, dd,
J ¼ 4.0 Hz, J ¼ 12.5 Hz, C14), 2.41 (4H, 2t, J ¼ 7.0 Hz, 2CH ), 2.54 (4H,
2t, J ¼ 7.0 Hz, 2CH ), 7.10 (4H, m, ArH), 7.28 (4H, m, ArH). C NMR
(ppm) (CDCl ) 11.37 (CH ), 42.84 (C11), 46.19 (C9), 47.03 (CH C13/
C14), 57.00 (CH
144.33 (C
377.2961: found 377.2961.
n
max (KBr) 1466 (Ar C]C), 2973 (ArCH) cm . H
*
NMR (ppm) (CDCl
3
) 30.54 (CH
3
), 31.30, 31.68 (C12), 36.37, 36.88
d
3
3
), 1.44 (2H, br m, C11/
*
*
*
(
5
1
CH
3.15, 53.35 (C13), 115.45, 115.47 (ArCHCOH), 122.70, 122.88,
23.01, 123.18, 123.27, 125.00, 125.41, 125.57, 125.68, 125.86, 126.06,
2
), 43.69, 43.75 (C10), 45.39, 45.46 (C9), 46.88, 46.90 (C11),
*
*
2
1
3
2
*
1
26.13 (ArH), 130.11, 130.22 (ArCHCCH
42.53, 142.38, 139.16, 138.91 (C ), 154.80, 154.85 (C
CH C]O), 172.80 (NHC]O). HRMS (ESI) calculated for C27
2
), 143.70, 143.49, 142.70,
3
3
2
1
4
4
), 171.78
2
), 122.55, 124.69, 125.13, 125.37 (ArCH), 141.21,
þ
(
[
3
H26NO
4
:
4
). HRMS (ESI) calculated for C26
H
37
N
2
: [M þ H]
þ
M
þ H] 428.1863: found 428.1848.
5
.1.1.11. Methyl-2-(9,10-dihydro-9,10-ethanoanthracene-11-
5.1.2.2. 9,10-Dihydro-N,N-dimethyl-9,10-ethanoanthracene-11-
methanamine (23).
9,10-Dihydro-N,N-dimethylamino-9,10-ethanoanthracene-11-
carboxyamido)-4-methylpentoate (20).
1-Hydroxycarbonyl-9,10-dihydro-9,10-ethanoanthracene
1.8 mmol, 0.50 g) and -leucine methyl ester (3.24 mmol, 0.49 g)
1
(
(5)
L
4
carboxyamide (9) (1 mmol, 0.27 g) was added to LiAlH according
were reacted together according to general procedure 1 above. The
to general procedure 2 above and purified by flash column chro-
product was then purified by flash column chromatography over
matography over silica gel (eluent: 95% DCM/MeOH) to afford the

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
345
ꢀ
product as colourless crystals (86%). M.p. 83e84 C [50]. IR
n
max
95% DCM: MeOH) to afford a brown resin (57%). IR
n
max (KBr) 2853
ꢁ
1 1
ꢁ1 1
(
KBr) 1456 (ArC]C), 2940 (ArH) cm . H NMR
ddd, J ¼ 16.8 Hz, J ¼ 12.3 Hz, J ¼ 2.5 Hz, H11), 2.01, 2.19 (2H, 2m,
H12), 2.37 (6H, s, 2CH ), 4.29 (1H, s, H9), 4.51 (1H, s, H10), 7.26 (4H,
m, ArH), 7.32 (2H, m, ArH), 7.43 (2H, m, ArH). C NMR (ppm)
d
(CDCl
3
) 1.21 (1H,
(ArCH), 3410 (NH) cm . H NMR
d
(CDCl
3
) 2.05 (2H, m, H13), 2.25
), 3.70 (1H, NH), 4.33
(1H, m, H11), 2.70 (1H, m, H12
a
), 2.79 (m, H12
b
2
3
(1H, t, J ¼ 3.0 Hz, H10), 4.38 (1H, d, J ¼ 2.0 Hz, H9), 6.58 (2H, d,
13
J ¼ 7.5 Hz, H17), 6.72 (2H, t, J ¼ 7.5 Hz, H15), 7.13e7.22 (6H, m, ArH,
1
3
(
CDCl
3
) 32.84 (CH
2
, C12), 35.52 (C11), 43.90 (C9), 44.90 (CH
, C13), 123.18, 123.54, 123.66, 125.73, 125.77,
).
22N: [M þ H] 264.1752: found
3
), 46.38
H16), 7.30 (4H, m, ArH). C NMR (ppm) (CDCl
3
) 32.28 (CH
C13), 112.36 (C17),
122.76 (C15), 128.81 (C16), 123.04, 124.93, 125.25, 125.30, 125.64
2
C12),
(
C10), 63.75 (CH
2
37.90 (C11), 43.68 (C10), 46.31 (C9), 48.43 (CH
2
1
25.79, 125.93, 126.17 (ArCH), 139.48, 142.84, 143.13, 143.30 (C
4
þ
HRMS (ESI) calculated for C19
H
(ArCH), 139.99, 143.39, 143.21 (C
4
), 147.79 (C
4
NH). HRMS (ESI)
þ
2
64.1749.
calculated for C23
H22N: [M þ H] 312.1752: found 312.1748.
5
.1.2.3. 9,10-Dihydro-N-pyrrolidinyl-9,10-ethanoanthracene-11-
5.1.2.7. 9,10-Dihydro-11-4-(4-chlorophenyl)piperazinyl-9,10-
ethanoanthracene-11-methanamine (31).
9,10-Dihydro-11-(4-{4-chlorophenyl}-piperazinyl)-9,10-
ethanoanthracene-11-carboxyamide (18) (0.49 mmol, 0.20 g) was
methanamine (26).
,10-Dihydro-11-N-pyrrolidinyl-9,10-ethanoanthracene-11-
carboxyamide (12) (1 mmol, 0.29 g) was reacted with LiAlH
9
4
ac-
cording to general procedure 2 above. The crude product was then
4
reacted with LiAlH according to general procedure 2 above. The
purified by flash column chromatography over silica gel (eluent: 95%
DCM: MeOH) to afford a pale brown solid (50%). M.p. 92e94 C. IR
crude product was then purified by flash column chromatography
over silica gel (eluent: 95% DCM/MeOH) to afford a pale brown oil
ꢀ
ꢁ
1 1
ꢁ1
n
max (KBr) 1457 (Ar C]C), 2941 (Ar CeH) cm . H NMR
.23 (1H, m, H11),1.80 (4H, br s, H15),1.96 (2H, m, H12), 2.15 (2H, m,
H13), 2.53 (4H, br m, H14), 4.27 (1H, s, H9), 4.39 (1H, s, H10), 7.10 (4H,
d
(CDCl
3
)
(66%). IR
H NMR
n
max (film) 751 (CeCl), 1598 (ArC]C), 2941 (ArCH) cm
(CDCl ) 1.25 (1H, br m, H11), 2.01 (3H, br s, CH
), 2.51 (2H, br s, CH ), 2.62 (2H, br s, CH
), 4.34 (1H, br s, H10), 4.45 (1H, br s, H9), 6.91 (2H, br
.
1
1
d
3
2
, H12
a
),
2.25 (1H, br s, H12
(4H, br s, CH
m, ArH), 7.10 (4H, m, ArH), 7.28 (6H, m, ArH). C NMR (ppm)
(CDCl ) 32.69 (C12), 35.25 (C11), 43.79 (C10), 46.74 (C10), 48.78
(CH ), 52.81, 52.98 (NCH ), 63.07, 63.15 (NCH ), 115.61, 116.75,
19.20, 122.63, 123.01, 125.03, 125.07, 125.16, 125.21, 125.35, 128.50,
b
2
2
), 3.23
13
m, ArCH), 7.26 (4H, m, ArCH). C NMR (ppm) (CDCl
3.04 (C12), 36.79 (C9), 43.67 (C10), 46.59 (C11), 54.04 (CH
C13),122.55,122.97,125.04,125.18 (ArH),140.05,143.44 (C
3
) 23.01 (CH
), 64.47
). HRMS
2
),
2
13
3
2
(
(
4
3
þ
ESI) calculated for C21
H
24N: [M þ H] 290.1909: found 290.1898.
2
2
2
1
5
.1. 2. 4. 9,10-Dihydro-N-methyl-N-cyclohexanyl-9,10-
ethanoanthracene-11-methanamine (27).
,10-Dihydro-11-N-methyl-N-cyclohexanyl-9,10-
ethanoanthracene-11-carboxyamide (13) (1 mmol, 0.33 g) was
reacted with LiAlH according to general procedure 2 above. The
128.68 (ArCH), 140.46, 143.43, 143.51, 143.84 (C4), 149.61 (C
4
N),
þ
150.99 (C
415.1941: found 415.1939.
4
Cl). HRMS (ESI) calculated for C27
H27NCl: [M þ H]
9
4
5.1.2.8. 9,10-Dihydropiperazinyl-9,10-ethanoanthracene-11-
methanamine (35). Preparation from 9,10-dihydro-11-piperizinyl-
9,10-ethanoanthracene-11-carboxyamide (34) (0.047 mmol, 13 mg)
was reacted with LiAlH following the general procedure 2 above.
4
The crude product was then purified by flash column chromatog-
crude product was then purified by flash column chromatography
over silica gel (eluent: 95% DCM/MeOH) to afford a pale brown solid
ꢀ
ꢁ1
(
50%). M.p. 80e82 C. IR
H NMR
n
max (KBr) 1456 (ArC]C), 2927 (ArCH) cm
) 1.05e1.23 (6H, m, H16, H17), 1.62 (1H, d,
), 2.15e2.40
5H, 2m, H12, H13, H14), 4.30 (1H, s, H10), 4.46 (1H, s, H9), 7.13e7.17
.
1
d
(CDCl
3
J ¼ 12.5 Hz, H11), 1.79 (4H, br s, H15), 2.00 (3H, m, CH
3
raphy over silica gel (eluent: 95% DCM/MeOH) to afford the product
(
(
as a pale resin (48%). IR
n
max (film) 3418.38 (NH), 2926.50 (CH),
(CDCl ): 0.91 (1H, m, H12 ),1.15 (1H,
), 2.48 (4H, br s, CH ),
2
), 3.14 (1H, br s, NH), 4.27 (1H, br s, H-9), 4.32 (1H,
13
ꢁ11
4H, m, ArH), 7.25e7.40 (4H, m, ArH). C NMR (ppm) (CDCl
3
) 25.62,
C12), 37.81 (C11), 43.79 (C10),
C13), 63.34 (CH ), 122.41, 122.93, 122.99,
). HRMS
30N: [M þ H] 332.2378: found 332.2373.
1651.38,1457.45 cm
m, H12
2.72 (4H, br s, CH
br s, H-10), 7.12 (4H, m, ArH), 7.29 (4H, m, ArH). C NMR (ppm)
(CDCl ) 29.41 (CH ), 32.38 (CH ), 35.01 (C12), 35.16 (C11), 43.63 (C9),
6.42 (C10), 52.69 (CH ), 62.77 (CH ), 122.65, 122.97, 124.89, 124.96,
H NMR
d
3
a
2
4
5.81, 27.41, 28.19 (CH
6.09 (C9), 57.98 (CH
2
), 32.80 (CH
2
b
), 1.93 (1H, m, H11), 2.10 (2H, m, CH
2
2
2
3
13
124.88, 125.04 (ArCH), 125.08, 125.24, 125.38, 143.71 (C
4
þ
(
ESI) calculated for C24
H
3
2
2
4
2
2
5
.1.2.5. 9,10-Dihydro-N-ethyl-9,10-ethanoanthracene-11-
methanamine (28).
,10-Dihydro-11-N-ethylamino-9,10-ethanoanthracene-11-
carboxyamide (14) (1 mmol, 0.26 g) was reacted with LiAlH
125.05,125.17,125.25,125.31 (ArCH),140.50,144.00 (C
4
). HRMS (ESI)
þ
calculated for C21
H
25
N
2
: [M þ H] 305.2018: found 305.2018.
9
4
ac-
5.1.3. General procedure 3: hydrolysis of esters
cording to general procedure 2 above and the product was purified
by flash column chromatography over silica gel (eluent: 95% DCM/
The appropriate ester (10 mmol) was dissolved in EtOH (100 mL)
and an aqueous solution of KOH (5 M, 150 mL) and heated at reflux
for 3 h. After this time, the solution was diluted with water (50 mL)
and washed with diethyl ether. The aqueous layer was acidified
with HCl (2 M) and the product was extracted using ethyl acetate
(3 ꢄ 50 mL). The organic phase wash washed with brine
MeOH) to afford a brown oil (33%). IR
n
max (film) 1466 (ArC]C),
) 1.12 (3H, t, J ¼ 7.0 Hz, CH ),1.19
1H, m H11), 2.01 (H, m, H12), 2.18 (1H, m, H12), 2.25 (2H, d,
J ¼ 7.0 Hz, H13), 2.60 (2H, m, CH ), 4.30 (1H, s, H10), 4.34 (1H, s, H9),
.12 (4H, m, ArH), 7.30 (4H, m, ArH). C NMR (ppm) (CDCl
CH ), 32.73 (C12), 38.07 (C11), 43.64 (CH ), 43.69 (C10), 46.42 (C9),
4.14 (C13), 122.60, 122.92, 123.00, 124.74, 125.03, 125.14, 125.39,
25.42 (ArCH), 143.22, 143.38, 143.58 (C ). HRMS (ESI) calculated
22N: [M þ H] 264.1752: found 264.1758.
ꢁ
1 1
2
943 (ArCH) cm . H NMR
d
(CDCl
3
3
(
2
13
7
3
) 14.59
(3 ꢄ 25 mL), dried over anhydrous Mg
2 4
SO and the solvent was
(
3
2
evaporated in vacuo. The product required no further purification.
5
1
4
5.1.3.1. 2-(9,10-Dihydro-9,10-ethanoanthracene-11-carboxamido)-3-
(4-hydroxyphenyl) propanoic acid (32). Methyl 2-(9,10-dihydro-
þ
for C19
H
9,10-ethanoanthracene-11-carboxamido)-3-(4-hydroxyphenyl)
5
.1.2.6. 9,10-Dihydro-N-anilinyl-9,10-ethanoanthracene-11-
methanamine (30).
,10-Dihydro-11-N-anilinyl-9,10-ethanoanthracene-11-
carboxyamide (17) (1 mmol, 0.33 g) was reacted with LiAlH
propanoate (19) (1.45 mmol, 0.62 g) was reacted with KOH (5 M,
15 mL) according to general procedure 3 above. The product was
9
obtained as pale brown crystals and no further purification was
ꢀ
4
ac-
required (98%). M.p. 161e163 C. IR
n
1 1
max (KBr) 1723 (OHC]O), 1650
ꢁ
cording to general procedure 2 above. The crude product was then
purified by flash column chromatography over silica gel (eluent:
(NHC]O), 3022, 3308 (OH) cm . H NMR
d
(CD
6
SO) 1.70 (1H, m,
),
*
*
H12
a
), 1.72 (1H, m, H12
a
), 1.85 (1H, m, H12
b
), 1.99 (1H, m, H12
b

346
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
*
*
2
.64 (1H, m, H11), 2.66 (1H, m, H11), 2.73 (1H, m, H14), 2.77 (1H,
(1H, q, J ¼ 5.0 Hz, H13), 4.29 (1H, t, J ¼ 2.5 Hz, H10), 4.46 (1H, d,
*
13
m, H14), 2.90 (1H, m, H14), 2.98 (1H, m, H14), 4.18 (1H, m, H13),
.20 (1H, m, H13), 4.32 (1H, m, H10), 4.34 (1H, m, H10), 4.36 (1H,
J ¼ 2.0 Hz, H9), 7.15 (4H, m, ArH), 7.28 (4H, m, ArH). C NMR (ppm)
*
*
4
3
(CDCl ) 30.55 (C12), 40.48 (C10), 43.56 (C11), 45.05 (C9), 65.63
*
*
m, H9), 4.95 (1H, m, H9), 6.61 (2H, d, J ¼ 8.0 Hz, ArCHCOH), 6.80
(CH ), 122.68, 122.99, 123.11, 124.86, 125.18, 125.23, 125.25, 125.53
2
*
(
7
(
4
2H, d, J ¼ 8.0 Hz, ArCHCOH), 6.96 (2H, d, J ¼ 8.0 Hz, ArCHCCH
2
),
(ArCH), 140.02, 143.35, 143.40 (C
4
). HRMS (ESI) calculated for:
13
þ
.14 (2H, d, J ¼ 8.0 Hz, ArCHCCH
2
), 7.10e7.35 (16H, m, ArH). C NMR
C
17
H17O [M þ H] 237.3163: found 237.3182.
*
*
6
ppm) (CD SO) 26.68, 30.12 (C12), 36.63, 36.44 (CH14), 44.00,
4.20 (C11), 54.54 (C13), 43.30, 43.40 (C10), 47.70, 47.90* (C9),
*
*
5.1.3.5. (E)-3-(9-Anthracenyl)-N,N-dimethylacrylamide
(51).
*
*
1
30.40 , 130.60 (ArCHCCH
2
), 115.30 , 115.50 (ArCHCOH), 128.20,
OH). HRMS (ESI)
Na: [M þ Na] 436.1525: found 436.1523.
3-(9-Anthracenyl)acrylic acid (50) (2.01 mmol, 0.50 g) and dime-
thylamine hydrochloride (3.60 mmol, 1.12 g) were reacted accord-
ing to the general procedure 1 above. The residue was purified by
flash column chromatography over silica gel (eluent: 2:1, hexane/
ethyl acetate) to afford the product as a dark brown solid (87%).
*
127.80 (C
4
CH
2
), 120e140 (ArCH), 155.20, 156.0 (C
4
þ
calculated for C26
H
23NO
4
5
.1.3.2. 9,10-Dihydro-9,10-ethanoanthracene-11-carboxamido-4-
methylpentanoic acid (33).
Methyl-2-[9,10-dihydro-9,10-ethanoantracene-11-carboxyamido]-
-methyl-pentoate (20) (0.52 mmol, 0.2 g) was treated with KOH
5 M, 5 mL) according to the general procedure 3 above. The
ꢀ
ꢁ1 1
3
nmax (KBr) 1645 (C]O) cm . H NMR d (CDCl )
M.p. 77e80 C. IR
3.17 (6H, s, CH
), 6.86 (1H, d, J ¼ 15.5 Hz, H12), 7.51 (4H, m, ArH),
8.29 (2H, d, J ¼ 9.5 Hz, H4/H5), 8.29 (2H, d, J ¼ 9.5 Hz, H1/H8), 8.60
3
4
(
13
(1H, s, H10), 8.59 (1H, d, J ¼ 15.5 Hz, H11). C NMR (ppm) (CDCl
3
)
product was obtained as colourless crystals and no further purifi-
cation was required (89%). M.p. 169e172 C. IR
34.43 (C9), 36.00 (CH ), 37.47 (CH ), 125.26, 125.33, 125.59, 126.00,
3
3
ꢀ
n
max (KBr)
), 1.49 (1H, br s,
), 2.12e2.16 (3H, br m, CH , H12 ),
126.70, 127.24, 127.51, 128.47, 128.76, 132.84 (ArCH, C12), 139.68
ꢁ
1
1
þ
3105 cm
.
H NMR
d
(CDCl
3
) 0.86 (6H, s, CH
3
(C11), 166.16 (C]O). HRMS (ESI) calculated for C19
276.1388: found 276.1380.
H
18NO: [M þ H]
CH CHCH
3
3
), 1.96 (1H, m, H12
a
2
b
2
.85 (1H, m, H11), 5.56, 5.75 (1H, 2 s, NH), 7.14 (4H, m, ArH), 7.28
4H, m, ArH). 13C NMR (ppm) (CDCl
) 20.43, 21.23 , 21.29, 22.37
*
*
5.1.3.6. (E)-3-(9-Anthracenyl)-N,N-diethylacrylamide
(52).
(
(
(
3
*
*
*
CH
CH
3
2
), 24.23, 24.33 (CH
3
CHCH
3
), 31.60, 31.89 (C12), 40.53, 40.48
3-(9-Anthracenyl)acrylic acid (51) (2.01 mmol, 0.50 g) and N,N,-
diethylamine hydrochloride (3.60 mmol, 1.22 g) were reacted ac-
cording to the general procedure 1 above. The residue was purified
by flash column chromatography over silica gel (eluent: 2:1, hex-
*
*
*
), 43.29, 43.35 (C10), 44.97, 45.19 (C9), 46.73 , 46.95 (C11),
*
*
*
*
5
0.34, 50.42 (CH), 122.95, 123.00 , 123.08, 123.20 , 123.27, 125.00 ,
*
*
*
125.54, 125.76 (ArCH), 126.04, 126.16 , 138.96, 139.16 , 142.22,
*
*
ꢀ
142.23 , 142.66, 142.75 (C
4
), 173.93 (COOH), 175.00 (NHC]O).
ane/ethyl acetate) to afford an orange solid (78%). M.p.78e81 C. IR
þ
ꢁ1 1
HRMS (ESI) calculated for C23
found 386.1721.
H25NO
3
Na: [M þ Na] 386.1732:
nmax (KBr) 1649 (C]O), 2974 (Ar C]C) cm . H NMR
d
(CDCl
), 6.80 (1H, d,
J ¼ 15.5 Hz, H12), 7.50 (4H, m, ArH), 8.03 (2H, m, H4/H5), 8.30 (2H,
3
) 1.29
(6H, s, CH
3
), 3.46e3.63 (4H, br d, J ¼ 6.0 Hz, CH
2
13
5.1.3.3. trans-9-10-Dihydroxymethyl-9,10-ethanoanthracene
(36).
m, H1/H8), 8.49 (1H, s, H10), 8.65 (1H, d, J ¼ 15.5 Hz, H11). C NMR
A
solution of compound trans-11,12-dihydroxycarbonyl-9,10-
(ppm) (CDCl ) 12.88, 14.80 (CH ), 40.78, 41.88 (CH ), 124.87, 125.17,
125.49, 125.64, 128.29 (ArCH), 126.98 (C12), 128.95, 130.65, 130.83
3
2
3
dihydro-9,10-ethanoanthracene (4) (5.7 mmol, 2.00 g) in dry THF
20 mL) was added dropwise to a solution of LIAlH (18.3 mmol,
.695 g) in dry THF (20 mL). The mixture was refluxed for 3 h and
then quenched with the careful addition of water (25 mL) and then
HCl (1 M, 25 mL). The aqueous phase was extracted with diethyl
ether. The organic phase was then washed with water, dried over
(
0
4
(C
4
), 139.15 (C11), 164.68 (C]O). HRMS (ESI) calculated for
þ
C
21
H22NO: [M þ H] 304.1714: found 304.1701.
5.1.3.7. (E)-3-(9-Anthracenyl)-1-(piperidinyl)prop-2-en-1-one (53).
3-(9-Anthracenyl)acrylic acid (50) (2.01 mmol, 0.50 g) and piperi-
dine (3.60 mmol, 1.13 g) were reacted according to the general
procedure 1 above. The residue was purified by flash column
chromatography over silica gel (eluent: 85.15, hexane/ethyl acetate)
to afford the product as a yellow solid (54%). M.p. 92e98 C. IR
2 4
anhydrous Mg SO and solvent evaporated in vacuo to give a col-
ourless powder. The product was then purified using flash column
chromatography over silica gel (eluent: DCM) and washed with
methanol to elute the product, colourless needles (40%). M.p. 194e
ꢀ
n
max
ꢀ
ꢁ1
1
ꢁ1 1
1
98 C [33]. IR
n
max (KBr) 3280 (OH), 1076 (CeO) cm
.
H NMR
3 2
(KBr) 1655 (C]O) cm . H NMR d (CDCl ) 1.68 (6H, br s, CH ), 3.56
d
(DMSO-d) 1.27 (2H, m, H11), 2.75 (2H, m, H12), 3.10 (2H, m, H12),
.34 (2H, s, H9), 4.68 (2H, t, J ¼ 5.0 Hz, OH), 7.08e7.27 (8H, m, ArH).
C NMR (ppm) (DMSO-d) 45.28 (C11), 45.96 (C9/C10), 64.42 (C12),
(4H, br s, CH
2
), 6.90 (1H, d, J ¼ 15.0 Hz, H12), 7.54 (4H, m, ArH), 8.04
4
(2H, d, J ¼ 8.0 Hz, ArH), 8.31 (2H, d, J ¼ 8.0 Hz, ArH), 8.48 (1H, s,
1
3
13
H10), 8.59 (1H, d, J ¼ 15.0 Hz, H11). C NMR (ppm) (CDCl
(CH ), 25.89 (CH ), 124.85, 125.16, 125.50, 128.14, 128.29 (ArCH),
127.33 (C12), 128.93, 130.83 (C
(ESI) calculated for C22
3
) 24.19
1
23.45, 125.61, 125.84, 126.07 (C1eC8), 141.68, 144.44 (C
4
). HRMS
2
2
þ
(
ESI) calculated for C18
H
18
O
2
Na: [M þ Na] 289.1204: found
4
), 139.07 (C11), 164.32 (C]O). HRMS
22NO: [M þ H] 316.1701: found 316.1692.
þ
2
89.1218.
H
5
of
.1.3.4. 11-Hydroxymethyl-9,10-ethanoanthracene (37). A solution
compound 11-ethoxycarbonyl-9,10-dihydro-9,10-
ethanoanthracene (5) (1.7 mmol, 0.50 g) in dry THF (20 mL) was
added dropwise to a solution of LIAlH (8.16 mmol, 0.31 g) in dry
5.1.3.8. (E)-3-(9-Anthracenyl)-1-(pyrrolidinyl)prop-2-en-1-one (54).
3-(9-Anthracenyl)acrylic acid (50) (2.01 mmol, 0.50 g) and pyrro-
lidine (3.60 mmol, 1.08 g) were reacted according to the general
procedure 1 above. The residue was purified by flash column
chromatography over silica gel (eluent: 85:15, hexane/ethyl ace-
tate) to afford the product as an orange powder (63%). M.p. 94e
4
THF (20 mL). The mixture was refluxed for 3 h and then quenched
with the careful addition of water (25 mL) and then HCl (1 M,
ꢀ
ꢁ1 1
2
5 mL). The aqueous phase was extracted with diethyl ether. The
organic phase was then washed with water, dried over anhydrous
Mg SO and solvent was evaporated in vacuo. The product was
95 C. IR
s, CH ), 3.66 (4H, 2s, CH
ArH), 8.02 (2H, m, H4/H5), 8.29 (2H, m, H1/H8), 8.45 (1H, s, H10),
n
max (KBr) 1656 (C]O) cm . H NMR
3
d (CDCl ) 2.00 (4H, br
2
2
), 6.73 (1H, d, J ¼ 16.0 Hz, H12), 7.50 (4H, m,
2
4
1
3
purified by flash column chromatography (eluent: 1:1 hexane/ethyl
acetate) and recrystallised from methanol as a colourless powder
8.63 (1H, d, J ¼ 16.0 Hz, H11). C NMR (ppm) (CDCl
53.01 (CH ), 125.25, 125.34, 125.61, 125.80, 126.02, 127.60, 127.85,
128.76 (ArCH), 127.02 (C12), 129.43, 130.84, 131.28 (C ), 139.36
3 2
) 46.49 (CH ),
2
ꢀ
ꢁ1 1
(
d
38%). M.p. 96e98 C [48]. IR
(CDCl
) 1.08 (1H, ddd, J ¼ 17.0 Hz, J ¼ 12.1 Hz, J ¼ 2.5 Hz, H11), 1.93
1H, m, H12 ), 2.15 (1H, m, H12
), 2.98 (1H, t, J ¼ 10.0 Hz, H13), 3.35
n
max (KBr) 3290 (OH) cm . H NMR
4
þ
3
(C11), 164.28 (C]O). HRMS (ESI) calculated for C21
H20NO: [M þ H]
(
a
b
302.1545: found 302.1555.

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
347
5.1.3.9. (E)-3-(9-Anthracenyl)-1-(N-methylpiperazinyl)prop-2-en-1-
126.00 (C2/C7),128.8 (C4/C5), 129.20 (C
4
),129.50 (C12),130.00 (C9),
one (55). 3-(9-Anthracenyl)acrylic acid (50) (2.01 mmol, 0.50 g)
and N-methylpiperazine (3.60 mmol,1.18 g) were reacted according
to the general procedure 1 above. The residue was purified by flash
column chromatography over silica gel (eluent: 85:15, hexane/ethyl
acetate) to afford the product as a brown solid (67%). M.p. 120e
131.30 (C
4
), 137.85 (C11), 165.50 (C]O). HRMS (ESI) calculated for
þ
C
18
H15NONa: [M þ Na] 284.1051: found 284.1052.
5.1.3.13. (E)-9-(4-Nitrostyryl)anthracene (49).
(4-Nitrophenyl)triphenylphosphonium bromide (2.18 mmol,
1.04 g) and 60% NaH in oil (2.9 mmol, 0.12 g) were stirred for 30 min
ꢀ
ꢁ1 1
1
25 C. IR
s, CH
), 2.66 (4H, 2 ꢄ br s, CH
CH
), 6.84 (1H, d, J ¼ 15.5 Hz, H12), 7.52 (4H, m, ArH), 8.03 (2H, m,
H5/H4), 8.25 (2H, m, H1/H8), 8.48 (1H, s, H10), 8.73 (1H, d,
n
max (KBr) 1644 (C]O) cm . H NMR
d
(CDCl
3
) 2.48 (3H,
ꢀ
3
2
), 3.79 (2H, br s, CH
2
), 4.01 (2H, br s,
in anhydrous THF (20 mL), in an inert atmosphere, at 0 C. 9-
2
Anthraldehyde 46 (1.45 mmol, 0.3 g) in dry THF (10 mL) was
added dropwise to the solution and it was heated at reflux for 12 h.
After this time the reaction was quenched with water (1e5 mL). The
product was diluted with water (20 mL) and the product extracted
with dichloromethane (3 ꢄ 20 mL). The solvent was removed in
vacuo and the residue was purified by flash column chromatog-
raphy over silica gel (eluent: 85:15 hexane/ethyl acetate) to afford
the product as orange crystals (35%). M.p. 89e91 C. IR
1339, 1512 (NO
13
J ¼ 15.5 Hz, H11). C NMR (ppm) (CDCl
9.50 (CH ), 124.89, 124.98, 125.55, 125.65, 127.24 (C12), 130.82,
28.91, 128.35 (C
lated for C22
3 3 2
) 30.52 (CH ), 45.24 (CH ),
4
1
2
4
N
), 140.08 (C11), 164.38 (C]O). HRMS (ESI) calcu-
þ
H
23
2
O: [M þ H] 331.1810: found 331.1810.
ꢀ
5
.1.3.10. (E)-Ethyl-4-(3-(9-anthracenyl)acryloyl)piperazine-1-
carboxylate (56). 3-(9-Anthracenyl)acrylic acid (50) (2.01 mmol,
.50 g) and ethyl piperazine-1-carboxylate (3.6 mmol, 0.56 g) were
n
max (KBr)
ꢁ
1 1
2
) cm . H NMR
d
(CDCl
3
) 7.05 (1H, d, J ¼ 16.5 Hz,
0
H12), 7.34 (2H, d, J ¼ 8.8 Hz, H13), 7.53 (4H, m, ArH), 7.83 (2H, d,
reacted according to the general procedure 1 above. The residue
was purified by flash column chromatography over silica gel
J ¼ 8.8 Hz, H14), 8.15 (1H, d, J ¼ 17.0 Hz, H11), 8.32 (4H, m, ArH), 8.49
13
3
(1H, s, H10). C NMR (ppm) (CDCl ) 124.28 (C15), 125.30, 125.46,
(
eluent: 85:15, hexane/ethyl acetate) to afford the product as or-
126.03, 127.40 (ArCH), 127.02 (C14), 128.92 (ArCH), 129.87 (C11),
ꢀ
ange crystals (65%). M.p. 80e85 C. IR
(
CH ), 4.82 (2H, br s, CH
n
max (KBr) 1648 (C]O), 1693
), 3.60 (6H, 2br s,
), 6.85 (1H, d, J ¼ 15.5 Hz,
129.64,131.27,131.46 (C
HRMS (ESI) calculated for C22
found 348.1007.
4
),135.15 (C12),143.63 (C
4
),148.04 (C
4
NO
2
).
ꢁ
1 1
þ
C]O) cm . H NMR
d
(CDCl
3
) 1.30 (3H, m, CH
), 4.17 (4H, m, CH
3
H15NO
2
Na: [M þ Na] 348.1000:
2
2
2
H11), 7.55 (4H, m, ArH), 8.04 (2H, d, J ¼ 7.0 Hz, ArH), 8.25 (2H, d,
1
3
J ¼ 7.0 Hz, ArH), 8.49 (1H, s, H10), 8.68 (1H, d, J ¼ 15.5 Hz, H12).
NMR (ppm) (CDCl ) 40.55 (CH ), 20.62 (CH ), 59.96, 61.01 (CH
24.73, 128.48, 129.07, 130.63 (C
C
),
5.1.3.14. (E)-4-(9-Anthracenyl)-N-methylbut-3-en-2-amine
(59).
3
2
3
2
To
a
solution of (E)-4-(9-anthracenyl)but-3-en-2-one (48)
1
1
4
), 124.90, 125.00, 125.72, 127.28,
(
(
1.12 mmol, 0.27 g) in dry MeOH (20 mL) were added NaCNBH
1.57 mmol, 0.10 g) and methylamine hydrochloride (8.96 mmol,
3
27.57, 127.81, 128.33 (ArCH), 131.87 (C11). HRMS (ESI) calculated
þ
for C24
24
H N
2
O
3
Na: [M þ Na] 411.4487: found 411.1691.
0.60 g). This solution was stirred under an atmosphere of N
2
for
7
2 h as indicated by TLC for completion of the reaction. The pH was
5
1
.1.3.11. (E)-3-(9-Anthracenyl)-1-(4-(p-tolyl)piperazinyl)prop-2-en-
-one (57). 3-(9-Anthracenyl)acrylic acid (50) (2.01 mmol, 0.50 g)
adjusted to 5e6 with 4 M methanolic HCl. When the reaction was
complete, excess hydride was quenched using 10% aq. HCl (25 mL).
The aqueous solution was washed with dichloromethane
and p-toluylpiperazine (3.60 mmol, 0.63 g) were reacted according
to general procedure above. The residue was purified by flash col-
umn chromatography over silica gel (eluent: 85:15, hexane/ethyl
acetate) to afford the product as orange crystals (67%). M.p. 76e
(
3 ꢄ 25 mL). The aqueous phase was basified with 2 M NaOH and
extracted with dichloromethane (3 ꢄ 25 mL). The organic phases
were combined and dried with anhydrous Mg SO and the solvent
ꢀ
ꢁ1 1
2
4
7
8 C. IR
CH
), 3.24 (4H, br d, J ¼ 30.0 Hz, CH
br s, CH
), 6.90 (1H, d, J ¼ 15.5 Hz, H11), 7.13 (2H, d, J ¼ 8.0 Hz, ArH),
.51 (4H, m, ArH), 8.04 (2H, dd, J ¼ 5.0 Hz, J ¼ 8.0 Hz, ArH), 8.28 (2H,
dd, J ¼ 5.0 Hz, J ¼ 8.0 Hz, ArH), 8.47 (1H, s, H10), 8.69 (1H, d,
n
max (KBr) 1643 (C]O) cm . H NMR
d
(CDCl
3
) 2.61 (3H, s,
was evaporated in vacuo. The crude product was purified by flash
column chromatography over silica gel (eluent: 2:1, hexane/ethyl
3
2
), 3.86 (2H, br s, CH
2
), 4.04 (2H,
2
ꢁ1 1
acetate) to afford a pale oil (89%). IR
NMR (CDCl
) 1.55 (3H, d J ¼ 6.5 Hz, CH
1H, q, J ¼ 6.5 Hz, H13), 6.00 (1H, dd, J ¼ 16.0 Hz, J ¼ 7.0 Hz, H12),
.35 (1H, d, J ¼ 16.5 Hz, H11), 7.50 (4H, m, ArH), 8.03 (2H, m, ArH),
nmax (film) 3109 (NH) cm . H
7
d
3
3 3
), 3.59 (3H, s, CH NH), 4.24
(
7
13
J ¼ 15.5 Hz, H12). C NMR (ppm) (CDCl
CH ), 124.73, 124.90, 125.00, 125.72, 127.01, 127.28, 128.48 (ArCH),
27.57 (C12), 131.84 (C11), 129.07, 130.63 (C ), 164.98 (C]O). HRMS
O: [M þ H] 407.2123: found 407.2174.
3 3
) 20.62 (CH ), 59.96, 61.01
(
1
2
13
8
(
1
.30 (2H, m, ArH), 8.45 (1H, s, H10). C NMR (ppm) (CDCl
CH ), 56.08 (CH NH), 78.06 (C13), 124.67, 125.01, 125.23, 125.33,
25.92, 128.23 (ArCH), 126.67 (C11), 128.98, 130.94, 131.76 (C , C9),
20N: [M þ H]
3
) 13.69
4
þ
3
3
(
27 2
ESI) calculated for C28H N
4
þ
139.74 (C12). HRMS (ESI) calculated for C19
H
5
.1.3.12. 3-(9-Anthracenyl)-N-methylacrylamide (58).
2
62.1596: found 262.1601.
Methylamine (10 mL of 2 M solution in THF) was added to 3-(9-
anthryl)-acrylic acid ethyl ester (47) (5.71 mmol, 2 g) and stirred
ꢀ
at 110 C in a sealed tube for 24 h. Yellow needles precipitated
5.1.3.15. 3-(9-Anthracenyl)propanenitrile
(60). Morpholine
during reaction were filtered off and washed with ethyl acetate
(0.70 mL) was added to a solution of anthraldehyde (5 mmol, 1 g)
and cyanoacetic acid (5.8 mmol, 0.49 g) in DMF (10 mL). The
(
10 mL). The filtrate was evaporated to remove the excess
ꢀ
methylamine. Water (25 mL) was added to the residue and the
product was extracted using ethyl acetate (3 ꢄ 25 mL). The organic
phase was washed with brine (3 ꢄ 25 mL), dried over anhydrous
mixture was refluxed for 7 h and then left at ꢁ20 C overnight to
allow precipitation of the product. The filtrate was diluted with
water (15 mL) to allow further precipitation of the product. The
product was combined, filtered and recrystallised from toluene to
Mg
2
SO
4
and the solvent evaporated in vacuo. The product was then
ꢀ
purified flash column chromatography over silica gel (eluent:
afford yellow crystals (30%). M.p. 150e155 C [36]. IR
n
max (KBr)
ꢁ1 1
8
5:15, hexane/ethyl acetate) followed by recrystallisation from
2217 (CN) cm . H NMR
d
(CDCl
3
) 5.65 (1H, d, J ¼ 17.0 Hz, H12), 7.56
ꢀ
dichloromethane as yellow needles (95%). M.p. 240 C. IR
n
max (KBr)
(4H, 2t, J ¼ 6.5 Hz, ArH), 8.06 (2H, d, J ¼ 8.5 Hz, H4/H5), 8.17 (2H, d,
ꢁ
1 1
3
296 (NeH, s), 1563 (NeH, br), 1360 (CeN), 1651 (C]O) cm . H
NMR (CDCl ) 3.05 (3H, s, CH ), 5.75 (1H, br s, NH), 6.34 (1H, d,
J ¼ 14.5 Hz, H12), 7.49 (4H, m, H2/H7, H3/H6), 8.02 (2H, m, H4/H5),
.23 (2H, m, H1/H8), 8.45 (1H, s, H10), 8.55 (1H, d, J ¼ 14.5 Hz, H11).
J ¼ 8.5 Hz, H1/H8), 8.35 (1H, d, J ¼ 17.0 Hz, H11), 8.53 (1H, s, H10).
13
d
3
3
3
C NMR (ppm) (CDCl ) 105.14 (C12), 117.18 (CN), 123.96, 125.12,
126.58, 128.89 (ArCH), 124.28, 126.27 (C
148.09 (C11). HRMS (ESI) calculated for C17
252.0789: found 252.0791.
4
), 127.62 (C9), 130.66 (C10),
þ
8
H11NNa: [M þ Na]
1
3
3 3
C NMR (ppm) (CDCl ) 26.16 (CH ), 125.30 (C3/C6), 125.5 (C1/C8),

348
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
0
0
5
.1.3.16. 3-(9-Anthracenyl)-2-cyanoacrylic
acid
(61).
5.1.4.3. 9-(1 -Hydroxy-1 -methoxymethyl)-9,10-dihydro-11-cyano-
0
Morpholine (0.70 mL) was added to a solution of anthraldehyde 46
9,10-ethanoanthracene (63 ).
9-(1 -Hydroxy-1 -methoxymethyl)-9,10-dihydro-11-cyano-9,10-
ethanoanthracene (63 ) crystals obtained by slow crystallisation of
63 from methanol over a period of 4e8 weeks. IR nmax (KBr) 3448
0
0
(
5.00 mmol, 1.00 g) and cyanoacetic acid (5.80 mmol, 0.49 g) in
ꢀ
0
DMF (10 mL). The mixture was heated at 90 C for 1 h. A solution of
KOH (1 g) in water/methanol (1:2) (1.5 mL) was added, followed by
diethyl ether (5 mL) which caused a yellow precipitate to form. The
mixture was filtered and washed with ether and recrystallised from
methanol. The crystals were dissolved in water and then acidified
using 10% aq. HCl. This caused a bright orange solid to precipitate.
The orange crystals were recrystallised from dichloro-
ꢁ1
(OH), 2238 (CN), 1727 (C]O) cm . HRMS (ESI) calculated for
þ
C
19
H18NO
2
: [M þ H] 292.1338: found 292.1329.
5.1.4.4. 9,10-Dihydro-11-cyano-9,10-ethanoanthracene-(9-acrylic
acid ethyl ester) (67). 3-(9-Anthracenyl)acrylic acid ethyl ester (47)
(10 mmol, 2.76 g) was reacted according to general procedure 4
above (method A). The product was then purified by flash column
chromatography over silica gel (eluent: 2:1, hexane/ethyl acetate),
ꢀ
ꢁ1
methane (76%). M.p. 70 C. IR
n
max (KBr) 2224 (CN), 3351 (OH) cm
.
1
H NMR
d
(CDCl
3
) 7.56e7.65 (4H, dt, J ¼ 7.0 Hz, H2/H7, H3/H6), 8.00
(
2H, d, J ¼ 8.5 Hz, H5/H4), 8.14 (2H, d, J ¼ 8.5 Hz, H5/H4), 8.68 (1H, s,
13
H10), 9.31 (1H, s, H11). C NMR (ppm) (CDCl
3
) 114.65, 114.8 (CN,
),
followed by recrystallisation from methanol, colourless crystals
ꢀ
C12), 124.87, 125.90, 127.32, 128.16 (ArCH), 128.99, 129.78 (ArC
4
(90%). M.p. 70 C. IR
n
max (KBr) 1190 (CeO), 1722 (C]O), 2237
(CDCl ), 2.15 (1H,
) 1.43 (3H, t, J ¼ 7.0 Hz, CH
), 2.35 (1H, m, H12
), 3.10 (1H, dd, J ¼ 4.0 Hz, J ¼ 10.5 Hz,
H10), 4.38 (2H, q, J ¼ 7.5 Hz, CH ), 4.46 (1H, s, H11), 6.50 (1H, d,
J ¼ 16.5 Hz, H13), 7.15e7.28 (8H, m, ArH), 8.01 (1H, d, J ¼ 16.5 Hz,
ꢁ
1 1
130.56 (C10), 154.79 (C11), 162.20 (C]O). HRMS (ESI) calculated
(CN) cm . H NMR
m, H12
d
3
3
þ
for: (M ꢁ H) 272.0717: found 272.0732.
a
b
2
5
.1.4. General procedure 4 e preparation of
13
dihydroethanoanthracenes
The appropriate anthracenyl compound (10 mmol) and acrylo-
nitrile (14 mmol), with hydroquinone (0.2 mmol) were heated
together in a sealed tube, at 130 C for 24 h (method A) or heated by
microwave irradiation at 160 C for 45 min (method B). The reac-
H14). C NMR (ppm) (CDCl
42.58 (CH , C12), 50.23 (C9), 60.63 (CH
127.02 (C14, ArCH), 138.72, 140.15, 141.38, 142.12 (C
165.28 (C]O). HRMS (ESI) calculated for C22
352.1313: found 352.1325.
3
) 13.87 (CH
3
), 31.04 (C11), 34.49 (C10),
2
2
), 120.07 (CN), 122.70e
4
), 143.17 (C13),
Na: [M þ Na]
ꢀ
þ
H19NO
2
ꢀ
tion mixture was then decanted into a large beaker with ethyl ac-
etate (10e20 mL). This was allowed to evaporate using air and N
2
.
5.1.4.5. 9,10-dihydro-9,10-ethanoanthracen-11-cyano-N-methyl-
acrylamide (68). 3-(9-Anthracenyl)-N-methyl-acrylamide (58)
(0.77 mmol, 0.2 g) was reacted according to general procedure 4
above (method A). The product was purified by flash column
This process was repeated to allow the excess acrylonitrile to
evaporate. The solid that remained was filtered and washed with
hexane. The crude product was then purified flash column chro-
matography over silica gel and recrystallised from methanol.
chromatography over silica gel (eluent: 2:1 hexane/ethyl acetate).
ꢀ
Colourless powder (88%). M.p. 180e182 C. IR
n
max (KBr) 1675 (C]
(CDCl ) 2.20 (1H, m,
, H11), 4.45 (1H,
ꢁ
1 1
5
.1.4.1. 9-(2-Cyanovinyl)-9,10-dihydro-9,10-ethanoanthracene-11-
carbonitrile (69).
-(2-Cyanovinyl)-9,10-dihydro-9,10-ethanoanthracene-11-
carbonitrile 69 was obtained from 3-(9-anthracenyl)acrylonitrile
O), 2240 (CN), 3289 (NH) cm
H12 ), 2.38 (1H, m, H12
.
H NMR
d
3
a
b
), 3.06 (4H, t, J ¼ 8.0 Hz, CH
3
9
s, H10), 5.85 (1H, br s, NH), 6.42 (1H, d, J ¼ 16.0 Hz, H14), 7.17 (2H, m,
ArH), 7.25 (3H, m, ArH), 7.33 (1H, d, J ¼ 7.0 Hz, ArH), 7.39 (2H, d,
13
(
(
60) (2.18 mmol, 0.5 g) according to general procedure 4 above
method A). The product was purified by flash column chroma-
J ¼ 7.0 Hz, ArH), 7.95 (1H, d, J ¼ 16.0 Hz, H13). C NMR (ppm)
3 3 2
(CDCl ) 26.16 (CH ), 30.99 (C11), 34.59 (CH ), 42.54 (C10), 49.95
tography over silica gel (eluent: 2:1 hexane/ethyl acetate) to afford
(C9), 120.42 (CN), 122.85, 123.04, 123.29, 123.43, 125.80, 126.10,
127.16 (ArCH), 126.83 (C14), 138.97 (C13), 139.45, 140.42, 141.35,
ꢀ
a colourless powder (67%). M.p. 222e226 C. IR
n
max (KBr) 2228
ꢁ1 1
(
CN), 3055 (C]C) cm . H NMR
d
(CDCl
3
) 1.93 (1H, ddd, J ¼ 3.4 Hz,
142.09 (C
[M þ Na] 337.1317: found 337.1329.
4
), 164.67 (C]O). HRMS (ESI) calculated for C21
H
18
N
2
ONa:
þ
J ¼ 14.8 Hz, H12 ), 2.30 (1H, m, H12
a
b
), 3.57 (1H, dd, J ¼ 3.9 Hz,
J ¼ 10.3 Hz, H11), 4.60 (1H, s, H10), 6.46 (1H, d, J ¼ 17.1 Hz, H14), 7.25
1
3
(
5H, m, ArH), 7.49 (3H, m, ArH), 8.08 (1H, d, J ¼ 16.6 Hz, H13).
C
5.1.5. General procedure 5 e hydrogenation of alkenes
The appropriate unsaturated compound was dissolved in ethyl
acetate (10 mL) and added to 10% palladium on charcoal (1 g). The
NMR (ppm) (CDCl
3
) 30.51 (C10), 39.75 (C9), 41.81 (C11), 105.23 (CN
vinyl), 115.62 (CN alkyl), 122.99, 123.30, 123.79, 124.16, 126.05,
1
26.14, 127.17, 127.24 (ArCH, C14), 138.99, 140.20, 142.26, 142.64
2
flask was filled with H and stirred for 48 h, while being monitored by
TLC. After this time, the solution was filtered through Celite and sol-
vent was evaporated in vacuo. No further purification was necessary.
þ
(
C
4
), 151.32 (C13). HRMS (ESI) calculated for C20
H
14
N
2
Na: [M þ Na]
3
05.1055: found 305.1047.
5
.1.4.2. 9-Formyl-9,10-dihydro-11-cyano-9,10-ethanoanthracene
g) and acrylonitrile
164.82 mmol, 8.75 g) were reacted together according to general
5.1.5.1. Ethyl 3-(11-cyano-9,10-dihydro-9,10-ethanoanthracenyl)-9-
propanoate (70).
9,10-Dihydro-9,10-ethanoanthracene-11-cyano-N-methyl-
acrylamide (68) (1.52 mmol, 0.5 g) was reacted according to general
procedure 5 above. The product was isolated as colourless crystals
(63). Anthraldehyde (91.39 mmol,
4
(
procedure 4 above (method A or method B). The product was then
purified by flash column chromatography over silica gel (eluent:
2
ꢀ
:1 hexane/ethyl acetate), followed by recrystallisation from
(95%) and no further purification was required. M.p. 132e138 C. IR
A
B
ꢀ
ꢁ1 1
methanol to afford pale yellow crystals (48%) (70%) . M.p. 160 C
nmax (KBr) 2233 (CN) cm . H NMR
d
(CDCl
), 2.83 (2H, m, CH
), 4.30 (2H, q, J ¼ 7.0 Hz, OCH
(1H, s, C10), 7.18e7.30 (4H, m, ArH), 7.35 (3H, m, ArH), 7.49 (1H, d,
3
) 1.38 (3H, t, J ¼ 7.0 Hz,
), 2.89
), 4.38
ꢀ
(
lit. [54] M.p. 172e176 C). IR
n
ꢁ
max (KBr) 2239 (CN), 1727 (C]O),
CH
3
), 2.10 (1H, m, H12
a
), 2.40 (1H, m, H12
b
2
1 1
2
831, 2728 (CeH aldehyde) cm . H NMR
H12 ), 2.35 (1H, m, H12
), 3.21 (1H, dd, J ¼ 4.7 Hz, J ¼ 10.5 Hz, H10),
.47 (1H, s, H11), 7.19e7.5 (8H, ArH), 10.93 (1H, s, H13). C NMR
ppm) (CDCl ) 28.61 (C12), 33.53 (C10), 42.87 (C11), 58.09 (C9),
19.84 (CN), 121.58, 122.58, 123.86, 124.03, 126.00, 126.34, 127.38,
27.42, 136.13, 137.54, 141.61, 142.02 (ArCH, C ), 199.80 (C13). HRMS
13NONa: [M þ Na] 282.0895: found
d
(CDCl
3
) 2.10 (1H, m,
(1H, m, H11), 3.13 (1H, m, CH
2
2
a
b
13
13
4
(
1
1
J ¼ 8.0 Hz, ArH). C NMR (ppm) (CDCl
29.45 (CH ), 33.79 (CH ), 38.50 (C11), 42.82 (C10), 46.41 (C9), 60.59
(OCH ), 119.97 (CN), 121.94, 122.54, 123.10, 123.70, 125.73, 126.06,
3 3
) 13.86 (CH ), 23.78 (C12),
3
2
2
2
4
126.32, 126.45 (ArCH), 139.99, 142.79, 143.43 (C
4
), 172.54 (C]O).
þ
þ
(
ESI) calculated for C18
H
HRMS (ESI) calculated for C22
found 354.1463.
2
H21NO Na: [M þ Na] 354.1470:
2
82.0921.

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
349
5
.1.5.2. 9,10-Dihydro-9,10-ethanoanthracen-11-cyano-N-methyl-
propanamide (71).
,10-Dihydro-9,10-ethanoanthracen-12-cyano-N-methyl-
anddried withanhydrous Mg
vacuo to afford the desired product.
2
SO
4
andthe solvent wasevaporatedin
9
acrylamide (68) (0.95 mmol, 0.3 g) was reacted according to general
5.1. 6.1. 9-((Methylamino)methyl)-9,10-dihydro-9,10-
procedure 5 above. The product was isolated as a grey solid (98%)
ethanoanthracene-11-carbonitrile (74).
and no further purification was required. IR
n
max (KBr) 2244
), 2.10 (1H, m, 12 ),
), 3.01 (1H, m, H11), 4.37 (1H, s,
H10), 5.85 (1H, br s, NH), 7.20 (4H, m, ArH), 7.25 (2H, m, ArH), 7.42
9-Formyl-9,10-dihydro-12-cyano-9,10-ethanoanthracene
(0.77 mmol, 0.2 g) in dry methanol (50 mL) was treated with
methylamine HCl (6.16 mmol, 0.42 g) and NaCNBH (1.09 mmol,
0.07 g) according to the general procedure 6 above to afford the
desired product as a brown oil (87%) which required no further
(63)
ꢁ1 1
(
CN) cm . H NMR
d
(CDCl
3
) 2.05 (1H, m, H12
a
b
2
.60 (1H, m, CH ), 2.98 (3H, s, CH
2
3
3
13
(
(
4
1
1
3
1H, d, J ¼ 8.0 Hz, ArH), 7.50 (1H, d, J ¼ 8.0 Hz, ArH). C NMR (ppm)
CDCl ) 24.60 (CH ), 26.18 (CH ), 31.35 (CH ), 31.44, 33.64 (C12),
2.79 (C10), 46.50 (C9), 120.22 (CN), 122.31, 122.52, 123.04, 123.62,
25.83, 126.03, 126.26, 126.39 (ArCH), 140.14, 142.92, 143.28 (C ),
O: [M þ H]
ꢁ1 1
3
2
3
2
purification. IR
(1H, ddd, J ¼ 18.0 Hz, J ¼ 12.4 Hz, J ¼ 2.0 Hz, H12
2.71 (1H, dd, J ¼ 12.0 Hz, J ¼ 8.0 Hz, H11), 3.08 (3H, s, CH
br s, NH), 4.30 (2H, s, CH
), 4.42 (1H, d, J ¼ 1.5 Hz, H10), 7.12 (5H, m,
ArH), 7.20 (1H, m, ArH), 7.29 (1H, m, ArH), 7.38 (1H, ArH). C NMR
ppm) (CDCl ) 27.95 (C12), 31.36 (CH ), 44.25 (C10), 49.76 (C9), 50.12
(CH ), 50.24 (C11),118.99 (CN),121.20,122.27,124.31,125.43,125.57,
n
max (KBr) 2333 (CN) cm . H NMR
), 2.16 (1H, m, H12
), 4.09 (1H,
d
(CDCl
3
) 1.72
a
b
),
4
3
þ
72.16 (C]O). HRMS (ESI) calculated for C21
39.1471: found 339.1462.
H
21
N
2
2
13
(
3
3
5
.1.5.3. 9-(2-Cyanoethyl)-9,10-dihydro-9,10-ethanoanthracene-11-
2
carbonitrile (72).
-(2-Cyanovinyl)-9,10-dihydro-9,10-ethanoanthracene-11-
carbonitrile (69) (0.7 mmol, 0.2 g) was reacted according to general
procedure 5 above. The residue was purified by flash column
125.90 (ArCH), 137.56, 141.87, 143.18, 145.67 (C
4
). HRMS (ESI) calcu-
þ
9
lated for C19H
19
N
2
: [M þ H] 275.1548: found 275.1537.
5.1.6.2. 11-N-Cyclohexyl-N-methyl-9-formyl-9,10-dihydro-9,10-
ethanoanthracene-11-carboxyamide (66).
9-Formyl-9,10-dihydro-9,10-ethanoanthracene-11-carboxylic acid
(65) (0.1 mmol, 0.03 g) was reacted with N-methyl-N-cyclohexyl-
chromatography over silica gel (eluent: 2:1 hexane/ethyl acetate) to
ꢀ
afford the product as a pale solid (75%). M.p. 149e151 C. IR
n
max
ꢁ
1 1
(
KBr) 2237 (CN) cm . H NMR
J ¼ 10.2 Hz, J ¼ 3.0 Hz, H12 ), 2.34 (1H, m, H12
J ¼ 10.0 Hz, J ¼ 4.0 Hz, H11), 2.83 (1H, dd, J ¼ 17.0 Hz, J ¼ 9.0 Hz,
H13 ), 3.17 (2H, t,
), 2.96 (1H, dd, J ¼ 16.8 Hz, J ¼ 8.0 Hz, H13
d
(CDCl
3
) 2.07 (1H, ddd, J ¼ 17.0 Hz,
a
b
), 2.74 (1H, dd,
amine (180.0
mmol, 0.02 g) according to general procedure 6 above.
The desired product was obtained as a pale brown resin (56%). IR
ꢁ
1 1
a
b
n
max (KBr) 1660 (C]O), 1708 (C]O) cm . H NMR
3.16 (15H, m, CH , CH , H12 , H12 ), 3.49 (1H, m, H11), 4.52 (1H, m,
H10), 7.18 (8H, m, ArH), 10.91 (1H, s, CHO). C NMR (ppm) (CDCl
24.78, 25.10, 25.31, 29.02, 29.29 (CH ), 27.33 (CH ), 42.07 (C11),
46.99 (C10), 52.46 (NCH), 119.81, 121.39, 123.35, 125.31, 125.60,
126.07, 126.14, 126.56 (ArCH), 140.20, 140.44, 140.51, 143.22 (C ),
3
d (CDCl ) 1.13e
J ¼ 7.5 Hz, H14), 4.42 (1H, J ¼ 2.7 Hz, H10), 7.25 (4H, m, ArH), 7.40
2
3
a
b
4H, m, ArH). 13C NMR (ppm) (CDCl
C11), 33.68 (C14), 42.71 (C10), 46.52 (C9), 118.71, 119.37 (CN),
21.58, 122.55, 123.84, 126.39, 124.54, 126.39, 126.68, 127.27, 127.31
) 12.97 (C12), 25.39 (C13), 31.62
13
(
(
3
3
)
2
3
1
(
C
ArCH), 138.79, 142.49, 143.21 (C
4
). HRMS (ESI) calculated for
4
þ
H
20 16
N
2
Na: [M þ Na] 307.1211: found 307.1195.
171.91 (C]O), 202.90 (CHO). HRMS (ESI) calculated for
þ
C
25
H27NO
2
Na: [M þ Na] 396.1939: found 396.1926.
5
.1.5.4. 9-(Hydroxymethyl)-9,10-dihydro-9,10-ethanoanthracene-11-
carbonitrile (73). To a solution of 9-formyl-9,10-dihydro-12-cyano-
,10-ethanoanthracene (63) (1.93 mmol, 0.5 g) in MeOH (30 mL)
and DCM (10 mL) was added NaBH (2.32 mmol, 0.88 g) in portions.
5.1.6.3. 9,10-Dihydro-11-N-methyl-N-cyclohexanyl-9,10-
ethenoanthracene-11-carboxyamide (42).
9,10-Dihydro-9,10-ethenoanthracene-11-carboxylic
9
4
acid
(41)
The mixture was stirred at room temperature and monitored by
TLC. After 2 h, the solvent was evaporated in vacuo. Chloroform
(0.8 mmol, 0.2 g) was reacted with N-methyl-N-cyclohexylamine
(1.41 mmol, 0.16 g) according to general procedure 6 above. Puri-
fication by flash column chromatography over silica gel (eluent: 2:1
(
50 mL) was added to the residue and the solution washed with
water (3 ꢄ 25 mL). The organic phase was dried over anhydrous
Mg SO , and the solvent was evaporated in vacuo to afford the
hexane/ethyl acetate) afforded the desired product as colourless
ꢀ
2
4
crystals (34%). M.p. 118e119 C. IR
n
max (KBr) 1635 (C]O), 3399
), 2.01 (3H, s,
), 5.22 (2H, s, H9, H10), 6.98 (5H, m,
ꢁ
1 1
desired product which required no further purification, colourless
(ArCH) cm . H NMR
NCH ), 2.70 (5H, br s, NCH, CH
ArH, H12), 7.46 (2H, m, ArH), 7.45 (2H, m, ArH). C NMR (ppm)
(CDCl ) 14.24, 21.09, 25.36, 30.56 (CH ), 50.93 (C10), 53.36 (C9),
60.43 (CH ), 123.22, 123.48, 124.81, 124.85 (ArCH), 145.13 (C12),
), 165.43 (C]O). HRMS (ESI) calculated for C24 25NONa:
3 2
d (CDCl ) 1.20e2.00 (6H, m, CH
ꢀ
solid (89%). M.p. 192e195 C. IR
n
max (KBr) 2238 (CN), 3485
), 2.37 (1H, m, H12 ),
3
2
ꢁ
1 1
13
(
OH) cm . H NMR
d
(CDCl
3
) 2.09 (1H, m, H12
a
b
3
.20 (1H, dd, J ¼ 10.5 Hz, J ¼ 4.5 Hz, H11), 4.39 (1H, s, H10), 4.94 (1H,
3
2
d, J ¼ 11.0 Hz, H13
a
), 5.05 (1H, d, J ¼ 11.0 Hz, H13
) 29.70 (C11), 33.41 (C12), 42.96 (C10),
), 120.49 (CN), 121.96, 122.67, 123.26, 123.34,
b
), 7.22 (8H, m,
3
ArH). 13C NMR (ppm) (CDCl
147.91 (C
H
3
4
þ
4
8.38 (C9), 60.65 (CH
2
[M þ Na] 366.1834: found 366.1822.
1
25.76, 125.96, 126.28, 126.52 (ArCH), 138.26, 139.69, 142.87, 143.16
þ
(
C
4
). HRMS (ESI) calculated for C18
H15NONa: [M þ Na] 284.1051:
5.1.6.4. 9,10-Dihydro-11-N-piperidinyl-9,10-etheneoanthracnene-11-
carboxyamide (43).
found 284.1041.
9,10-Dihydro-9,10-ethenoanthracene-11-carboxylic
acid
(41)
5
.1.6. General procedure 6: preparation of amines
To solution of 9-formyl-9,10-dihydro-12-cyano-9,10-
ethanoanthracene (63) (0.77 mmol, 0.2 g) in dry methanol (50 mL)
wereadded the appropriateamine (6.16 mmol, 0.42 g) and NaCNBH
(0.8 mmol, 0.2 g) was reacted with piperidine (1.41 mmol, 0.12 g)
according to general procedure 6 above. The product was purified
by flash column chromatography over silica gel (eluent: 2:1 hex-
a
ꢀ
3
ane/ethyl acetate) to afford a brown solid (66%). M.p.123e124 C. IR
ꢁ
1 1
(
1.09 mmol, 0.07 g). Themixturewas stirred at roomtemperaturefor
n
max (KBr) 1626 (C]O), 2937 (ArCH) cm . H NMR
(6H, br s, CH ), 3.40 (4H, br s, CH
), 5.22 (1H, d, J ¼ 6.0 Hz, H10), 5.35
(1H, s, H9), 6.99 (4H, m, ArH), 7.07 (1H, d, J ¼ 6.0 Hz, H12), 7.32 (4H,
3
d (CDCl ) 1.64
7
5
2 h and monitored by TLC. The pH was adjusted occasionally to pH
e6 using 4 M methanolic HCl. When the reaction was complete,
2
2
13
excess hydride was quenched using 10% aq. HCl (50 mL). The
aqueous solution was washed with dichloromethane (3 ꢄ 25 mL).
The aqueous phase was basified with 2 M NaOH and extracted with
dichloromethane (3 ꢄ 25 mL). The organic phases were combined
m, ArH). C NMR (ppm) (CDCl
3 2
) 24.18 (CH ), 50.53 (C10), 52.85
(C9), 122.78, 122.96, 124.34, 124.41 (ArCH), 138.93 (C12), 144.65,
144.92, 146.72 (C
4
), 167.44 (C]O). HRMS (ESI) calculated for
þ
C
22
H21NONa: [M þ Na] 338.1521: found 338.1512.

350
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
5
.1. 6. 5. 9,10-Dihydro-N-methyl-N-cyclohexanyl-9,10-
ethenoanthracene-11-methanamine (44).
,10-Dihydro-11-N-methyl-N-cyclohexane-9,10-
etheneoanthracnene-11-carboxyamide (42) (0.29 mmol, 0.11 g)
was added to LiAlH according to general procedure 2 above. The
ethanoanthracene-11-carbonitrile (75) (0.73 mmol, 0.2 g) and
diethylcarbamoyl chloride (0.87 mmol, 0.12 g) were reacted ac-
cording to general procedure 7 above. Purification by flash column
9
chromatography (eluent: 2:1, hexane/ethyl acetate) afforded the
ꢀ
4
product as a colourless solid (70%). M.p. 189e193 C. IR
n
max (film)
(CDCl ) 1.23,
), 2.32 (1H, m,
), 3.26 (1H, dd, J ¼ 10.5 Hz, J ¼ 4.0 Hz, H11), 3.43 (2H, q,
J ¼ 7.0 Hz, CH ), 3.50 (2H, q, J ¼ 7.0 Hz, CH ), 4.49 (1H, s, H10), 7.25
(6H, m, ArH), 7.35 (1H, d, J ¼ 7.5 Hz, ArH), 7.41 (1H, s, ArH), 8.55
ꢁ
1 1
crude product was then purified by flash column chromatography
over silica gel (eluent: 95% DCM: MeOH) to afford a colourless solid
1625 (C]O), 2250 (CN), 3364 (C]N) cm . H NMR
1.26 (6H, 2ꢄt, J ¼ 6.0 Hz, CH ), 2.14 (1H, m, H12
H12
d
3
3
a
ꢀ
ꢁ1 1
(
d
87%). M.p. 160e163 C. IR
(CDCl ) 1.27e1.69 (6H, m, CH
NCH, CH ), 3.19 (2H, s, CH
), 5.21 (1H, d, J ¼ 6.0 Hz, H10), 5.28 (1H, s,
H9), 7.00 (5H, m, ArH, H12), 7.49 (4H, m, ArH). C NMR (ppm)
CDCl ) 14.26, 20.99, 25.60, 29.63 (CH ), 50.24 (C10), 54.90 (C9),
1.65 (CH ), 60.57 (CH ), 123.48, 123.98, 124.22, 124.99 (ArCH),
45.01, 145.23, 146.11 (C ), 149.98 (C12). HRMS (ESI) calculated for
28N: [M þ H] 330.2222: found 330.2229.
n
max (KBr) 3034 (ArCH) cm . H NMR
b
3
2
), 1.80 (3H, s, NCH ), 2.60 (5H, br s,
3
2
2
2
2
13
13
(1H, s, HC]N). C NMR (ppm) (CDCl
(C11), 33.90 (C12), 42.65 (C10), 44.00, 45.28 (CH
120.76 (CN), 122.41, 122.80, 123.20, 123.66, 125.82, 126.20, 126.98,
3
) 12.41, 13.29 (CH
3
), 30.42
(
6
1
C
3
2
2
), 49.61 (C9),
2
3
4
127.07 (ArCH), 138.08, 139.89, 141.39, 142.14 (C
4
), 149.01 (C]O).
þ
þ
24
H
HRMS (ESI) calculated for C23
found 396.1751.
23
H N
3
O
2
Na: [M þ Na] 396.1688:
5
.1.6.6. 9,10-Dihydro-N-piperidinyl-9,10-ethenoanthracene-11-
methanamine (45).
,10-Dihydro-11-N-piperidinyl-9,10-etheneoanthracnene-11-
carboxyamide (43) (0.8 mmol, 0.2 g) was added to LiAlH according to
5.1.7.3. ((E)-((Benzoyloxy)imino)methyl)-9,10-dihydro-9,10-
ethanoanthracene-11-carbonitrile (80).
9-((E)-(Hydroxyimino)methyl)-9,10-dihydro-9,10-
9
4
general procedure 2 above. The crude product was then purified by
flash column chromatographyover silicagel (eluent: 95%DCM: MeOH)
ethanoanthracene-11-carbonitrile (75) (0.36 mmol, 0.1 g) and
benzoyl chloride (0.5 mmol, 0.07 g) were reacted according to
general procedure 7 above. Purification by flash column chroma-
to afford the desired product as a brown resin (85%). IR
n
max (film) 2937
),1.97 (4H, m, CH ),
), 5.05 (1H, d, J ¼ 6.0 Hz, H10), 5.26 (1H, s, H9), 6.66 (1H,
d, J ¼ 6.0 Hz, H12), 6.95 (2H, m, ArH), 6.96 (2H, m, ArH), 7.10 (4H, m,
ꢁ1 1
(ArCH) cm . H NMR
d
(CDCl
3
) 1.53 (6H, br m, CH
2
2
tography over silica gel (eluent: 2:1, hexane/ethyl acetate) afforded
ꢀ
3
.11 (2H, s, CH
2
the product as a colourless solid (74%). M.p. 180e183 C. IR
n
max
ꢁ1 1
(KBr) 1741 (C]O), 2242 (CN), 3065 (C]N) cm . H NMR
d
(CDCl
3
)
13
ArH). C NMR (ppm) (CDCl
2.85 (C9), 60.88 (CH ), 64.12 (CH
ArCH), 138.93 (C12), 144.65, 144.91, 146.72 (C
3
) 24.18 (CH
), 122.73, 122.96, 124.34, 124.40
),145. HRMS (ESI)
24N: [M þ H] 302.1909: found 302.1911.
2
), 25.42 (CH
2
), 50.53 (C10),
2.16 (1H, m, H12 ), 2.34 (1H, m, H12
a
b
), 3.55 (1H, dd, J ¼ 10.5 Hz,
5
2
2
J ¼ 4.0 Hz, H11), 4.51 (1H, s, H10), 7.21e7.33 (6H, m, ArH), 7.39 (1H,
d, J ¼ 7.0 Hz, ArH), 7.49 (2H, m, ArH), 7.57 (2H, t, J ¼ 7.0 Hz, ArH),
7.69 (1H, t, J ¼ 7.0 Hz), 8.24 (2H, d, J ¼ 8.0 Hz, ArH), 9.10 (1H, s, HCN).
(
4
þ
calculated for C22
H
13
3
C NMR (ppm) (CDCl ) 30.87 (C11), 33.75 (C12), 42.72 (C10), 50.41
5
.1.7. General procedure 7: preparation of esters and carbamates
The appropriate acid chloride (1.4 mmol) was dissolved in
anhydrous DCM (10 mL) and added dropwise to a stirring solution
of 9-((E)-(hydroxyimino)methyl)-9,10-dihydro-9,10-
(C9), 120.14 (CN), 122.58, 123.38, 123.94, 126.01, 126.30, 127.29,
127.38, 128.22, 129.48, 133.25 (ArCH), 137.26, 138.90, 141.42, 141.94
(C
4
), 156.58 (HCN), 162.97 (C]O). HRMS (ESI) calculated for
þ
C
25
18
H N
2
O
2
Na: [M þ H] 401.1266: found 401.1309.
ethanoanthracene-11-carbonitrile (75) or 11-hydroxymethyl-9,10-
ethanoanthracene (73) (1 mmol) and triethylamine (3 mmol) in
anhydrous DCM (10 mL). The solution was heated at reflux for 3 h.
After this time, the solution was cooled, diluted with DCM (50 mL)
and washed with water (3 ꢄ 25 mL) and brine (3 ꢄ 25 mL). The
5.1.7.4. 11-Cyano-9,10-dihydro-9,10-ethanoanthracenyl-9-methyl
acetate (76). 11-Hydroxymethyl-9,10-ethanoanthracene (73)
(0.24 mmol, 0.06 g) and acetyl chloride (0.29 mmol, 0.02 g) were
reacted according to the general procedure 7 above. Purification by
flash column chromatography over silica gel (eluent: 2:1, hexane/
ethyl acetate) afforded the product as colourless crystals (67%). M.p.
2 4
organic phase was then dried over anhydrous Na SO and the
solvent evaporated in vacuo. The product was then purified by flash
column chromatography over silica gel to afford the pure product.
ꢀ
ꢁ1 1
.
66e69 C. IR
(CDCl ) 2.08 (1H, m, H12
3.15 (1H, dd, J ¼ 10.5 Hz, J ¼ 4.0 Hz, H11), 4.42 (1H, s, H10), 5.23 (1H,
d, J ¼ 12.0 Hz, CH ), 5.48 (1H, d, J ¼ 12.0 Hz, CH ), 7.19e7.35 (8H, m,
ArH). C NMR (ppm) (CDCl ) 29.27 (CH ), 30.39 (C11), 33.55 (C12),
42.85 (C10), 46.55 (C9), 62.34 (OCH ), 119.84 (CN), 121.89, 122.04,
123.42, 123.44, 125.81, 126.16, 126.55, 126.80 (ArCH), 137.49, 139.13,
142.42, 142.95 (C ), 170.36 (C]O). HRMS (ESI) calculated for
n
max (KBr) 1640 (C]O), 2234 (CN) cm
H NMR
d
3
a
), 2.24 (3H, s, CH ), 2.39 (1H, m, H12
3
b
),
5
.1.7.1. 9-((E)-(Acetoxyimino)methyl)-9,10-dihydro-9,10-
ethanoanthracene-11-carbonitrile (78).
-((E)-(Hydroxyimino)methyl)-9,10-dihydro-9,10-
2
2
13
9
3
3
ethanoanthracene-11-carbonitrile (75) (1 mmol, 0.26 g) and
acetyl chloride (1.2 mmol, 0.09 g) were reacted according to
general procedure 7 above. Purification by flash column chro-
2
4
þ
matography (eluent: 2:1, hexane/ethyl acetate) afforded the
C
20
H
17NO
2
Na: [M þ Na] 326.1157: found 326.1149.
ꢀ
product as colourless crystals (74%). M.p. 64e68 C. IR
n
max (KBr)
), 2.36 (1H,
), 3.41 (1H, dd, J ¼ 10.5 Hz, J ¼ 4.0 Hz,
H11), 4.49 (1H, s, H10), 7.19e7.30 (5H, m, ArH), 7.37 (2H, d,
ꢁ
1 1
2
251 (C]O) cm . H NMR
d
(CDCl
3
) 2.13 (1H, m, H12
a
5.1.7.5. 9-(11-Cyano-9,10-dihydro-9,10-ethanoanthracenyl)methyl
benzoate (77). 11-Hydroxymethyl-9,10-ethanoanthracene (73)
(0.38 mmol, 0.1 g) and benzoyl chloride (0.53 mmol, 0.08 g) were
reacted according to the general procedure 7 above. Purification by
flash column chromatography over silica gel (eluent: 2:1, hexane/
m, H12 ), 2.46 (3H, s, CH
b
3
13
J ¼ 7.0 Hz, ArH), 7.43 (1H, m, ArH), 8.85 (1H, s, HCN). C NMR
ppm) (CDCl ) 13.76 (CH ), 30.53 (C11), 33.70 (C12), 42.63 (C10),
9.97 (C9), 120.10 (CN), 122.31, 122.52, 123.43, 123.91, 125.99,
26.32, 127.32, 127.30 (ArCH), 137.18, 138.84, 141.35, 141.91 (C ),
(
5
1
3
3
ethyl acetate) afforded the product as a colourless solid (74%). M.p.
ꢀ
4
169e172 C. IR
n
max (KBr) 2238 (CN), 1540 (C]O), 3454
(CDCl ) 2.08 (1H, m, H12 ), 2.39 (1H, m,
), 3.21 (1H, dd, J ¼ 11.0 Hz, J ¼ 4.0 Hz, H11), 4.39 (1H, s, H10),
.95 (1H, d, J ¼ 11.0 Hz, CH ), 5.06 (1H, d, J ¼ 11.0 Hz, CH ), 7.20
(12H, m, ArH), 7.60 (1H, d, J ¼ 7.0 Hz, H12). C NMR (ppm) (CDCl
30.71 (C11), 33.61 (C12), 42.27 (C10), 48.35 (C9), 59.24 (OCH
122.63 (CN), 123.37, 123.67, 123.80, 125.50, 125.78, 126.09, 126.33,
ꢁ
1 1
155.07 (C]N), 168.73 (C]O). HRMS (ESI) calculated for
(ArCH) cm . H NMR
H12
d
3
a
þ
C
20
H
16
N
2
O
2
Na: [M þ Na] 339.1109: found 339.1109.
b
4
2
2
13
5
.1.7.2. 9-((E)-(((1-(Diethylamino)vinyl)oxy)imino)methyl)-9,10-
3
)
2
),
dihydro-9,10-ethanoanthracene-11-carbonitrile (79).
-((E)-(Hydroxyimino)methyl)-9,10-dihydro-9,10-
9

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
351
1
1
27.80, 127.80, 129.20, 129.36, 130.38, 130.81 (ArCH), 135.18, 139.87,
44.89, 145.01 (C ). HRMS (ESI) calculated for C25 Na:
þ Na] 388.1313: found 388.1321.
5.3.2. Cell lines
4
H19NO
2
The DG-75 cell line is a B-lymphocyte, Burkitt’s lymphoma line
derived froma metastatic pleuraleffusion (lung) of a sporadic case of
Burkitt’s lymphoma [56]. The MUTU-I (c179) cell line is an isogenic
stable group I BL cell line derived from a BL biopsy [57]. The parental
HL-60 cell line is an acute promyelocytic leukaemia line derived
from peripheral blood leukocytes obtained by leukapheresis from a
36 year old Caucasian female with acute promyelocytic leukaemia
[58]. The HL60-P-gp cells had been drug-selected by chronic expo-
sure to adriamycin, while the HL60-BCRP cells had been retrovirally
transduced then further selected by exposure to mitoxantrone [44].
Cell lines were cultured in RPMI-1640 medium containing phenol
þ
[M
5
.2. X-ray crystallography
Crystals of compounds 6, 9 and 63 were obtained by slow
0
crystallisation from a dilute solution of methanol over a period of
4
were collected on a Rigaku Saturn 724 CCD Diffractometer. A suit-
able crystal from each crystal compound was selected and mounted
using inert oil on a 0.3 mm diameter glass fibre tip or loop and
0
e8 weeks. The data for the crystal structures 74, 78, 81 and 127
placed on the goniometer head in a 150 K N
2
gas stream. Each data
red and supplemented with 10% (v/v) foetal bovine serum (FBS),
glutamine (2 mM), penicillin and streptomycin (100 g/ml). The
MUTU-I cell line also required the additional supplements of alpha-
thioglycerol (5 mM in phosphate buffered saline (PBS) with 20
L-
set was collected using Crystalclear-SM 1.4.0 software. Data inte-
gration, reduction and correction for absorption and polarization
effects were all performed using Crystalclear-SM 1.4.0 software.
Space group determination, structure solution and refinement
were obtained using Bruker Shelxtl Ver. 6.14 software [55]. Each
structure was solved with Direct Methods using the SHELXTL
program and refined against IF2I with the program XL from SHELX-
m
m
M
bathocuprione disulfonic acid), sodium pyruvate (100 mM) and
ꢀ
HEPES (1 mM). Cells were maintained at 37 C in a humidified at-
mosphere of 95% oxygen, and 5% carbon dioxide.
9
7 using all data. Non-hydrogen atoms were refined with aniso-
5.3.3. Generation of human peripheral blood mononuclear cells
(PBMCs)
tropic thermal parameters. Hydrogen atoms were placed into
geometrically calculated positions and refined using a riding model.
Blood was obtained from a healthy donor, transferred into a
50 mL falcon tube and diluted 1:2 with PBS. LymphoPrep was used
5
.2.1. Crystal data for compound 6
Cambridge Database Deposition number: CCDC 920112.
to separate the blood into red blood cells, white blood cell ring and
serum. The blood was slowly added to 20 mL of ficoll pague plus.
The tubes were centrifuged at 1700 g for 30 min. The white blood
cell ring was transferred into a new 50 mL tube. The volume was
adjusted to 50 mL and the samples were centrifuged again at 1700 g
for 10 min. The supernatant was removed. This step was repeated
again, the pellet was then resuspended in 10 mL of complete IMDM
media (10% FBS, 0.1% Ciprofloxacin (10 mg/mL)).
C
72
H
64
N
8
O
8
, M ¼ 1104.8, triclinic, a ¼ 9.4200(19), b ¼ 12.123(2),
ꢀ
ꢀ
ꢀ
ꢀ
c ¼ 14.275(3) A,
a
¼ 99.13(3) ,
b
¼ 10151(3) ,
g
¼ 110.87(3) ,
ꢀ
3
U ¼ 1444.9(5) A , T ¼ 150 K, space group P-1, Z ¼ 1,
m(Mo
ꢁ
1
3
K
5
a
) ¼ 0.086 mm
061 unique (Rint ¼ 0.0609), aR
Gof ¼ 1.198, aR1 ¼ jjF j ꢁ jF jj/jF
,
r
¼ 1.270 g/cm , 22,667 reflections collected,
1
¼ 0.0808, wR [I > 2 (I)] ¼ 0.2413,
2
s
2
2
2
2 1=2
o
c
o
j, wR ¼ ½wðF ꢁ F Þ =wðF
2
o
c
o
Þ ꢅ
.
5
.2.2. Crystal data for compound 9
Cambridge Database Deposition number: CCDC 920111.
, M ¼ 277.35, monoclinic, a ¼ 10.622(2), b ¼ 9.7423(19),
5.3.4. Alamar Blue viability assay
4
1e5 ꢄ 10 cells/well were seeded in a 96-well plate and treated
C
76
H
76
N
4
O
4
with the respective drug (1 mM to 1 mM concentration range) for
ꢀ
ꢀ
ꢀ
3
c ¼ 14.343(3) A,
b
¼ 97.02(3) , U ¼ 1473.10(5) A , T ¼ 150 K, space
the desired length of time. Each well was then treated with 20
ml of
ꢁ
1
3
ꢀ
group P2(1)/c, Z ¼ 1,
m
(Mo K
a
) ¼ 0.077 mm
,
r
¼ 1.251 g/cm ,
Alamar Blue and left to incubate at 37 C in the dark for 4e6 h.
Fluorescence was read using at 590 nm (excitation 544 nm). The
background fluorescence of the media without cells þ Alamar Blue
was taken away from each group, and the control untreated cells
represented 100% cell viability. The antifungal agent miconazole
12,367 reflections collected, 2588 unique (Rint
¼
0.061),
j ꢁ jF jj/
aR
jF
1
¼0.0673, wR
2
[I > 2
s
(I)] ¼ 0.1487, Gof ¼ 1.263, aR
1
¼ jjF
o
c
j, wR2 ¼ ½wðF o2 ꢁ F Þ =wðF
2
2
Þ ꢅ
2 1=2
.
o
c
o
0
5.2.3. Crystal data for compound 63
(10 mM) was used as a positive control for cell death in each of the
Cambridge Database Deposition number: CCDC 920114.
, M ¼ 1096.8, monoclinic, a ¼ 9.920(2), b ¼ 17.200(3),
cell lines, resulting in 90% cytotoxicity. All data points (mean ꢂ
SEM) were analysed using GRAPHPAD Prism (San Diego, CA) and
subjected to non-linear regression analysis. Each experiment was
performed in triplicate on two independent days.
C
76 68 4 8
H N O
ꢀ
ꢀ
ꢀ
3
c ¼ 8.3340(17) A,
b
¼ 94.39(3) , U ¼ 1417.8(5) A , T ¼ 150 K, space
ꢁ
1
3
group P2(1)/c, Z ¼ 1,
m
(Mo K
a
) ¼ 0.086 mm
,
r
¼ 1.285 g/cm ,
1
aR
jF
1,149 reflections collected, 2456 unique (Rint
¼
0.0355),
1
¼ 0.0530, wR
2
[I > 2
s
(I)] ¼ 0.1839, Gof ¼ 1.197, aR
1
¼ jjF
o
j ꢁ jF
c
jj/
5.3.5. Quantification of apoptosis
j, wR2 ¼ ½wðF o2 ꢁ F Þ =wðF
2
2
Þ ꢅ
2 1=2
.
o
c
o
5
Propidium iodide FACS analysis. 7.5 ꢄ 10 cells/5 mL were
5
5
.3. Biochemistry: experimental methods
treated with the appropriate amount of compound and incubated
for a specified time. Cells were harvested by centrifugation at 300 g
for 5 min and washed with 5 mL of ice-cold PBS. The pellet was
.3.1. Materials
DG-75 and MUTU-I (c179) BL cell lines were gifts from Dr.
resuspended in 200
cells were fixed overnight at 4 C. After fixation, the cells were
pelleted by centrifugation at 300 g for 5 min and the ethanol was
m
L PBS and 2 mL of ice-cold 70% ethanol and
ꢀ
Dermot Walls (School of Biotechnology, Dublin City University,
Ireland) and Professor Martin Rowe (Division of Cancer Studies, The
University of Birmingham, UK) respectively. HL-60 cells were
originally obtained from Prof. Balazs Sarkadi’s research group
carefully removed. The pellet was resuspended in 400 mL of PBS
with 25
mL of RNAse A (10 mg/mL stock) and 75
m
Lof propidium
ꢀ
(
National Medical Center, Hungary). RPMI-1640, IMDM, FBS, HEPES,
iodide (1 mg/mL). The tubes were incubated in the dark at 37 C for
30 min. Cell cycle analysis was performed using appropriate gates
counting 10,000 cells and analysed using CELLQUEST software
package. Untreated cells had <5% cells in the pre-G1 phase of the
sodium pyruvate and glutamine were from Gibco (Invitrogen).
Alamar Blue was obtained from BioSource, Belgium, LymphoPrep
from Biosciences Ltd, Ireland. The Apotox-Glo Triplex assay was
provided by Promega, U.K. All other chemicals were purchased
through SigmaeAldrich Inc., Ireland.
cell cycle and 10
death.
mM Taxol was used as a positive control for cell

3
52
Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
against Burkitt lymphoma independently of the norepinephrine and seroto-
5
.3.6. Caspase activation assay
nin transporters, Leuk. Lymphoma 51 (2010) 523e539.
[
17] M. Wilhelm, P. Schmidt, [Synthesis and properties of 1-aminoalkyl-diben-
Activation of caspase 3 and 7 was assessed using an Apotox-Glo
zo(b,e)bicyclo(2,2,2) octadienes], Helv. Chim. Acta 52 (1969) 1385e1395.
Triplex assay (Promega). Cells were seeded at a density of 10,000
cells/well in opague 96-well plates and treated with the appropriate
[18] M. Tatsumi, K. Groshan, R.D. Blakely, E. Richelson, Pharmacological profile of
antidepressants and related compounds at human monoamine transporters,
Eur. J. Pharmacol. 340 (1997) 249e258.
compound (10
mM) for 8 h. After this time, Caspase-Glo reagent
[
19] P. Gareri, U. Falconi, P. De Fazio, G. De Sarro, Conventional and new antide-
pressant drugs in the elderly, Prog. Neurobiol. 61 (2000) 353e396.
20] V. Hajhashemi, H. Sadeghi, M. Minaiyan, A. Movahedian, A. Talebi, Central and
peripheral anti-inflammatory effects of maprotiline on carrageenan-induced
paw edema in rats, Inflamm. Res. 59 (2010) 1053e1059.
(
100 L) wasadded to each well and the mixture wasmixed byorbital
m
[
shaking (500 rpm for 30 s). This was incubated at room temperature
for 30 min and then the luminescence was read on a luminescence
plate reader. Vinblastine (100 nM) was used as a positive control.
[21] S.M. Cloonan, D.C. Williams, The antidepressants maprotiline and fluoxetine
induce type-II autophagic cell death in drug resistant burkitt’s lymphoma, Int.
J. Cancer 128 (2011) 1712e1723.
5
.3.7. Statistical analysis
[22] D. Szabo, G.J. Szabo, I. Ocsovszki, A. Aszalos, J. Molnar, Anti-psychotic drugs
reverse multidrug resistance of tumor cell lines and human AML cells ex-vivo,
Cancer Lett. 139 (1999) 115e119.
Statistical analysis was performed using the Student’s t-test
[
23] A.J. Bitonti, A. Sjoerdsma, P.P. McCann, D.E. Kyle, A.M.J. Oduola, R.N. Rossan,
W.K. Milhous, D.E. Davidson Jr., Reversal of chloroquine resistance in malaria
parasite Plasmodium falciparum by desipramine, Science 242 (1988) 1301e
comparing vehicle versus treated samples. For illustrative purposes
p values are presented as *p < 0.05; **p < 0.01 and ***p < 0.001.
1303.
[
[
24] S. Alibert, C. Santelli-Rouvier, M. Castaing, M. Berthelot, G. Spengler, J. Molner,
J. Barbe, Effects of dihydroanthracenes on drug efflux in multidrug resistant
cancer cells, Eur. J. Med. Chem. 38 (2003) 253e263.
25] S. Alibert, C. Santelli-Rouvier, B. Pradines, C. Houdoin, D. Parzy, J. Karolak-
Wojciechowska, J. Barbe, Synthesis and effects on chloroquine susceptibility
in Plasmodium falciparum of a series of new dihydroanthracene derivatives,
J. Med. Chem. 45 (2002) 3195e3209.
Acknowledgements
The authors would like to thank the Irish Research Council
(
IRCSET Postgraduate research scholarship, YMMcN) and Trinity
College Dublin (AJB, SAB) for funding this work. We would like to
thank Darren Fayne for help with the ADMET results.
[
26] B. Pradines, S. Alibert, C. Houdoin, C. Santelli-Rouvier, J. Mosnier, T. Fusai,
C. Rogier, J. Barbe, D. Parzy, In vitro increase in chloroquine accumulation
induced by dihydroethano- and ethenoanthracene derivatives in Plasmodium
falciparum-parasitized erythrocytes, Antimicrob. Agents Chemother. 46
(2002) 2061e2068.
Appendix A. Supplementary material
[
[
[
27] P. Yates, P. Eaton, Acceleration of the Diels-Alder reaction by aluminum
chloride, J. Am. Chem. Soc. 82 (1960) 4436e4437.
Supplementary material associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.ejmech.2013.10.076.
28] Molecular Operating Environment (MOE), Developed and distributed by
Chemical Computing Group. Available from: http://www.chemcomp.com.
29] J. Karolak-Wojciechowska, H.B. Trzezwinska, S. Alibert-Franco, C. Santelli-
Rouvier, J. Barbe, The crystal and molecular structures of 9,10-dihydro-9,10-
ethano- and etheno-anthracenes, J. Chem. Crystallogr. 28 (1998) 905e911.
30] H.P. Figeys, A. Dralants, Olefinic and acetylenic compounds. II. New routes to
dibenzobarrelenes, Tetrahedron 28 (1972) 3031e3036.
References
[
[
[
[
[
[
[
[
1] D. Burkitt, A sarcoma involving the jaws in African children, Br. J. Surg. 46
1958) 218e223.
2] K.A. Blum, G. Lozanski, J.C. Byrd, Adult Burkitt leukemia and lymphoma, Blood
04 (2004) 3009e3020.
3] G. Brady, G.J. MacArthur, P.J. Farrell, EpsteineBarr virus and Burkitt lym-
phoma, J. Clin. Pathol. 60 (2007) 1397e1402.
4] W. Hammerschmidt, B. Sugden, EpsteineBarr virus sustains Burkitts lym-
phoma and Hodghin’s disease, Trends Mol. Med. 10 (2004).
5] L.S. Young, P.G. Murray, EpsteineBarr virus and oncogenesis: from latent
genes to tumours, Oncogene 22 (2003) 5108e5121.
6] J. Gerecitano, D.J. Straus, Treatment of Burkitt lymphoma in adults, Expert Rev.
Anticancer Ther. 6 (2006) 373e381.
7] I.T. Aldoss, D.D. Weisenburger, K. Fu, W.C. Chan, J.M. Vose, P.J. Bierman,
R.G. Bociek, J.O. Armitage, Adult Burkitt lymphoma: advances in diagnosis and
treatment, Oncology (Williston Park) 22 (2008) 1508e1517.
(
[31] A. Fruzinski, J. Karolak-Wojciechowska, S. Alibert-Franco, C. Santelli-Rouvier,
J. Barbe, Synthesis and X-ray structure of 11-N-benzylamido-9,10-dihydro-
9,10-ethenoanthracene, J. Chem. Crystallogr. 29 (1999) 1201e1204.
[32] J.S. Meek, B.T. Poon, S.J. Cristol, Diels-Alder reactions of 9-substituted an-
thracenes. I. Some reactions of 9-anthraldehyde, J. Am. Chem. Soc. 74 (1952)
761e763.
[33] H.M. Walborsky, cis- and trans-2,3-Dimethyldibenzobicyclo[2.2.2]octadiene,
Helv. Chim. Acta 36 (1953) 1251e1256.
[34] P. Arjunan, N. Shymasundar, K.D. Berlin, D. Najjar, M.G. Rockley, Syntheses of
1
selected 3 -(2- or 9-anthryl)alkanoic acids and certain esters e carbon-13 spin-
lattice relaxation time measurements of methyl 5-(2-anthryl)pentanoate and
methyl 7-(2-anthryl)heptanoate, J. Org. Chem. 46 (1981) 626e629.
[35] R.A. Hann, Dimethylformamide as a solvent for the Knoevenagel reaction,
J. Chem. Soc., Perkin Trans. 1 11 (1974) 1379e1380.
[
8] M.W. Jann, J.H. Slade, Antidepressant agents for the treatment of chronic pain
and depression, Pharmacotherapy 27 (2007) 1571e1587.
[36] H.D. Becker, H. Soerensen, K. Sandros, Photochemical isomerization and
dimerization of 1-(9-anthryl)-2-nitroethylene, J. Org. Chem. 51 (1986) 3223e
3226.
[37] P.V. Alston, R.M. Ottenbrite, J. Newby, Regioselectivity in the DielseAlder
reaction of 9-substituted anthracenes, J. Org. Chem. 44 (1979) 4939e4943.
[38] Y.H. Lee, M. Kim, J.M. Harrowfield, P. Thuery, Y. Kim, Ligands for metal ion
detection e crystal structure of a fluorophore precursor, Bull. Korean Chem.
Soc. 31 (2010) 3797e3799.
[9] E.J. Nestler, M. Barrot, R.J. DiLeone, A.J. Eisch, S.J. Gold, L.M. Monteggia,
Neurobiology of depression, Neuron 34 (2002) 13e25.
[
10] E.J. Meredith, M.J. Holder, A. Chamba, A. Challa, A. Drake Lee, C.M. Bunce,
M.T. Drayson, G. Pilkington, R.D. Blakely, M.J.S. Dyer, N.M. Barnes, J. Gordon,
The serotonin transporter (SLC6A4) is present in B-cell clones of diverse
malignant origin: probing a potential antitumor target for psychotropics,
FASEB J. 19 (2005) 1187e1189.
11] A. Serafeim, M.J. Holder, G. Grafton, A. Chamba, M.T. Drayson, Q.T. Luong,
C.M. Bunce, C.D. Gregory, N.M. Barnes, J. Gordon, Selective serotonin reuptake
inhibitors directly signal for apoptosis in biopsy-like Burkitt lymphoma cells,
Blood 101 (2003) 3212e3219.
12] Z. Xia, A. Bergstrand, J.W. DePierre, L. Nassberger, The antidepressants imip-
ramine, clomipramine, and citalopram induce apoptosis in human acute
myeloid leukemia HL-60 cells via caspase-3 activation, J. Biochem. Mol. Tox-
icol. 13 (1999) 338e347.
13] Z. Xia, J.W. DePierre, L. Nassberger, Modulation of apoptosis induced by tri-
cyclic antidepressants in human peripheral lymphocytes, J. Biochem. Mol.
Toxicol. 12 (1998) 115e123.
[39] J. Chen, P.R. Pokkuluri, J.R. Scheffer, J. Trotter, Structure of dimethyl 9-formyl-
9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate, Acta Crystallogr.,
Sect. C: Cryst. Struct. Commun. C49 (1993) 2018e2019.
[
[
[40] W.E. Hahn, R. Bartnik, W. Szalecki, W. Kalczynski, Ethaneanthracenes. Part I.
Synthesis
of
9,12-methanoiminomethano-9,10-ethano-9,10-
dihydroanthracene and its derivatives, Roczniki Chemii 51 (1977) 2315e
2320.
[41] Y.M. McNamara, S.M. Cloonan, A.J. Knox, J.J. Keating, S.G. Butler, G.H. Peters,
M.J. Meegan, D.C. Williams, Synthesis and serotonin transporter activity of
1,3-bis(aryl)-2-nitro-1-propenes as a new class of anticancer agents, Bioorg.
Med. Chem. 19 (2011) 1328e1348.
[42] D.F. Veber, S.R. Johnson, H.-Y. Cheng, B.R. Smith, K.W. Ward, K.D. Kopple,
Molecular properties that Influence the oral bioavailability of drug candidates,
J. Med. Chem. 45 (2002) 2615e2623.
[43] S. Elmore, Apoptosis: a review of programmed cell death, Toxicol. Pathol. 35
(2007) 495e516.
[44] C. Ozvegy-Laczka, T. Hegedus, G. Varady, O. Ujhelly, J.D. Schuetz, A. Varadi,
G. Keri, L. Orfi, K. Nemet, B. Sarkadi, High-affinity interaction of tyrosine ki-
nase inhibitors with the ABCG2 multidrug transporter, Mol. Pharmacol. 65
(2004) 1485e1495.
[
[
[
[
14] Z. Xia, H. Karlsson, J.W. De Pierre, L. Nassberger, Tricicylic antidepressants
induce apoptosis in human T-lymphocytes, Int. J. Immunopharmacol. 19
(
1997) 645e654.
15] C. Schuster, N. Fernbach, U. Rix, G. Superti-Furga, M. Holy, M. Freissmuth,
H.H.Sitte,V.Sexl, Selectiveserotoninreuptakeinhibitorse anewmodalityforthe
treatmentof lymphoma/leukaemia? Biochem. Pharmacol.74(2007) 1424e1435.
16] S.M. Cloonan, A. Drozgowska, D. Fayne, D.C. Williams, The antidepressants
maprotiline and fluoxetine have potent selective antiproliferative effects

Y.M. McNamara et al. / European Journal of Medicinal Chemistry 71 (2014) 333e353
353
[
[
[
[
[
45] D. Winicker, M. Bolte, Diethyl 9,10-dihydro-9,10-ethanoanthracene-1,12-
trans-dicarboxylate, Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 56
[52] Y. Chung, B.F. Duerr, T.A. McKelvey, P. Nanjappan, A.W. Czarnik, Structural
effects controlling the rate of the retro-DielseAlder reaction in anthracene
cycloadducts, J. Org. Chem. 54 (1989) 1018e1032.
[53] A. Mustafa, Reactions with 9-anthraldehyde, Science 112 (1950) 440.
[54] W.E. Hahn, W. Szalecki, Ethanoanthracenes. Part II. Synthesis of the system of
(
2000) 271e272.
46] N.A. Anisimova, V.M. Berestovitskaya, I.S. Bagryanskaya, M.E. Ivanova,
G.A. Berkova, A.A. Kuzhaeva, Acrylate and its 3-nitro derivatives in reactions
with anthracene, Russ. J. Gen. Chem. 80 (2010) 308e315.
9,12-(methanoiminomethano)-9,10-ethano-9,10-dihydroanthracene
by
47] P. Camps, F.-B. Merce, S. Gimenez, F. Perez, X. Solans, N. Soldevilla, (R)- and
cyclization of corresponding alcohols, Pol. J. Chem. 52 (1978) 2215e2221.
(
S)-3-Hydroxy-4,4-dimethyl-1-phenyl-2-pyrrolidinone as chiral auxiliaries in
[55] G.M. Sheldrick, SHELXTL, An Integrated System for Data Collection, Process-
ing, Structure Solution and Refinement. Software Reference Manual, Bruker
AXS, Inc, Madison, WI, 2001.
[56] H. Ben-Bassat, N. Goldblum, S. Mitrani, T. Goldblum, J.M. Yoffey, M.M. Cohen,
Z. Bentwich, B. Ramot, E. Klein, G. Klein, Establishment in continuous culture
of a new type of lymphocyte from a “Burkitt like” malignant lymphoma (line
D.G.-75), Int. J. Cancer 19 (1977) 27e33.
[57] C.D. Gregory, M. Rowe, A.B. Rickinson, Different Epstein-Barr virus-B cell in-
teractions in phenotypically distinct clones of a Burkitt’s lymphoma cell line,
J. Gen. Virol. 71 (1990) 1481e1495.
[58] S.J. Collins, R.C. Gallo, R.E. Gallagher, Continuous growth and differentiation of
human myeloid leukaemic cells in suspension culture, Nature 270 (1977)
347e349.
DielseAlder reactions, Tetrahedron: Asymmetry 10 (1999) 3123e3138.
48] N.M. Gray, P.C. Contreras, Use of Bridged Tricyclic Amine Derivatives for
Treating Neurodegenerative Disorders and Neurotoxic Injury, US 5055468 A
19911008, 1991.
49] R. Jones, A.G.M. Rattray, S.J. Rettig, J.R. Scheffer, J. Trotter, Structures and
photochemistry of dibenzobarrelene monoamides, Acta Crystallogr., Sect. B:
Struct. Sci. 52 (1996) 1007e1013.
[
[
50] H.
Schroeter,
D.A.
Prins,
9,10-Dihydro-11-aminoalkylene-9,10-
ethanoanthracenes, US 3422104 A 19690114, 1969.
51] J.R. Boissier, R. Ratouis, C. Dumont, L. Taliani, J. Forest, Synthesis and phar-
macological properties of new 9,10-dihydro-9,10-ethanoanthracene de-
rivatives, J. Med. Chem. 10 (1967) 86e91.