Discovery of oxime-bearing naphthalene derivatives as a novel structural type of Nrf2 activators

Article abstract of DOI:10.1016/j.bmc.2015.03.046

Abstract Recent studies have demonstrated that oxidative stress insult is one of major causes of tumor formation. Therefore, identify the effective anti-oxidative agents as a preventive approach to stop cancer progression has widely explored. Although, ma

Full text of DOI:10.1016/j.bmc.2015.03.046

Bioorganic & Medicinal Chemistry xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Discovery of oxime-bearing naphthalene derivatives as a novel
structural type of Nrf2 activators
Ken-Ming Chang a, Fong-Pin Liang b, I-Li Chen c, Shyh-Chyun Yang a,d, Shin-Hun Juang b,e,f,
,
⇑
Tai-Chi Wang c, , Yeh-Long Chen g,h, Cherng-Chyi Tzeng a,g,h,
⇑
⇑
a School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan
b School of Pharmacy, China Medical University, Taichung, Taiwan
c Department of Pharmacy, Tajen University, Pingtung, Taiwan
d Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
e Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
f Department of Pediatrics, Children’s Hospital, China Medical University, Taichung, Taiwan
g Department of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan
h Research Center for Natural Products & Drug Development, Kaohsiung Medical University, Kaohsiung City 807, Taiwan
a r t i c l e i n f o
a b s t r a c t
Article history:
Recent studies have demonstrated that oxidative stress insult is one of major causes of tumor formation.
Therefore, identify the effective anti-oxidative agents as a preventive approach to stop cancer progression
has widely explored. Although, many potent anti-oxidative ingredients in the natural products have been
identified but the amount from the nature source hindrances the clinical application. Compound which
can activate Nrf2 signaling pathway result unregulated the cellular antioxidant-responses has been
demonstrated as an effective chemopreventive approach for cancer treatment. In the present study, cer-
tain oxime-bearing naphthalene derivatives were synthesized and evaluated for their Nrf2 activation and
anti-proliferative activities. Results indicated (E)-1-(naphthalen-2-yloxy)propan-2-one oxime (11) which
increased 2.04-fold Nrf2/ARE-driven luciferase activity was more active than its 1-substituted isomer 10
(1.17-fold) and t-BHQ (1.77-fold), the known Nrf2 activator. The activities were further increased by the
replacement of the peripheral methyl group with the phenyl ring in which (Z)-2-(naphthalen-2-yloxy)-1-
phenylethanone oxime (13a) exhibited 3.49-fold potency of the positive control. It is worth to mention
that compounds 11, 13a, and 13b which showed significant Nrf2 activation are non-cytotoxic to the
Received 5 January 2015
Revised 16 March 2015
Accepted 17 March 2015
Available online xxxx
Keywords:
Chemoprevention
Oxime-bearing naphthalene derivatives
Nrf2 activation
Antiproliferative activities
tested cells with IC50 > 50 lM. This observation strongly suggested that these compounds can be used
for chemoprevention. Mechanism studies indicated that these compounds were capable of inducing
the phosphorylation of Nrf2 protein at serine 40 which led to the activation of the Nrf2 transcriptional
activity.
Ó 2015 Elsevier Ltd. All rights reserved.
1. Introduction
neoplastic development and mortality.3 A substantial amount of
evidence has shown that many small synthetic molecules or herbal
Cancer mortality remains the leading cause of death in Taiwan
for the past 30 years and also the second mortality in the world.
Recent studies clearly demonstrated that DNA damage caused by
environmental carcinogen1 and ischemic or hypoxic condition
induced by unexpectedly oxidative stress from uncontrolled reac-
tive oxygen species (ROS)2 are the major reasons for the tumor for-
mation. Chemoprevention is an important approach which utilizes
non-toxic natural or synthetic substances to interfere with
products can exert chemopreventive effects.
Chronic redox imbalance is known to cause facilitated aging and
develop a wide spectrum of diseases such as cancer, neurode-
generative disorders, and cardiovascular diseases. Nuclear factor
E2-related factor 2 (Nrf2), a ꢀ600 amino acid residue transcrip-
tional factor which is expressed ubiquitously in most organs espe-
cially in the systems that receive external environmental stresses
like gastrointestinal tract and skin. Generally, the Nrf2 protein is
restrained in cytoplasm by the Kelch-like ECH-associated protein
1 (Keap1) with a short half-life of ꢀ20 min.4 While cellular oxida-
tive stress or environmental carcinogens induce the modification
of the Keap1 protein phosphorylated status, Nrf2 protein is then
⇑
Corresponding authors. Tel.: +886 7 3121101x2684; fax: +886 7 3125339
(C.-C.T.).
E-mail address: tzengch@kmu.edu.tw (C.-C. Tzeng).
http://dx.doi.org/10.1016/j.bmc.2015.03.046
0968-0896/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Chang, K.-M.; et al. Bioorg. Med. Chem. (2015), http://dx.doi.org/10.1016/j.bmc.2015.03.046

2
K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
released from the complex. Free Nrf2 protein can spontaneously
translocate to nucleus, forms heterodimers with small Maf protein
and recognizes antioxidant-responsive element (ARE) for further
topoisomerase 2 inhibitor), and cisplatin (a platin compound that
cross-links DNA strands) were all able to induce luciferase reporter
gene activity. The metabolic processes by which these agents act as
inducers of ARE genes, and how they impinge on Keap1, is not
known. Based on results which indicated that Nrf2 can be activated
by certain anticancer agents, the Nrf2/ARE-driven luciferase activi-
ties of newly synthesized naphthalene derivatives have also been
evaluated.
transcription.
Subsequently,
different
genes
such
as
NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione peroxi-
dase (GPx) and heme oxygenase-1 (HO-1) are produced for cellular
protection.5,6
Beside the Keap1 function, the phosphorylated status of Nrf2
also governs the function of Nrf2. Multiple protein kinases (p44/
42 MAP-kinase, p38 MAPK, JNK, PKC and PI3-kinase/Akt) are
reported responsible for N-terminal serine phosphorylation of
Nrf2 under oxidative stress, electrophiles and carcinogens
insults.7,8 The Nrf2 activation could reduce the sensitivity of cells
toward toxins, oxidative and carcinogens insults by elevating
antioxidant and detoxifying enzymes which could prevent the car-
cinogenesis process at the initiating stage. Drugs that activate Nrf2
mitigate the ability of tumor formation and recently many evi-
dences have shown that Nrf2-activating drugs display a disease-
preventing role in several chronic disorders including diabetes
and neurodegenerative disorders.5
The naphthalene ring can be recognized in various biologically
active compounds with clinical applications. The most noteworthy
example is propranolol, an anti-angina drug, which consists of
aromatic naphthalene ring and the propanolamine side chain.
Duloxetine is another example of naphthalene derivative which
blocks the transport proteins for both norepinephrine and serotonin
and clinically used for the treatment of depression. Other examples
of naphthalene derivatives, nafimidone and its oxime ester deriva-
tive (1), were found to possess anticonvulsant activity which can
be further developed for the treatment of epilepsy.9–11 Therefore,
preparation and extensive biological evaluations on naphthalene
derivatives have continuously attracted our attention.12–14
Recently, we have synthesized and evaluated anti-proliferative
activities of certain naphthalene derivatives.15–18 Among them,
N-(naphthalen-2-yl)-2-(2-oxo-1,2,3,4-tetrahydroquinolin-6-yloxy)-
acetamide (2)18 was the most active against NPC-TW01 with an IC50
2. Chemistry
The preparation of oxime-containing naphthalene derivatives is
illustrated in Scheme 1. Alkylation of 1-naphthol (4) with
chloroacetone under basic conditions gave 1-(naphthalen-1-ylox-
y)propan-2-one (6)12 which was then treated with NH2OH to
afford exclusively (E)-1-(naphthalen-1-yloxy)propan-2-one oxime
(10) in a good overall yield. The configuration of the oxime moiety
was determined by through-space nuclear Overhauser effect spec-
troscopy (NOESY), which revealed coupling connectivity to CH3
protons. Accordingly, reaction of 1-(naphthalen-2-yloxy)propan-
2-one (7)12 with NH2OH afforded exclusively (E)-1-(naphthalen-
2-yloxy)propan-2-one oxime (11). Alkylation of 1-naphthol (1)
with 2-(bromoacetyl)naphthalene under basic conditions gave 2-
(naphthalen-1-yloxy)-1-(naphthalen-2-yl)ethanone (8h) in a yield
of 94%. Preparation of compounds 8a–8e, 8g, 9a–9e, and 9g was
previously reported.12 Compound 8h was then treated with
NH2OH to afford exclusively (Z)-2-(naphthalen-1-yloxy)-1-(naph-
thalen-2-yl)ethanone oxime (12h) in a good yield. The same syn-
thetic procedure was applied for the synthesis of naphthalen-1-yl
oximes 12a–12i, and 12j, and naphthalen-2-yl oxime derivatives
13a–13j from their respective ketone precursors. The configuration
of the oxime moiety was determined by the 13C NMR spectra. The
carbon of CH2 which is anti to the oxime moiety (E-form) shifted
downfield, while that of the syn isomer (Z-form) shifted upfield
(for examples, d 71.65 for 8h shifted upfield to 59.03 for (Z)-12h;
d 71.47 for 8f shifted upfield to 59.01 for (Z)-12f).20
value of 0.6 lM. On the other hand, we have also found that the
introduction of oxime functional group into its ketone precursors
significantly enhanced anti-proliferative activities of the respective
parent compounds. Among all the flavone derivatives synthesized,
(Z)-6-[2-hydroxyimino-2-(4-methoxyphenyl)ethoxy]-2-phenyl-
4H-1-benzopyran-4-one (3)15 exhibited the most potent anti-
proliferative activities against the growth of SKHep1, HeLa, and
3. Results and discussion
All the synthesized oxime-bearing naphthalene derivatives
were evaluated in vitro against a panel of three cancer cell lines
(NPC-TW 01, H226, and Jurkat) using MTT assay. The concentration
that inhibited the growth of 50% of cells (IC50) was determined
from the linear portion of the curve by calculating the concentra-
tion of tested agent that reduced absorbance in treated cells, com-
pared to control cells, by 50%. Results from Table 1 indicated
except (Z)-1-(2,5-dimethoxyphenyl)-2-(naphthalen-2-yloxy)etha-
none oxime (13j) showed noticeable anti-proliferative activity
against all the tested human cancer cell lines, NPC-TW 01, H226,
SAS cancer cells with IC50 value of 0.8, 1.0, and 0.8 lM, respectively.
The present study describes the synthesis and anti-proliferative
evaluations of oxime-bearing naphthalene derivatives (Fig. 1)
whose structures resemble compounds 3 in which the flavone
scaffold is replaced with naphthalene ring.
Wang et al.19 reported that in addition to the induction of ARE-
driven gene expression by certain alkylating agents, anticancer
drugs such as mitoxantrone (a cytotoxic antibiotic), etoposide (a
and Jurkat, with IC50 values of 16.7, 8.6, and 10.1 lM, respectively.
Nevertheless, all other compounds are either very weakly
S
Cl
O
O
N
H
O
O
OH
N
N
O
NHMe
N
N
N
Propranolol
Duloxetine
Nafimidone
HO
1
HO
O
O
N
N
O
O
H
N
N
H
O
O
OMe
R
O
3
2
Target compounds
Figure 1. Structures of propranolol, duloxetine, nifimidone, compounds 1–3, and target compounds.
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K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
3
Table 2
O
Naphthalene derivatives and tBHQ (20
l
M) on Nrf2/ARE-driven luciferase activity
O
Br
R
O
Aryl
OH
4, 5
Aryl
R
K2CO3, DMF
R
O
8, 9
NOH
H3C
K2CO3
DMF
Cl
Compound
Position
R
Luciferase activity
NH2OH
O
10
Naphthalene-1-yl
Naphthalene-2-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-1-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
Naphthalene-2-yl
(Positive control)
–CH3
1.17
2.04
1.14
1.09
1.00
1.03
1.10
1.01
1.19
1.25
0.86
0.93
3.49
2.61
1.07
0.95
1.65
1.05
1.18
1.36
1.42
0.65
1.77
1.00
11
–CH3
Ph
4-F-Ph
O
12a
12b
12c
12d
12e
12f
12g
12h
12i
HO
O
N
Aryl
CH3
O
4-Cl-Ph
4-Br-Ph
4-OMe-Ph
4-CF3-Ph
4-Ph-Ph
Naphthalene
3,4-F-Ph
2,5-OMe-Ph
Ph
Aryl
R
6, 7
12, 13
a: R = Ph
NH2OH
OH
b
: R = 4-F-Ph
c: R = 4-Cl-Ph
d
: R = 4-Br-Ph
12j
N
e: R = 4-MeO-Ph
f: R = 4-CF3-Ph
13a
13b
13c
13d
13e
13f
13g
13h
13i
O
4-F-Ph
Aryl
CH3
g
: R = 4-Ph-Ph
4-Cl-Ph
4-Br-Ph
4-OMe-Ph
4-CF3-Ph
4-Ph-Ph
Naphthalene
3,4-F-Ph
2,5-OMe-Ph
10, 11
h: R = Naphthalen-2-yl
i
: R = 3,4-di-F-Ph
j: R = 2,5-di-MeO-Ph
4, 6, 8, 10: Aryl = Naphthalene-1-yl
5, 7, 9, 11: Aryl = Naphthalene-2-yl
Scheme 1.
13j
t-BHQ
Control
Table 1
Antiproliferative activities of naphthalene derivatives
tert-Butylhydroquinone (t-BHQ).
R
O
oxime (13a) exhibited 3.49-fold potency of the control. However,
further substitution on the phenyl ring decreased activities and
the potency decreased in an order of 13b (4-F, 2.61) > 13e (4-
MeO, 1.65) > 13i (3,4-di-F, 1.42); 13h (4-Ph, 1.36). The high steric
hindrance of phenyl ring caused by either bulky group or di-func-
tional group substitution is unfavorable for Nrf2 activation. It is
worth to mention that compounds 11, 13a, and 13b which showed
more potent Nrf2 activation than the positive t-BHQ are non-cyto-
NOH
Compound Position
R
IC50
(lM)
NPC-TW 01 H226 Jurkat
10
11
Naphthalene-1-yl –CH3
Naphthalene-2-yl –CH3
Naphthalene-1-yl Ph
>50.0
>50.0
>50.0
>50.0
>50.0
>50.0
32.3
>50.0 >50.0
>50.0 >50.0
47.1
>50.0 >50.0
>50.0 >50.0
>50.0 >50.0
36.7
>50.0 >50.0
>50.0 >50.0
38.9
>50.0 42.6
41.5 >50.0
>50.0 >50.0
>50.0 >50.0
34.9
39.1
>50.0 35.8
34.1 36.2
>50.0 >50.0
37.1
42.8
8.6
12a
12b
12c
12d
12e
12f
12g
12h
12i
12j
13a
13b
13c
13d
13e
13f
13g
13h
13i
13j
>50.0
Naphthalene-1-yl 4-F-Ph
Naphthalene-1-yl 4-Cl-Ph
Naphthalene-1-yl 4-Br-Ph
Naphthalene-1-yl 4-OMe-Ph
Naphthalene-1-yl 4-CF3-Ph
Naphthalene-1-yl 4-Ph-Ph
toxic to the tested cells with IC50 > 50 lM (Table 1). The observa-
tion clearly indicated that these compounds might be used for
chemoprevention without any cytotoxic effect. However, com-
pound 13j (2,5-dimethoxy derivative) is the only compound that
can slow down the cell proliferation (Table 1) and also paradoxi-
cally, inhibits Nrf2-driven luciferase activity.
To further explore the Nrf2-signaling activation mechanisms of
oxime-bearing naphthalene, the expression level and phosphoryla-
tion status of Nrf2 protein were monitored. The TW01-pGL4-9ARE
cells were treated with selected compounds (11, 13a, 13b, and 13e)
which activated Nrf2-signaling pathway in the cell-based lucifer-
ase assay and the phosphorylated level of Nrf2 at serine 40 which
contributes to Nrf2 transcriptional activation24 was observed.
Results from Figure 2 indicated that although these compounds
could not up-regulated the expression level of Nrf2 protein but
are capable to induce the phosphorylation of Nrf2 protein at
31.8
46.4
>50.0
Naphthalene-1-yl Naphthalene 36.1
>50.0
Naphthalene-1-yl 3,4-F-Ph
Naphthalene-1-yl 2,5-OMe-Ph
Naphthalene-2-yl Ph
Naphthalene-2-yl 4-F-Ph
Naphthalene-2-yl 4-Cl-Ph
Naphthalene-2-yl 4-Br-Ph
Naphthalene-2-yl 4-OMe-Ph
Naphthalene-2-yl 4-CF3-Ph
Naphthalene-2-yl 4-Ph-Ph
36.8
32.3
>50.0
>50.0
26.0
27.9
>50.0
30.7
37.3
47.2
>50.0
Naphthalene-2-yl Naphthalene >50.0
Naphthalene-2-yl 3,4-F-Ph
Naphthalene-2-yl 2,5-OMe-Ph
24.3
44.6
10.1
36.1
16.7
(IC50 > 25
lM) or non-cytotoxic (IC50 > 50 lM) toward the tested
cancer cells.
These oxime-bearing naphthalene derivatives were also sub-
jected to the Nrf2-activation evaluation and results have shown
in Table 2. Although majority of compounds exhibited only weak
Nrf2 activation ability, (E)-1-(naphthalen-2-yloxy)propan-2-one
oxime (11) which increased 2.04-fold Nrf2/ARE-driven luciferase
activity was more active than its 1-substituted isomer 10 (1.17-
fold) and the known Nrf2 activator, tert-butylhydroquinone (t-
BHQ) (1.77-fold).21–23 The activities were further increased by
the replacement of the peripheral methyl group with the phenyl
ring in which (Z)-2-(naphthalen-2-yloxy)-1-phenylethanone
Figure 2. Naphthalene derivatives induced the phosphorylation of Nrf2 protein at
serine 40. Treated TW01-pGL4-9ARE cells were harvested at indicated time and
total cell lysates were extracted for Western blot analysis. After separation and
transfer, the blots were incubated with antibodies specifically against p-Nrf2-S40,
total Nrf2 or actin. Finally, the images were acquired by a biomolecular imager.
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K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
Figure 3. The pre-treatment of oxime-containing naphthalenes diminished H2O2-induced free radical production. TW01-pGL4-9ARE cells were seeded into 6-well plates
(1 ꢁ 105 cells per well) and grown overnight. Subsequently, the cells were pre-treated with oxime-containing naphthalenes (20 M) for 6 h incubation, followed by
incubation of hydrogen peroxide (500 M) for additional 16 h. Finally, DCFH-DA staining was utilized to detect intracellular free radical level and data were presented as
geometric mean (Geo Mean) in each group. Asterisk (⁄) indicated significant difference between the co-treated group and H2O2-treated group (p <0.05).
l
l
Ser-40 position, which led to the activation of the Nrf2 transcrip-
tional activity. Further experiments also clearly demonstrated that
pre-treatment of compounds 11, 13a, 13b, and 13e could diminish
the H2O2-induced intracellular oxidative stress, implying the ROS
scavenging and chemopreventive capabilities of the oxime-bearing
naphthalenes (Fig. 3). Therefore, the specific molecular target(s) of
these oxime-bearing naphthalenes are worthy of further study.
Our preliminary results demonstrated that staurosporine, a PKC
signal-pathway inhibitor, significantly diminished the Nrf2-activa-
tion effects of oxime-containing naphthalenes, suggested that the
PKC signaling pathways might involve in the oxime-containing
naphthalenes-induced Nrf2 activation. However, specific molecu-
lar target(s) of these naphthalenes are currently under active
investigation.
resonance (1H and 13C) spectra were recorded on a Varian-Unity-
400 spectrometer. Chemical shifts were expressed in parts per mil-
lion (d) with tetramethylsilane (TMS) as an internal standard. Thin-
layer chromatography was performed on silica gel 60 F-254 plates
purchased from E. Merck and Co. The elemental analyses were per-
formed in the Instrument Center of National Science Council at
National Cheng-Kung University using Heraeus CHN-O Rapid EA,
and all values are within 0.4% of the theoretical compositions.
5.1.1. 2-(Naphthalen-1-yloxy)-1-(naphthalen-2-yl)ethanone (8h)
1-Naphthol (4, 1.44 g, 10 mmol), K2CO3 (1.38 g, 10 mmol), and
dry DMF (50 mL) were stirred at room temperature (rt) for
30 min. To this solution was added 2-(bromoacetyl)naphthalene
(2.49 g, 10 mmol) in DMF (10 mL) in one portion. The resulting
mixture was stirred continuously at rt for 24 h (TLC monitoring)
and then poured into ice-water (100 mL). The white solid thus
obtained was collected and crystallized from Et2O to give 8h
(2.92 g, 94%). Mp: 158–159 °C; 1H NMR (400 MHz, CDCl3-d6): d
5.56 (s, 2H, OCH2), 6.86 (dd, J = 0.8, 7.6 Hz, 1H-C(2)), 7.37 (t,
J = 7.6 Hz, 1H-C(3)), 7.48–7.66 (m, 4H, Ar-H), 7.81–7.84 (m, 1H,
Ar-H), 7.90–7.99 (m, 3H, Ar-H), 8.13 (dd, J = 1.6, 8.8, 1H-C(5)),
8.41 (m, 1H, Ar-H), 8.65 (d, J = 1.2 Hz, 1H-C(8)); 13C NMR
4. Conclusion
Many studies have showed that compounds that activate Nrf2-
regulated cellular anti-oxidative responses could play a very
important disease-preventing role in several chronic disorders
including diabetes and neurodegenerative disorders and mitigate
the ability of tumor formation.5 In this study, certain oxime-bear-
ing naphthalene derivatives were synthesized and evaluated for
their Nrf2 activation and anti-proliferative activities. Among them,
compound 13e was less active while compounds 11, 13a, and 13b
showed more potent Nrf2 activation than the positive t-BHQ.
Mechanism studies indicated that these compounds were capable
of inducing the phosphorylation of Nrf2 protein at serine 40 which
led to the activation of the Nrf2 transcriptional activity. To the best
of our knowledge, this is the first study showed that compounds
contain the naphthalene pharmacophore have the chemo-preven-
tive activity through the activation the Nrf2-signaling pathway.
Detail structure activity relationship and molecular mechanisms
of activating the Nrf2-signaling pathway of oxime-bearing naph-
thalene are currently investigated.
(400 MHz, CDCl3-d6):
d 71.65 (CH2O), 105.53 (C(2)), 121.57,
122.37, 124.01, 125.78, 125.80, 125.85, 126.84, 127.22, 127.68,
128.1, 128.97, 130.51, 132.25, 132.67, 134.84, 136.15, 154.06
(C(1)), 194.82 (C@O). Anal. calcd for C22H16O2: C, 84.59; H, 5.16;
found: C, 84.52; H, 5.26.
The same reaction procedures were applied for the preparation
of 8f, 8i, and 8j from compound 4; compounds 9f, 9i, and 9j from 2-
naphthol (5).
5.1.2. 2-(Naphthalen-1-yloxy)-1-(4-(trifluoromethyl)phenyl)eth-
anone (8f)
81% yield. Mp: 91–92 °C; 1H NMR (400 MHz, CDCl3-d6): d 5.40
(s, 2H, OCH2), 6.79 (d, J = 7.6 Hz, 1H-C(2)), 7.35 (t, J = 8 Hz, 1H-
C(3)), 7.47–7.54 (m, 3H, Ar-H), 7.75–7.82 (m, 3H, Ar-H), 7.82 (dd,
J = 2.8, 8 Hz, 1H-C(5)), 8.19 (dd, J = 0.8, 8.8 Hz, 2H, Ar-H), 8.30
(dd, J = 2.8, 9.2 Hz, 1H-C(8)); 13C NMR (400 MHz, CDCl3-d6): d
71.47 (CH2O), 105.2 (C(2)), 121.63, 121.91, 125.48, 125.68,
125.79, 125.83, 125.87, 125.91, 126.73, 127.52, 128.83, 134.61,
137.37, 153.52 (C(1)), 194.21 (C@O). Anal. calcd for C19H13 F3O2:
C, 69.09; H, 3.97; found: C, 69.05; H, 3.99.
5. Experimental
5.1. General
Melting points were determined on an Electrothermal IA9100
melting point apparatus and are uncorrected. Nuclear magnetic
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K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
5
5.1.3. 1-(3,4-Difluorophenyl)-2-(naphthalen-1-yloxy)ethanone
(8i)
5.1.8. (E)-1-(Naphthalen-1-yloxy)propan-2-one oxime (10)
A solution of 1-(naphthalen-1-yloxy)propan-2-one (6)12 (0.2 g,
1 mmol) in EtOH (20 mL) was added a solution of hydroxylamine
hydrochloride (0.14 g, 2 mmol) in EtOH (2 mL). The mixture was
heated at reflux for 4 h (TLC monitoring) and evaporated to give
a residual solid. The white solid thus obtained was collected, pur-
ified by flash column chromatography (FC; silica gel; n-hexane/
EtOAc 5:1) to give 10 (0.21 g, 89%). liquid; 1H NMR (400 MHz,
DMSO-d6): (400 MHz, DMSO-d6): 1.95 (s, 3H, CH3), 4.76 (s, 2H,
OCH2), 7.04 (d, J = 7.6 Hz, 1H-C(2)), 7.49–7.56 (m, 4H, Ar-H), 7.90
(dd, J = 2.0, 7.2 Hz, 1H-C(5)), 8.20 (dd, J = 1.6, 7.6 Hz, 1H-C(8)),
11.03 (s, 1H-NOH); 13C NMR d 11.82 (CH3), 69.74 (CH2O), 107.68
(C(2)), 118.90, 124.08, 126.76, 126.96, 127.79, 128.88, 129.67,
134.34, 152.41 (C(1)), 156.24 (C@NOH). Anal. calcd for
86% yield. Mp: 139–140 °C; 1H NMR (400 MHz, CDCl3-d6): d
5.33 (s, 2H, OCH2), 6.70 (d, J = 7.6 Hz, 1H-C(2)), 7.24–7.36 (m, 2H,
Ar-H), 7.47–7.53 (m, 3H, Ar-H), 7.80–7.83 (m, 1H, Ar-H), 7.85–
7.95 (m, 2H, Ar-H), 8.30 (dd, J = 2.8, 9.2 Hz, 1H-C(8)); 13C NMR
(400 MHz, CDCl3-d6):
d 71.33 (CH2O), 105.19 (C(2)), 117.69,
117.81, 117.88, 118.0, 118.02, 121.62, 121.86, 125.48, 125.57,
125.61, 125.65, 125.68, 126.71, 127.52, 134.6, 153.47 (C(1)),
192.067 (C@O). Anal. calcd for C18H12F2O2: C, 72.48; H, 4.05;
found: C, 72.35; H, 4.05.
5.1.4. 1-(2,5-Dimethoxyphenyl)-2-(naphthalen-1-yloxy)ethanone
(8j)
73% yield. Mp: 128–129 °C; 1H NMR (400 MHz, CDCl3-d6): d
3.81 (s, 3H, OMe), 3.90 (s, 3H, OMe), 5.42 (s, 2H, OCH2), 6.70 (d,
J = 7.2 Hz, 1H-C(2)), 6.97 (d, J = 8.8, 1H, Ar-H), 7.13 (dd, J = 3.2,
8.8 Hz, 1H, Ar-H), 7.32 (t, J = 8 Hz, 1H-C(3)), 7.43–7.50 (m, 4H,
Ar-H), 7.81 (dd, J = 1.6, 9.6 Hz, 1H-C(5)), 8.39 (dd, J = 2, 9.6 Hz,
1H-C(8)); 13C NMR (400 MHz, CDCl3-d6): d 55.84 (MeO), 56.8
(MeO), 74.62 (CH2O), 105.24 (C(2)), 112.99, 113.8, 120.8, 121.71,
122.35, 125.24, 125.28, 125.56, 125.74, 126.44, 127.33, 134.59,
153.77, 153.89, 154.21 (C(1)), 195.03 (C@O). Anal. calcd for
C13H13NO2: C, 72.54; H, 6.09; N, 6.51; found: C, 72.55; H, 6.13; N,
6.40.
5.1.9. (E)-1-(Naphthalen-2-yloxy)propan-2-one oxime (11)
From 1-(naphthalen-2-yloxy)propan-2-one (7) as described for
10: 80% yield. Mp: 127–128 °C; 1H NMR (400 MHz, DMSO-d6): d
1.89 (s, 3H, CH3), 4.68 (s, 2H, OCH2), 7.22 (dd, J = 2.4, 2.8 Hz,
1H-C(3)), 7.34–7.38 (m, 2H, Ar-H), 7.49 (t, J = 1.2, 2.8, 0.8 Hz,
1H-C(7)), 7.77–7.85 (m, 1H-C(4), 1H-C(5), 1H-C(8)), 11.01 (s,
1H-NOH); 13C NMR (400 MHz, DMSO-d6): d 11.61 (CH3), 69.59
(CH2O), 107.47 (C(1)), 118.70, 123.81, 126.51, 126.73, 127.58,
128.67, 129.42, 134.16, 152.0 (C(2)), 156.06 (C@NOH). Anal. calcd
for C13H13NO2: C, 72.54; H, 6.09; N, 6.51; found: C, 72.69; H,
6.15; N, 6.37.
C20H18O4: C, 74.52; H, 5.63; found: C, 74.24; H 5.66.
5.1.5. 2-(Naphthalen-1-yloxy)-1-(4-(trifluoromethyl)phenyl)eth-
anone (9f)
83% yield. Mp: 91–92 °C; 1H NMR (400 MHz, DMSO-d6): d 5.77
(s, 2H, OCH2), 7.30 (d, J = 2.8, 8.8 Hz, 1H-C(3)), 7.38 (ddd, J = 1.2,
7.4, 1.2 Hz, 1H, Ar-H), 7.41 (d, J = 2.8 Hz, 1H-C(1)), 7.48 (ddd,
J = 1.2, 7.4, 1.2 Hz, 1H, Ar-H), 7.78 (d, J = 8.4 Hz, 1H, Ar-H), 7.84–
7.87 (m, 2H, Ar-H), 7.99 (d, J = 8.0 Hz, 2H, Ar-H), 8.28 (d,
J = 8.0 Hz, 1H-C(5), 1H-C(8)); 13C NMR (400 MHz, DMSO-d6): d
70.46 (CH2O), 107.35 (C(1)), 118.51, 123.8, 125.78, 125.82,
125.85, 125.89, 126.5, 126.68, 127.56, 128.7, 128.85, 129.4,
132.85, 133.17, 134.12, 137.66, 155.69 (C(2)), 193.99 (C@O).
Anal. calcd for C19H13F3O2: C, 69.09; H, 3.97; found: C, 69.07; H,
4.05.
5.1.10. (Z)-2-(Naphthalen-1-yloxy)-1-phenylethanone oxime (12a)
From 2-(naphthalen-1-yloxy)-1-phenylethanone (8a) as
described for the preparation of 10: 71% yield. Mp: 121–122 °C;
1H NMR (400 MHz, DMSO-d6): d 5.48 (s, 2H, OCH2), 7.10 (d,
J = 7.6 Hz, 1H-C(2)), 7.36–7.46 (m, 7H, Ar-H), 7.72 (d, J = 2.4 Hz,
1H, Ar-H), 7.74 (d, J = 7.6 Hz, 1H-C(4)), 7.85 (d, J = 8 Hz, 1H-C(5)),
7.92 (d, J = 8 Hz, 1H-C(8)), 11.98 (s, 1H-NOH); 13C NMR
(400 MHz, DMSO-d6):
d 59.17 (CH2O), 105.11(C(2)), 120.40,
121.27, 124.80, 125.36, 126.14, 126.48, 127.43, 128.27, 128.90,
134.02, 134.22, 153.04, 153.25 (C@NOH). Anal. calcd for
C
5.07.
18H15NO2: C, 77.96; H, 5.45; N, 5.05; found: C, 77.96; H, 5.53; N,
5.1.6. 1-(3,4-Difluorophenyl)-2-(naphthalen-2-yloxy)ethanone
(9i)
66% yield. Mp: 122–123 °C; 1H NMR (400 MHz, DMSO-d6): d
5.70 (s, 2H, OCH2), 7.29 (dd, J = 2.8, 8.8 Hz, 1H-C(3)), 7.34–7.39
(m, 2H, Ar-H), 7.48 (ddd, J = 1.2, 7.6, 1.6, 1H, Ar-H), 7.66–7.77
(m, 2H, Ar-H), 7.84–7.87 (dd, J = 4.0, 8.0, 2H, Ar-H), 8.00 (m, 1H,
Ar-H), 8.18 (m, 1H, Ar-H); 13C NMR (400 MHz, DMSO-d6): d
70.23 (CH2O), 107.35 (C(1)), 117.39, 117.56, 118.12, 118.29,
118.5, 123.8, 125.83, 125.86, 125.9, 126.5, 126.65, 127.56,
128.69, 129.4, 131.86, 131.9, 131.94, 134.11, 148.27, 148.4,
150.74, 150.86, 151.63, 151.75, 154.15, 154.28, 155.7 (C(2)),
192.37 (C@O). Anal. calcd for C18H12F2O2: C, 72.48; H, 4.05;
found: C, 72.51; H, 4.21.
5.1.11. (Z)-1-(4-Fluorophenyl)-2-(naphthalen-1-yloxy)ethanone
oxime (12b)
From 1-(4-fluorophenyl)-2-(naphthalen-1-yloxy)ethanone (8b)
as described for 10: 67% yield. Mp: 144–145 °C; 1H NMR
(400 MHz, DMSO-d6): d 5.48 (s, 2H, OCH2), 7.09 (d, J = 7.2 Hz, 1H-
C(2)), 7.21–7.23 (m, 2H, Ar-H), 7.40–7.50 (m, 4H, Ar-H), 7.77 (d,
J = 6.8 Hz, 1H-C(4)), 7.78 (d, J = 2.0 Hz, 1H, Ar-H), 7.85 (d,
J = 8.0 Hz, 1H-C(5)), 7.92 (d, J = 8.2 Hz, 1H-C(8)), 12.0 (s, 1H-
NOH); 13C NMR (400 MHz, DMSO-d6): d 59.16 (CH2O), 105.22
(C(2)), 115.11, 115.33, 120.47, 121.22, 124.77, 125.41, 126.13,
126.49, 127.45, 128.65, 128.74, 130.65, 134.01, 152.28, 153.13
(C@NOH), 161.23, 163.67. Anal. calcd for C18H14FNO2: C, 73.21;
H, 4.78; N, 4.74; found: C, 73.10; H, 4.78; N, 4.47.
5.1.7. 1-(2,5-Dimethoxyphenyl)-2-(naphthalen-2-yloxy)ethanone
(9j)
70% yield. Mp: 128–129 °C; 1H NMR (400 MHz, DMSO-d6): d
3.75 (s, 3H, OMe), 3.95 (s, 3H, OMe), 5.43 (s, 2H, OCH2), 7.21–
7.28 (m, 5H, Ar-H), 7.37 (ddd, J = 1.2, 7.6, 1.6, 1H, Ar-H), 7.46
(ddd, J = 1.2, 7.4, 1.2 Hz, 1H, Ar-H), 7.77 (d, J = 8 Hz, 1H-C(8)),
7.86 (dd, J = 3.2, 8.8 Hz, 2H, Ar-H); 13C NMR (400 MHz, DMSO-
d6): d 55.6 (MeO), 56.51 (MeO), 73.33 (CH2O), 107.09 (C(1)),
113.32, 114.24, 118.55, 120.9, 123.67, 124.96, 126.4, 126.71,
127.5, 128.59, 129.34, 134.11, 153.14 (C(2)), 153.56, 155.93,
194.78 (C@O). Anal. calcd for C20H18O4: C, 74.52; H, 5.63; found:
C, 74.25; H, 5.63.
5.1.12. (Z)-1-(4-Chlorophenyl)-2-(naphthalen-1-yloxy)ethanone
oxime (12c)
From 1-(4-chlorophenyl)-2-(naphthalen-1-yloxy)ethanone (8c)
as described for 10: 69% yield. Mp: 176–177 °C; 1H NMR (400 MHz,
DMSO-d6): d 5.48 (s, 2H, OCH2), 7.08 (d, J = 7.2 Hz, 1H-C(2)), 7.40–
7.51 (m, 6H, Ar-H), 7.76 (dd, J = 2.8, 8.4 Hz, 1H, Ar-H, 1H-C(4)), 7.85
(d, J = 8.0 Hz, 1H-C(5)), 7.92 (d, J = 8.4 Hz, 1H-C(8)), 12.09 (s, 1H-
NOH); 13C NMR (400 MHz, DMSO-d6): d 58.88 (CH2O), 104.98
(C(2)), 120.38, 121.09, 124.64, 125.32, 126.0, 126.38, 127.34,
128.14, 128.23, 132.91, 133.45, 133.90, 152.08, 152.98 (C@NOH).
Please cite this article in press as: Chang, K.-M.; et al. Bioorg. Med. Chem. (2015), http://dx.doi.org/10.1016/j.bmc.2015.03.046

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K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
Anal. calcd for C18H14ClNO2: C, 69.35; H, 4.53; N, 4.49; found: C,
69.26; H, 4.61; N, 4.42.
(400 MHz, DMSO-d6): d 59.03 (CH2O), 105.15 (C(2)), 120.42,
121.25, 123.76, 124.82, 125.36, 126.16, 126.23, 126.46, 126.67,
127.43, 127.51, 127.70, 128.34, 131.61, 132.65, 133.0, 134.03,
152.89, 153.24 (C@NOH). Anal. calcd for C22H17NO2: C, 80.71; H,
5.23; N, 4.28; found: C, 80.58; H, 5.30; N, 4.27.
5.1.13. (Z)-1-(4-Bromophenyl)-2-(naphthalen-1-yloxy)ethanone
oxime (12d)
From
1-(4-bromophenyl)-2-(naphthalen-1-yloxy)ethanone
(8d) as described for 10: 66% yield. Mp: 178–179 °C; 1H NMR
(400 MHz, DMSO-d6): d 5.47 (s, 2H, OCH2), 7.08 (d, J = 7.6 Hz, 1H-
C(2)), 7.40–7.51 (m, 4H, Ar-H), 7.58 (d, J = 8.4 Hz, 2H, Ar-H), 7.68
(d, J = 7.6 Hz, 1H, Ar-H, 1H-C(4)), 7.85 (d, J = 8 Hz, 1H-C(5)), 7.92
(d, J = 8 Hz, 1H-C(8)), 12.10 (s, 1H-NOH); 13C NMR (400 MHz,
DMSO-d6): d 58.83 (CH2O), 104.97 (C(2)), 120.38, 121.09, 122.18,
124.63, 125.33, 126.0, 126.34, 127.34, 128.40, 131.15, 133.27,
133.90, 152.18, 152.98 (C@NOH). Anal. calcd for C18H14BrNO2: C,
60.69; H, 3.96; N, 3.93; found: C, 60.58; H, 4.00; N, 3.96.
5.1.18. (Z)-1-(3,4-Difluorophenyl)-2-(naphthalen-1-yloxy)etha-
none oxime (12i)
From 1-(3,4-difluorophenyl)-2-(naphthalen-1-yloxy)ethanone
(8i) as described for 10: 76% yield. Mp: 130–131 °C; 1H NMR
(400 MHz, DMSO-d6): 5.48 (s, 2H, OCH2), 7.08 (d, J = 7.6 Hz, 1H-
C(2)), 7.40–7.58 (m, 6H, Ar-H), 7.77 (m, 1H, Ar-H, 1H-C(4)), 7.85
(d, J = 8 Hz, 1H-C(5)), 7.92 (d, J = 8 Hz, 1H-C(8)), 12.18 (s, 1H-
NOH); 13C NMR (400 MHz, DMSO-d6): d 58.98 (CH2O), 105.18
(C(2)), 115.35, 115.53, 117.36, 117.54, 120.53, 121.1, 123.58,
123.61, 123.64, 123.68, 124.73, 125.43, 126.07, 126.48, 127.45,
134.0, 147.92, 148.04, 148.44, 148.58, 150.35, 150.47, 150.9,
151.0, 151.5, 152.98 (C@NOH). Anal. calcd for C18H13F2NO2: C,
69.01; H, 4.18; N, 4.47; found: C, 68.98; H, 4.20; N, 4.43.
5.1.14. (Z)-1-(4-Methoxyphenyl)-2-(naphthalen-1-yloxy)ethanone
oxime (12e)
From 1-(4-methoxyphenyl)-2-(naphthalen-1-yloxy)ethanone
(8e) as described for 10: 82% yield. Mp: 129–130 °C; 1H NMR
(400 MHz, DMSO-d6): d 3.74 (s, 3H, OCH3), 5.45 (s, 2H, OCH2),
6.94 (dd, J = 9.2, 2.4 Hz, 2H, Ar-H), 7.09 (d, J = 7.2 Hz, 1H-C(2)),
7.40–7.51 (m, 4H, Ar-H), 7.67 (d, J = 2.0 Hz, 1H, Ar-H), 7.69 (d,
J = 6.8 Hz, 1H-C(4)), 7.85 (d, J = 8.0 Hz, 1H-C(5)), 7.96 (d,
J = 8.0 Hz, 1H-C(8)), 11.77 (s, 1H-NOH); 13C NMR (400 MHz,
DMSO-d6): d 55.12 (MeO), 59.06 (CH2O), 105.06 (C(2)), 113.70,
120.34, 121.31, 124.81, 125.38, 126.16, 126.47, 126.58, 127.44,
127.80, 134.02, 152.48, 153.27 (C@NOH), 159.80. Anal. calcd for
5.1.19. (Z)-1-(2,5-Dimethoxyphenyl)-2-(naphthalen-1-yloxy)-
ethanone oxime (12j)
From 1-(2,5-dimethoxyphenyl)-2-(naphthalen-1-yloxy)etha-
none (8j) as described for 10: 59% yield. Mp: 150–151 °C; 1H
NMR (400 MHz, DMSO-d6): d 3.61 (s, 3H, MeO), 3.62 (s, 3H,
MeO), 5.32 (s, 2H, OCH2), 6.76 (d, J = 2.8 Hz, 1H, Ar-H)), 6.89 (d,
J = 2.8 Hz, 1H, Ar-H), 6.91 (d, J = 7.6 Hz, 1H-C(2)), 6.93–6.96 (m,
2H, Ar-H), 7.29–7.46 (m, 4H, Ar-H), 7.61 (d, J = 8 Hz, 1H-C(5)),
7.81 (d, J = 8.4 Hz, 1H-C(8)), 11.68 (s, 1H-NOH); 13C NMR
(400 MHz, DMSO-d6): d 55.24 (MeO), 55.89 (MeO), 62.35 (CH2O),
104.98 (C(2)), 112.13, 114.59, 115.47, 120.05, 121.04, 124.33,
124.70, 124.99, 126.01, 126.26, 127.22, 133.82, 151.60, 152.57,
153.44, 154.71 (C@NOH). Anal. calcd for C20H19NO4: C, 71.20; H,
5.68; N, 4.15; found: C, 70.85; H, 5.71; N, 4.11.
C
19H17NO3ꢂ0.01H2O: C, 74.21; H, 5.57; N, 4.56; found: C, 73.68;
H, 5.65; N, 4.53.
5.1.15. (Z)-2-(Naphthalen-1-yloxy)-1-(4-(trifluoromethyl)phenyl)-
ethanone oxime (12f)
From 2-(naphthalen-1-yloxy)-1-(4-(trifluoromethyl)phenyl)-
ethanone (8f) as described for 10: 83% yield. Mp: 155–156 °C; 1H
NMR (400 MHz, DMSO-d6): 5.53 (s, 2H, OCH2), 7.10 (d, J = 7.6 Hz,
1H-C(2)), 7.38–7.50 (m, 4H, Ar-H), 7.76 (d, J = 8.4 Hz, 2H, Ar-H,
1H-C(4)), 7.85 (d, J = 8 Hz, 1H-C(5)), 7.90 (d, J = 8.2 Hz, Ar-H), 7.95
(d, J = 8 Hz, 1H-C(8)), 12.33 (s, 1H-NOH); 13C NMR (400 MHz,
DMSO-d6): d 59.01 (CH2O), 105.15 (C(2)), 120.57, 121.16, 124.73,
125.13, 125.17, 125.21, 125.42, 125.49, 126.10, 126.49, 127.20,
127.45, 128.81, 129.13, 134.0, 138.18, 152.19, 153.07 (C@NOH).
Anal. calcd for C19H14F3NO2: C, 66.09; H, 4.09; N, 4.06; found: C,
65.76; H, 4.10; N, 4.03.
5.1.20. (Z)-2-(Naphthalen-2-yloxy)-1-phenylethanone oxime (13a)
From 2-(naphthalen-2-yloxy)-1-phenylethanone (9a) as
described for 10: 63% yield. Mp: 143–144 °C; 1H NMR (400 MHz,
DMSO-d6): d 5.48 (s, 2H, OCH2), 7.10 (dd, J = 1.2, 7.6 Hz, 1H-C(3)),
7.34–7.50 (m, 7H, Ar-H), 7.71–7.74 (m, 1H, Ar-H, 1H-C(4)), 7.84
(d, J = 8 Hz, 1H-C(5)), 7.92 (d, J = 7.8 Hz, 1H-C(8)), 11.97 (s, 1H-
NOH); 13C NMR (400 MHz, DMSO-d6): d 59.15 (CH2O), 105.09
(C(1)), 120.40, 121.27, 124.79, 125.36, 126.15, 126.48, 127.44,
128.27, 128.91, 134.02, 134.21, 153.03, 153.25 (C@NOH). Anal.
calcd for C18H15NO2: C, 77.96; H, 5.45; N, 5.05; found: C, 78.08;
H, 5.45; N, 5.05.
5.1.16. (Z)-1-(Biphenyl-4-yl)-2-(naphthalen-1-yloxy)ethanone
oxime (12g)
From 1-(biphenyl-4-yl)-2-(naphthalen-1-yloxy)ethanone (8g)
as described for 10: 70% yield. Mp: 182–183 °C; 1H NMR
(400 MHz, DMSO-d6): d 5.51 (s, 2H, OCH2), 7.13 (d, J = 7.2 Hz, 1H-
C(2)), 7.35–7.50 (m, 7H, Ar-H), 7.70 (t, J = 7.2, 8.4 Hz, 1H-C(4)),
3H, Ar-H), 7.83 (d, J = 2.4 Hz, 2H, Ar-H), 7.85 (d, J = 8.4 Hz, 1H-
C(5)), 7.98 (d, J = 8.0 Hz, 1H-C(8)), 12.04 (s, 1H-NOH); 13C NMR
(400 MHz, DMSO-d6): d 59.07 (CH2O), 105.15 (C(2)), 120.44,
121.31, 124.82, 125.41, 126.17, 126.51, 126.59, 126.98, 127.45,
127.70, 128.99, 133.29, 134.03, 139.39, 140.47, 152.61, 153.29
(C@NOH). Anal. calcd for C24H19NO2: C, 81.56; H, 5.42; N, 3.96;
found: C, 81.39; H, 5.55; N, 3.96.
5.1.21. (Z)-1-(4-fluorophenyl)-2-(naphthalen-2-yloxy)ethanone
oxime (13b)
From 1-(4-fluorophenyl)-2-(naphthalen-2-yloxy)ethanone (9b)
as described for 10: 71% yield. Mp: 139–140 °C; 1H NMR
(400 MHz, DMSO-d6): d 5.37 (s, 2H, OCH2), 7.11 (dd, J = 2.4,
8.8 Hz, 1H-C(3)), 7.19–7.25 (m, 2H, Ar-H), 7.38 (t, J = 1.6, 2.4, 1.2,
1H, Ar-H), 7.42 (d, J = 2.4 Hz, 1H-C(4)), 7.49 (ddd, J = 1.2, 2.4,
1.2 Hz, 1H, Ar-H), 7.69–7.83 (m, 5H, Ar-H), 12.01 (s, 1H-NOH);
13C NMR (400 MHz, DMSO-d6): d 58.86 (CH2O), 106.97 (C(1)),
115.2, 115.42, 118.4, 123.85, 126.55, 126.74, 127.58, 128.58,
128.67, 128.71, 129.46, 130.76, 130.79, 134.14, 152.1, 155.73
(C@NOH), 161.29, 163.74. Anal. calcd for C18H14FNO2: C, 73.21;
H, 4.78; N, 4.74; found: C, 73.24; H, 4.83; N, 4.74.
5.1.17. (Z)-2-(Naphthalen-1-yloxy)-1-(naphthalen-2-yl)ethanone
oxime (12h)
From
2-(naphthalen-1-yloxy)-1-(naphthalen-2-yl)ethanone
5.1.22. (Z)-1-(4-Chlorophenyl)-2-(naphthalen-2-yloxy)ethanone
oxime (13c)
From 1-(4-chlorophenyl)-2-(naphthalen-2-yloxy)ethanone (9c)
as described for 10: 71% yield. Mp: 142–143 °C; 1H NMR (400 MHz,
DMSO-d6): d 5.37 (s, 2H, OCH2), 7.10 (dd, J = 2.4, 8.8 Hz, 1H-C(3)),
(8h) as described for 10: 67% yield. Mp: 158–159 °C; 1H NMR
(400 MHz, DMSO-d6): d 5.60 (s, 2H, OCH2), 7.16 (d, J = 7.0 Hz, 1H-
C(2)), 7.33–7.53 (m, 6H, Ar-H), 7.78–7.97 (m, 1H-C(4), 1H-C(5),
4H, Ar-H), 8.28 (s, 1H-C(8)), 12.11 (s, 1H-NOH); 13C NMR
Please cite this article in press as: Chang, K.-M.; et al. Bioorg. Med. Chem. (2015), http://dx.doi.org/10.1016/j.bmc.2015.03.046

K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
7
7.38 (dd, J = 1.2, 1.6 Hz, 1H-(C1)), 7.41–7.49 (m, 4H, Ar-H), 7.71 (dd,
J = 2.0, 8.0 Hz, 2H, Ar-H), 7.76–7.83 (m, 3H, Ar-H), 12.11 (s, 1H-
NOH); 13C NMR (400 MHz, DMSO-d6): d 58.69 (CH2O), 106.93
(C(1)), 118.38, 123.83, 126.55, 126.72, 127.57, 128.19, 128.42,
128.69, 129.45, 133.12, 133.6, 134.1, 152.04, 155.67 (C@NOH).
Anal. calcd for C18H14ClNO2: C, 69.35; H, 4.53; N, 4.49; found: C,
69.38; H, 4.61; N, 4.51.
(400 MHz, DMSO-d6): d 5.49 (s, 2H, OCH2), 7.16 (dd, J = 2.4,
8.8 Hz, 1H-C(3)), 7.38 (dd, J = 1.2, 1.6 Hz, 1H-(C1)), 7.46–7.54 (m,
4H, Ar-H), 7.77–7.83 (m, 3H, Ar-H), 7.89–7.96 (m, 4H, Ar-H), 8.22
(s, 1H, Ar-H), 12.12 (s, 1H-NOH); 13C NMR (400 MHz, DMSO-d6):
d
58.7 (CH2O), 107.0 (C(1)), 118.48, 123.74, 123.82, 126.11,
126.51, 126.55, 126.72, 126.75, 127.55, 127.58, 127.83, 128.41,
128.7, 129.44, 131.82, 132.72, 133.06, 134.18, 152.76, 155.9
(C@NOH). Anal. calcd for C22H17NO2: C, 80.71; H, 5.23; N, 4.28;
found: C, 80.86; H, 5.23; N, 4.28.
5.1.23. (Z)-1-(4-Bromophenyl)-2-(naphthalen-2-yloxy)ethanone
oxime (13d)
From 1-(4-bromophenyl)-2-(naphthalen-2-yloxy)ethanone (9d)
as described for 10: 60% yield. Mp: 143–144 °C; 1H NMR (400 MHz,
DMSO-d6): d 5.37 (s, 2H, OCH2), 7.10 (dd, J = 2.4, 8.8 Hz, 1H-C(3)),
7.38 (dd, J = 0.8, 1.2 Hz, 1H-(C1)),7.42 (d, J = 2.8 Hz, 1H, Ar-H),
7.49 (dd, J = 0.8, 8.0 Hz, 1H, Ar-H), 7.57–7.64 (m, 4H, Ar-H), 7.76–
7.83 (m, 3H, Ar-H), 12.12 (s, 1H-NOH); 13C NMR (400 MHz,
DMSO-d6): d 58.66 (CH2O), 106.93 (C(1)), 118.38, 122.33, 123.85,
126.55, 126.73, 127.58, 128.47, 128.7, 129.46, 131.34, 133.49,
134.11, 152.14, 155.67 (C@NOH). Anal. calcd for C18H14BrNO2: C,
60.69; H, 3.96; N, 3.93; found: C, 60.73; H, 3.96; N, 3.93.
5.1.28. (Z)-1-(3,4-Difluorophenyl)-2-(naphthalen-2-yloxy)ethan-
one oxime (13i)
From 1-(3,4-difluorophenyl)-2-(naphthalen-2-yloxy)ethanone
(9i) as described for 10: 93% yield. Mp: 121–122 °C; 1H NMR
(400 MHz, DMSO-d6): 5.37 (s, 2H, OCH2), 7.11 (dd, J = 2.8, 8.8 Hz,
1H-C(3)), 7.38 (dd, J = 1.2, 1.6 Hz, 1H-(C1)), 7.42–7.54 (m, 4H, Ar-
H), 7.67–7.84 (m, 4H, Ar-H), 12.19 (s, 1H-NOH); 13C NMR
(400 MHz, DMSO-d6): d 58.63 (CH2O), 107.01 (C(1)), 115.23,
115.42, 117.45, 117.62, 118.33, 123.56, 123.83, 126.51, 126.7,
127.54, 128.7, 129.44, 134.07, 151.29, 155.58 (C@NOH). Anal. calcd
for C18H13F2NO2: C, 69.01; H, 4.18; N, 4.47; found: C, 68.97; H,
4.21; N, 4.48.
5.1.24. (Z)-1-(4-Methoxyphenyl)-2-(naphthalen-2-yloxy)ethanone
oxime (13e)
From 1-(4-methoxyphenyl)-2-(naphthalen-2-yloxy)ethanone
(9e) as described for 10: 73% yield. Mp: 129–130 °C; 1H NMR
(400 MHz, DMSO-d6): d 3.76 (s, 3H, OCH3), 5.34 (s, 2H, OCH2),
6.94 (dd, J = 2.0, 8.8 Hz, 2H, Ar-H), 7.11 (dd, J = 2.4, 9.2 Hz, 1H-
C(3)), 7.37 (dd, J = 1.2, 1.6 Hz, 1H-C(1)), 7.43–7.49 (m, 2H, Ar-H),
7.64 (dd, J = 2.0, 8.8 Hz, 1H-C(6), 1H-C(7)), 7.76–7.83 (m, 3H, Ar-
H), (s, 1H-NOH); 13C NMR (400 MHz, DMSO-d6): d 55.17 (MeO),
58.77 (CH2O), 106.9 (C(1)), 113.80, 118.45, 123.79, 126.53,
126.73, 127.58, 128.67, 129.42, 134.17, 152.33, 155.87, 159.86
(C@NOH). Anal. calcd for C19H17NO3ꢂ0.1H2O: C, 73.86; H, 5.55; N,
4.53; found: C, 73.61; H, 5.55; N, 4.47.
5.1.29. (Z)-1-(2,5-Dimethoxyphenyl)-2-(naphthalen-2-yloxy)-
ethanone oxime (13j)
From 1-(2,5-dimethoxyphenyl)-2-(naphthalen-2-yloxy)etha-
none (9j) as described for 10: 60% yield. liquid; 1H NMR
(400 MHz, DMSO-d6): d 3.60 (s, 3H, MeO), 3.66 (s, 3H, MeO), 5.25
(s, 2H, OCH2), 6.68 (d, J = 2.8 Hz, 1H, Ar-H)), 6.88–6.97 (m, 3H,
Ar-H), 7.28 (d, J = 2.4 Hz, 1H, Ar-H), 7.36 (dd, J = 1.6, 8.0 Hz, 1H-
(C3)), 7.47 (dd, J = 1.2, 1.6 Hz, 1H-(C1)), 7.73–7.81 (m, 3H, Ar-H),
11.73 (s, 1H-NOH); 13C NMR (400 MHz, DMSO-d6):
d 55.28
(MeO), 56.15 (MeO), 61.89 (CH2O), 106.87 (C(1)), 112.44, 114.61,
115.61, 118.39, 123.65, 124.48, 126.39, 126.67, 127.47, 128.52,
129.24, 134.1, 151.62, 152.68, 154.61, 155.99 (C@NOH). Anal. calcd
for C20H19NO4: C, 71.20; H, 5.68; N, 4.15; found: C, 70.80; H, 5.69;
N, 4.10.
5.1.25. (Z)-2-(Naphthalen-2-yloxy)-1-(4-(trifluoromethyl)phe-
nyl)ethanone oxime (13f)
From 2-(naphthalen-2-yloxy)-1-(4-(trifluoromethyl)phenyl)-
ethanone (9f) as described for 10: 66% yield. Mp: 131–132 °C;
1H NMR (400 MHz, DMSO-d6): 5.42 (s, 2H, OCH2), 7.10 (dd,
J = 2.4, 8.8 Hz, 1H-C(3)), 7.38 (dd, J = 1.2, 1.2 Hz, 1H-(C1)),
7.43–7.50 (m, 2H, Ar-H), 7.75–7.84 (m, 5H, Ar-H), 7.91 (d,
J = 8.4 Hz, 2H, Ar-H), 12.34 (s, 1H-NOH); 13C NMR (400 MHz,
DMSO-d6): d 58.75 (CH2O), 107.01 (C(1)), 118.38, 123.91, 125.25,
125.29, 125.32, 126.59, 126.76, 127.20, 127.60, 128.75, 129.51,
134.13, 138.29, 152.1, 155.66 (C@NOH). Anal. calcd for
5.2. Pharmacological methods
Materials: The antibody against p-Nrf2-S40 was purchased from
Abcam (Cambridge, UK). The Nrf2 and actin antibodies were
obtained from Santa Cruz Biotechnology (Dallas, Texas). Human
T-cell leukemia (Jurkat) and non-small cell lung carcinoma (NCI-
H226) cell lines were obtained from the American Type Culture
Collection (Rockville, MD). A nasopharyngeal carcinoma (NPC-
TW01) cell line was purchased from the Taiwan Food Industry
Research and Development Institute, Hsinchu, Taiwan, Republic
of China. All cells were grown in minimum essential medium
(MEM) or RPMI1640 medium (Invitrogen) containing 10% fetal
C19H14F3NO2: C, 66.09; H, 4.09; N, 4.06; found: C, 66.20; H, 4.43;
N, 4.06.
5.1.26. (Z)-1-(Biphenyl-4-yl)-2-(naphthalen-2-yloxy)ethanone
oxime (13g)
bovine serum (FBS) (Thermo), 100 units/ml penicillin, 100
lg/ml
From 1-(biphenyl-4-yl)-2-(naphthalen-2-yloxy)ethanone (9g)
as described for 10: 64% yield. Mp: 183–184 °C; 1H NMR
(400 MHz, DMSO-d6): d 5.41 (s, 2H, OCH2), 7.14 (dd, J = 2.4,
8.8 Hz, 1H-C(3)), 7.34–7.40 (m, 2H, Ar-H), 7.45–7.50 (m, 4H, Ar-
H), 7.68–7.71 (m, 4H, Ar-H), 7.78–7.84 (m, 5H, Ar-H), 12.05 (s,
1H-NOH); 13C NMR (400 MHz, DMSO-d6): d 58.75 (CH2O), 106.96
(C(1)), 118.46, 123.83, 126.55, 126.62, 126.74, 126.94, 127.58,
127.73, 128.70, 129.02, 129.46, 133.40, 134.18, 139.45, 140.52,
152.48, 155.87 (C@NOH). Anal. calcd for C24H19NO2: C, 81.56; H,
5.42; N, 3.96; found: C, 81.73; H, 5.42; N, 3.97.
streptomycin, 2 mM -glutamine and 1 mM sodium pyruvate
(Invitrogen) and were cultured in a humidified incubator with 5%
CO2 set at 37 °C.
L
5.2.1. Cell viability
MTT assay was employed to determine the cell viability.
Treated cells were incubated with MEM with 5 lg/ml MTT for
2 h at 37 °C. Afterward, the cells were further incubated with sol-
ubilization buffer (40% DMF and 20% SDS in H2O) overnight at
37 °C. The absorbance at 570 nm was then detected by a micro-
plate reader (Molecular Device).
5.1.27. (Z)-1-(Naphthalen-2-yl)-2-(naphthalen-2-yloxy)ethanone
oxime (13h)
5.2.2. Establishment of ARE-luciferase expressing cells
The antioxidant-responsive element reporter plasmids (pGL4-
ARE9) were kindly provided by Dr. Ching-Chuan Kuo (National
From
1-(naphthalen-2-yloxy)-2-(naphthalen-2-yl)ethanone
(9h) as described for 10: 77% yield. Mp: 143–144 °C; 1H NMR
Please cite this article in press as: Chang, K.-M.; et al. Bioorg. Med. Chem. (2015), http://dx.doi.org/10.1016/j.bmc.2015.03.046

8
K.-M. Chang et al. / Bioorg. Med. Chem. xxx (2015) xxx–xxx
Health Research Institutes, Tainan, Taiwan). NPC-TW01 or HONE-1
cells were electroporated with pGL4-ARE9 plasmids by electro-
porator (Thermo Electron Corp.). Subsequently, electroporated
cells were maintained in completed MEM in the presence of
1 mg/ml G418 (Gibco) for at least four weeks. Single clones were
then isolated and grown for further studies.
subjected to flowcytometry analysis on a Canto II cytometer. The
acquired data was finally evaluated by the FCS express software.
Acknowledgment
Financial supports of this work by the Ministry of Science and
Technology of the Republic of China, KMU-TP103H06, KMU-
TP103H07, and KMU-TP103H08 are gratefully acknowledged.
5.2.3. Luciferase activity assay
Cells (1 ꢁ 106 cells/well) were seeded into 12-well plates and
incubated overnight, followed by drug treatment for additional
16 h. Treated cells were trypsinized and collected by centrifugation
at 300ꢁg for 10 min. Samples were then lyzed with lysis buffer (1%
Triton X-100, 25 mM glycylglycine, 15 mM MgSO4, 4 mM EGTA
and 1 mM DTT) and centrifuged at 15000ꢁg for 10 min. Finally,
the supernatants were mixed with luciferase assay buffer
(25 mM glycylglycine, 15 mM potassium phosphate, 15 mM
MgSO4, 4 mM EGTA, 2 mM ATP and 1 mM DTT) and luciferin solu-
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pH 8.0, 0.5% NP-40, 1 mM PMSF, 1 mM NaF, 1 mM Na3VO4 and
20
each sample was measured by a BCA protein assay kit (Thermo).
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lg/ml aprotinin in distilled H2O) and protein concentration of
l
and then transferred to PVDF membranes. After blocking with 5%
BSA/TBS-Tween, the membranes were reacted with primary
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To detect the level of intracellular oxidative stress, control and
treated cells were incubated with 20 l
M of DCFH-DA (20,70-
dichlorodihydrofluorescein diacetate) for 30 min. at 37 °C prior to
analysis. Cells were harvested and re-suspended in 1 ꢁ PBS and
Please cite this article in press as: Chang, K.-M.; et al. Bioorg. Med. Chem. (2015), http://dx.doi.org/10.1016/j.bmc.2015.03.046