Synthesis, biological evaluation and molecular docking of calix[4]arene-based β-diketo derivatives as HIV-1 integrase inhibitors

Article abstract of DOI:10.1002/ardp.201400390

In this publication, we design and report the synthesis of calix[4]arene-based β-diketo derivatives as novel HIV-1 integrase (IN) inhibitors. The target compounds were obtained using Claisen condensation, and their structures were characterized by NMR and

Full text of DOI:10.1002/ardp.201400390

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Arch. Pharm. Chem. Life Sci. 2015, 348, 1–8
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Full Paper
Synthesis, Biological Evaluation and Molecular Docking of
Calix[4]arene-Based b-Diketo Derivatives as HIV-1 Integrase
Inhibitors
1
1
1
2
2
2
3
Zaigang Luo , Yu Zhao , Chao Ma , Zhipeng Li , Xuemei Xu , Liming Hu , Nianyu Huang ,
4
and Hongqiu He
1
College of Chemical Engineering, AnHui University of Science & Technology, Huainan, P. R. China
College of Life Sciences and Bioengineering, Beijing University of Technology, Beijing, P. R. China
College of Chemistry and Life Sciences, China Three Gorges University, Yichang, P. R. China
Chongqing Academy of Science and Technology, Chongqing, P. R. China
2
3
4
In this publication, we design and report the synthesis of calix[4]arene-based b-diketo derivatives as novel
HIV-1 integrase (IN) inhibitors. The target compounds were obtained using Claisen condensation, and
their structures were characterized by NMR and ESI-MS. Preliminary bioassays showed that calix[4]arene-
based b-diketo derivatives inhibit strand transfer (ST) with IC50 values between 5.9 and 21.2 mM. Docking
studies revealed the predominant binding modes that were distinct from the binding modes of
raltegravir, which suggests a novel binding region in the IN active site. Moreover, these compounds are
predicted not to interact with some of the key amino acids (GLN148 and ASN155) implicated in viral
resistance. Therefore, this series of compounds can further be investigated for a possible chemotype to
circumvent resistance to clinical HIV-1 IN inhibitors.
Keywords: Calix[4]arene / b-Diketo derivatives / HIV-1 integrase inhibitors / Molecular docking /
Synthesis
Received: October 22, 2014; Revised: December 30, 2014; Accepted: January 6, 2015
DOI 10.1002/ardp.201400390
Additional supporting information may be found in the online version of this article at the publisher’s web-site.
:
Over the last two decades, numerous small-molecule HIV-1
integrase inhibitors have been described, the most predomi-
Introduction
HIV-1 integrase (IN), which inserts a double-stranded DNA
copy of the viral RNA genome into the chromosomes of an
infected cell through a multi-step process that involves
nant class of inhibitors being the diketo acids (DKAs) [3],
and the DKA moiety was believed to be the most crucial
pharmacophore for the inhibition of IN inhibitors [4]. It is
believed that their IN-binding mechanism is connected to
the presence of DKA pharmacophoric motif which could
be involved in a functional sequestration of one or both
divalent metal ions in the enzyme catalytic site to form a
ligand–M –IN complex. This would subsequently block the
transition state of the IN–DNA complex by competing with
the target DNA substrate [5]. Raltegravir, elvitegravir, and
dolutegravir, optimized from the initial DKA pharmacophore,
were believed to inhibit IN function at the strand transfer
stage by a similar mechanism [6]. However, the partial cross-
resistance with raltegravir and elvitegravir has been already
found for this compound [7, 8]. Dolutegravir, a second
generation integrase strand transfer inhibitor, displays
superior characteristics to raltegravir, but partially shares
0
0
3
-processing (3 -P) and strand transfer (ST) or integration,
is an essential enzyme necessary for the replication of the HIV
virus [1]. Since IN has no homologue in human cells, it has
been recognized as a promising target that were exemplified
by the FDA approved HIV-1 IN inhibitors (raltegravir,
elvitegravir, and dolutegravir) and those under advanced
clinical trials [2].
2
þ
Correspondence: Dr. Zaigang Luo, College of Chemical Engi-
neering, AnHui University of Science & Technology, Huainan
2
32001, P. R. China.
E-mail: luozi139@163.com
Fax: þ86-554-6668485
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the resistance pathways [9]. Due to the limited chemical space
available for designing inhibitors of the catalytic activity of
IN inevitable overlap of resistance for second generation
integrase strand transfer inhibitors is likely [10]. Thus, it is
imperative to design new chemical classes as new generation
HIV-1 integrase inhibitors possessing novel mechanism of
action that not only have potent inhibitory activities, but
also have the potential to circumvent the viral resistance to
present IN inhibitors.
activities against HIV-1. It may be helpful to understand the
mechanism of this novel class of IN inhibitors. Furthermore, to
gain understanding of the binding mode at the IN active site
and provide insights for further structure-based drug design,
molecular docking study was performed on the selected
molecules, Ig and 4i.
Results and discussion
As assessed by recent reviews [11, 12], calixarenes have been
given special attention as new molecular platform for the
design and development of new drugs. Many pharmacologi-
cal properties are described for calixarenes (such as antiviral,
antibacterial, anticancer) [12]. Anti-HIV activity of calixarene
derivatives has been initially reported by Hwang et al. [11, 12].
Subsequently, calixarene derivatives were described as
inhibitors of fusion, integrase, and protease enzyme in HIV
infection [11, 12]. Also, few investigations of calixarenes as
new chemical entities with distinct anti-HIV activities have
been made [13, 14]. However, the mechanism of inhibition of
HIV activity of the calixarene derivatives is not clear until now.
Taking into consideration the above facts, we recently used
the calix[4]arene skeleton as a platform to design a new class
of integrase inhibitors Ia–h (Fig. 1) [15]. Compounds Ie–h were
active toward IN strand transfer reaction (Ie: ST, IC50 ¼ 7.4 mM;
If: ST, IC50 ¼ 8.8 mM; Ig: ST, IC50 ¼ 6.1 mM; Ih: ST, IC50 ¼ 10.9 mM,
respectively), while Ia–d showed no activities. In order to
investigate whether the 1,2,3-triazole moieties of Ia–h play an
important role in the ST assay or not, therefore, in the present
study, we design and synthesize another series of novel
calix[4]arene derivatives 4a–j (Fig. 1) incorporating two b-
diketo subunits disposed in alternate position at the lower
rim, which have simplified structures by deleting 1,2,3-triazole
moieties compared with Ia–h, and evaluate their anti-IN
Chemistry
Depicted in Scheme 1 is our synthetic route developed to
allow for efficient introduction of b-diketo moieties on the
calix[4]arene skeleton toward the end of the synthesis. The
synthesis of inhibitors 4a–j starts with treatment of tert-
butylcalix[4]arene 1a and calix[4]arene 1b [16] with ethyl
bromoacetate in DMF to obtain the intermediates 2a and
2b [17]. Then, compounds 2a and 2b underwent Claisen
condensation with a range of acetophenones 3a–e to afford
the tert-butylcalix[4]arene-based b-diketo derivatives 4a–e
and calix[4]arene-based b-diketo derivatives 4f–j in the
alkaline medium (NaH) with a moderate yield (42–71%).
The new compounds have been characterized by
a
1
13
combination of H NMR, C NMR, and MS (ESI). The NMR
spectra of the title compounds revealed that both the tert-
butylcalix[4]arene and calix[4]arene moieties maintain the
cone conformation [18, 19]. The bridging methylene groups
of 4a–j exhibit two sets of doublets (absorptions of the
doublets near d 3.5 and 4.3 ppm, J ¼ 13.2 Hz for ArCH
2
Ar
1
13
protons) in their H NMR spectra. And in the C NMR spectra,
the methylene carbon appears as one signal (absorption near
2
31 ppm for methylene carbon of ArCH Ar). The chemical shift
values are close to those reported for other calix[4]arene
molecules in the same conformation [20, 21]. Meanwhile, the
Figure 1. Design of novel calix[4]arene-based b-diketo derivatives as IN inhibitors.
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2 2
Scheme 1. Reagents and conditions: (i) BrCH COOEt, K CO3, DMF, 60–80°C; (ii) NaH, THF, reflux.
b-diketo moiety possess enol-keto tautomerism and the enol
configuration is usually the main configuration in the CDCl
solvent [22]. From the NMR spectra, the enol configuration of
the b-diketo moieties of 4a–j was also observed in CDCl . This
3
and 4j with an electron-donating OCH group on the phenyl
3
ring (ST, IC50 ¼ 21.2 mM). While 4g, with Cl substitution on the
phenyl ring, showed the best anti-IN activities. This observa-
tions somewhat indicate that such substitution has no notable
impact on their activities. Compared with the slightly
different inhibition activities between Ie–h (ST, IC50 ¼ 6.1–
10.9 mM) and 4f–j (ST, IC50 ¼ 5.9–21.2 mM), the 1,2,3-triazole
moieties existing in the skeleton of calix[4]arene derivatives
of Ie–h maybe do not play an important role in the ST assay.
3
1
was readily proved by their H NMR (absorption near 7.5 ppm
for the methylene proton of the b-diketo moiety) and
13
C NMR spectra (absorption for the methylene carbon of
the b-diketo moiety near 97 ppm), respectively.
Biological evaluation
The inhibition effects of the calix[4]arene derivatives 4a–j
were measured by an HIV-1 integrase strand transfer activity
assay, which was carried out as described previously [23]. As
shown in Table 1, p-tert-butylcalix[4]arene derivatives 4a–e
proved to be inactive in the ST assay, but the calix[4]arene
derivatives 4f–j exhibit activities at low micromolar concen-
trations (ST, IC50 ¼ 5.9–21.2 mM). In comparing the potencies
of 4f–j and 4a–e in the ST assay, it was seen that removal of the
tert-butyl groups at the upper rim of calix[4]arene in 4a–e
gave 4f–j improved IN inhibition activities. The most potent
derivative is 4g, which IC50 value for strand transfer is 5.9 mM.
This experimental observation seems to indicate that the
bulky tert-butyl groups of 4a–e show reduced combination
ability with integrase comparable to H atoms at the upper rim
of calix[4]arene, which is similar to the p-tert-butylcalix[4]-
arene derivatives Ia–d in our previous study [15].
Molecular docking
In order to explore the binding mode of these compounds
against the catalytic active site of IN, a docking study of the
Table 1. Inhibition of HIV-1 integrase strand transfer
a)
catalytic activities .
1
2
b)
Compounds
R
R
IC50 (mM)
4
4
4
4
4e
4f
a
b
c
t-Bu
t-Bu
t-Bu
t-Bu
t-Bu
H
H
Cl
F
CH
À c
À c
À c
d
3
À c
OCH3
À c
H
Cl
F
CH
OCH
16.3
5.9
4g
H
H
H
H
4
4
4
h
i
j
13.4
13.1
21.2
0.86
Moreover, in order to investigate the substituent effect
on the phenyl ring adjacent to b-diketo moiety, electron-
donating and electron-withdrawing groups were utilized
3
3
Raltegravir
(
4a–j). Interestingly, the IC50 values of 4h with an electron-
withdrawing F atom on the phenyl ring (ST, IC50 ¼ 13.4 mM)
and 4i with an electron-donating CH group on the phenyl
À c indicates that the HIV-IN inhibitory effect was less than
0% at the initial concentration (50 mM).
3
5
a)
ring (ST, IC50 ¼ 13.1 mM) are almost equal to each other. And
the similar inhibition activities are also exhibited between 4f
with no substitution on the phenyl ring (ST, IC50 ¼ 16.3 mM)
HIV-1 IN inhibitory activities were measured according to the
procedure described [23].
Inhibition of strand transfer.
b)
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compounds Ig and 4i was performed using AutoDock 4.2
software package and the aid of the AutoDock Tools [24]. The
X-ray structure of prototypic foamy virus integrase (PFV-IN)
2þ
with DNA and two Mg ions (PDB: 3OYA) was selected for
the docking study since it has been demonstrated that PFV IN
is a good model for the development of HIV-1 IN inhib-
itors [25]. Moreover, the secondary structures of the HIV-1 IN
catalytic core domain and PFV IN have a high similarity with
calculated root-mean square deviations [25, 26]. Raltegravir
was also re-docked into the X-ray structure of 3OYA in order
to validate the docking protocol, and the docking results are
shown in Figs. 2 and 3.
Fig. 2a, b, and c depict the binding of raltegravir, Ig and 4i
in the active site, respectively. The docking poses of raltegravir
showed a similar binding mode with the X-ray position
(
Fig. 2a) [25]. The p-fluorobenzyl group and the oxadiazole
ring of raltegravir were accommodated at the hydrophobic
Figure 3. Interactions of compounds raltegravir (a), Ig (b) and 4i
(
c) with catalytic residues of PFV IN. Intermolecular and
intramolecular hydrogen bond interactions were displayed by
green dash line; hydrophobic interactions were displayed
by pink dash line; the interactions between magnesium and
oxygen of inhibitor were displayed by gray dash line. The green
ball represents Mg . Drug atoms are colored: gray, C; blue,
N; green, F; red, O.
Figure 2. The best docking position of raltegravir, Ig and 4i in
2
þ
the active site of PFV IN. The green ball represents Mg ; (a) the
gray stick represents the docking position of raltegravir; (b) the
gold stick represents the docking position of Ig; (c) the light
purple stick represents the docking position of 4i. Drug atoms
are colored: purple and gray, C; blue, N; green, F; red, O.
2þ
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cavity, and the pyrimidone ring of raltegravir formed metal
of Ig and 4i is just formed metal chelation partially with the
two Mg ions and do not interact with other amino acid
2þ
2þ
chelation with the two Mg ions. The macrocyclic skeleton of
calix[4]arene of Ig and 4i could occupy the hydrophobic cavity
of the catalytic core region of IN (Fig. 2a and b). Obviously,
one of the triazolyl b-diketo arms of Ig formed metal
residues in the docking simulation, which has a different
binding behavior compared with the pyrimidone ring of
raltegravir. And the other b-diketo arm of compound 4i was
accommodated at a new hydrophobic cavity, which no groups
of raltegravir interact with it. Common integrase strand
transfer inhibitors resistance pathways involve mutations of
HIV-1 IN GLN148 or ASN155, which correspond to PFV IN
residues SER217 and ASN224, respectively [25]. Obviously, the
compounds Ig and 4i are predicted not to interact significantly
with these key amino acids (GLN148 and ASN155) implicated
in viral resistance in the docking studies [7, 8], which may be
active toward IN strand transfer inhibitor resistant viral
strains.
Clearly, the similar anti-IN activities between calix[4]arene
derivatives Ia–h with triazolyl b-diketo arms and 4a–j with b-
diketo arms are very interesting, though these structures of
Ia–h and 4a–j are much more complicated than the structure
of raltegravir. In the docking study, the binding modes of
these novel calix[4]arene derivatives Ig and 4i are also similar
to each other, but they have a different binding behavior
distinguish with raltegravir. Based on the biological and
virtual docking results, calix[4]arene derivatives incorporating
two proper bi-substituted arms disposed in alternate positions
at the lower rim maybe enhance the anti-IN activities.
2
þ
chelation with the two Mg
1
ions, but the nitrogen of
2þ
,2,3-triazole moiety did not chelate with the Mg ions. The
distortion of the other triazolyl b-diketo arm of Ig was also
observed, thus it was not accommodated at the hydrophobic
cavity in the IN active site (Fig. 2b). In Fig. 2c, one of the
b-diketo arms of 4i could dock into the hydrophobic cavity of
the catalytic core region of IN, and the other b-diketo arm
2þ
partially chelated with one of the two Mg ions, for the
b-diketo moieties are not at the same side, that is not coplane.
Fig. 3a, b, and c show the binding interactions of raltegravir,
Ig and 4i with PFV IN. In Fig. 3a, The p-fluorobenzyl group of
raltegravir interacts with DC16 via p–p interaction. And the
oxadiazole ring of raltegravir interacts with IN amino acid
residue TYR212 via p–p interaction and hydrogen bond
interaction. The pyrimidone ring of raltegravir plays an
important role, which formed metal chelation with the two
2þ
Mg ions and interacted with DA17 via p–p interactions and
IN amino acid residue ASP128 via hydrogen bond interactions.
The macrocyclic skeleton of calix[4]arene moiety of Ig and 4i
may be fit for occupying the hydrophobic cavity and interact
with TYR212 and PRO214 via p–p interactions. The poor
inhibitory activities of compounds Ia–d and 4a–e probably
attribute to the bulky tert-butyl groups, which probably
prevent the macrocyclic skeleton of tert-butylcalix[4]arene
moiety from entering into the same hydrophobic cavity
region.
Conclusions
In summary, a series of calix[4]arene derivatives incorporating
two b-diketo subunits disposed in alternate positions at
the lower rim were synthesized and evaluated as HIV-1
integrase inhibitors. In general, compounds 4f–j were active
against the ST catalytic step, while the tert-butyl groups at the
upper rim of calix[4]arene have an negative effect on inhibiting
HIV-1 integrase ST reaction. Compared with the inhibition
activities between our previous and current studies, the 1,2,3-
triazole moiety maybe do not play an important role in the ST
assay. Docking studies suggest that the macrocyclic skeletons of
calix[4]arene moiety of the compounds Ig and 4i bind to the
hydrophobic cavity in the IN active site. In particular, one of the
b-diketo arms of compound 4i dock into the hydrophobic cavity
formed by IN amino acid residues, which is different from
raltegravir binding behavior. Furthermore, no contacts with
two of the most critical residues implicated in viral resistance,
GLN148 and ASN155, were observed. This series of compounds
could be further optimized to develop agents to overcome viral
resistance against currently used HIV-1 IN inhibitors.
In Fig. 3b, the oxygen of the distorted triazolyl b-diketo arm
of Ig interacts with IN amino acid residue ALA188 via hydrogen
bond interaction. Clearly, the oxygens of the other triazolyl
2þ
b-diketo arm of Ig formed metal chelation with the two Mg
ions and interacts with IN amino acid residue GLU221 via
hydrogen bond interaction. And the 1,2,3-triazole moiety
interacts with PRO214 via C–H–p and p–p interactions.
In Fig 3c, the 4-methylphenyl group of one of the b-diketo
arms of 4i was accommodated at the hydrophobic cavity
formed by IN amino acid residues ALA188, ALA189, PHE190,
PRO161, and TYR129 with multiple C–H–p and p–p inter-
actions, while raltegravir dose not have any interactions in
such hydrophobic cavity region [25]. Also, the 4-methylphenyl
group of the other b-diketo arm of compound 4i interacts
with PRO214 and viral DNA via C–H–p and p–p interactions.
Such interactions may result in that the b-diketo moiety or
triazolyl b-diketo moiety are not coplane and lead to form
2þ
partially metal chelation with the two Mg ions.
The docking results reveal that the binding modes of these
novel calix[4]arene derivatives Ig and 4i are different from
the mechanism of action of the DKAs IN inhibitors raltegravir
Experimental
[
5, 25]. The macrocyclic skeleton of calix[4]arene moiety of Ig
and 4i may be fit for occupying the hydrophobic cavity and
interact both with TYR212 and PRO214. While, raltegravir has
no interaction with PRO214. One of the DKA pharmacophores
Chemistry
Unless otherwise noted, all materials were obtained from
commercial suppliers and dried and purified by standard
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procedures. The melting point was measured on an SGW X-4
monocular microscope melting point apparatus with ther-
mometer unadjusted. H NMR and C NMR spectra were
acquired on a Bruker Avance III 400 MHz spectrometer with
J ¼ 8.4 Hz), 7.15 (4H, s), 7.28 (2H, s), 7.56 (2H, s), 7.92–7.95 (4H,
1
3
3
m), 15.43 (2H, s); C NMR (100 MHz, CDCl ) d 190.9, 183.0,
1
13
150.3, 148.8, 148.2, 142.6, 132.2, 130.2, 130.1, 127.7, 126.0,
125.4, 115.5, 115.3, 93.8, 34.1, 33.9, 31.7, 31.5, 30.9; ESI-MS
–
CDCl
3
as the solvent and tetramethylsilane (TMS) as the
(m/z): 1003.6 (M–H) .
internal standard. The chemical shifts were reported in d (ppm).
Mass spectra (MS) data were obtained using Esquire 6000 mass
spectrometer.
25,27-Bis[(Z)-4-(p-methylphenyl)-4-hydroxybut-3-en-2-
one-1-methyl]-26,28-dihydroxy-5,11,17,23-tert-
butylcalix[4]arene 4d
1
General methods for preparing compounds 4a–j
White powder, 43% yield; mp: 185–188°C; H NMR (400 MHz,
To a suspension of sodium hydride (60% dispersion in oil)
3
CDCl ) d 0.94 (18H, s), 1.32 (18H, s), 2.42 (6H, s), 3.42 (4H, d,
(
30 mmol) in dry THF (10 mL) was slowly added a range
of acetophenones 3a–e (22 mmol) in dry THF (10 mL) at
°C and the mixture was stirred for 10 min. After that,
J ¼ 13.2 Hz), 4.33 (4H, d, J ¼ 13.2 Hz), 4.56 (4H, s), 6.83 (4H, s),
7.11–7.15 (8H, m), 7.19 (2H, s), 7.48 (2H, s), 7.75 (4H, d,
1
3
0
J ¼ 8.4 Hz), 15.49 (2H, s); C NMR (100 MHz, CDCl
3
) d 191.1,
compound 2a or 2b (10 mmol) in dry THF (15 mL) was
added to the above solution at 0°C and then the reaction
mixture was slowly heated to refluxing for about 90 min
with stirring till TLC confirmed that the reaction had
finished. And then the cooled mixture was poured into a
mixture of ice-water (20 mL) and concentrated HCl (5 mL),
extracted with EtOAc and purified by flash chromatogra-
phy on silica gel eluting with petroleum ether/ethyl acetate
184.0, 150.4, 149.0, 148.0, 143.6, 142.3, 132.2, 131.2, 128.8,
127.8, 125.9, 125.3, 93.7, 34.0, 33.9, 31.7, 31.4, 30.9,21.8;
–
ESI-MS (m/z): 995.7 (M–H) .
25,27-Bis[(Z)-4-(p-methoxyphenyl)-4-hydroxybut-3-en-2-
one-1-methyl]-26,28-dihydroxy-5,11,17,23-tert-
butylcalix[4]arene 4e
1
White powder, 61% yield; mp: 144–147°C; H NMR (400 MHz,
(
15:1 to 8:1).
CDCl
3
) d 0.94 (18H, s), 1.32 (18H, s), 3.43 (4H, d, J ¼ 13.2 Hz),
1
13
The H NMR, C NMR, and MS (ESI) spectra of 4a–j are
provided online as Supporting Information.
3.89 (6H, s), 4.33 (4H, d, J ¼ 13.2 Hz), 4.57 (4H, s), 6.80–6.82 (8H,
m), 7.14 (4H, s), 7.20 (2H, s), 7.46 (2H, s), 7.83 (4H, d, J ¼ 8.4 Hz),
1
3
1
3
5.68 (2H, s); C NMR (100 MHz, CDCl ) d 189.8, 184.2, 163.4,
2
5,27-Bis[(Z)-4-phenyl-4-hydroxybut-3-en-2-one-1-
150.5, 148.9, 147.9, 142.3, 132.2, 129.8, 127.8, 126.5, 125.9,
125.3, 113.5, 93.3, 55.6, 34.0, 33.9, 31.7, 31.5, 30.9; ESI-MS
(m/z): 1027.5 (M–H) .
methyl]-26,28-dihydroxy-5,11,17,23-tert-butylcalix[4]-
arene 4a
White powder, 58% yield; mp: 198–200°C; H NMR (400 MHz,
–
1
CDCl
3
) d 0.95 (18H, s), 1.31 (18H, s), 3.42 (4H, d, J ¼ 13.2 Hz),
25,27-Bis[(Z)-4-phenyl-4-hydroxybut-3-en-2-one-1-
4
7
.30 (4H, d, J ¼ 13.2 Hz), 4.55 (4H, s), 6.83 (4H, s), 7.13 (4H, s),
.29 (2H, s), 7.35 (4H, t, J ¼ 7.6 Hz), 7.50 (2H, t, J ¼ 7.6 Hz), 7.58
methyl]-26,28-dihydroxy-calix[4]arene 4f
1
White powder, 58% yield; mp: 201–203°C; H NMR (400 MHz,
13
(
2H, s), 7.88 (4H, d, J ¼ 7.6 Hz), 15.34 (2H, s); C NMR (100 MHz,
CDCl
3
) d 3.51 (4H, d, J ¼ 13.2 Hz), 4.33 (4H, d, J ¼ 13.2 Hz), 4.52
CDCl
3
) d 192.1, 183.3, 150.4, 148.9, 147.9, 142.3, 133.7, 132.7,
(4H, s), 6.73–6.81 (4H, m), 6.94 (4H, d, J ¼ 7.6 Hz), 7.14 (4H, d,
J ¼ 7.6 Hz), 7.39 (4H, t, J ¼ 7.6 Hz), 7.52 (2H, t, J ¼ 7.2 Hz), 7.63
(2H, s), 7.84 (2H, s), 7.93 (4H, d, J ¼ 7.2 Hz), 15.25 (2H, s);
1
3
32.2, 128.1, 127.7, 127.6, 125.9, 125.2, 94.1, 34.0, 33.9, 31.7,
1.5, 30.9; ESI-MS (m/z): 991.4 (MþNa) .
þ
1
3
3
C NMR (100 MHz, CDCl ) d 191.6, 183.3, 152.9, 151.2, 134.0,
2
5,27-Bis[(Z)-4-(p-chlorophenyl)-4-hydroxybut-3-en-2-
132.8, 132.6, 129.5, 128.9, 128.2, 127.8, 127.5, 126.3, 119.8,
94.2, 31.4; ESI-MS (m/z): 767.1 (MþNa) .
þ
one-1-methyl]-26,28-dihydroxy-5,11,17,23-tert-
butylcalix[4]arene 4b
White powder, 71% yield; mp: 188–190°C; H NMR (400 MHz,
1
25,27-Bis[(Z)-4-(p-chlorophenyl)-4-hydroxybut-3-en-2-
CDCl
3
) d 0.96 (18H, s), 1.33 (18H, s), 3.44 (4H, d, J ¼ 13.2 Hz),
one-1-methyl]-26,28-dihydroxy-calix[4]arene 4g
White powder, 62% yield; mp: 177–180°C; H NMR (400 MHz,
1
4
7
.30 (4H, d, J ¼ 13.2 Hz), 4.58 (4H, s), 6.85 (4H, s), 7.15 (4H, s),
.22 (2H, s), 7.33 (4H, d, J ¼ 8.4 Hz), 7.55 (2H, s), 7.85 (4H, d,
CDCl
3
) d 3.53 (4H, d, J ¼ 13.2 Hz), 4.32 (4H, d, J ¼ 13.2 Hz), 4.56
13
J ¼ 8.4 Hz), 15.33 (2H, s); C NMR (100 MHz, CDCl
3
) d 191.7,
(4H, s), 6.75–6.83 (4H, m), 6.95 (4H, d, J ¼ 7.6 Hz), 7.15 (4H, d,
J ¼ 7.6 Hz), 7.36 (4H, d, J ¼ 8.4 Hz), 7.57 (2H, s), 7.76 (2H, s), 7.87
1
1
82.4, 150.2, 148.7, 148.1, 142.6, 139.1, 132.3, 132.1, 128.9,
28.5, 127.7, 125.9, 125.3, 94.0, 34.1, 33.9, 31.7, 31.5, 30.9;
1
3
(4H, d, J ¼ 8.4 Hz), 15.24 (2H, s); C NMR (100 MHz, CDCl
3
)
À
ESI-MS (m/z): 1035.5 (M–H) .
d 191.2, 182.5, 152.6, 151.0, 139.2, 132.7, 132.5, 129.6, 129.0,
28.8, 128.6, 127.8, 126.4, 120.0, 94.1, 31.4; ESI-MS (m/z): 811.3
1
–
2
5,27-Bis[(Z)-4-(p-fluorophenyl)-4-hydroxybut-3-en-2-
(M–H) .
one-1-methyl]-26,28-dihydroxy-5,11,17,23-tert-
butylcalix[4]arene 4c
Pink powder, 60% yield; mp: 202–204°C; H NMR (400 MHz,
25,27-Bis[(Z)-4-(p-fluorophenyl)-4-hydroxybut-3-en-2-
1
one-1-methyl]-26,28-dihydroxy-calix[4]arene 4h
1
CDCl
3
) d 0.96 (18H, s), 1.32 (18H, s), 3.44 (4H, d, J ¼ 13.2 Hz),
White powder, 66% yield; mp: 204–206°C; H NMR (400 MHz,
4
.31 (4H, d, J ¼ 13.2 Hz), 4.58 (4H, s), 6.86 (4H, s), 7.05 (4H, t,
CDCl
3
) d 3.52 (4H, d, J ¼ 13.2 Hz), 4.33 (4H, d, J ¼ 13.2 Hz),
ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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6

Arch. Pharm. Chem. Life Sci. 2015, 348, 1–8
Calix[4]arene-b-Diketo Derivatives as Integrase Inhibitors
ARCH PHARM
Archiv der Pharmazie
4
.55 (4H, s), 6.75–6.85 (4H, m), 6.96 (4H, d, J ¼ 7.6 Hz), 7.08
were generated by Discovery studio 4.0 (Accelrys Software,
Inc., Discovery Studio Modeling Environment, Release 4.0, San
Diego, CA).
(
(
4H, t, J ¼ 8.4 Hz), 7.15 (4H, d, J ¼ 8.4 Hz), 7.59 (2H, s), 7.81
13
2H, s), 7.95–7.99 (4H, m), 15.33 (2H, s); C NMR (100 MHz,
) d 190.4, 183.1, 152.8, 151.0, 132.7, 130.5, 130.1, 129.6,
28.9, 127.8, 126.4, 120.0, 115.6, 115.4, 93.9, 31.4; ESI-MS
CDCl
1
3
The authors gratefully thank the financial supports of the
Natural Science Foundation of China (Nos. 21102003,
–
(
m/z): 779.3 (M–H) .
2
1272020, 21102084, 81202438), Scientific Research Founda-
2
5,27-Bis[(Z)-4-(p-methylphenyl)-4-hydroxybut-3-en-2-
tion for the Introduction of Talent of AnHui University of
one-1-methyl]-26,28-dihydroxy-calix[4]arene 4i
White powder, 48% yield; mp: 199–201°C; H NMR (400 MHz,
Science & Technology.
1
CDCl
3
) d 2.43 (6H, s), 3.52 (4H, d, J ¼ 13.2 Hz), 4.35 (4H, d,
The authors have declared no conflict of interest.
J ¼ 13.2 Hz), 4.54 (4H, s), 6.74–6.83 (4H, m), 6.94 (4H, d,
J ¼ 7.6 Hz), 7.14 (4H, d, J ¼ 7.6 Hz), 7.17 (4H, d, J ¼ 8.4 Hz), 7.51
1
3
(
2H, s), 7.73 (2H, s), 7.78 (4H, d, J ¼ 8.4 Hz), 15.40 (2H, s);
C
References
3
NMR (100 MHz, CDCl ) d 190.7, 184.0, 153.1, 151.3, 143.7,
1
9
32.7, 131.3, 129.5, 129.0, 128.9, 127.8, 127.6, 126.2, 119.8,
3.8, 31.4, 21.8; ESI-MS (m/z): 771.3 (M–H) .
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þ
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