Design, synthesis and evaluation of N-hydroxypropenamides based on adamantane to overcome resistance in NSCLC

Article abstract of DOI:10.1016/j.bioorg.2019.02.047

A series of novel N-hydroxypropenamides containing adamantane moiety were identified and most of them exhibited HDAC inhibitory activity and could reverse the resistance of cisplatin in NSCLC cell lines. In this process, molecular docking was employed to verify the rationality of designing, subsequently, target compounds were synthesized and conducted to enzyme- and cell-based biological evaluation. Most of synthesized compounds could inhibit HDAC activity with the IC₅₀ values lower than 50 nM and result in the increase of Ac-H4 and p21 in A549 cells. Importantly, we assessed the reversal effect of those compounds and found several compounds display an anti-resistant effect in lung cancer cells, especially compound 8f. As compared to belinostat and cisplatin, compound 8f showed improved inhibitory activity against A549/CDDP cell lines with IC₅₀ value of 5.76 μM, and far lower resistance index of 1.24. Moreover, the structure–activity relationships of these compounds were summarized and compound 8f could serve as a research tool for identifying the mechanism of reversing resistance and a template for designing novel compounds to reverse cisplatin resistance.

Full text of DOI:10.1016/j.bioorg.2019.02.047

BioorganicChemistry86(2019)696–704
Contents lists available at ScienceDirect
Bioorganic Chemistry
journal homepage: www.elsevier.com/locate/bioorg
Design, synthesis and evaluation of N-hydroxypropenamides based on
adamantane to overcome resistance in NSCLC
Xuefei Baoa,1, Yuhong Sunb,c,1, Changshun Baoa, Jiayu Zhangb,c, Shenglan Zoua, Jingyu Yangb,c
,
⁎
⁎
Chunfu Wub,c, Lihui Wangb,c, , Guoliang Chena,
a Key Laboratory of Structure-Based Drugs Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang, PR China
b Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
c Benxi Institute of Pharmaceutical Research, Shenyang Pharmaceutical University, Shenyang, PR China
A R T I C L E I N F O
A B S T R A C T
Keywords:
A series of novel N-hydroxypropenamides containing adamantane moiety were identified and most of them
exhibited HDAC inhibitory activity and could reverse the resistance of cisplatin in NSCLC cell lines. In this
process, molecular docking was employed to verify the rationality of designing, subsequently, target compounds
were synthesized and conducted to enzyme- and cell-based biological evaluation. Most of synthesized com-
pounds could inhibit HDAC activity with the IC50 values lower than 50 nM and result in the increase of Ac-H4
and p21 in A549 cells. Importantly, we assessed the reversal effect of those compounds and found several
compounds display an anti-resistant effect in lung cancer cells, especially compound 8f.
HDAC
Cisplatin resistance
N-hydroxypropenamide
Molecular docking
Lung cancer
As compared to belinostat and cisplatin, compound 8f showed improved inhibitory activity against A549/
CDDP cell lines with IC50 value of 5.76 μM, and far lower resistance index of 1.24. Moreover, the structure–-
activity relationships of these compounds were summarized and compound 8f could serve as a research tool for
identifying the mechanism of reversing resistance and a template for designing novel compounds to reverse
cisplatin resistance.
1. Introduction
increased in cisplatin resistant NSCLC cells, suggesting targeting HDAC
might be a novel approach to reverse cisplatin resistance in NSCLC
Non-small cell lung cancer (NSCLC) is the major histologic subtype
of lung cancers which is the main cause of cancer-related death
worldwide [1]. Although molecular-targeted drugs made a great pro-
gress for the treatment of NSCLC in recent years, only patients with
specific genetic abnormality benefits from these drugs [2]. The standard
therapeutic approach for advanced NSCLC is still conventional cyto-
toxic drugs-based chemotherapy [3]. Cisplatin (CDDP) is one of the
first-line chemotherapeutic agents [4], however, the continuous ex-
posure to CDDP often results in the development of acquired multidrug
resistance (MDR) [5,6]. The resistance to CDDP can be caused by nu-
merous mechanisms, such as changes in cellular uptake, drug efflux,
increased detoxification, inhibition of apoptosis and increased DNA
repair [7,8].
[10]. In fact, the previous literature has verified that the inhibition of
HDAC might be a promising way to treat drug resistance. Belinostat, a
histone deacetylases (HDACs) inhibitor, was approved for the treatment
of refractory peripheral T-cell lymphoma [11]. It has been reported to
circumvent the resistance in NSCLC through inhibition of both ABCC2
and DNA repair-mediated mechanisms [12]. Meanwhile, in our pre-
vious work, SNOH-3 derived from belinostat could effectively reverse
paclitaxel resistance in non-small cell lung cancer via multiple me-
chanisms [13].
A widely accepted pharmacophore model for HDAC inhibitors
consists of a metal binding head group, a linker domain and a cap
group, which is a common group for modification [14]. Although a
large number of derivatives of belinostat were obtained, the caps of
them were almost all aromatic groups. Therefore, non-planar ada-
mantane moieties were employed to replace the terminal phenyl group
of belinostat, and the substituted pattern of phenyl linker is changed
Recently, several studies have shown that the aberrant epigenetic
regulations also play a crucial role in cisplatin resistance of NSCLC [9].
In our previous study, we demonstrated that HDAC activity was
⁎ Corresponding authors at: Key Laboratory of Structure-Based Drugs Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University,
Shenyang, PR China (G. Chen); Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China (L. Wang).
E-mail addresses: lhwang@syphu.edu.cn (L. Wang), spucgl@163.com (G. Chen).
1 These authors contributed equally to the work.
https://doi.org/10.1016/j.bioorg.2019.02.047
Received 7 September 2018; Received in revised form 19 February 2019; Accepted 21 February 2019
Availableonline22February2019
0045-2068/©2019ElsevierInc.Allrightsreserved.

X. Bao, et al.
BioorganicChemistry86(2019)696–704
H
N
O
O
S
S
OH
OH
O
N
H
O
OH
N
H
Belinostat
O
S
N
O
R2
O
R1
N
H
O
F3C
N
O
H
SNOH-3
Fig. 1. The design rationale for the final compounds.
from meta-position to para-position (Fig. 1). It was expected to in-
vestigate the influence of non-planar cap on inhibitory activity against
HDAC, and discovery novel compounds with potential capability to
reverse drug resistance in NSCLC. In this paper, we describe the results
obtained from the synthesis, docking modeling, enzyme- and cell-based
assay on these novel compounds.
2.2. Chemistry
The route adopted for the preparation of target compounds is de-
picted in Scheme 1. Cinnamic acid 1, as the starting material, was re-
acted with chlorosulfonic acid at 0 °C to furnish (E)-3-(4-(chlor-
osulfonyl)phenyl)acrylic acid 2, which was subsequently transformed
into methyl (E)-3-(4-(chlorosulfonyl)phenyl)acrylate 3 via reacting with
sulfoxide chloride then methanol. Compound 3 was reacted with the
corresponding primary amines to afford sulfonamide derivatives 4,
which were transformed into the alkylates 5 via reaction with dimethyl
sulfate or diethyl sulfate. Next, cinnamic acid derivatives 6 obtained
from 4 to 5 were reacted with sulfoxide chloride and then hydro-
xylamine protected by THP to afford the amide derivatives 7, and the N-
hydroxypropenamides 8 were obtained via deprotection. The structures
of target compounds 8 were characterized by 1H NMR, MS and HRMS.
As for the synthesis of intermediates 4, the appropriate base was
essential. Only a small amount of 4 was obtained via column chroma-
tography on silica gel when the reaction was conducted in the presence
of triethylamine. The yield of 4 was increased by replacing triethyla-
mine with pyridine. The amount of pyridine also influenced the yield of
products. When the amount of pyridine was less than 8 equiv, starting
material 3 could be detected by TLC analysis. Considering the large
amount of pyridine, we employed it as both solvent and acid binding
agent, which could improve the yield and simplify the work-up pro-
cedure. The next step was alkylation, which was influenced by solvent.
When the substrate was containing terminal phenyl group, satisfactory
result was obtained in acetone, while the result of substrate containing
2. Results and discussion
2.1. Molecular docking
The docking study revealed that belinostat and 8f could bind to the
same cavity of HDAC1 (PDB ID: 4BKX), with similar binding affinity of
−8.28 (XP GScore) and −7.68 (XP GScore), respectively (Fig. 2). The
hydroxamic acid group, attached with its aliphatic chain lying in the
channel, binds to the zinc atom at the bottom of this channel. There are
very similar interactions between the amino acid residues and hydro-
xamic acid groups of ligands. The ionization of hydroxamic acid groups
is favor to form salt bridge, which would stabilize the receptor-ligand
complex. However, the hydrogen bonds between belinostat and His178
is missing in terms of 8f, and the adamantane group of 8f is close to
hydrophobic pocket S, whereas the terminal phenyl of belinostat is
solvent exposure. The difference interactions caused by adamantane
group may produce different biological activities.
Fig. 2. Molecular docking 3D and 2D models of belinostat and 8f in HDAC1. (A) Docked image of belinostat (orange) and 8f (green) in the HDAC1 crystal structure
(PBD ID: 4BKX). (B) 2D binding model of belinostat with HDAC1. Hydrogen bonds are indicated with purple dashed arrow, pi–pi interaction is indicated with green
line, salt bridges is indicated with purple-red line, solvent exposure is indicated with shadow, colour lines around belinostat stand for the binding pocket and the
residues in colours nearby established the pocket. (C) 2D binding model of 8f with HDAC1. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
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BioorganicChemistry86(2019)696–704
Scheme 1. Synthesis of N-hydroxypropenamides incorporating adamantane moiety.
(NH) of sulfamide, while the signal disappeared when the (NH) was
alkylation. And two doublets (2H) were observed in the range of
7.84–7.55 ppm showing para-disubstituted pattern which is a char-
acteristic of phenyl group. Moreover, the characteristic signal of the
alkenyl protons exhibited two doublets at 7.53–7.50 ppm (1H) and
6.59–6.56 ppm (1H) corresponding to trans-alkene. In addition, the
signal of adamantane group appeared at 2.20–1.38 ppm.
Table 1
The inhibition of synthesized compounds on HDAC activity.
Compounds
IC50
SEM(nM)
Compounds
IC50
SEM(nM)
Belinostat
40.1
49.8
230.1
89.6
315.8
43.7
36.5
33.6
43.7
189.6
76.5
1.2
8k
8l
29. 2
42.8
43.4
46.8
81.2
35.9
29.2
51.3
39.6
519.7
0.5
0.9
0.6
0.9
2.1
2.4
2.8
4. 6
3.8
22.8
8a
8b
8c
8d
8e
8f
1.5
10.5
6.2
8m
8n
8o
8p
8q
8r
12.5
0.9
2.3. HDAC activity study
1.5
8g
8h
8i
1.2
4.3
8s
In order to assess the biological activity of the synthesized com-
pounds, we first measure the HDAC inhibitory action of those com-
pounds. The synthesized compounds could obviously inhibit the HDAC
activity with the IC50 values lower than 50 nM concentration. Among
them, 12 compounds, including 8a, 8e–h, 8k–8n, 8p, 8q, 8s exhibited a
similar inhibitory potential with positive compounds Belinostat
(Table 1). If the capping group of compounds is phenyl, the introduc-
tion of ethyl into the nitrogen would reduce HDAC inhibition activity
(8a and 8b, or 8c and 8d). But if the capping group is adamantane,
small substituents do not influence the HDAC inhibition activity (8e, 8f
and 8g). And Small substitutes on adamantane and substitution sites of
adamantane also have no significant effect on the HDAC inhibition
activity (Fig. 3).
11.6
3.6
8t
8j
terminal adamantane was poor. We postulated that the poor result
might be due to the stereospecific blockade of adamantane. we in-
vestigated the influence of the base, other strong bases, such as po-
tassium tert-butoxide and potassium hydroxide, also could not afford
satisfactory yields in acetone. Then we replaced acetone with acetoni-
trile to increase the operating temperature and an improved yield was
obtained.
The 1H NMR spectra represented two characteristic signal (1H) that
appeared as two broad singlets in the range of 10.89–9.15 ppm corre-
sponding to the (OH) and (NH) of N-hydroxypropenamide. Another
singlet signal appeared at 7.59–7.88 ppm (1H) corresponding to the
Furthermore, we evaluated the synthesized compounds on the ex-
pression of Ac-H4, which is considered as direct substrate of HDAC, in
A549 cells. Western blot data showed that most of these compounds
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BioorganicChemistry86(2019)696–704
Fig. 3. Structure-activity relationship of compounds according their HDAC inhibition activity.
Fig. 4. Expression of Acetylated Histone 4 and target protein p21 in A549 cells after treated with various compounds. A. The expression level of Acetylated Histone
4(Ac-H4) was detected by western blot. Histone4 was used as loading control. B. The expression level of p21, a HDAC target gene, was detected by western blot and
integrated optical density was shown. Actin was used as loading control.
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Table 2
Cytotoxicity against several NSCLC cell lines and resistance index of synthesized compounds.
Compd.
Antiproliferative activity IC50
SEM (μM) and Resistance index for each cisplatin resistance NSCLC cells
A549
A549/CDDP
RI*
NCI-H1299
NCI-H1299/CDDP
RI
NCI-H460
NCI-H460/CDDP
RI
8a
8b
8c
8d
8e
8f
0.40
2.59
1.95
3.73
3.10
4.64
5.32
0.95
22.13
9.77
1.37
7.89
4.46
2.76
6.83
7.95
2.08
13.75
6.26
12.59
0.24
2.33
0.03
1.03
0.43
1.01
0.15
1.15
1.51
0.27
7.60
14.46
20.22
23.83
9.60
5.76
7.94
9.73
32.31
9.86
8.40
7.08
13.09
7.96
9.35
9.09
9.40
8.98
9.23
40.96
8.85
16.86
1.02
19.00
5.58
10.37
6.39
3.10
1.24
1.49
10.24
1.46
1.01
6.13
0.90
2.93
2.88
1.37
1.14
4.52
0.65
1.47
3.25
36.88
8.46
10.15
8.84
2.53
46.64
72.52
39.64
90.58
13.62
21.64
49.01
31.33
51.90
37.37
46.21
40.00
61.06
14.61
71.53
19.34
24.11
22.62
29.14
112.15
32.38
93.07
13.93
14.68
13.97
16.85
1.44
4.60
8.20
4.83
9.42
1.35
4.43
1.22
2.61
5.99
1.46
1.67
4.39
0.89
1.32
0.47
2.25
1.06
1.08
1.37
1.20
0.24
5.11
59.58
164.18
128.38
689.50
15.62
16.00
38.74
172.43
18.34
38.08
55.06
25.32
68.35
28.78
39.24
54.98
91.59
69.243
21.53
265.98
166.56
27.35
18.80
61.43
111.57
0.61
71.06
77.13
135.96
241.87
209.18
17.25
110.99
27.01
42.40
103.02
62.02
21.34
50.49
18.60
75.59
46.44
123.25
19.13
36.93
97.77
1263.27
25.81
19.26
11.23
75.15
27.15
38.68
9.96
1.19
0.47
1.06
0.35
13.39
1.08
2.86
0.16
2.31
2.71
1.13
0.84
0.74
0.65
1.93
0.84
1.35
0.28
1.72
0.37
7.58
5.18
2.92
2.62
3.02
1.26
5.31
2.05
8.21
9.62
2.33
10.11
4.89
1.12
0.71
1.63
1.04
0.05
9.36
3.36
12.03
7.66
2.29
8g
8h
8i
40.15
11.99
8.67
7.62
39.85
12.83
20.13
48.21
26.01
13.08
19.63
2.50
0.96
90.03
6.64
3.91
3.24
1.73
2.73
8j
1.80
0.71
3.77
1.40
0.81
1.56
1.25
0.58
1.34
3.77
1.83
25.57
27.66
9.12
1.55
5.67
4.46
2.31
8k
8l
12.59
12.95
14.31
5.15
19.29
1.26
2.67
8m
8n
8o
8p
8q
8r
3.48
68.84
11.08
152.29
8.61
26.84
4.45
6.10
0.90
2.09
2.13
2.68
1.78
2.05
9.19
13.45
25.16
5.17
17.79
11.16
49.02
43.67
1.73
16.19
3.69
0.36
22.65
20.86
21.32
93.21
135.98
18.19
3.99
7.90
2.20
15.63
31.63
1.70
6.82
68.07
1.24
3.45
0.59
4.26
8s
0.88
21.45
32.77
61.72
0.95
8t
1.40
4.53
7.33
133.11
31.63
Bel
CDDP
0.16
0.14
3.47
2.21
18.93
2.87
4.98
0.35
* Resistance Index(RI): the ratio of IC50 in resistance cells to IC50 in parental cells.
Fig. 5. Structure-activity relationship of compounds according their anti-proliferative effects.
could increase the expression of Ac-H4 at 10 μM concentration, which is
consistent with the enzyme-based results (Fig. 4). When the activity of
HDAC decrease, chromosome structure will become loose and con-
tribute to gene transcription, such as tumor suppressor gene p21. Thus,
we further detected the effect the synthesized compounds on the ex-
pression of p21. Our data showed most of these compounds could in-
crease the expression of p21 at 10 μM concentration, which suggested
those compounds own the potential of anti-tumor.
The proliferations of A549, NCI-H460, A549/CDDP and NCI-H460/
CDDP were inhibited in a dose dependent manner, and some com-
pounds exhibited the capacity to reverse cisplatin resistance. Moreover,
the IC50 values of synthesized compounds against A549/CDDP was
lower than that of NCI-H460/CDDP. However, these compounds did
not show cytotoxicity against NCI-H460 and NCI-H460/CDDP, which
was in accordance with the effect of belinostat.
Five of the tested compounds (8a, 8f, 8g, 8l and 8n) showed ob-
vious anti-proliferation effect on A549/CDDP cell lines with IC50
values < 8.0 μM, while the IC50 values of belinostat and cisplatin were
8.85 μM and 16.86 μM respectively. Specifically, 8f exhibited eminent
growth inhibition against A549/CDDP cell lines with IC50 value of
5.76 μM. It was more noteworthy that the resistance index (RI) of 8f
was 1.24, which was far lower than that of belinostat (RI: 36.88) and
cisplatin (RI: 8.46). The above results indicated that 8f was potential to
reverse cisplatin resistance in A549 cell lines, and the mechanism of
which was distinct from belinostat. Though 8f showed enhanced an-
ticancer activity against NCI-H1299/CDDP and NCI-H460/CDDP cell
lines compared to belinostat and cisplatin, the inhibition strength was
2.4. Reversing cisplatin resistance assay
We assessed the synthesized compounds on parental and cisplatin-
resistant cells, including A549 and A549/CDDP (A549/cisplatin re-
sistance cells), NCI-H1299 and NCI-H1299/CDDP (NCI-H1299/cis-
platin resistance cells), NCI-H460 and NCI-H460/CDDP (NCI-H460/
cisplatin resistance cells). For comparison purposes cisplatin and beli-
nostat were used as positive controls. All compounds were treated with
NSCLC cells for 48 h and MTT assay was applied to assess the viability
of cells. All of IC50 values in micromolar (μM) were listed in Table 2.
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X. Bao, et al.
BioorganicChemistry86(2019)696–704
still moderate to low.
determined with a X-4 apparatus and were uncorrected. The nuclear
magnetic resonance (NMR) spectra were recorded on a Bruker Ascend
400 (Billerica, MA, USA) using tetramethylsilane (TMS) as an internal
standard. Electrospray ionization mass spectrometry (ESI-MS) analyses
was recorded in an Agilent 1100 Series MSD Trap SL (Santa Clara, CA,
USA). The reactions were monitored by thin-layer chromatography
(TLC; HG/T2354-92, GF254).
Based on the results of anti-proliferation assay against A549/CDDP
cell lines, the structure–activity relationship (SAR) could be summar-
ized and demonstrated in Fig. 5. In general, the inhibitory activity
against cisplatin resistance cells and the reversal effect were improved
when the terminal phenyl groups were replaced by non-planar ada-
mantane groups. While this group was replaced by ethyl (8t), a dra-
matic decrease in activity was observed. And the behavior of small alkyl
group on the nitrogen of sulphonamide affected clearly the activity of
such derivatives and considered as balancing strategy improving re-
versal effect but reducing anti-proliferation activity. Compared the in-
hibitory activity of 8e, 8f and 8h, 8i, the result was shown that the
connection position of adamantane influences anticancer activity, and
8f was the best one. Additional, the introduction of substituents such as
chloro (8n) and ethoxy (8q) at 3-position of the adamantane (8h), re-
sulted in a decrease of the RI, which did not influence the anti-pro-
liferation activity. As introduction of more methyl groups (8r and 8s)
resulted in a more significant decrease of RI. Therefore, the substituents
at the adamantane would benefit the reversal of cisplatin resistance,
which might be due to the increase of stereospecific blockade.
4.2.1. Methyl (E)-3-(4-(chlorosulfonyl)phenyl)acrylate (3)
Compound 3 were prepared according to the literature procedure
[16,17].
4.2.2. General procedure for the synthesis of methyl (E)-3-(4-(N-substituted
sulfamoyl)phenyl) acrylate derivatives (4)
To a stirred solution of primary amine (7.69 mmol) in anhydrous
pyridine (5.0 mL, 61.5 mmol) was added methyl (E)-3-(4-(chlor-
osulfonyl)phenyl)acrylate (2.0 g, 7.69 mmol) solution in anhydrous
pyridine (5.0 mL, 61.5 mmol) at 0 °C. The mixture was stirred at 0 °C for
4 h until completion monitored by TLC. The reaction mixture was
poured into vigorously stirred 1 N hydrochloric acid (50 mL) and stirred
for 1 h. Then the mixture was filtered and washed with water. The re-
sidue was dried to produce white solids in 88–99% yields.
3. Conclusions
Firstly, we designed novel compounds based on the knowledge of
HDAC, then we verified our design strategy via docking these com-
pounds intoHDAC1. Fortunately, molecular docking confirmed the ra-
tionality of designing, and these compounds were synthesized.
Subsequently, we assessed the effect of the synthesized compounds on
HDAC activity in enzyme- and cell-based assay. Finally, because of the
complexity of cisplatin resistance, phenotypic screening was employed
to evaluate the reversal effect and anti-proliferation activity against
cisplatin resistance NSCLC cell lines.
4.2.3. General procedure for the synthesis of methyl (E)-3-(4-(N,N-
disubstituted sulfamoyl) phenyl) acrylate derivatives (5)
To a solution of 4 (5 mmol) in 10 mL acetonitrile, potassium car-
bonate (4.1 g, 30 mmol) and dimethyl sulfate/diethyl sulfate (15 mmol)
were added and heated under reflux for 17 h. Then the solvent was
evaporated under reduced pressure and saturated sodium bicarbonate
was added. After string for 30 min, the title compound precipitated and
collected by filtering.
In conclusion, we obtained a series of N-hydroxypropenamide de-
rivatives incorporating adamantane moiety with strong reversal effect
and potent inhibitory activity against cisplatin resistance A549 cell
lines (NSCLC). Compound 8f, identified by cell-based screening, ex-
hibited obvious reversal of cisplatin resistance with RI of 1.24 and
stronger anti-proliferation activity with IC50 value of 5.76 μM compared
to reference drugs including belinostat and cisplatin. The structure–-
activity relationship of these compounds was summarized and com-
pound 8f could serve as a template for designing novel compounds to
develop drugs for cisplatin resistance NSCLC.
4.2.4. General procedure for the synthesis of acrylic acid derivatives (6)
To a solution of 4 or 5 (4.53 mmol) in methanol (20 mL) was added
1 M NaOH (15 mL) and the reaction mixture was refluxed for 2 h. After
the completion of the reaction monitored by TLC, the mixture was
adjusted to pH 1.0 with 3 N HCl, filtered the precipitated solid, washed
with chilled water, and dried to obtain the white crude products 6 in
87–98% yields, which were used in the next step without further pur-
ification.
4. Experimental
4.2.5. General procedure for the synthesis of isohydroximic acid derivatives
(8)
4.1. Molecular docking study
To a solution of cinnamic acid derivative 6 (1.17 mmol) in di-
chloromethane (10 mL) was added sulfoxide chloride (1 mL,
9.37 mmol) and the reaction mixture was refluxed for 30 min, then the
solvent was evaporated under vacuum to get the product cinnamoyl
chloride in the form of solid residue in quantitative yield.
Hydroxylamine protected by THP (0.5 g, 4.68 mmol) and anhydrous
pyridine (0.5 mL, 5.85 mmol) were dissolved in anhydrous ethyl acetate
(10 mL) and stirred at 0 °C. Cinnamoyl chloride was dissolved in dry
ethyl acetate (20 mL) and added dropwise to above stirred solution at
0 °C. The reaction mixture was stirred for 10 min, then the reaction
mixture was poured into vigorously stirred ice water (100 mL) and
extracted with ethyl acetate. The organic layer was washed with brine,
dried over magnesium sulfate. Most of the ethyl acetate was evaporated
in vacuo, protected hydroxamate was precipitated and collected by
filtering.
All designed compounds were screened by molecular docking using
the Glide program (version 10.2, Schrodinger, LLC, New York, 2015).
The crystal structure of human HDAC1 (ID: 4BKX) were obtained from
the Protein Data Bank (www.pdb.org) and the Protein Preparation
Wizard module was applied for the protein structure preparation. The
ligands were minimized by means of the LigPrep module. The Glide
module was used to generate a receptor grid file that determine the
position and size of the active site according the literatures [15], which
reported the key amino acids forming the binding pocket. Glide docking
was performed using the SP mode with default protocols, and the li-
gands were treated as flexible. All the docked complexes were scored by
the Glide scoring function, and the complexes with higher Glide-score
were selected for further analysis of binding mode and critical inter-
actions with the key amino acids.
To a solution of protected hydroxamate (0.38 mmol) in 40 mL of
methanol was added 3 N HCl (5 mL) at room temperature. The reaction
was monitored by TLC until its completion after stirring for 2 h at 30 °C.
The reaction mixture was poured into water (100 mL), filtered the
precipitated solid, which was washed with chilled water and dryed to
afford target compounds.
4.2. Chemistry
All of the starting materials, reagents and solvents are commercially
available and used without further purification. Melting points were
701

X. Bao, et al.
BioorganicChemistry86(2019)696–704
4.2.5.1. (E)-3-(4-(N-(3,5-difluorophenyl)-N-methylsulfamoyl)phenyl)-N-
hydroxyacrylamide (8a) Light pink solid
4.2.5.8. (E)-3-(4-(N-((1r,3r,5r,7r)-adamantan-2-yl)sulfamoyl)phenyl)-N-
hydroxyacrylamide (8h) Light pink solid
Yield: 95%. mp: 159–162 °C. 1H NMR (400 M Hz, DMSO‑d6): δ
(ppm) 10.90 (s, 1H, OH), 9.17 (s, 1H, NH), 7.78 (d, J = 8.24 Hz, 2H,
AreH), 7.58 (d, J = 8.24 Hz, 2H, AreH), 7.52 (d, J = 15.8 Hz, 1H,
CH]CH), 7.21 (t, J = 9.24 Hz, 1H, AreH), 6.99 (d, J = 8.52 Hz, 2H,
AreH), 6.60 (d, J = 15.8 Hz, 1H, CH]CH), 3.17 (s, 3H, NCH3); ESI-MS
Yield: 40%. mp: 172–175 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.87 (brs, 1H, OH), 9.15 (brs, 1H, NH), 7.84 (d, J = 8.16 Hz, 2H,
AreH), 7.75 (t, 内含d, J = 8.32 Hz, 2H, AreH, 1H, SO2NH), 7.50 (d,
J = 15.88 Hz, 1H, CH]CH), 6.57 (d, J = 15.84 Hz, 1H, CH]CH), 3.21
(brs, 1H, CH), 1.97 (d, 2H, CH), 1.69 (d, 4H, CH2), 1.62 (d, 4H, CH2),
(m/z): 369.2 [M+H]+, 366.9 [M−H]−
.
1.56 (d, 2H, CH), 1.38 (d, 2H, CH2); ESI-MS(m/z): 377.1 [M+H]+
,
399.1 [M+Na]+, 375.0 [M−H]−
.
4.2.5.2. (E)-3-(4-(N-(3,5-difluorophenyl)-N-ethylsulfamoyl)phenyl)-N-
hydroxyacrylamide (8b) Light pink solid
4.2.5.9. (E)-3-(4-(N-((1r,3r,5r,7r)-adamantan-2-yl)-N-methylsulfamoyl)
Yield: 61%. mp: 171–172 °C. 1H NMR (400 M Hz, DMSO‑d6): δ
(ppm) 10.89 (brs, 1H, OH), 9.16 (brs, 1H, NH), 7.78 (d, J = 7.92 Hz,
2H, AreH), 7.62 (d, J = 8.16 Hz, 2H, AreH), 7.53 (d, J = 15.76 Hz, 1H,
CH]CH), 7.28 (t, J = 9.16 Hz, 1H, AreH), 6.94 (d, J = 6.32 Hz, 2H,
AreH), 6.60 (d, J = 15.76 Hz, 1H, CH]CH), 3.63 (q, J = 6.88 Hz, 2H,
NCH2), 0.99 (t, J = 6.96 Hz, 3H, NCH2CH3); ESI-MS(m/z): 383.4 [M
phenyl)-N-hydroxyacrylamide (8i) Light pink solid
Yield: 60%. mp: 184–187 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.89 (brs, 1H, OH), 9.17 (brs, 1H, NH), 7.80 (d, J = 8.36 Hz, 2H,
AreH), 7.76 (d, J = 8.4 Hz, 2H, AreH), 7.53 (d, J = 15.84 Hz, 1H,
CH]CH), 6.60 (d, J = 15.84 Hz, 1H, CH]CH), 3.08 (s, 1H, CH), 2.84
(s, 3H, NCH3), 2.20 (s, 2H, CH), 1.95 (d, 2H, CH), 1.78 (m, 4H, CH2),
+H]+, 405.4 [M+Na]+, 381.2 [M−H]−
.
1.63 (d, 4H, CH2), 1.51 (d, 2H, CH2); ESI-MS(m/z): 391.2 [M+H]+
,
413.2 [M+Na]+, 389.2 [M−H]−
.
4.2.5.3. (E)-3-(4-(N-methyl-N-(3-(trifluoromethyl)phenyl)sulfamoyl)
phenyl)-N-hydroxyacrylamide (8c) Light pink solid
4.2.5.10. (E)-3-(4-(N-((1r,3r,5r,7r)-adamantan-2-yl)-N-ethylsulfamoyl)
Yield: 96%. mp: 162–165 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.89 (brs, 1H, OH), 9.16 (brs, 1H, NH), 7.76 (d, J = 8.4 Hz, 2H,
AreH), 7.68 (d, J = 7.52 Hz, 1H, AreH), 7.60 (t, J = 7.56 Hz, 1H,
AreH), 7.52 (d, J = 8.4 Hz, 2H, AreH), 7.48 (d, J = 15.24 Hz, 1H,
CH]CH), 7.45 (m, 2H, AreH), 6.59 (d, J = 15.84 Hz, 1H, CH]CH)
phenyl)-N-hydroxyacrylamide (8j) Light pink solid
Yield: 40%. mp: 171–174 °C. 1H NMR (400 M Hz, DMSO- d6):
δ(ppm) 10.88 (s, 1H, OH), 9.16 (s, 1H, NH), 7.80 (d, J = 8.36 Hz, 2H,
AreH), 7.75 (d, J = 8.44 Hz, 2H, AreH), 7.51 (d, J = 16.04 Hz, 1H,
CH]CH), 6.58 (d, J = 15.84 Hz, 1H, CH]CH), 3.46 (s, 1H, CH), 3.40
(q, J1 = 13.68 Hz J2 = 6.76 Hz, 2H, NCH2), 2.15 (s, 2H, CH), 1.75 (s,
6H, CH2), 1.69 (d, 2H, CH2), 1.62 (s, 2H, CH), 1.40 (d, 2H, CH2), 1.15
3.20 (s, 3H, NCH3); ESI-MS(m/z): 401.5 [M+H]+, 423.5 [M+Na]+
,
399.3 [M−H]−
.
(t, J = 6.8 Hz, 3H, NCH2CH3); ESI-MS(m/z): 403.3 [M−H]−
.
4.2.5.4. (E)-3-(4-(N-ethyl-N-(3-(trifluoromethyl)phenyl)sulfamoyl)
phenyl)-N-hydroxyacrylamide (8d) Light pink solid
4.2.5.11. (E)-3-(4-(N-((1 s,3s,5R,7S)-3-chloroadamantan-1-yl)
Yield: 89%. mp: 125–128 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (brs, 1H, OH), 9.16 (brs, 1H, NH), 7.76 (d, J = 8.04 Hz, 2H,
AreH), 7.72 (d, J = 7.48 Hz,1H, AreH), 7.60 (t, J = 7.96 Hz, 1H,
AreH), 7.55 (d, J = 8.04 Hz, 2H, AreH), 7.52 (d, J = 15.88 Hz, 1H,
CH]CH), 7.40 (m, 2H, AreH), 6.60 (d, J = 15.84 Hz, 1H, CH]CH),
3.66 (q, J = 6.84 Hz, 2H, NCH2), 0.97(t, J = 6.96 Hz, 3H, NCH2CH3);
sulfamoyl)phenyl)-N-hydroxyacrylamide (8k) Light pink solid
Yield: 77%. mp: 155–158 °C. 1H NMR (400 M Hz, DMSO- d6):
δ(ppm) 10.87 (brs, 1H, OH), 9.14 (brs, 1H, NH), 7.88 (s, 1H, SO2NH),
7.84 (d, J = 8.36 Hz, 2H, AreH), 7.74 (d, J = 8.28 Hz, 2H, AreH), 7.51
(d, J = 15.8 Hz, 1H, CH]CH), 6.57 (d, J = 15.8 Hz, 1H, CH]CH), 2.09
(d, 4H, CH2), 1.93 (d, 2H, CH2), 1.86 (d, 2H, CH2), 1.66 (d, 2H, CH2),
1.59 (d, 2H, CH), 1.46 (d, 1H, CH2), 1.36 (d, 1H, CH2); ESI-MS(m/z):
ESI-MS(m/z): 453.6 [M + K]+, 412.5 [M−H]−
.
411.1 [M+H]+
,
433.1 [M+Na]+
,
435.0 [M+2+Na]+
, 409.1
4.2.5.5. (E)-3-(4-(N-((3 s,5s,7s)-adamantan-1-yl)sulfamoyl)phenyl)-N-
hydroxyacrylamide (8e) Light pink solid
[M−H]−, 411.0 [M+2−H]−
.
Yield: 81%. mp: 149–152 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.19 (brs, 1H, OH), 9.39 (brs, 1H, NH), 7.84 (d, J = 7.92 Hz, 2H,
AreH), 7.73 (d, J = 8.04 Hz, 2H, AreH), 7.59 (s, 1H, SO2NH), 7.50 (d,
J = 15.72 Hz, 1H, CH]CH), 6.57(d, J = 15.8 Hz, 1H, CH]CH), 1.91
(s, 3H, CH), 1.68 (s, 6H, CH2), 1.49 (q, 6H, CH2); ESI-MS(m/z): 377.1
4.2.5.12. (E)-3-(4-(N-((1 s,3s,5R,7S)-3-chloroadamantan-1-yl)-N-
methylsulfamoyl)phenyl)-N-hydroxyacrylamide (8l) Light pink solid
Yield: 95%. mp: 153–156 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (s, 1H, OH), 9.16 (s, 1H, NH), 7.84 (d, J = 8.24 Hz, 2H, AreH),
7.76 (d, J = 8.32 Hz, 2H, AreH), 7.52 (d, J = 15.8 Hz, 1H, CH]CH),
6.58 (d, J = 15.8 Hz, 1H, CH]CH), 2.92 (s, 3H, NCH3), 2.34(s, 2H,
CH2), 2.19 (brs, 2H, CH2), 1.97 (d, 6H, CH2), 1.84 (d, 2H, CH), 1.46 (t,
[M+H]+, 399.1 [M+Na]+, 375.0 [M−H]−
.
4.2.5.6. (E)-3-(4-(N-((3 s,5s,7s)-adamantan-1-yl)-N-methylsulfamoyl)
phenyl)-N-hydroxyacrylamide (8f) Light pink solid
2H, CH2); ESI-MS(m/z): 423.1 [M−H]−, 425.1 [M+2−H]−
.
Yield: 61%. mp: 115–118 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.89 (brs, 1H, OH), 9.15 (brs, 1H, NH), 7.80 (d, J = 8 Hz, 2H, AreH),
7.74 (d, J = 8.08 Hz, 2H, AreH), 7.51 (d, J = 16 Hz, 1H, CH]CH),
6.57(d, J = 15.8 Hz, 1H, CH]CH), 2.92 (s, 3H, NCH3), 2.00 (s, 3H,
CH), 1.93 (s, 6H, CH2), 1.54 (s, 6H, CH2); ESI-MS(m/z): 391.1 [M
4.2.5.13. (E)-3-(4-(N-((1 s,3s,5R,7S)-3-chloroadamantan-1-yl)-N-
ethylsulfamoyl)phenyl)-N-hydroxyacrylamide (8m) Light pink solid
Yield: 81%. mp: 152–155 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (s, 1H, OH), 9.16 (s, 1H, NH), 7.82 (d, J = 8.36 Hz, 2H, AreH),
7.75 (d, J = 8.36 Hz, 2H, AreH), 7.52 (d, J = 15.84 Hz, 1H, CH]CH),
6.58 (d, J = 15.84 Hz, 1H, CH]CH), 3.47 (q, J1 = 13.48 Hz,
J2 = 6.6 Hz, 2H, NCH2), 2.29 (s, 2H, CH2), 2.16(s, 2H, CH2), 1.94 (d,
6H, CH2), 1.79 (d, 2H, CH), 1.44 (q, 2H, CH2), 1.23 (t, J = 6.72 Hz, 3H,
+H]+, 413.1 [M+Na]+, 389.0 [M−H]−
.
4.2.5.7. (E)-3-(4-(N-((3 s,5s,7s)-adamantan-1-yl)-N-ethylsulfamoyl)
phenyl)-N-hydroxyacrylamide (8 g) Light pink solid
CH2CH3); ESI-MS(m/z): 437.0 [M−H]−, 439.0 [M+2−H]−
.
Yield: 49%. mp: 177–180 °C. 1H NMR (400 M Hz, DMSO‑d6): δ
(ppm) 10.87 (brs, 1H, OH), 9.15 (brs, 1H, NH), 7.81 (d, J = 8.24 Hz,
2H, AreH), 7.73 (d, J = 8.28 Hz, 2H, AreH), 7.51 (d, J = 15.8 Hz, 1H,
CH]CH), 6.57(d, J = 15.84 Hz, 1H, CH]CH), 3.46 (q,
J1 = 13.52 Hz J2 = 6.64 Hz, 2H, NCH2), 1.98 (s, 3H, CH), 1.90 (s, 6H,
CH2), 1.52 (s, 6H, CH2), 1.24 (t, J = 6.72 Hz, 3H, NCH2CH3); ESI-MS
4.2.5.14. (E)-3-(4-(N-((1R,3S,5s,7s)-5-chloroadamantan-2-yl)sulfamoyl)
phenyl)-N-hydroxyacrylamide (8n) Light pink solid
Yield: 93%. mp: 212–215 °C 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (s, 1H, OH), 9.15 (s, 1H, NH), 7.85 (d, J = 8.08 Hz, 2H, AreH),
7.78 (s, 1H, SO2NH), 7.61 (d, J = 8.68 Hz, 2H, AreH), 7.51 (d,
J = 15.8 Hz, 1H, CH]CH), 6.58 (d, J = 15.88 Hz, 1H, CH]CH), 3.27
(m/z): 405.1 [M+H]+, 427.1 [M+Na]+, 403.0 [M−H]−
.
702

X. Bao, et al.
BioorganicChemistry86(2019)696–704
(s, 1H, NHCH), 2.03 (s, 6H, CH2), 1.98 (s, 1H, CH2), 1.90 (d, 2H, CH2),
4.3. Enzyme-based activity assay
1.84 (s, 2H, CH), 1.36 (d, 2H, 1H, CH, 1H, CH2); ESI-MS(m/z): 409.0
[M−H]−, 410.9 [M+2−H]−
.
The in vitro HDAC assay was performed with an HDAC fluorescent
activity assay kit (BioVision, San Francisco, CA, USA) as our previous
reported. Briefly, A549 nuclear proteins were incubated with various
concentrations( 1 nM to 10 uM ) compounds and belinostat at 37 °C for
30 min in the presence of na HDAC fluorimetric substrate. The HDAC
assay developer (which produces a fluorophore in reaction mixture)
was added, and the fluorescence was measured using a microplate
reader (Molecular Devices, Sunnyvale, CA, USA).
4.2.5.15. (E)-3-(4-(N-((1R,3S,5s,7s)-5-chloroadamantan-2-yl)-N-
methylsulfamoyl)phenyl)-N-hydroxyacrylamide (8o) Light pink solid
Yield: 84%. mp: 191–194 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.91 (s, 1H, OH), 9.17 (s, 1H, NH), 7.82 (d, J = 8.28 Hz, 2H, AreH),
7.79 (d, J = 8.32 Hz, 2H, AreH), 7.55 (d, J = 15.76 Hz, 1H, CH]CH),
6.61 (d, J = 15.88 Hz, 1H, CH]CH), 3.02 (s, 1H, NCH), 2.78 (s, 3H,
NCH3), 2.46 (s, 2H, CH2), 2.08 (brs, 7H, CH2), 1.89 (d, 2H, CH), 1.49 (d,
2H, 1H, CH, 1H, CH2); ESI-MS(m/z): 423.6 [M−H]−, 425.0 [M
4.4. Western blot analysis
+2−H]−
.
About 1 × 107 A549 cells were gathered after pre-treatment com-
pounds for 48 h. Western blotting was performed as previously de-
scribed. Briefly, an equal amount of total protein extracts from cultured
cells or tissues was fractionated by 10–15% SDS-PAGE and then elec-
trically transferred onto polyvinylidene difluoride (PVDF) membranes.
Mouse or rabbit primary antibodies(Ac-Histone 4, p21) and appropriate
horseradish peroxidase (HRP)- conjugated secondary antibodies were
used to detect the designated proteins. The bound secondary antibodies
on the PVDF membrane were reacted with ECL detection reagents
(Pierce, Rockford, IL, USA) and exposed to X-ray films. Results were
normalized to the internal control Histone4 or β-actin.
4.2.5.16. (E)-3-(4-(N-((1R,3S,5s,7s)-5-chloroadamantan-2-yl)-N-
ethylsulfamoyl)phenyl)-N-hydroxyacrylamide (8p) Light pink solid
Yield: 59%. mp: 128–131 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.89 (s, 1H, OH), 9.16 (s, 1H, NH), 7.82 (d, J = 8.24 Hz, 2H, AreH),
7.77 (d, J = 8.4 Hz, 2H, AreH), 7.52 (d, J = 15.8 Hz, 1H, CH]CH),
6.59 (d, J = 15.88 Hz, 1H, CH]CH), 3.46 (s, 1H, NCH), 3.36 (q, 2H,
NCH2), 2.39 (s, 2H, CH2), 2.13 (q, 4H, CH2), 2.03 (d, 3H, CH2), 1.69 (d,
2H, CH), 1.39 (d, 2H, 1H, CH2, 1H, CH); 1.12(t, J = 6.8 Hz, 3H, N CH2
CH2 CH3); ESI-MS(m/z): 437.2 [M−H]−, 439.1 [M+2−H]−
.
4.2.5.17. (E)-3-(4-(N-((1R,3S,5s,7s)-5-ethoxyadamantan-2-yl)-N-
ethylsulfamoyl)phenyl)-N-hydroxyacrylamide (8q) Light pink solid
Yield: 41%. mp: 112–115 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.89 (s, 1H, OH), 9.16 (s, 1H, NH), 7.81 (d, J = 8.4 Hz, 2H, AreH),
7.76 (d, J = 8.44 Hz, 2H, AreH), 7.52 (d, J = 15.8 Hz, 1H, CH]CH),
6.58 (d, J = 15.84 Hz, 1H, CH]CH), 3.39 (m, 3H, 含NCH, OCH2), 3.36
(brs, 2H, NCH2), 2.35 (s, 1H, CH2), 2.00 (brs, 1H, CH2), 1.69 (brs, 5H,
CH2), 1.63 (s, 3H, CH), 1.27 (d, 2H, CH2) 1.14 (t, J = 6.76 Hz, 3H,
OCH2CH3), 1.02 (t, J = 7 Hz, 3H, NCH2CH3); ESI-MS(m/z): 447.2
4.5. Cell viability assay
Human lung cancer cell lines A549, NCI-H1299 and NCI-H460 were
obtained from the American Type Culture Collection (Manassas, VA,
USA). These cancer cells were routinely cultured in RPMI-1640 or
DMEM supplemented with 10% fetal bovine serum (FBS) and main-
tained at 37 °C in a humidified incubator with 5% CO2. Specially, the
resistance of these lung cancer cells was maintained by continuously
exposing to increasing concentrations of cisplatin and later maintain at
200 ng/ml.
[M−H]−
.
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide
(MTT) was purchased from Sigma. Synthesized compounds and re-
ference agents were dissolved in DMSO to 100 mM and stored at
−20 °C. Before treatment, the stock solution is diluted to different
concentrations. The final concentration of DMSO in cultures is 0.1% (v/
v) or less.
4.2.5.18. (E)-3-(4-(N-((1r,3R,5S,7r)-3,5-dimethyladamantan-1-yl)-N-
methylsulfamoyl)phenyl)-N-hydroxyacrylamide (8r) Light pink solid
Yield: 60%. mp: 164–167 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (s, 1H, OH), 9.15 (s, 1H, NH), 7.79 (d, J = 8.2 Hz, 2H, AreH),
7.74 (d, J = 8.24 Hz, 2H, AreH), 7.51 (d, J = 15.8 Hz, 1H, CH]CH),
6.58 (d, J = 15.8 Hz, 1H, CH]CH), 2.89 (s, 3H, NCH3), 2.05 (s, 1H,
CH), 1.77 (s, 2H, CH2), 1.58 (q, 4H, CH2), 1.20 (q, 4H, CH2), 1.04 (s,
The in vitro cell viability was determined by MTT assay. The cells
(1 × 105 cells/ml) were seeded into 96-well culture plates. After
overnight incubation maintained at 37 °C in a humidified incubator
with 5% CO2., the cells were treated with various concentrations of
agents for 48 h. Then 10 μl MTT solution (2.5 mg/ml in PBS) was added
to each well, and the plates were incubated for an additional 4 h at
37 °C. After centrifugation (2500 r.p.m., 10 min), the medium with MTT
was aspirated, followed by the addition of 100 μl DMSO. The optical
density of each well was measured at 570 nm with a Biotek Synergy HT
Reader (Winooski, VT, USA).
2H, CH2), 0.77 (s, 6H, CH3); ESI-MS(m/z): 417.1 [M−H]−
.
4.2.5.19. (E)-3-(4-(N-((1r,3R,5S,7r)-3,5-dimethyladamantan-1-yl)-N-
ethylsulfamoyl)phenyl)-N-hydroxyacrylamide (8s) Light pink solid
Yield: 40%. mp: 161–164 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (s, 1H, OH), 9.15 (s, 1H, NH), 7.79 (d, J = 8.36 Hz, 2H, AreH),
7.74 (d, J = 8.32 Hz, 2H, AreH), 7.51 (d, J = 15.8 Hz, 1H, CH]CH),
6.57 (d, J = 15.88 Hz, 1H, CH]CH), 3.44 (q, J1 = 13.44 Hz,
J2 = 6.56 Hz, 2H, NCH2), 2.03 (s, 1H, CH), 1.73 (s, 2H, CH2), 1.55 (q,
4H, CH2), 1.22 (t, J = 6.56 Hz, 3H, NCH2CH3), 1.17 (m, 4H, CH2), 1.02
(brs, 2H, CH2), 0.75 (s, 6H, CH3); ESI-MS(m/z): 433.0 [M+H]+, 455.1
Acknowledgements
[M+Na]+, 431.1 [M−H]−
.
This work was financially supported by Liaoning Provincial Natural
Science Foundation of China (No. 201602707), Scientific Research
Fund of Liaoning Provincial Education Department (No. 2017LFW01),
Discipline Construction Program of Shenyang Pharmaceutical
University (No. 52134606), and National Natural Science Foundation of
China (No. 81572947).
4.2.5.20. (E)-3-(4-(N,N-diethylsulfamoyl)phenyl)-N-hydroxyacrylamide
(8t) Light pink solid
Yield: 19%. mp: 132–135 °C. 1H NMR (400 M Hz, DMSO‑d6): δ(ppm)
10.88 (s, 1H, OH), 9.16 (s, 1H, NH), 7.80 (d, J = 8.36 Hz, 2H, AreH),
7.76 (d, J = 8.44 Hz, 2H, AreH), 7.52 (d, J = 15.8 Hz, 1H, CH]CH),
6.68 (d, J = 15.88 Hz, 1H, CH]CH), 3.16 (q, J1 = 14.16 Hz,
J2 = 7.04 Hz, 4H, CH2), 1.03 (t, J = 7.08 Hz, 6H, NCH2CH3); ESI-MS
Conflict of interest
(m/z): 297.1 [M−H]−
.
The authors declare that there is no conflict of interest.
703

X. Bao, et al.
BioorganicChemistry86(2019)696–704
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