The synthesis of trifluoromethylated N-nitroaryl-2-amino-1,3-dichloropropane derivatives and their evaluation as potential anti-cancer agents

Article abstract of DOI:10.1016/j.bmcl.2019.126910

Six N-nitroaryl-2-amino-1,3-dichloropropane derivatives have been prepared and evaluated against 18 cancer cell lines and two non-cancerous cell lines. Analysis of cell viability data and IC₅₀ values indicated that the presence of a trifluorome

Full text of DOI:10.1016/j.bmcl.2019.126910

Journal Pre-proofs
The synthesis of trifluoromethylated N-nitroaryl-2-amino-1,3-dichloropropane
derivatives and their evaluation as potential anti-cancer agents
Lucy Chappel, Lai Chun Wong, Chee-Onn Leong, Chun-Wai Mai, Ian T.
Meikle, Stephen P. Stanforth, Thang V. Truong
PII:
S0960-894X(19)30888-1
DOI:
https://doi.org/10.1016/j.bmcl.2019.126910
BMCL 126910
Reference:
Bioorganic & Medicinal Chemistry Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
16 September 2019
12 December 2019
13 December 2019
Please cite this article as: Chappel, L., Chun Wong, L., Leong, C-O., Mai, C-W., Meikle, I.T., Stanforth, S.P.,
Truong, T.V., The synthesis of trifluoromethylated N-nitroaryl-2-amino-1,3-dichloropropane derivatives and their
evaluation as potential anti-cancer agents, Bioorganic & Medicinal Chemistry Letters (2019), doi: https://doi.org/
10.1016/j.bmcl.2019.126910
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The synthesis of trifluoromethylated N-nitroaryl-2-amino-1,3-dichloropropane derivatives and their evaluation as
potential anti-cancer agents
Lucy Chappel, Lai Chun Wong, Chee-Onn Leong, Chun-Wai Mai, Ian T. Meikle, Stephen P. Stanforth,* Thang
V. Truong
NO2
CF3
NO2
CF3
i. MsCl, Et3N
ii. LiCl, heat
NO2
CF3
NH2
+
K2CO3
HO
HO
HO
NH
NH
Cl
F
Evaluated against
Cl
18 cancerous cell lines
HO
The synthesis of trifluoromethylated N-nitroaryl-2-amino-1,3-dichloropropane derivatives and their evaluation as
potential anti-cancer agents
Lucy Chappel,a Lai Chun Wong,b Chee-Onn Leong, c,d Chun-Wai Mai, b,c Ian T. Meikle,a Stephen P. Stanforth,a* Thang V.
Truong.a
a Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
b Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University Malaysia, 57000
Kuala Lumpur, Malaysia.
c Centre for Cancer and Stem Cells Research, Institute for Research, Development and Innovation, International
Medical University Malaysia, 57000 Kuala Lumpur, Malaysia.
d Department of Life Science, School of Pharmacy, International Medical University Malaysia, 57000 Kuala Lumpur,
Malaysia.
* Corresponding author. E-mail address: steven.stanforth@northumbria.ac.uk
Abstract: Six N-nitroaryl-2-amino-1,3-dichloropropane derivatives have been prepared and evaluated against 18
cancer cell lines and two non-cancerous cell lines. Analysis of cell viability data and IC50 values indicated that the
presence of a trifluoromethyl group in the nitroaryl moiety is an important structural feature associated with the
compounds’ cytotoxicities.
Key words: nitroaromatic drugs; anti-cancer agents; trifluoromethylated drugs; nitrogen mustards.
The design, synthesis and therapeutic utility of nitroaromatic pro-drugs has attracted considerable interest and this
area of medicinal chemistry has been recently reviewed.1 Within this general class of pro-drugs, the nitrogen-
mustards of general structure 1 have received particular attention as potential anti-cancer agents (Scheme 1).2,3 In
these compounds, the bioreduction of an appropriately positioned ortho- or para-nitro group produces the
corresponding hydroxylamine/amine derivative 2 with a concomitant augmentation of the nucleophilic character of
the mustard’s nitrogen atom. An intramolecular nucleophilic substitution reaction subsequently follows producing a
highly reactive aziridinium ion 3 which is believed to be responsible for DNA alkylation. The remaining chloroethyl
group can then participate in a similar reaction forming a second aziridinium ion hence resulting in dialkylation.

NO2
NHOH/NH2
NHOH/NH2
bioreduction
DNA
alkylation
:
DNA
_
N
N
+
N
Cl
Cl
Cl
Cl
Cl
Cl
3
2
1
NO2
NHOH/NH2
NHOH/NH2
_
bioreduction
Cl
DNA
alkylation
NH
+
NH
N
Cl
Cl
H
Cl
Cl
Cl
:
DNA
4
5
6
Scheme 1. Nitroaromatic pro-drugs acting as anti-cancer agents.
Compounds of general structure 4 appear to be under-represented in the literature and a similar mode of DNA
alkylation might be feasible for these compounds via the hydroxylamine/amine 5 and the aziridinium ion 6 (Scheme
1). In view of the extensive interest in fluorinated drugs,4-7 and our work in this area,8 we were particularly interested
in evaluating the anti-cancer properties of trifluoromethylated nitroaromatics and hence compounds 10d-f were
chosen as target molecules (Scheme 2). One potential benefit of the secondary amine group in compounds 10d-f is
the opportunity for the >NH group to participate in intramolecular hydrogen bonding with either an appositely
located ortho-nitro or -trifluoromethyl group. The mono-nitro derivatives 10a and 10b were chosen as reference
compounds and compound 10c was also included in this study because the 2,4-di-nitro structural motif is a common
feature of many known pro-drugs of general structure 1.3 The series of nitroaromatic compounds 10a-f were
prepared from their diol precursors 9a-f respectively which in turn were synthesised from an appropriately
substituted fluoroaromatic 7a-f and serinol 8 (Scheme 2).
R2
R2
R1
NO2
H
R2
R3
R2
R3
H
H
R3
a
b
c
d
e
f
R3
NH2
(ii)
HO
(i)
NO2
H
H
H
H
+
R1
NO2 NO2
NO2 CF3
CF3 NO2
R1
R1
30-94%
58-87%
HO
NH
NH
F
HO
Cl
H
NO2 CF3
7
8
HO
Cl
10
9
Scheme 2. Reagents and conditions: (i) K2CO3, DMSO, heat 70-80 oC, 3 h; (ii) (a) MeSO2Cl, Et3N, rt, (b) LiCl, DMF, heat
70 oC, 2 h.
The cell viabilities (Table 1) and the IC50 values (Table 2) relating to a selection of 18 cancer cell lines and 2 non-
cancerous cell lines were determined in the presence of the diols 9a-f and the dichloro compounds 10a-f. The ratio
of the percentage cell viability 9 / percentage cell viability 10 is also reported in Table 1 as an indication of the
efficacy of the dichloro compounds 10 compared to their diol counterparts 9.

ra
ti
o
ra
ti
o
ra
ti
o
ra
ti
o
ra
ti
o
ra
ti
o
Cancer
type
Cell
line
9a
10a
9b
10b
9c
10c
9d
10d
9e
10e
9f
10f
Breast
Cancer
MC
F7
66.6
± 2.4
37.7
± 1.1
1.
8
65.6
± 1.2
38.8
± 0.4
1.
7
55.5
± 4.4
25.1
± 2.1
2.
2
57.4
± 1.9
21.4
± 4.3
2.
7
45.7
± 1.9
10.5
± 0.9
4.
4
49.7
± 2.1
20.5
± 0.5
2.
4
MD
A-
MB-
231
MD
A-
MB-
468
SKB
R3
T47
D
Breast
Cancer
91.8
± 3.3
85.1
± 2.1
1.
1
87.7
± 2.1
72.4
± 1.1
1.
2
79.4
± 8.4
83.4
± 2.5
1.
0
67.3
± 1.8
32.1
± 0.5
2.
1
93.1
± 5.5
31.8
± 3.9
2.
9
65.7
± 1.7
57.4
± 2.7
1.
1
Breast
Cancer
104.0
± 5.0
63.6
± 6.1
1. 102.2
6
45.1
± 2.4
2.
3
105.8
± 7.1
61.3
± 4.3
1. 100.4 65.1
± 4.1 ± 6.6
1.
5
93.2
± 3.2
20.4
± 4.9
4.
6
98.7
± 2.7
58.6
± 2.1
1.
7
± 5.5
7
Breast
Cancer
Breast
Cancer
Colorec
tal
Cancer
Colorec
tal
Cancer
Colorec
tal
Cancer
Colorec
tal
100.9
± 7.9
76.2
79.9
± 0.8
69.8
± 1.9
1.
3
1.
1
93.1
± 1.1
73.6
± 1.0
73.1
± 1.1
65.2
± 1.5
1.
3
1.
1
98.9
± 3.4
79.9
± 2.2
71.6
± 5.0
58.7
± 3.4
1. 66.40 38.5
1.
7
2.
7
75.2
± 3.5
59.1
± 2.2
55.6
± 1.1
24.3
± 1.7
1.
4
2.
4
1
0.
6
79.4
± 2.1
71.2
± 5.5
52.7
± 1.5
33.2
± 0.9
1.
5
2.
1
4
1.
4
± 5.1
68.6
± 2.0
± 0.9
25.6
± 1.1
± 5.9
Cac
o2
95.1
± 4.7
104.0 0. 100.6
± 0.4
91.6
± 5.7
1.
1
102.2 105.1
± 8.4
1.
0
89.5
± 4.4
21.9
± 0.8
4. 100.9 9.5 ±
1
96.1
± 2.7
20.9
± 3.9
4.
6
9
± 1.8
± 2.5
± 1.9
0.4
HCT
116
76.9
± 4.9
64.9
± 1.1
1.
2
89.7
± 3.0
79.4
± 7.0
1.
1
81.9
± 2.2
73.1
± 3.2
1.
1
83.9
± 4.9
45.1
± 1.9
1.
9
84.9
± 2.1
24.5
± 1.8
3.
5
86.8
± 2.1
45.0
± 2.9
1.
9
HT2
9
86.1
± 5.2
65.3
± 1.1
1.
3
96.3
± 2.0
60.9
± 1.9
1.
6
89.6
± 3.4
89.1
± 3.2
1.
0
95.2
± 5.1
47.1
± 1.7
2.
0
84.2
± 3.3
45.3
± 1.9
1. 109.8 38.4
9
2.
9
± 2.3
± 1.7
SW
48
101.6
± 4.2
62.6
± 1.2
1.
6
95.3
± 2.2
58.8
± 2.1
1.
6
88.2
± 6.6
55.2
± 3.0
1.
6
98.8
± 3.1
32.8
± 0.9
3.
0
61.8
± 2.2
26.5
± 1.1
2.
3
78.9
± 0.5
29.1
± 0.5
2.
7
Cancer
Lung
Cancer
Lung
Cancer
Nasoph
aryngea
l Cancer
Nasoph
A54
9
H12
99
74.9
± 4.1
96.7
± 4.9
82.9
± 0.1
109.1 0.
± 5.1
0.
9
96.7
± 1.1
92.7
± 3.2
73.5
± 3.1
67.4
± 6.4
1.
3
1.
4
77.4
± 6.1
89.8
± 9.1
59.4
± 3.2
96.3
± 0.9
1.
3
0.
9
57.9
± 6.1
91.3
± 6.6
24.6
± 1.7
52.4
± 4.1
2.
4
1.
7
99.6
± 2.5
93.1
± 3.3
37.1
± 1.1
38.1
± 0.8
2.
7
2.
4
61.9
± 1.5
72.3
± 1.1
27.8
± 0.9
43.7
± 0.8
2.
2
1.
7
9
CNE 102.2
1
72.5
± 1.5
1. 104.3
4
88.1
± 0.9
1.
2
102.2
± 6.5
70.5
± 1.2
1. 106.4 27.1
4
3.
9
82.5
± 2.1
12.4
± 0.5
6. 100.3 32.6
7
3.
1
± 3.1
± 2.4
± 5.5
± 1.0
± 2.2
± 0.9
90.1
± 1.3
101.3 0.
± 4.1
99.6
± 1.2
76.9
± 1.1
1.
3
103.3
± 5.1
88.9
± 3.2
1.
2
92.9
± 1.1
59.7
± 0.5
1.
6
90.4
± 2.5
61.4
± 3.7
1.
5
92.8
± 1.1
59.7
± 1.9
1.
6
aryngea HK1
l Cancer
9
Nasoph
SUN
99.3
± 1.0
80.5
± 3.4
1. 109.1 109.6 1.
105.7
± 5.4
68.6
± 3.1
1.
5
83.4
± 5.0
42.3
± 5.5
2.
0
52.4
± 1.5
38.6
± 2.5
1. 104.2 44.9
2.
3
aryngea
E1
2
± 1.2
± 5.4
0
4
± 2.7
± 2.5
l Cancer
Neurobl SHS
89.7
± 3.1
60.8
± 1.2
1.
5
99.9
± 2.4
65.8
± 3.3
1.
5
86.1
± 7.2
63.6
± 0.9
1.
4
84.9
± 8.1
33.7
± 0.7
2.
5
74.7
± 5.5
21.6
± 2.9
3.
5
70.8
± 1.5
30.6
± 2.9
2.
3
astoma
Pancrea
tic
Cancer
Pancrea
tic
Y5Y
AsP
C1
101.2
± 0.9
75.2
± 0.9
1.
3
96.4
± 1.1
67.7
± 2.1
1.
4
108.5 106.2
± 3.3 ± 4.4
1.
0
81.8
± 1.7
51.1
± 0.9
1.
6
84.7
± 2.2
40.2
± 2.7
2.
1
87.3
± 1.1
58.7
± 1.7
1.
5
BxP
C3
101.9 105.3 1. 100.1
± 5.3
82.9
± 7.0
1.
2
103.6 102.9
± 5.5
1. 108.2 62.9
0
1. 108.8 23.2
7
4. 107.8 56.5
7
1.
9
± 5.4
0
± 0.4
± 3.3
± 0.9
± 1.7
± 1.9
± 2.1
± 2.3
± 1.0
Cancer
Pancrea SW
91.9
± 5.3
64.4
± 8.1
1.
4
87.5
± 2.4
55.1
± 5.2
1.
6
65.8
± 2.1
69.8
± 3.2
0.
9
68.5
± 5.5
42.1
± 1.9
1.
6
72.4
± 2.2
28.6
± 1.6
2.
5
71.5
± 5.5
36.7
± 2.3
1.
9
tic
199
0
Cancer
Breast
Cells
MC
F10
A
100.4
± 0.3
88.7
± 9.4
1. 102.8
1
82.7
± 1.9
1.
2
104.9
± 5.2
78.8
± 1.2
1. 102.4 77.1
3
1.
3
88.8
± 0.9
47.5
± 2.0
1. 102.5 59.7
9
1.
7
(non-
cancero
us)
± 1.4
± 8.1
± 4.5
± 3.5
± 4.4
Lung
Cells
(non-
cancero
us)
MR
C5
100.9
± 9.1
54.8
± 4.2
1.
8
32.2
± 3.5
44.9
± 2.2
0.
7
78.9
± 4.5
24.3
± 4.4
3.
2
64.9
± 6.1
29.9
± 4.3
1.
8
74.9
± 4.5
22.2
± 2.2
3.
4
32.8
± 2.1
22.1
± 2.4
1.
5
Table 1. Cell viabilities (%) of diols 9a-f and dichlorides 10a-f (all at 100 µM). Results are expressed as the average
percentage of cell viability ± standard deviation from three independent experiments.
Examination of Table 1 reveals that in the majority of entries, the cell viabilities of the diols 9a-f exceeds that of the
corresponding dichloro derivatives 10a-f and hence the ratio is greater than 1. This demonstrates that the presence
of the mustard moiety is efficacious in reducing the cell viabilities in comparison to the diol substituents. The
magnitude of this ratio is generally low (between 1 and 2) for the majority of the non-trifluoromethylated series of

compounds whereas the trifluoromethylated compounds exhibit significantly larger values across the majority of cell
lines. The pair of trifluoromethylated compounds 9e/10e exhibit the highest ratios in 13 of the 20 cell lines.
With the exception of the breast cancer MDA-MB-468 and the lung cell MRC5 cell lines, all of the other cell lines
have their three lowest cell viabilities associated with the three trifluoromethylated compounds 10d-10f. The
magnitude of the difference between the cell viabilities of the trifluoromethylated and non-trifluoromethylated
compounds is noteworthy; for example for the lung cancer A549 cell line the cell viabilities recorded for the
trifluoromethylated derivatives 10d-10f (24.6-37.1%) are lower than those displayed by the non-trifluoromethylated
compounds 10a-10c (59.4-82.9%). It is also evident from the data in Table 1 that some dichloro-compounds exhibit
enhanced cytotoxicity towards the non-cancerous lung cell line MRC5. For example, in the presence of compounds
10d and 10e, 13 of the 18 cancerous cell lines are associated with higher cell viabilities compared to the MRC5 cell
line.
Inspection of the IC50 data presented in Table 2 indicates that the majority of the IC50 values associated with the diols
9a-9f are greater than 100 µM regardless of the presence/absence of a trifluoromethyl group in the aryl ring. Only
the diols 9b (MRC5 cell line), 9e (MCF7 cell line) and 9f (MCF7 and MRC5 cell lines) showed values less than 100 µM.
Within the non-trifluoromethylated series of dichloro-compounds 10a-10c, only six IC50 values below 100 µM are
observed; these are associated with the MCF7 cell line (all three compounds), the MRC5 cell line (compounds 10b
and 10c) and the T47D cell line (compound 10c only). In contrast, the trifluoromethylated derivatives 10d-10f exhibit
IC50 values below 100 µM for the majority of the entries in Table 2 (14, 18 and 12 entries for each compound
respectively) thus supporting the hypothesis that the trifluoromethyl group is an important factor associated with
the cytotoxicity of these compounds. Compound 10e displayed the lowest IC50 values and is the only compound
associated with IC50 values below 20 µM in 3 cell-lines [MCF7 (12.1 µM), Caco2 (10.1 µM) and CNE1 (15.3 µM)].
It is also evident from the data in Table 2 that the five derivatives 10b-f are cytotoxic towards the non-cancerous
lung cell line MRC5 with IC50 values within the range 31.0-62.1 µM. The only compound to show an IC50 value under
100 µM against the other non-cancerous cell line studied (the MCF10A breast cell line) was the trifluoromethylated
derivative 10e (81 µM).
Cancer
type
Breast
Cancer
Breast
Cancer
Cell
line
MCF7 >1
00
MDA- >1
MB-
231
9a
10a
9b
>100
>100
10b
9c
10c
9d
10d
9e
10e
9f
10f
50.9 ±
7.8
>100
70.2 ±
5.3
>100
>1
00
>1
00
44.3 ±
7.5
>100
>1
00
>1
00
34.3 ±
1.3
54.5 ±
2.3
88.3 ±
1.1
>100
12.1 ±
3.3
42.4 ±
4.6
88.1 ±
0.9
>100
33.1 ±
1.8
>100
00
Breast
Cancer
MDA- >1
>100
>100
>100
>1
00
>100
>100
>1
00
>100
>100
52.1 ±
5.1
>100
>100
>100
MB-
468
SKBR
3
00
Breast
Cancer
Breast
>1
00
>1
00
>1
00
>1
00
>1
00
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
67.8 ±
1.9
35.1 ±
0.9
39.9 ±
1.7
82.1 ±
0.5
87.8 ±
2.2
62.3 ±
2.3
33.3 ±
1.9
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
T47D
85.3 ±
2.1
>100
34.7 ±
1.2
10.1 ±
1.8
33.1 ±
8.1
92.1 ±
2.1
33.4 ±
4.5
57.7 ±
1.7
49.1 ±
2.1
15.3 ±
1.9
64.1 ±
2.1
37.1 ±
0.8
83.8 ±
8.1
63.1 ±
3.0
43.4 ±
4.9
70.4 ±
1.1
Cancer
Colorectal
Cancer
Colorectal
Cancer
Colorectal
Cancer
Colorectal
Cancer
Lung
Cancer
Lung
Cancer
Nasophary
ngeal
Caco
2
HCT1
16
>100
>100
>100
>100
>100
>100
HT29
SW48 >1
00
A549
>1
00
>1
00
>1
00
H129
9
CNE1
>100
32.1 ±
3.2
33.2 ±
2.8
Cancer
Nasophary
ngeal
HK1
>1
00
>100
>100
>100
>1
00
>100
>1
00
>100
>100
>100
>100
>100
Cancer

Nasophary
ngeal
SUNE >1
>100
>100
>100
>1
00
>100
>1
00
92.9 ±
5.2
>100
55.1 ±
2.5
>100
93.1 ±
1.9
1
00
Cancer
Neuroblast
oma
Pancreatic
Cancer
SHSY
5Y
AsPC
1
>1
00
>1
00
>100
>100
>100
>100
>100
>100
>1
00
>1
00
>100
>100
>1
00
>1
00
62.5 ±
4.4
>100
>100
>100
33.7 ±
2.7
85.1 ±
1.9
>100
>100
56.4 ±
6.9
>100
Pancreatic
Cancer
BxPC
3
>1
00
>100
>100
>100
>100
>100
>100
>100
>100
>100
>1
00
>100
>100
>100
>1
00
>100
>100
>100
>100
52.1 ±
3.3
>100
>100
>100
>100
Pancreatic
Cancer
SW19 >1
90 00
>1
00
>1
00
92.1 ±
7.7
33.3 ±
2.5
55.8 ±
4.3
Breast Cells MCF1 >1
(non-
>1
00
>1
00
>100
81.0 ±
0.7
>100
0A
00
cancerous)
Lung Cells
(non-
MRC
5
>1
00
>100
60.2 ±
3.7
58.3 ±
4.4
>1
00
54.1 ±
4.4
>1
00
62.1 ±
3.2
>100
31.0 ±
0.9
41.0 ±
0.9
33.9 ±
2.8
cancerous)
Table 2. IC50 values (µM) of diols 9a-f and dichlorides 10a-f. Results are expressed as the average IC50 value
± standard deviation from three independent experiments.
A commonly accepted mode of action of nitroaromatic pro-drugs is through bioreduction of a nitro group leading to
highly reactive aziridinium ions as already illustrated in Scheme 1. A possible explanation of the mode of action of
the trifluoromethylated compounds 10d-f is that bioreduction of the nitro group in these compounds (eg compound
10e, Scheme 3) would give the amine (or hydroxylamine) derivative 11 from which HF may be evolved resulting in
the production of the difluoro derivative 12 as a potential alkylating agent.9 The presence of the 1,3-dichloroproane
moiety is important for biological activity suggesting that this group could also be a potential alkylating agent.
Compounds 10a-f may have the potential to act as alkylating reagents (rather than pro-drugs) without the prior
reduction of a nitro group; our previously work demonstrated that compound 13 can be transformed into compound
15 presumably via an intermediate aziridinium ion 14 (Scheme 3).10 However, this potential mode of alkylation
would not account for the clear differences in biological activity shown between the non-trifluoromethylated
compounds 10a-c and the trifluoromethylated structures 10d-f.
NH2
NH2
DNA
alkylation
F
F
F
:
DNA
N
F
N
F
Cl
Cl
H
H+
Cl
Cl
11
12
NO2
NO2
NO2
NO2
Cl
NO2
NO2
Cl
+
N
N
N
_
Cl
15
13
14
Scheme 3. Potential modes of DNA alkylation.
In conclusion, we have demonstrated that the elevated cytotoxicities of compounds 10d-f compared to compounds
10a-c can be attributed to the presence of a trifluoromethyl group. Of the three trifluoromethylated compounds

evaluated, compound 10e appears to be the most cytotoxic to the majority of cell lines but it is also cytotoxic to non-
cancerous cell lines.
Acknowledgements
We thank the EPSRC UK National Mass Spectrometry Facility at Swansea University, UK, for high resolution mass
spectra.
References
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alkylating anticancer agents: Historic to future perspectives. Eur J Med Chem. 2018;151:401-433.
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6. Gillis EP, Eastman KJ, Hill MD, Donnelly DJ, Meanwell NA. Applications of Fluorine in Medicinal Chemistry. J Med
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7. Meyer F. Trifluoromethyl nitrogen heterocycles: synthetic aspects and potential biological targets. Chem
Commun. 2016;52:3077-3094.
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reduction and cytotoxicity of a series of nitroaromatic prodrugs, Bioorg Med Chem Lett. 2016;26:5851-5854.
9. Pan Y. The dark side of fluorine. ACS Med Chem Lett. 2019;10:1016-1019.
10. Burke PJ, Wong LC, Clegg W, Harrington RW, Jenkins TC, Knox RJ, Meikle IT, Stanforth SP. An unexpected ring
contraction of two nitroaryl pro-drugs: conversion of N-(nitroaryl)-3-chloropiperidine derivatives into N-(nitroaryl)-2-
chloromethylpyrrolidines. Tetrahedron Lett. 2010;51:3918-3921.
ra
ti
o
ra
ti
o
ra
ti
o
ra
ti
o
ra
ti
o
ra
ti
o
Cancer
type
Cell
line
9a
10a
9b
10b
9c
10c
9d
10d
9e
10e
9f
10f
Breast
Cancer
MC
F7
66.6
± 2.4
37.7
± 1.1
1.
8
65.6
± 1.2
38.8
± 0.4
1. 55.5 ±
4.4
25.1
± 2.1
2.
2
57.4
± 1.9
21.4
± 4.3
2.
7
45.7
± 1.9
10.5
± 0.9
4.
4
49.7
± 2.1
20.5
± 0.5
2.
4
7
MD
A-
MB-
231
MD
A-
MB-
468
SKB
R3
T47
D
Breast
Cancer
91.8
± 3.3
85.1
± 2.1
1.
1
87.7
± 2.1
72.4
± 1.1
1. 79.4 ±
83.4
± 2.5
1.
0
67.3
± 1.8
32.1
± 0.5
2.
1
93.1
± 5.5
31.8
± 3.9
2.
9
65.7
± 1.7
57.4
± 2.7
1.
1
2
8.4
Breast
Cancer
104.0
± 5.0
63.6
± 6.1
1.
6
102.2
± 5.5
45.1
± 2.4
2.
3
105.8
± 7.1
61.3
± 4.3
1.
7
100.4
± 4.1
65.1
± 6.6
1.
5
93.2
± 3.2
20.4
± 4.9
4.
6
98.7
± 2.7
58.6
± 2.1
1.
7
Breast
Cancer
Breast
Cancer
Colorect
al
100.9
± 7.9
76.2
79.9
± 0.8
69.8
± 1.9
1.
3
1.
1
93.1
± 1.1
73.6
± 1.0
73.1
± 1.1
65.2
± 1.5
1. 98.9 ±
3.4
71.6
± 5.0
1.
4
66.40
± 5.1
68.6
38.5
± 0.9
25.6
± 1.1
1.
7
2.
7
75.2
± 3.5
59.1
± 2.2
55.6
± 1.1
24.3
± 1.7
1.
4
2.
4
79.4
± 2.1
71.2
± 5.5
52.7
± 1.5
33.2
± 0.9
1.
5
2.
1
3
1. 79.9 ± 58.7 ± 1.
± 5.9
1
2.2
3.4
4
± 2.0
Cac
o2
95.1
± 4.7
104.0
± 0.4
0.
9
100.6
± 1.8
91.6
± 5.7
1.
1
102.2
± 8.4
105.1
± 2.5
1.
0
89.5
± 4.4
21.9
± 0.8
4.
1
100.9 9.5 ± 10
± 1.9 0.4 .6
96.1
± 2.7
20.9
± 3.9
4.
6
Cancer

Colorect
al
Cancer
Colorect
al
Cancer
Colorect
al
HCT
116
76.9
± 4.9
64.9
± 1.1
1.
2
89.7
± 3.0
79.4
± 7.0
1. 81.9 ± 73.1 ± 1.
83.9
± 4.9
45.1
± 1.9
1.
9
84.9
± 2.1
24.5
± 1.8
3.
5
86.8
± 2.1
45.0
± 2.9
1.
9
1
2.2
3.2
1
HT2
9
86.1
± 5.2
65.3
± 1.1
1.
3
96.3
± 2.0
60.9
± 1.9
1. 89.6 ±
3.4
89.1
± 3.2
1.
0
95.2
± 5.1
47.1
± 1.7
2.
0
84.2
± 3.3
45.3
± 1.9
1.
9
109.8
± 2.3
38.4
± 1.7
2.
9
6
SW
48
101.6
± 4.2
62.6
± 1.2
1.
6
95.3
± 2.2
58.8
± 2.1
1. 88.2 ±
6.6
55.2
± 3.0
1.
6
98.8
± 3.1
32.8
± 0.9
3.
0
61.8
± 2.2
26.5
± 1.1
2.
3
78.9
± 0.5
29.1
± 0.5
2.
7
6
Cancer
Lung
Cancer
Lung
A54
9
H12
99
74.9
± 4.1
96.7
± 4.9
82.9
± 0.1
109.1
± 5.1
0.
9
0.
9
96.7
± 1.1
92.7
± 3.2
73.5
± 3.1
67.4
± 6.4
1. 77.4 ±
6.1
1. 89.8 ±
59.4
± 3.2
96.3
± 0.9
1.
3
0.
9
57.9
± 6.1
91.3
± 6.6
24.6
± 1.7
52.4
± 4.1
2.
4
1.
7
99.6
± 2.5
93.1
± 3.3
37.1
± 1.1
38.1
± 0.8
2.
7
2.
4
61.9
± 1.5
72.3
± 1.1
27.8
± 0.9
43.7
± 0.8
2.
2
1.
7
3
Cancer
Nasoph
aryngea
l Cancer
Nasoph
aryngea
l Cancer
Nasoph
aryngea
l Cancer
Neurobl
astoma
Pancrea
tic
Cancer
Pancrea
tic
Cancer
Pancrea
tic
4
9.1
CNE
1
102.2
± 3.1
72.5
± 1.5
1.
4
104.3
± 2.4
88.1
± 0.9
1.
2
102.2
± 6.5
70.5
± 1.2
1.
4
106.4
± 5.5
27.1
± 1.0
3.
9
82.5
± 2.1
12.4
± 0.5
6.
7
100.3
± 2.2
32.6
± 0.9
3.
1
90.1
± 1.3
101.3
± 4.1
0.
9
99.6
± 1.2
76.9
± 1.1
1.
3
103.3
± 5.1
88.9
± 3.2
1.
2
92.9
± 1.1
59.7
± 0.5
1.
6
90.4
± 2.5
61.4
± 3.7
1.
5
92.8
± 1.1
59.7
± 1.9
1.
6
HK1
SUN
E1
99.3
± 1.0
80.5
± 3.4
1.
2
109.1 109.6
± 1.2
1.
0
105.7
± 5.4
68.6
± 3.1
1.
5
83.4
± 5.0
42.3
± 5.5
2.
0
52.4
± 1.5
38.6
± 2.5
1.
4
104.2
± 2.7
44.9
± 2.5
2.
3
± 5.4
SHS
Y5Y
89.7
± 3.1
60.8
± 1.2
1.
5
99.9
± 2.4
65.8
± 3.3
1. 86.1 ±
63.6
± 0.9
1.
4
84.9
± 8.1
33.7
± 0.7
2.
5
74.7
± 5.5
21.6
± 2.9
3.
5
70.8
± 1.5
30.6
± 2.9
2.
3
5
7.2
AsP
C1
101.2
± 0.9
75.2
± 0.9
1.
3
96.4
± 1.1
67.7
± 2.1
1.
4
108.5
± 3.3
106.2
± 4.4
1.
0
81.8
± 1.7
51.1
± 0.9
1.
6
84.7
± 2.2
40.2
± 2.7
2.
1
87.3
± 1.1
58.7
± 1.7
1.
5
BxP
C3
101.9 105.3
± 5.3
1.
0
100.1
± 0.4
82.9
± 7.0
1.
2
103.6
± 5.5
102.9
± 3.3
1.
0
108.2
± 0.9
62.9
± 1.7
1.
7
108.8
± 1.9
23.2
± 2.1
4.
7
107.8
± 2.3
56.5
± 1.0
1.
9
± 5.4
SW
199
0
91.9
± 5.3
64.4
± 8.1
1.
4
87.5
± 2.4
55.1
± 5.2
1.
6
65.8
± 2.1
69.8
± 3.2
0.
9
68.5
± 5.5
42.1
± 1.9
1.
6
72.4
± 2.2
28.6
± 1.6
2.
5
71.5
± 5.5
36.7
± 2.3
1.
9
Cancer
Breast
Cells
(non-
cancero
us)
MC
F10
A
100.4
± 0.3
88.7
± 9.4
1.
1
102.8
± 1.4
82.7
± 1.9
1.
2
104.9
± 5.2
78.8
± 1.2
1.
3
102.4
± 8.1
77.1
± 4.5
1.
3
88.8
± 0.9
47.5
± 2.0
1.
9
102.5
± 3.5
59.7
± 4.4
1.
7
Lung
Cells
(non-
cancero
us)
MR
C5
100.9
± 9.1
54.8
± 4.2
1.
8
32.2
± 3.5
44.9
± 2.2
0.
7
78.9
± 4.5
24.3
± 4.4
3.
2
64.9
± 6.1
29.9
± 4.3
1.
8
74.9
± 4.5
22.2
± 2.2
3.
4
32.8
± 2.1
22.1
± 2.4
1.
5
Cancer
type
Breast
Cancer
Breast
Cancer
Cell
line
MCF7 >1
00
MDA- >1
MB-
231
9a
10a
9b
>100
>100
10b
9c
10c
9d
10d
9e
10e
9f
10f
50.9 ±
7.8
>100
70.2 ±
5.3
>100
>1
00
>1
00
44.3 ±
7.5
>100
>1
00
>1
00
34.3 ±
1.3
54.5 ±
2.3
88.3 ±
1.1
>100
12.1 ±
3.3
42.4 ±
4.6
88.1 ±
0.9
>100
33.1 ±
1.8
>100
00
Breast
Cancer
MDA- >1
>100
>100
>100
>1
00
>100
>100
>1
00
>100
>100
52.1 ±
5.1
>100
>100
>100
MB-
468
SKBR
3
00
Breast
Cancer
Breast
Cancer
Colorectal
Cancer
Colorectal
Cancer
Colorectal
Cancer
Colorectal
Cancer
Lung
Cancer
Lung
>1
00
>1
00
>1
00
>1
00
>1
00
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
>1
00
67.8 ±
1.9
35.1 ±
0.9
39.9 ±
1.7
82.1 ±
0.5
87.8 ±
2.2
62.3 ±
2.3
33.3 ±
1.9
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
>100
T47D
85.3 ±
2.1
>100
34.7 ±
1.2
10.1 ±
1.8
33.1 ±
8.1
92.1 ±
2.1
33.4 ±
4.5
57.7 ±
1.7
49.1 ±
2.1
64.1 ±
2.1
37.1 ±
0.8
83.8 ±
8.1
63.1 ±
3.0
43.4 ±
4.9
70.4 ±
1.1
Caco
2
HCT1
16
>100
>100
>100
>100
>100
HT29
SW48 >1
00
A549
>1
00
>1
00
H129
9
>100
Cancer

Nasophary
ngeal
Cancer
Nasophary
ngeal
Cancer
CNE1
HK1
>1
00
>100
>100
>100
>100
>100
>100
>100
>100
>100
>1
00
>100
>100
>100
>1
00
32.1 ±
3.2
>100
>100
>100
15.3 ±
1.9
>100
>100
>100
33.2 ±
2.8
>1
00
>1
00
>1
00
>100
>100
>100
Nasophary
ngeal
SUNE >1
1
>1
00
>1
00
92.9 ±
5.2
55.1 ±
2.5
93.1 ±
1.9
00
Cancer
Neuroblast
oma
Pancreatic
Cancer
SHSY
5Y
AsPC
1
>1
00
>1
00
>100
>100
>100
>100
>100
>100
>1
00
>1
00
>100
>100
>1
00
>1
00
62.5 ±
4.4
>100
>100
>100
33.7 ±
2.7
85.1 ±
1.9
>100
>100
56.4 ±
6.9
>100
Pancreatic
Cancer
BxPC
3
>1
00
>100
>100
>100
>100
>100
>100
>100
>100
>100
>1
00
>100
>100
>100
>1
00
>100
>100
>100
>100
52.1 ±
3.3
>100
>100
>100
>100
Pancreatic
Cancer
SW19 >1
90 00
>1
00
>1
00
92.1 ±
7.7
33.3 ±
2.5
55.8 ±
4.3
Breast Cells MCF1 >1
(non-
>1
00
>1
00
>100
81.0 ±
0.7
>100
0A
00
cancerous)
Lung Cells
(non-
MRC
5
>1
00
>100
60.2 ±
3.7
58.3 ±
4.4
>1
00
54.1 ±
4.4
>1
00
62.1 ±
3.2
>100
31.0 ±
0.9
41.0 ±
0.9
33.9 ±
2.8
cancerous)
Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal relationships that could
have appeared to influence the work reported in this paper.
☐The authors declare the following financial interests/personal relationships which may be considered as potential
competing interests: