Boronic acid-containing diarylpyrimidine derivatives as novel HIV-1 NNRTIs: Design, synthesis and biological evaluation

Article abstract of DOI:10.1016/j.cclet.2021.02.033

Drug resistance remains to be a serious problem with type I human immunodeficiency virus (HIV-1) non-nucleoside reverse transcriptase inhibitors (NNRTIs). A series of novel boronic acid-containing diarylpyrimidine (DAPY) derivatives were designed via bioisosterism and scaffold-hopping strategies, taking advantage of the ability of a boronic acid group to form multiple hydrogen bonds. The target compounds were synthesized and evaluated for their anti-HIV activities and cytotoxicity in MT-4 cells. Compound 10j yielded the most potent activity and turned out to be a single-digit nanomolar inhibitor towards the HIV-1 IIIB [wild-type (WT) strain], L100I and K103N strains, with 50% effective concentration (EC₅₀) values of 7.19–9.85 nmol/L. Moreover, 10j inhibited the double-mutant strain RES056 with an EC₅₀ value of 77.9 nmol/L, which was 3.3-more potent than that of EFV (EC₅₀ = 260 nmol/L) and comparable to that of ETR (EC₅₀ = 32.2 nmol/L). 10j acted like classical NNRTIs with high affinity for WT HIV-1 reverse transcriptase (RT) with 50% inhibition concentration (IC₅₀) value of 0.1837 μmol/L. Furthermore, molecular dynamics simulation indicated that 10j was proposed as a promising molecule for fighting against HIV-1 infection through inhibiting RT activity. Overall, the results demonstrated that 10j could serve as a lead molecule for further modification to address virus-drug resistance.

Full text of DOI:10.1016/j.cclet.2021.02.033

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CCLET-6162; No. of Pages 5
Chinese Chemical Letters xxx (xxxx) xxx–xxx
Contents lists available at ScienceDirect
Chinese Chemical Letters
journal homepage: www.elsevier.com/locate/cclet
Communication
Boronic acid-containing diarylpyrimidine derivatives as novel HIV-1
NNRTIs: Design, synthesis and biological evaluation
Da Fenga, Fenju Weia, Yanying Suna, Prem Prakash Sharmab, Tao Zhanga, Hao Lina,
*
Brijesh Rathib, Erik De Clercqc, Christophe Pannecouquec, Dongwei Kanga,e,
,
a,d,
Peng Zhana,d, , Xinyong Liu
*
*
a
Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of
Medicine, Shandong University, Ji’nan 250012, China
b
Laboratory for Translational Chemistry and Drug Discovery, Department of Chemistry, Hansraj College, University of Delhi, Delhi 110007, India
Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, K.U. Leuven, Leuven B-3000, Belgium
China-Belgium Collaborative Research Center for Innovative Antiviral Drugs of Shandong Province, Ji’nan 250012, China
Suzhou Research Institute, Shandong University, Suzhou 215123, China
c
d
e
A R T I C L E I N F O
A B S T R A C T
Article history:
Drug resistance remains to be a serious problem with type I human immunodeficiency virus (HIV-1) non-
Received 29 January 2021
Received in revised form 5 February 2021
Accepted 17 February 2021
Available online xxx
nucleoside reverse transcriptase inhibitors (NNRTIs).
A series of novel boronic acid-containing
diarylpyrimidine (DAPY) derivatives were designed via bioisosterism and scaffold-hopping strategies,
taking advantage of the ability of a boronic acid group to form multiple hydrogen bonds. The target
compounds were synthesized and evaluated for their anti-HIV activities and cytotoxicity in MT-4 cells.
Compound 10j yielded the most potent activity and turned out to be a single-digit nanomolar inhibitor
towards the HIV-1 IIIB [wild-type (WT) strain], L100I and K103N strains, with 50% effective concentration
(EC50) values of 7.19–9.85 nmol/L. Moreover, 10j inhibited the double-mutant strain RES056 with an EC50
value of 77.9 nmol/L, which was 3.3-more potent than that of EFV (EC50 = 260 nmol/L) and comparable to
that of ETR (EC50 = 32.2 nmol/L). 10j acted like classical NNRTIs with high affinity for WT HIV-1 reverse
Keywords:
HIV-1
NNRTIs
NNIBP
DAPY
transcriptase (RT) with 50% inhibition concentration (IC50) value of 0.1837 mmol/L. Furthermore,
Boronic acid
Molecular dynamics simulation
molecular dynamics simulation indicated that 10j was proposed as a promising molecule for fighting
against HIV-1 infection through inhibiting RT activity. Overall, the results demonstrated that 10j could
serve as a lead molecule for further modification to address virus-drug resistance.
© 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
Published by Elsevier B.V. All rights reserved.
With the morbidity and mortality increasing rapidly world-
wide, the acquired immunodeficiency syndrome (AIDS) keeps to
be one of the most serious global public health problems, and the
type I human immunodeficiency virus (HIV-1) is the main
causative agent for it [1]. In the life cycle of HIV-1, the reverse
transcriptase (RT) utilizes RNA genome to synthesize double-
stranded viral DNA, which was one of the most important enzymes
in viral infection and a major target for antiretroviral therapies
[2,3]. RT inhibitors can be divided into the nucleoside reverse
transcriptase inhibitors (NRTIs) and non-nucleoside reverse
transcriptase inhibitors (NNRTIs). NNRTIs distort the enzyme’s
active site and perturb the alignment of the primer terminus by
interacting in a noncompetitive manner with the allosteric site
(NNRTIs binding pocket, NNIBP) about 10 angstroms distant from
the polymerase active site of RT, resulting in inhibition of the
reverse transcription step of HIV-1 replication [4,5]. NNRTIs are a
component of highly active antiretroviral therapy (HAART)
regimens used to fight HIV-1 due to their potent antiviral activity,
high selectivity and modest toxicity [6].
Up to now, six NNRTIs have been approved by the U.S. Food and
Drug Administration (FDA). Nevirapine (NVP), delavirdine (DLV)
and efavirenz (EFV) constitute the first-generation, but the rapid
emergence of drug-resistance and toxicities limit their clinical use
[7]. Etravirine (ETR), rilpivirine (RPV) and doravirine (DOR) are the
second-generation NNRTIs (Fig. 1), in which ETR and RPV belong to
the diarylpyrimidine (DAPY) family and exhibit a broad spectrum
of activity against the clinically relevant NNRTIs-resistance strains.
However, their clinical application has also been complicated by
* Corresponding authors at: Department of Medicinal Chemistry, Key Laboratory
of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences,
Cheeloo College of Medicine, Shandong University, Ji’nan 250012, China.
E-mail addresses: kangdongwei@126.com (D. Kang), zhanpeng1982@sdu.edu.cn
(P. Zhan), xinyongl@sdu.edu.cn (X. Liu).
https://doi.org/10.1016/j.cclet.2021.02.033
1001-8417/© 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
Please cite this article as: D. Feng, F. Wei, Y. Sun et al., Boronic acid-containing diarylpyrimidine derivatives as novel HIV-1 NNRTIs: Design,
synthesis and biological evaluation, Chin. Chem. Lett., https://doi.org/10.1016/j.cclet.2021.02.033

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Chinese Chemical Letters xxx (xxxx) xxx–xxx
establish hydrogen bond with K101 and E138 directly or through
a bridging water molecule; the piperidine nitrogen develops
water-mediated hydrogen bonds with K103 and P236; and the
surface-positioned sulfonamide group of the right wing developed
a double-hydrogen bond with the carbonyl oxygen of K104 and the
backbone nitrogen of V106. These extensive hydrogen-bonding
networks between the inhibitor and the backbone of residues
proved to be responsible for the stabilization of K-5a2 to the NNIBP.
Similar to the sulfonamide group, the boronic acid group proves
to have the distinct ability to form hydrogen bonds [16,17].
Recently, boronic acid have been extensively used for the purposes
of biological probe development and drug discovery [18],
especially for antiviral drugs, such as HIV-1 protease and hepatitis
C
virus (HCV) non-nucleoside polymerase (NS5B) inhibitors
[16,19,20]. In boronic acid, there are two hydroxy groups acting
as both donors and acceptors of hydrogen bonds. The hydroxy
groups display four lone pairs and two hydrogen-bond donors,
which provide six opportunities to form hydrogen bonds with one
group [16]. Inspired by this, we tried boronic acid to replace the
sulfonamide group in the lead K-5a2 by utilizing the bioisosterism
strategy in this work. We anticipated that the hydroxy groups of
boronic acid could form interactions with K104 and V106.
Meanwhile, bioisosterism and scaffold-hopping strategies were
also employed to displace the center core of K-5a2 with different
fused pyrimidine rings and yielded twelve novel boronic acid-
containing DAPY derivatives [21]. Moreover, the privileged 4-
cyanovinyl-2,6-dimethylphenyl structure was introduced to the
left wing of the most potent inhibitor 5j (Fig. 3). The detailed
structure À activity relationship (SAR) study of the derivatives and
molecular dynamics simulation were also studied.
The synthetic protocols for the newly designed compounds
5a–k and 10j are outlined in Schemes 1 and 2, respectively. All
derivatives were prepared by well-established methods as
described in our previous articles [10–13]. Commercially available
2,4-dichloropyrimidines 1a–k were selected as the starting
materials, which were reacted with 4-hydroxy-3,5-dimethylben-
zonitrile or 4-hydroxy-3,5-dimethylbenzaldehyde through nucle-
ophilic substitution to afford 2a–k and 6j. Then, 6j was treated
with (EtO)2P(O)CH2CN in the presence of t-BuOK to give 7j. Next,
2a–k or 7j were reacted with 4-amino-1-Boc-piperidine to afford
3a–k or 8j via Buchwald-Hartwig reaction. Removal of the Boc
protecting group gave the corresponding key analogues 4a–k or 9j,
which led to the desired compounds by nucleophilic substitution
with (4-(chloromethyl)phenyl)boronic acid.
Fig. 1. Chemical structures of six NNRTIs approved by the U.S. FDA.
emergence of drug-resistance mutations (such as E138K and
RES056) [7]. Besides, multiple lipophilic aromatic rings in their
structure led to their poor solubility and lower oral bioavailability
[7]. In 2017, elsulfavirine was marketed as a prodrug in Russia for
the treatment of HIV, which displayed antiviral nanomolar potency
[EC50 wild-type (WT) HIV-1 strain (IIIB) = 1.2 nmol/L] [7,8].
Therefore, it is imperative to discover novel NNRTIs with improved
drug resistance profiles and favorable solubility.
Our previous studies have discovered a series of novel DAPY
derivatives with more potent activity against the WT and mutant
HIV-1 strains than the approved drug ETR [9–14]. Especially, the
two piperidine-substituted thiophene[3,2-d]pyrimidine deriva-
tives, K-5a2 and 25a (Fig. 2A), exhibited highly effective anti-HIV-1
activities and improved resistance profiles [15]. The co-crystal
structure of HIV-1 RT in complex with K-5a2 confirmed the “four-
point pharmacophore model” of DAPY in NNIBP, which includes
the hydrophobic domain, the hydrogen bonding domain, tolerant
region I and tolerant region II (Fig. 2B) [15]. Specifically, the
interactions between K-5a2 and RT were elucidated. As depicted in
Fig. 2C, the central thiophene[3,2-d]pyrimidine core could
The antiviral potency of the synthesized compounds was
evaluated in cultured MT-4 cells infected with WT HIV-1 strain
(IIIB) or a panel of NNRTIs-resistant single and double mutant
strains, including L100I, K103N, Y181C, Y188L, E138K,
F227L + V106A and K103N + Y181C (RES056). ETR and EFV were
selected as control drugs. The values of 50% effective concentration
(EC50, anti-HIV potency), 50% cytotoxicity concentration (CC50
,
cytotoxicity) and selectivity index (SI, CC50/EC50 ratio) are
summarized in Table 1 and Table S1 (Supporting information).
As shown in Table 1, compounds containing sulfur atom in the
central ring (5aÀd) exhibited nanomolar antiviral activity against
HIV-1 IIIB, L100I, K103N, Y181C, Y188L and E138K. For the K103N
mutation, 5aÀd displayed the most potent activities with EC50
values of 6.19, 8.18, 11.3 and 14.6 nmol/L, they were 12-, 9-, 7-, and
5-fold more potent than the reference drug EFV (EC50 = 75.4 nmol/
L) but a little bit lower than ETR (EC50 = 3.33 nmol/L). However, all
derivatives showed weaker efficacy against the double-mutant
strain RES056.
With the aim to effectively occupy the tolerant region II and
establish more interactions with NNIBP, the five-membered
thiophene ring of K-5a2 was changed to six-membered aromatic
and alicyclic rings, yielding derivatives 5eÀg and 5hÀk. Among
Fig. 2. (A) Chemical structures of our previously reported potent HIV-1 NNRTIs; (B)
The co-crystal structure of K-5a2/RT complexes (PDB code: 6c0J) and the four-point
pharmacophore model; (C) The detailed interactions with WT RT of K-5a2.
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Fig. 3. Design and optimization of the boronic acid-containing DAPY derivatives.
Scheme 1. Synthesis of 5aÀka. aReagents and conditions: i) 3,5-dimethyl-4-hydroxybenzonitrile, K2CO3, DMF, r.t.; ii) BINAP, Pd2(dba)3, Cs2CO3,1,4-dioxane, 90 ꢀC, N2; iii) TFA,
DCM, r.t.; iv) (4-(chloromethyl)phenyl)boronic acid, K2CO3, DMF, r.t.
them, 5eÀg turned out to be nanomolar inhibitors of HIV-1 IIIB,
K103N and E138K, with EC50 values ranging from 2.73 nmol/L to
24.5 nmol/L. In addition, compound 5g, with a single pyrimidine
central core, displayed extremely potent activity against HIV-1 IIIB
(EC50 = 2.73 nmol/L), which was comparable to that of ETR
(EC50 = 3.13 nmol/L) and EFV (EC50 = 2.49 nmol/L). Compound 5e
with the quinazoline central core showed acceptable activity
against HIV-1 IIIB and K103N (EC50 = 6.06 and 16.2 nmol/L,
respectively), and introducing nitrogen atom at the C-8 position
of the quinazoline core led to a similar potency (5f, EC50 = 6.53
and 12.2 nmol/L, respectively). However, these compounds still
showed low activities against the double-mutant strain RES056. 5i
exhibited high potency against WT HIV-1 (EC50 = 4.87 nmol/L) and
the single mutant K103N (EC50 = 5.98 nmol/L), being equipotent to
that of ETR (EC50 = 3.13 and 3.33 nmol/L, respectively). Moreover,
5k displayed moderate activity (EC50 = 15.1–71.8 nmol/L) against
L100I, Y181C, Y188L and E138K. Introduction of sulfur or oxygen
atoms at the C-6 position of 5i yielded compounds 5h and 5j,
Scheme 2. Synthesis of 10ja. aReagents and conditions: i) 4-hydroxy-3,5-
among which, 5h displayed moderate potency against HIV-1 IIIB
and K103N (EC50 = 6.60 and 10.2 nmol/L, respectively). Compound
5j was also effective against IIIB and K103N (EC50 = 7.01 and
dimethylbenzaldehyde, K2CO3, DMF, r.t.; ii) (EtO)2P(O)CH2CN, t-BuOK, THF, 0 ꢀ
C
to r.t.; iii) BINAP, Pd2(dba)3, Cs2CO3, 1,4-dioxane, 90 ꢀC, N2; iv) TFA, DCM, r.t.; v)
(4-(chloromethyl)phenyl)boronic acid, K2CO3, DMF, r.t.
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Table 1
Anti-HIV activity and cytotoxicity of 5a–k and 10j.
Compd.
R
Central core EC50 (nmol/L)a
CC50 (m
mol/L)b
IIIB
L100I
K103N
Y181C
Y188L
E138K
F227L +
V106A
RES056
5a
CN
8.10 Æ 1.98
49.7 Æ 29.8 6.19 Æ 2.03
34.5 Æ 9.62
51.6 Æ 19.9 39.4 Æ 5.83 158 Æ 58.9 1300 Æ 407 > 244
5b
5c
5d
5e
5f
CN
CN
CN
CN
CN
7.85 Æ 2.12
13.5 Æ 10.9
6.71 Æ 2.12
6.06 Æ 1.94
6.53 Æ 1.61
46.5 Æ 18.2 8.18 Æ 1.18
59.9 Æ 12.4 11.3 Æ 1.69
47.5 Æ 10.6
32.1 Æ 5.22
26.0 Æ 6.27
66.1 Æ 20.2
35.3 Æ 6.44
52.4 Æ 11.8 39.3 Æ 13.1
225 Æ 70.0 1111 Æ 461 126 Æ 5.35
98.5 Æ 29.5 35.6 Æ 5.93 381 Æ 100 618 Æ 98.7 30.8 Æ 6.13
133 Æ 117
14.6 Æ 3.16
125 Æ 44.6 36.0 Æ 4.74
136 Æ 48.7 16.0 Æ 5.11
374 Æ 59.1 760 Æ 196
99.4 Æ 9.11
162 Æ 90.6 16.2 Æ 4.69
55.2 Æ 26.6 12.2 Æ 5.77
319 Æ 84.0 2219 Æ 336 25.9 Æ 0.661
61.8 Æ 6.71 24.5 Æ 6.60 134 Æ 29.5 1439 Æ 213 27.2 Æ 1.56
5g
5h
CN
CN
2.73 Æ 0.521 94.1 Æ 37.3 7.44 Æ 2.14
20.4 Æ 2.95
29.4 Æ 3.10
326 Æ 101
15.7 Æ 1.86
288 Æ 121
311 Æ 126
1003 Æ 221 17.0 Æ 2.48
1776 Æ 542 > 243
6.60 Æ 1.91
4.87 Æ 1.54
7.01 Æ 2.09
15.6 Æ 6.02
45.5 Æ 21.8 10.2 Æ 2.45
71.8 Æ 37.1 5.98 Æ 1.82
37.7 Æ 12.8 7.11 Æ 1.21
105 Æ 10.5 33.8 Æ 2.78
40.8 Æ 18.7 31.5 Æ 3.02
30.7 Æ 9.81 15.1 Æ 4.79
5i
CN
CN
CN
27.1 Æ 11.4
20.4 Æ 4.49
76.3 Æ 13.1
94.4 Æ 15.7 861 Æ 317
> 251
5j
47.9 Æ 9.18 13.6 Æ 0.633 146 Æ 38.6 1262 Æ 580 82.2 Æ 4.96
79.9 Æ 31.9 50.5 Æ 8.64 387 Æ 57.9 3312 Æ 901 > 244
5k
10j
7.23 Æ 1.82
9.85 Æ 2.21 7.19 Æ 0.547 19.7 Æ 6.45
39.9 Æ 6.02 17.3 Æ 3.78
43.2 Æ 9.66 77.9 Æ 11.2 25.6 Æ 0.929
EFV
ETR
–
–
–
–
2.49 Æ 0.547 33.9 Æ 8.39 75.4 Æ 10.8
5.42 Æ 0.994 196 Æ 54.8 4.36 Æ 1.05
254 Æ 65.5 260 Æ 47.6 > 6.34
15.7 Æ 3.69 32.2 Æ 12.2 > 4.59
3.13 Æ 0.902 5.94 Æ 1.60 3.33 Æ 0.589 14.8 Æ 2.47
14.1 Æ 3.83 6.46 Æ 1.71
a
EC50: concentration of compound required to achieve 50% protection of MT-4 cell cultures against HIV-1-induced cytopathic effect, as determined by the MTT method.
CC50: concentration required to reduce the viability of mock-infected cell cultures by 50%, as determined by the MTT method.
b
7.11 nmol/L). Moreover, it turned out to be an effective inhibitor
be improved. Our previous research has demonstrated that
dihydrofuro[3,4-d]pyrimidine was a privileged scaffold for improv-
ing the anti-HIV-1 activity and physiochemical properties [13]. So,
the cyano group in the left wing of 5j was replaced by cyanovinyl to
obtain derivative 10j, with the aim to establish more stronger
interactions with highly conserved residues F227 and W229. As
with EC50 values of 13.6 À 47.9 nmol/L against the other mutant
strains, except for RES056.
Although compounds 5j and 5i exhibited potent activities
against most mutant HIV-1 strains, their activities against the
double-mutant strain RES056 (EC50 = 1262 and 861 nmol/L) need to
4

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Table 2
Inhibitory activity against WT HIV-1 RT.
Compd.
IC50
(m
mol/L)a
Compd.
IC50
(m
mol/L)a
Compd.
IC50 (m
mol/L)a
5a
5b
5c
5d
5e
0.1977 Æ 0.0234
0.1091 Æ 0.0028
0.2644 Æ 0.0082
0.2391 Æ 0.0137
0.1232 Æ 0.0042
5f
5g
5h
5i
0.2804 Æ 0.0153
0.0678 Æ 0.0155
0.1504 Æ 0.0124
0.1267 Æ 0.0228
0.1663 Æ 0.0057
5k
10j
NVP
EFV
0.2425 Æ 0.0083
0.1837 Æ 0.0094
0.4766 Æ 0.2099
0.0067 Æ 0.0014
5j
a
IC50: inhibitory concentration of test compound required to inhibit biotin deoxyuridine triphosphate (biotin-dUTP) incorporation into WT HIV-1 RT by 50%.
shown in Table 1, 10j showed good inhibition against L100I with an
EC50 value of 9.85 nmol/L, which was about 3.8-fold more potent
than 5j (EC50 = 37.7 nmol/L). Especially, it is noteworthy that 10j
inhibitedthedouble-mutantF227L + V106AstrainandRES056with
EC50 values of 43.2 and 77.9 nmol/L, which were 3.4- and 16.2-fold
more potent than those of 5j (EC50 = 146 and 1262 nmol/L). Besides,
10j showedacceptableantiviralactivityagainstotherviralstrains,it
was equipotent (IIIB, EC50 = 7.23 nmol/L; K103N, EC50 = 7.19 nmol/L;
Y181C, EC50 = 19.7 nmol/L; Y188L, EC50 = 39.9 nmol/L; E138K,
EC50 = 17.3 nmol/L) with 5j (EC50 = 7.01, 7.11, 20.4, 47.9 and
13.6 nmol/L). These results verified that introducing the cyanovinyl
group in the left wing of 10j remarkably increased the antiviral
activities, especially against the double-mutant strains. Moreover,
10j demonstrated higher SI values towards HIV-1 IIIB and all the
tested mutant strains (Table S1).
a lead for further modification to get more potent NNRTIs of
important practical significance.
Declaration of competing interest
The authors report no declarations of interest.
Acknowledgments
We gratefully acknowledge financial support from the National
Natural Science Foundation of China (Nos. 81973181, 81903453),
Shandong Provincial Natural Science Foundation (No.
ZR2019BH011), Natural Science Foundation of Jiangsu Province
(No. BK2019041035), China Postdoctoral Science Foundation (Nos.
2019T120596, 2018M640641), Science Foundation for Outstanding
Young Scholars of Shandong Province (ZR2020JQ31), Science
Foundation for Excellent Young Scholars of Shandong Province
(ZR2020YQ61), National Science and Technology Major Projects
for "Major New Drugs Innovation and Development"
(2019ZX09301126), Shandong Provincial Key Research and Devel-
opment Project (Nos. 2017CXGC1401, 2019JZZY021011), Foreign
cultural and educational experts Project (GXL20200015001), the
Taishan Scholar Program at Shandong Province and KU Leuven (No.
GOA 10/014).
In order to confirm their binding target, all derivatives were
evaluated for their inhibitory activity against recombinant WT
HIV-1 RT enzyme (Table 2). All compounds showed high binding-
affinity with WT HIV-1 RT (IC50 = 0.0678–0.6585
compared to that of NVP (IC50 = 0.4766 mol/L). Among these,
compound 5g, with a pyrimidine scaffold, exhibited the highest RT
inhibitory activity (IC50 = 0.0678 mol/L), which was in accordance
mmol/L) as
m
m
with the anti-HIV-1 potency. These results suggest that the newly
synthesized derivatives behave as typical NNRTIs.
Furthermore, we carried out the molecular dynamics analysis of
10j–RT complexes (Supporting information). The results were
substantiated with molecular dynamics simulation for 100 ns that
indicated the stability of all three protein structures with < 0.5%
outlier residues in the Ramachandran plot (Fig. S2 and Table S4 in
Supporting information). The boronic acid group of the compound
10j displayed H-bond interaction to K223 residue for wildtype RT
while the similar interaction was shown with K104 for mutant
K103N/Y181C RT (Fig. S5 in Supporting information). Therefore,
the boronic acid group helps formation of multiple hydrogen
bonds to improve the antiviral activity of the compounds.
In this study, a series of boronic acid-containing diarylpyr-
imidine derivatives were designed, synthesized and evaluated for
their anti-HIV-1 potency. The results demonstrated that com-
pounds 5j and 5i displayed nanomolar activities against HIV-1 IIIB
and single-mutant strains (EC50 = 4.87 À 71.8 nmol/L), while their
activities against the double-mutant strains F227L + V106A and
RES056 decreased sharply. Equipment with a cyanovinyl group at
the left wing of 5j yielded the most potent inhibitor 10j with EC50
values of 7.23 nmol/L (IIIB), 9.85 nmol/L (L100I), 7.19 nmol/L
(K103N), 19.7 nmol/L (Y181C), 39.9 nmol/L (Y188L), 17.3 nmol/L
(E138K), 43.2 nmol/L (F227L + V106A) and 77.9 nmol/L (RES056),
which was comparable with those of ETR. The HIV-1 RT enzyme
Appendix A. Supplementary data
Supplementarymaterialrelatedtothisarticlecanbefound, inthe
online version, at doi:https://doi.org/10.1016/j.cclet.2021.02.033.
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activity inhibition assay suggest that 10j (IC50 = 0.1837 mmol/L)
acted as a typical NNRTIs. Finally, based on molecular dynamics
simulation, we propose the molecule 10j promising for fighting
against HIV-1 infection through inhibiting RTactivity. Consequent-
ly, the compound 10j, the best inhibitor of this series, could serve as
5