Copper mediated one-pot synthesis of quinazolinones and exploration of piperazine linked quinazoline derivatives as anti-mycobacterial agents

Article abstract of DOI:10.1039/d0ra08644d

A facile method was developed for the synthesis of quinazolinone derivatives in a one-pot condensation reaction via in situ amine generation using ammonia as the amine source and with the formation of four new C-N bonds in good to excellent yields. With the optimised method, we synthesized a library of piperazine linked quinazoline derivatives and the synthesized compounds were evaluated for their inhibitory activity against Mycobacterium tuberculosis. The compounds 8b, 8e, 8f, 8m, 8n and 8v showed potent anti-mycobacterial activity with MIC values of 2-16 μg mL-1. All the synthesized compounds follow Lipinski's rules for drug likeness. This journal is

Full text of DOI:10.1039/d0ra08644d

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Copper mediated one-pot synthesis of
quinazolinones and exploration of piperazine
linked quinazoline derivatives as anti-
mycobacterial agents†
Cite this: RSC Adv., 2020, 10, 43533
a
a
b
a
Satyaveni Malasala, Jitendra Gour, Md. Naiyaz Ahmad, Srikanth Gatadi,
b
b
b
a
Manjulika Shukla, Grace Kaul, Arunava Dasgupta, Y. V. Madhavi,
b
a
Sidharth Chopra
and Srinivas Nanduri
*
A facile method was developed for the synthesis of quinazolinone derivatives in a one-pot condensation
reaction via in situ amine generation using ammonia as the amine source and with the formation of four
new C–N bonds in good to excellent yields. With the optimised method, we synthesized a library of
piperazine linked quinazoline derivatives and the synthesized compounds were evaluated for their
inhibitory activity against Mycobacterium tuberculosis. The compounds 8b, 8e, 8f, 8m, 8n and 8v
Received 10th October 2020
Accepted 29th October 2020
DOI: 10.1039/d0ra08644d
À1
showed potent anti-mycobacterial activity with MIC values of 2–16 mg mL . All the synthesized
rsc.li/rsc-advances
compounds follow Lipinski's rules for drug likeness.
synthesis of quinazolinone by using 2-bromobenzoic acid and
substituted amidines as starting materials. Abe et al. reported
Introduction
12
Nitrogen-containing heterocycles are present in a wide range of the synthesis of quinazolinones by using 2-amino benzoic acid
1
bioactive natural products and synthetic drug candidates.
with substituted nitriles (Scheme 1).
Among them, quinazolines and their derivatives represent
Tuberculosis is a transmissible disease caused by Mycobac-
medicinally important structural cores present in a number of terium tuberculosis (Mtb) complex and recognized to have high
2
13
drug candidates. They possess a wide range of biological mortality rate globally According to WHO reports, 10 million
3
4
5
activities including anticancer, antiviral, antitubercular and cases were reported in the year 2017, where India is the leading
6
14
antibacterial properties.
country with the highest burden of TB. Emergence of drug-
Recently, ammonia has attracted wide attention as a cost-
7
effective and efficient nitrogen source. A number of homoge-
neous transition-metal catalysed reactions for the synthesis of
organic amines using gaseous or liquid ammonia are re-
8,9
ported. Owing to its safety and ease of handling, aqueous
ammonia is even more attractive as a substrate.
In view of the medicinal and pharmacological importance of
quinazolinones, several methods on the synthesis of this class
10
of compounds have been reported. Zhan and co-workers in
013 reported an interesting approach by condensation of
2
substituted anthranilamides with different aldehydes in pres-
ence of copper oxide for the synthesis of substituted quinazo-
11
linone derivatives. In 2014, Hung and co-workers reported
a
National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad,
5
00037, India. E-mail: nanduri.niperhyd@gov.in; nandurisrini92@gmail.com
b
Division of Microbiology, CSIR-Central Drug Research Institute, Sitapur Road, Sector
1
0, Janakipuram Extension, Lucknow-226031, Uttar Pradesh, India. E-mail: skchopra.
07@cdri.res.in; skchopra007@gmail.com
0
†
Electronic supplementary information (ESI) available: Synthetic procedures,
1
13
experimental details, spectral information ( H and C spectra) and biological
evaluation. See DOI: 10.1039/d0ra08644d
Fig. 1 Structures of mycobacterial agents.
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as inhibitors of uridyl transferase activity of M. tuberculosis
17d
GlmU and Naik et al. reported the quinolone based deriva-
17e
tives as potent anti-mycobacterial agents (F, Fig. 1).
In the present method, we have developed a copper medi-
ated oxidative coupling of different aldehydes and 2-bromo-
benzoic acid, using aq. ammonia as a less expensive nitrogen
source. We explored the double amination of aryl halides to the
corresponding amines and also acids to amides at the same
substrate. With the established method, we could successfully
synthesize 4-substituted piperazine/piperidine linked C2-aryl/
heteroaryl quinazolines. The synthesized compounds were
evaluated for their in vitro inhibitory activity against Mycobac-
terium tuberculosis H37Rv. clog P values were determined using
SwissADME.
Scheme 1 Methodologies for the synthesis of quinazolinones.
resistant TB or accompanying chronic diseases like HIV and Results and discussion
diabetes certainly limits the current treatment options and
hence drives the researchers to full the growing demand for
Direct employment of ammonia as a reagent in transition-metal
1
5
catalysis is generally a challenging task. In the current opti-
mised method, copper mediated oxidative coupling is devel-
oped between aldehydes and 2-bromobenzoic acid, using aq.
ammonia as a nitrogen source. Various conditions for the
conversion of 1 to 3 are studied and the results are discussed in
Table 1. We initiated our studies by using copper oxide and
new agents (Fig. 1) that are effective against drug resistant TB.
16
Bedaquiline (A, Fig. 1) led the drug discovery efforts towards
the exploration of different heterocycles as anti-mycobacterial
agents. Gatioxacin (B, Fig. 1) and delamanid (C, Fig. 1) are
nd
17a,b
the 2
aminopyrazolyl)-substituted quinazolines (D, Fig. 1) as inhibi-
tors of protein kinases (PknA & PknB) of Mycobacterium tuber-
line anti-TB drugs.
Wang et al. reported 4-
(
ꢀ
NMP as solvent in the absence of oxygen at 80 C for 24 h (Table
17c
1, entry 1). The reaction did not proceed. However, we observed
the formation of the product in small quantities when the
culosis; Tran et al. developed 4-aminoquinazolines (E, Fig. 1),
a
Table 1 Optimization of reaction conditions
Temperature
ꢀ
Entry Catalyst
Solvent
O
2
( C)
Time (h) Yield (%)
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
Cu
Cu
Cu
Cu
CuCl
CuCl
CuBr
CuBr
2
2
2
2
O
O
O
O
NMP
NMP
NMP
NMP
NMP
DMSO
NMP
DMSO
DMSO
DMSO
ACN
Toluene Yes 100
DMF
NMP
DMSO
DMF
No 80
Yes 80
Yes 80
24
24
12
10
10
10
10
10
10
10
10
10
10
10
10
12
10
0
12
25
40
>20
24
Trace
>20
55
Yes 100
Yes 100
Yes 100
Yes 100
Yes 100
Yes 100
Yes 100
Yes 100
2
Cu O
0
1
2
3
4
5
6
7
CuI
CuI
CuI
CuI
CuI
Cu(OAc)
Cu(OAc)
Cu(OTf)
70
Trace
Trace
40
50
38
Yes 100
Yes 100
Yes 100
Yes 100
Yes 100
2
2
26
33
2
DMSO
a
Reaction conditions: 1 (1 mmol), aq. ammonia (2 mmol), aldehyde (1
mmol), catalyst (5.0 mol%), solvent (5 mL) the reaction was performed
ꢀ
at 100 C for 10 h under oxygen atmosphere.
Scheme 2 Reaction scope.
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oxide and CuI as catalysts in presence of oxygen, NMP and
DMSO as the solvent, the reaction proceeded smoothly. DMSO
as a solvent was found to be more favourable (Table 1, entry 9–
1
0). The reaction was studied with different solvents viz., ACN,
toluene, DMF and the reaction proceeded with altered yields
Table 1, entry 11–14). When the catalyst was changed to copper
(
diacetate and coppertriate the reaction was sluggish and
resulted in low yields (Table 1, entry 15–17). The reaction was
found to proceed with optimal yields with CuI as catalyst and
DMSO as the solvent (entry 10).
Scheme 3 Gram-scale synthesis and control experiments.
Aer optimizing the reaction conditions, we focussed on
expanding the substrate scope of this transformation and the
results are summarized in (Scheme 2). It is observed that elec-
tron-donating substituents such as methoxy, amino, and
methyl on 2-phenyl were well tolerated under the optimal
reaction conditions, with 70–78% yields (3b, 3c, 3g and 3h).
Similarly, halogen substituents like 2,4-dichloro, 2,6-dichloro
Scheme 4 Plausible reaction mechanism.
reaction was conducted in presence of oxygen (Table 1, entry 2).
With changes in time and temperature we observed the product
formation to be improved (Table 1, entry 3–4). Moderate yields
were observed with the change of catalyst to CuCl or CuBr with
DMSO or NMP as solvents (Table 1, entry 5–8). With copper
Scheme 5 Synthetic route for the synthesis of piperazine linked qui-
nazolines derivatives (8a–z).
Fig. 2 ESI-MS monitoring of the reaction.
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À1
Table 2 MIC (mg mL ) values of 2-aryl/heteroaryl quinazoline based amide derivatives 8a–z against anti-bacterial and M. tuberculosis strains
S. aureus
E. coli
K. pneumoniae
A. baumannii
P. aeruginosa
Sample code
ATCC 29213
ATCC 25922
BAA 1705
BAA 1605
ATCC 27853
Mtb H37Rv ATCC 27294
clog P
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
0.125
—
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
0.015
—
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
8
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
>64
0.5
>64
16
>64
>64
16
3.84
3.65
3.9
3.77
4.77
4.49
4.95
4.54
4.45
4.92
4.7
3.56
3.56
4.76
3.13
4.05
3.14
3.02
3.76
2.25
4.22
3.77
4.93
3.07
2.99
2.48
2
>64
>64
>64
>64
64
>64
16
4
>64
>64
>64
>64
>64
32
>64
16
64
s
t
u
v
w
x
64
y
z
>64
>64
Not tested
0.03
0.06
Levooxacin
Isoniazid
Rifampicin
—
—
—
—
—
—
—
—
and 3-nitro are also tolerated, yielding the desired products (3j, was [M + H] at m/z of 137.0021 was observed aer 2 h. Inter-
i and 3l) in good to high yields (75–79%). Heterocycles like mediate V on oxidation gets converted into imine intermediate
pyridyl, furan, thiophene and isoxazole at C-2 position (3d, 3e, VI which on addition of substituted aldehydes, the mass peak
f and 3m) are also well tolerated with good to moderate yields was observed with [M + H] at m/z of 225.0094, gives intermediate
78–82%). With 4-bromo and 4-cyano (3o and 3n) substituents, VII which nally on oxidation gives the desired products 3a–o in
the reactions proceeded smoothly (Scheme 2). good to moderate yields, for the corresponding product the
3
3
(
We performed the gram scale synthesis with 1.5 gm of 2- peak was observed with [M + H] at m/z of 223.0896. The product
bromo benzoic acid and benzaldehyde as the starting materials formation was observed aer 6 h but not completely, further
which resulted in 1.2 g of the nal product (Scheme 3). As the preceding the reaction for 10–12 h to get the complete conver-
reaction with TEMPO did not show the product formation, the sion (Fig. 2).
free radical mediated mechanism is observed and conventional
A series of 2-arylquinazoline derivatives were synthesized
mechanism in one-pot protocol is proposed (Scheme 3). Based with the optimized method as described in Scheme 2. The ob-
on the control experiments, a plausible reaction mechanism is tained quinazolinones (3a–f) were further chlorinated using
proposed and depicted in Scheme 4. Our mechanistic investi- POCl and N,N-diethyl aniline to provide the corresponding 2-
3
gation was supported by ESI-QTOF-MS technique and collected aryl chloroquinazoline intermediates 4a–f. The chlorinated
the mass data at different time intervals with <5 ppm error. intermediates 4a–f were treated with piperazine 5 to yield 2-aryl-
Initially, under copper catalysis substrate 1 gets converted to 4-(piperazin-1-yl)quinazoline 6a–f. Coupling of 6a–f with
intermediate I. Next addition of aq. ammonia gives the inter- a number of carboxylic acids 7a–i using HATU as coupling
mediate II, the observed mass was [M+] at m/z of 198.8620 aer reagent afforded the corresponding amide derivatives 8a–z in
nd
3
0 min. The replacement of halo atom from the 2 position moderate to excellent yields. Structures of all the newly
1
13
with amine will give the intermediate III, the obtained mass synthesized compounds were conrmed by H NMR, C NMR
result was [M+] at m/z of 198.8620. Aer that another equivalent and HRMS (ESI) spectroscopic techniques (Scheme 5).
of aq. ammonia will be addition to the intermediate III to give
The synthesized derivatives were evaluated for their antimi-
the intermediate IV, the mass was shown with [M + H] at m/z of crobial activity against ESKAP pathogen panel (results included
18–20
216.9222, detected the peak aer 1 h, which on further rear- in the ESI†) and Mycobacterium tuberculosis H37Rv strain.
rangements gets converted to stable intermediate V, the mass While, the compounds were found to be inactive against ESKAP
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Acknowledgements
S. M is thankful to Department of Pharmaceuticals, Ministry of
Chemicals & Fertilizers, Govt. of India, for the award of NIPER
fellowship. This study was supported by the DST grant from
Department of Science and Technology, Govt. of India to S. N.
and S. C. (EMR/2017/000220).
Notes and references
Fig. 3 Structure activity relationship (SAR) of new 2-aryl/heteroaryl
quinazoline derivatives.
1
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and 8n
À1
À1
four compounds 8b, 8e, 8m and 8v showed MIC of 16 mg mL
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and 8m resulted in moderate activity with MIC of 16–64 mg
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2
a favourable lead. Substitution of R position with electron
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À1
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2
3
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,4,5-trimethoxy 8s and 8q were found to be inactive but 4-N,N-
dimethylphenyl was found to be good lead with MIC of 2 mg
À1
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À1
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bonds in one pot operation through in situ amine generation,
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f exhibited selective and potent anti-mycobacterial activity
À1
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À1
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