Synthesis and antimicrobial activity of polyhalo isophthalonitrile derivatives

Article abstract of DOI:10.1016/j.bmcl.2013.02.033

A series of polyhalo isophthalonitrile derivatives (3 and 4) that incorporate a variety of substituents at the 2-, 4-, 5- and/or 6-positions of the isophthalonitrile moieties have been designed and synthesized. These derivatives were evaluated for their antimicrobial activity against Staphylococcus aureus, Bacillus cereus (Gram-positive bacteria), Escherichia coli, Pseudomonas aeruginosa (Gram-negative bacteria); and Candida albicans (Fungi). Compounds 3 and 4 showed stronger inhibition of Gram-positive bacteria and fungi growth, and the antimicrobial ability of compound 3j (a 4-(benzylamino)-5-chloro-2,6-difluoro analog, MIC[SA] = 0.5 μg/mL; MIC[BC] = 0.4 μg/mL; MIC[CA] = 0.5 μg/mL) were close to nofloxacin and fluconazole and identified as the most potent antimicrobial agents in the series. The preliminary analysis of structure-activity relationships is also discussed.

Full text of DOI:10.1016/j.bmcl.2013.02.033

Bioorganic & Medicinal Chemistry Letters 23 (2013) 2399–2403
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and antimicrobial activity of polyhalo isophthalonitrile
derivatives
a,
Chao Huang a,b, , Sheng-Jiao Yan a, , Neng-Qin He a, Ya-Juan Tang a, Xing-Hong Wang c, , Jun Lin
⇑
⇑
a Key Laboratory of Medicinal Chemistry for Natural Resource (Yunnan University), Ministry of Education, School of Chemical Science and Technology,
Yunnan University, Kunming 650091, PR China
b Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission and Ministry of Education, Yunnan University of Nationalities,
Kunming 650050, PR China
c Institute of Microbiology, Yunnan University, Kunming 650091, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of polyhalo isophthalonitrile derivatives (3 and 4) that incorporate a variety of substituents at the
2-, 4-, 5- and/or 6-positions of the isophthalonitrile moieties have been designed and synthesized. These
derivatives were evaluated for their antimicrobial activity against Staphylococcus aureus, Bacillus cereus
(Gram-positive bacteria), Escherichia coli, Pseudomonas aeruginosa (Gram-negative bacteria); and Candida
albicans (Fungi). Compounds 3 and 4 showed stronger inhibition of gram-positive bacteria and fungi
growth, and the antimicrobial ability of compound 3j (a 4-(benzylamino)-5-chloro-2,6-difluoro analog,
MIC[SA] = 0.5 lg/mL; MIC[BC] = 0.4 lg/ML; MIC[CA] = 0.5 lg/mL) were close to nofloxacin and fluconaz-
ole and identified as the most potent antimicrobial agents in the series. The preliminary analysis of struc-
ture–activity relationships is also discussed.
Received 21 October 2012
Revised 29 January 2013
Accepted 6 February 2013
Available online 16 February 2013
Keywords:
4-(Benzylamino)-5-chloro-2,6-
difluoroisophthalonitrile
Polyhalo isophthalonitrile
Antimicrobial activity
Gram-positive bacteria
Anti-fungi
Ó 2013 Elsevier Ltd. All rights reserved.
It is well known that halogen plays an important role in living
organisms.1 As an important part of biological activity organic hal-
ogenated compounds are widely used as antibacterial, antineoplas-
tic, hormones, pheromones, pesticides.2 Due to its special
character, organic halide plays an important role in drug research.
In particular, the antimicrobial activity of organic halide deriva-
tives is also well documented in the literatures,3,4 for example or-
ganic chlorides (Vancomycin, Chlorotetracycline, Chloramphenicol,
Calicheamycin, Rebeccamycin, and Ambigol A), bromides (Pyrolni-
trin) and iodide (Calicheamicin). Recently, the use of fluorinated
compounds as bioactive or functional molecules has increased in
pharmaceutical research due to the unique effects of F-substitu-
ents in pharmaceutical formulations. Fluorine incorporation into
biologically-active compounds can alter drug metabolism or en-
zyme substrate recognition.5 The hydrophobic nature of fluori-
nated compounds has also been cited for its ability to improve
transport across the blood–brain barrier. Improved oral bioavail-
ability is seen in some systems where fluorine substitution leads
to improved hydrolytic stability. Moreover, polyhalo compounds
are also widely present in nature, its anti-microbial activity is
attracting more attention. A series of polyhalo compound deriva-
tives have been identified as potent antimicrobial agents.6,7
Organic cyanide is halogen isostere and often called virtual ana-
log halogen.8 The biological compatibility, stability of cyanoacrylate
and ability to build relationship plays a key role. In particular, organ-
ic cyanide and organic halogenated compounds were expected to
have the similar effects of anti-bacterial active. Organic cyanide
has an important role in the study of drugs and drug intermediates
in the development,9 cyanoacrylate derivatives can also generate
further amine, aldehyde carboxylic acid, and such compounds, and
more and more cyanide-containing drugs are being used for clinical
treatment. Recently, isophthalonitrile derivatives, one of the most
important organic cyanide compounds, have received much atten-
tion. They are biologically active. For example, they are inhibitory
of HIV-1 reverse transcriptase10 and mPGES-1,11 and they have
anti-inflammatory12 and insecticidal activity, etc. Such properties
have been explored and a lot of preparation methods of this type
of compounds have been developed.13,14
Polyhalo isophthalonitriles, especially polyfluoro-isophthalonit-
rile, have been widely used as anti-cancer,15 anti-inflammatory16
and insecticidal17 agents, among other uses18 in pharmaceuticals.
Our previously works have explored the antitumor and anti-HIV
activities of polyhalo isophthalonitriles, and all were found to have
good bio-activities.19–22
⇑
Corresponding authors. Tel./fax: +86 871 5033215 (J.L.).
E-mail address: linjun@ynu.edu.cn (J. Lin).
These authors contributed equally to this work.
0960-894X/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2013.02.033

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C. Huang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 2399–2403
R1
X
Y
R1=F, Cl, R'Z
R2=R4=F, Cl,
NH2, R'Z
NC
X
CN
R
NC
R4
CN
R2
K2CO3
DMF
R' ZH
R3
3: Z=NH
4: Z=S
R3=F, Cl, R'Z
1: X= Cl, F; Y=Cl, F;
2: Z= NH, S;
R'= Alkyl, Aryl
R= Cl, F, NH2
Scheme 1.
Table 1
Zone of inhibition of data for polyhalo isophthalonitrile against different bacteria and fungi at a concentration of 1000 lg/mL
Compound
R1
R2
R3
R4
Time (h)
Yield (%)
Zone of inhibition (in mm)
Gram-positivea Gram-negativeb
Fungic
CA
SA
BC
EC
PA
1a
1b
1c
1d
1e
1f
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
4a
4b
4c
4d
4e
4f
4g
4h
Cl
F
F
Cl
F
F
Cl
F
F
Cl
F
F
F
F
Cl
F
Cl
F
F
NH2
NH2
NH2
Cl
F
F
Cl
F
F
F
F
Cl
F
Cl
Cl
F
Cl
Cl
F
Cl
Cl
F
Cl
Cl
F
Cl
F
Cl
Cl
F
Cl
F
Cl
Cl
Cl
F
Cl
F
F
Cl
F
F
20.1
N
N
20.2
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
31.0
N
N
N
N
N
7.8
N
7.5
8.0
N
N
N
7.6
7.8
N
N
N
N
N
N
N
N
N
N
N
N
N
9.9
N
N
12
3
0.75
8
1
0.5
8
1
1
10
1
5
1
0.5
3
1
8
16
1
12
2
24
10
3
98
85
81
95
96
96
93
95
96
93
95
92
95
93
91
92
84
88
61
56
73
52
70
85
83
85
N
N
N
8.6
11.8
N
13.0
23.0
N
7.4
8.0
N
14.6
17.8
N
6.8
8.6
12.2
16.7
N
22.6
18.1
15.0
7.1
N
7.0
N
9.8
7.5
N
7.0
7.6
N
7.4
15.2
7.3
7.5
15.3
13.6
17.3
N
N
N
N
13.3
N
13.9
11.6
—
—
—
6.8
N
N
N
—
PhNH
PhNH
PhNH
p-MeOPhNH
p-MeOPhNH
p-MeOPhNH
p-ClPhNH
p-ClPhNH
BnNH
BnNH
BnNH
Me2N(CH2)3NH
Me2N(CH2)3NH
Cyclohexane
PhS
N
8.7
10.7
19.8
N
23.1
19.3
14.2
7.0
N
7.3
N
N
8.8
N
F
F
F
F
NH2
NH2
NH2
Cl
PhS
PhS
CH3CH2CH2S
NH2
NH2
NH2
NH2
NH2
Cyclohexane
Cl
F
PhS
F
PhS
Cl
F
PhS
PhS
Cl
PhS
Cl
Cl
Cl
F
CH3CH2CH2S
PhS
CH3CH2CH2S
CH3CH2CH2S
CH3CH2CH2S
CH3CH2CH2S
7.0
8.5
7.5
7.9
19.9
—
—
—
—
CH3CH2CH2S
CH3CH2CH2S
6
3
N
N
18.0
4i
Norfloxacin
Fluconazole
22.5
N-No inhibition zone.
a
Gram-positive bacteria; BS, Bacillus cereus ATCC 14579; SA, Staphyloccocus aureus ATCC 6538.
Gram-negative bacteria; EC, Escherichia coli ATCC 8099; PA, Pseudomonas aeruginosa ATCC 15442.
CA, Candida albicans ATCC 10231.
b
c
In view of the high degree of bio-activity shown by polyhalo
This type of reaction features a SNAr mechanism,18 R2 and R4
were the most active part due to strong electron withdrawing
group (halogen and cyano group) on the benzene ring. The desired
compounds (3a–3n) and (4a–4i) were formed from 2a–2n and 2o–
2w in excellent yields: 84–96% and 52–88%, respectively. Compar-
ative data for these compounds with respective to reaction time
and yield of product are provided in Table 1. All of the synthesized
compounds were characterized by 1H NMR, 13C NMR and 19F NMR
spectrometry and HRMS analysis.24
Derivatives (1a–1f, 3a–3n and 4a–4i) were initially screened for
in vitro antibacterial activity against gram-positive bacterial
strains (Staphyloccocus aureus ATCC 6538 [SA], Bacillus cereus ATCC
14579 [BC]), gram-negative bacterial strains (EC, Escherichia coli
ATCC 8099 [EC], Pseudomonas aeruginosa ATCC 15442 [PA]), and
fungal strains (Candida albicans ATCC 10231 [CA]) utilizing the disk
diffusion assay.25,26 The antibiotic drug, norfloxacin was also used
as a positive control. Antibacterial screening for derivatives and the
isophthalonitriles derivatives, we have focused on the design of no-
vel structural entities that incorporate both polyhalo and cyanide
structural moieties into a single molecular scaffold to evaluate
the potential additive effects of these two atoms systems on bio-
logical activity, especially with regard to antimicrobial activity.
At the same time, the halo-atoms of polyhalo isophthalonitrile
can be employed in nucleophilic substitution with nucleophiles.
The cyano group can also be modified into an amido or carboxyl
group, providing many opportunities for constructing more molec-
ular libraries for biological activity screening.
In the continuation of our investigation on the utility of mild
conditions for the synthesis of useful bioactive organic molecules
under mild conditions,16,23 we have utilized K2CO3 as an efficient
and ecofriendly catalyst in DMF assisted synthesis of a series of
amino-isophthalonitrile (3a–3n) and thio-isophthalonitrile (4a–
4i) derivatives. These compounds were different molecular diver-
sity substitute products. The synthetic routes to these two series
of compounds (3a–3n and 4a–4i) are illustrated in Scheme 1.
positive control was performed at
1000 g/mL.
a fixed concentration of
l

C. Huang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 2399–2403
2401
P. Aeruginosa
C. Albicans
S. Aureus
B. Cereus
E. Coli
Figure 1. Antibacterial activity of halogenated derivatives of polyhalo isophthalonitrile screening of partial results.
rile (4g, ZOI[SA] = 8.5 mm, ZOI[BC] = 7.6 mm) showed good antibac-
terial activity against all gram-positive bacterial strains. Based on
the data from the antibacterial studies against gram-positive bacte-
rial strains, the following observations can be made. Derivatives 3
and 4 mostly exhibited moderate to high antibacterial activity. More
importantly, introducing fluorine atom substituents at the benzene
rings in a series of isophthalonitrile derivatives can improve their
antibacterial activity, and compounds 1a, 3c, 3j and 3k exhibited
similar antibacterial activities as the standard antibiotic drug, nor-
floxacin. For results of the experiment see Table 1.
Table 2
Minimum inhibitory concentration values for polyhalo isophthalonitrile against
different bacteria and fungi
Compound
Minimum inhibitory concentrationa
Gram-positiveb Fungic
BC
SA
CA
1a
1e
1f
3b
0.5
0.7
0.5
46.9
125
3.9
>1000
104.2
125
15.6
62.5
0.5
Derivatives (1a, 1e, 1f, 3a–3c, 3h, 3j, 3k and 4a) were also
examined for antifungal activity against fungal strains, that is
Candida albicans [CA] (Table 1, Fig. 1). The antifungal drug, Fluconaz-
ole was used as a positive control. The fungal strains were grown and
maintained on Sabouraud glucose agar plates. The plates were incu-
bated at 26 °C for 72 h, and the resulting ZOIs were measured.27,28
Antifungal screening for derivatives and positive control was
3c
3f
3g
3h
3j
3k
4a
4d
3.3
375
26
1.5
0.5
6.8
3.9
n
n
2.3
>1000
416.7
31.3
0.4
3.9
>1000
>1000
>1000
>1000
>1000
0.5À2
—
0.5
1.3
10.4
>500
>500
>1000
>500
>1000
—
250
11.7
500
1.6
250
0.5À2
—
4f
4g
4h
performed at a fixed concentration of 1000
6-(phenylamino)isophthalonitrile (3a,
l
g/mL. 2,4,5-Trichloro-
ZOI[CA] = 15.3 mm),
5-chloro-2,4-difluoro-6-(phenylamino)isophthalonitrile (3b, ZOI[-
CA] = 13.6 mm), 2,4,5-trifluoro-6-(phenylamino)isophthalonitrile
(3c, ZOI[CA]=15.3 = 15.3 mm), 4-((4-chlorophenyl)amino)-2,5,
6-trifluoroisophthalonitrile (3h, ZOI[CA] = 13.3 mm), 4-(benzyl-
Norfloxacin
Fluconazole
1À3
a
MIC were determined by microbroth dilution technique and values reported in
the table represent the values obtained in triplicate.
Gram-positive bacteria; BS, Bacillus cereus ATCC 14579; SA, Staphyloccocus
aureus ATCC 6538.
b
amino)-5-chloro-2,6-difluoroisophthalonitrile
(3j,
ZOI[CA] =
13.9 mm), 4-(benzylamino)-2,5,6-trifluoroisophthalonitrile (3k
,ZOI[CA] = 13.9 mm), 2,4,5-trichloro-6-(phenylthio)isophthalonitri-
le (4a, ZOI[CA] = 6.8 mm) were identified as the most potent anti-
fungal agents against all three fungal strains. Based on the
screening data from the antifungal studies, the following observa-
tions can be made. Thio-isophthalonitrile (4a–4i) derivatives have
few effects on fungi, while compounds 3a–3c, 3h, 3j and 3k have
good antifungal activity.
The minimum inhibitory concentration (MIC) values for deriva-
tives (1a–1f, 3a–3n and 4a–4i) and the positive control drugs nor-
floxacin and fluconazole were also determined against the two
bacterial strains and the one fungal strains by the liquid dilution
method.29,30 Concentrations of derivatives and positive control
drugs at 0.98, 1.95, 3.91, 7.81, 15.63, 31.25, 62.5, 125, 250, 500
c
CA, Candida albicans ATCC 10231.
All of the compounds in Table 1 exhibited different antibacterial
activities for all five bacterial strains. Mostly, compounds exhibited
antibacterial activity against gram-positive bacterial strains with
zones of inhibition (ZOI) ranging to a maximum of 23.1 mm
(Fig. 1). However, compounds 1b–1d, 3a, 3d, 3e, 3i, 3n, 4b and 4e
showed no significant inhibition of growth of bacterial activity to
four kinds of bacteria strains. Derivatives 1a, 1e, 1f, 3b, 3c, 3f–3h,
3j, 3k, 4a, 4d, and 4f–4h were identified as potent antibacterial
agent against gram-positive bacterial strains. 2,4,5,6-tetrachloro-
isophthalonitrile (1a, ZOI[SA] = 20.1 mm, ZOI[BC] = 20.2 mm, ZOI[-
CA] = 9.9 mm); 2,4,5-trifluoro-6-(phenylamino)isophthalonitrile
(3c, ZOI[SA] = 23.0 mm, ZOI[BC] = 17.8 mm, ZOI[CA] = 17.3 mm);
4-(benzylamino)-5-chloro-2,6-difluoroisophthalonitrile (3j, ZOI[-
SA] = 23.1 mm, ZOI[BC] = 22.6 mm, ZOI[CA] = 13.9 mm); 4-(benzyl-
amino)-2,5,6-trifluoroisophthalonitrile (3k, ZOI[SA] = 23.1 mm,
ZOI[BC] = 22.6 mm, ZOI[CA] = 13.9 mm); 5-chloro-2-fluoro-4,6-
bis(propylthio)isophthalonitrile (4d, ZOI[SA] = 8.8 mm, ZOI[BC] =
7.5 mm), 4-amino-5-chloro-2-fluoro-6-(propylthio)isophthalonit-
and 1000 lg/mL were prepared in dimethyl sulfxide (DMSO) solu-
tion. Inoculums of the bacterial and fungal cultures were also pre-
pared. Inoculum and sterile water were added to a series of tubes
each containing 1 mL of test compound solution at the 11 different
concentrations. The tubes were incubated for 24 h and carefully
observed for the presence of turbidity. The minimum concentra-
tion at which no growth was observed was taken as the MIC value.
The MIC values for all the derivatives examined ranged from 0.98
F
R1 = F > Cl
Best
R1
R3
NC
CN
F
NC
R4
CN
R2
R2 = F > Cl and NH2
Best
N
H
Cl 3j
R4 = BnNH> PhNH>p-ClPhNH>CH3CH2CH3S
Best
Best Potent Compound
> PhS> p-MeOPhNH
Figure 2. Structure–activity relationship of polyhalo isophthalonitrile.

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C. Huang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 2399–2403
to 500 lg/mL. Several derivatives exhibited superior antimicrobial
References and notes
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19. Yan, S. J.; Liu, Y. J.; Chen, Y. L.; Liu, L.; Lin, J. Bioorg. Med. Chem. Lett. 2010, 20,
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24. Analytical data and yields for the new active compounds: 4-(benzylamino)-2,5,6-
(1a, MIC[SA] = 0.5
5-chloro-2,6-difluoro-isophthalo nitrile (3j, MIC[SA] = 0.5
MIC[BC] = 0.4 g/mL) and 4-(benzylamino)-2,5,6-trifluoroisopht-
halonitrile (3k, MIC[SA] = 1.3 g/mL; MIC[BC] = 3.9 g/mL) were
lg/mL; MIC[BC] = 0.7
lg/mL), 4-(benzylamino)-
l
g/mL;
l
l
l
identified as potent antibacterial agents against gram-positive bac-
terial strains; these derivatives showed the same magnitude of
antibacterial activity as the standard antibiotic, norfloxacin. Four
compounds, 1a, 3b, 3h and 3j, showed good potency against Can-
dida albicans [CA], and the antifungal activities of derivatives 1a,
3b and 3j were superior to the antifungal drug fluconazole. How-
ever, analog 4 had poor antifungal activity. The MIC data for all
of the derivatives against the different bacterial and fungal strains
are shown in Table 2.
A comparison of the activities of the polyhalo isophthalonitrile
derivatives 1 and 4 suggested that most polyhalo isophthalonitrile
derivatives showed good activity against Gram-positive bacteria
and antifungal activity, and were selectively anti-microbial. Com-
pounds 1a, 3c, 3h, 3j and 3k showed strong antibacterial activity,
similar to the positive control drugs. Substitution at the 6-positions
with S-substituted groups resulted in lower activity than N-substi-
tuted groups, especially with regard to antifungal activity. The
number of fluorine atoms in Benzene ring and BnNH group was
found to have a positive influence on the antimicrobial properties
of polyhalo isophthalonitrile. We speculated that these compounds
have effect on the cell wall, which can suspend the growth of the
cell membrane, leading to the growth inhibitor or death of bacteria
or fungi.
We found that substitution at the 2- and 4-positions with a
fluorine atom, and at the 6-position with n-BnNH, plays an impor-
tant role in regulating antimicrobial and antifungal activity (Fig. 2).
This was evident as 3j and 3k showed good activity against the mi-
crobes and fungi used in our study (Table 2). Compound 3j proved
to be the most promising for further structural modifications
guided by the valuable information provided by the detailed SARs
described here.
In summary, a series of polyhalo isophthalonitrile derivatives (3
and 4) that incorporate a variety of substituents at the 2-, 4-,
5- and/or 6-positions of the isophthalonitrile moieties, have been
designed and synthesized. These derivatives (1, 3, and 4) were
evaluated for their antimicrobial activity against gram-positive
bacteria, gram-negative bacteria and Fungi strains. Compounds 3
and 4 showed stronger inhibition of gram-positive bacteria and
fungi growth, and compound 3j exhibited the most significant anti-
microbial activity, (a 4-(benzylamino)-5-chloro-2,6-difluoro ana-
trichloroisophthalonitrile (3i): white solid; mp 163À164 °C; IR (KBr) (mmax,
cmÀ1) 3338, 2938, 2226, 1571, 1512, 1200, 1090, 735; 1H NMR (500 MHz,
DMSO-d6): d 8.11 (br, 1H, NH), 7.36À7.30 (m, 5H, PhH), 5.05 (m, 2H, CH2); 13
C
NMR (125 MHz, DMSO-d6): d 150.5, 141.9, 138.6, 138.3, 128.9, 127.6, 127.0,
119.9, 114.6, 113.9, 101.8, 94.5, 47.6; HRMS (TOF ESÀ) m/z calcd for
C
15H7Cl3NÀ3 [(MÀH)À], 333.9711; found, 333.9718. 4-(Benzylamino)-5-chloro-
2,6-difluoroisophthalonitrile (3j): white solid; mp 106À108 °C; IR (KBr) (mmax
,
cmÀ1) 3396, 2231, 1627, 1528, 1458, 1079, 744, 449; 1H NMR (500 MHz,
Acetone-d6): d 7.67 (br, 1H, NH), 7.40À7.30 (m, 5H, PhH), 5.17À5.16 (d,
J = 6.5 Hz, 2H, CH2); 13C NMR (125 MHz, Acetone-d6): d 167.2 (d, J = 261.3 Hz),
161.4 (d, J = 257.5 Hz), 151.9, 138.8, 130.0, 129.0, 128.4, 112.6, 109.3, 105.8 (d,
J = 18.8 Hz), 83.5 (d, J = 20.0 Hz), 81.9, 48.8; HRMS (TOF ESÀ) m/z calcd for
C
15H7ClF2NÀ3 [(MÀH)À], 302.0302; found, 302.0294. 4-(Benzylamino)-2,5,6-
trifluoroisophthalonitrile (3k): white solid; mp 122À124 °C; IR (KBr) (mmax,
cmÀ1) 3399, 2926, 2230, 1641, 1529, 1295, 1072, 750, 605, 485; 1H NMR
(500 MHz, DMSO-d6): d 8.73 (br, 1H, NH), 7.34À7.27 (m, 5H, PhH), 4.84 (m, 2H,
CH2); 13C NMR (125 MHz, DMSO-d6):
d 162.8 (d, J = 258.8 Hz), 151.9 (d,
J = 256.3 Hz), 144.9, 138.5, 136.0 (dd, J1 = 241.3 Hz, J2 = 11.3 Hz), 128.9, 127.3,
126.9, 111.6, 109.1, 82.3 (d, J = 17.5 Hz), 78.6 (t, J = 20.0 Hz), 46.9; HRMS (TOF
ES+) m/z calcd for C15H8F3N3Na+ [(M+Na)+], 310.0563; found, 310.0570. 4-
Amino-5-chloro-6-(3-(dimethylamino)propylamino)-2-fluoroisophthalonitrile
(3l): white solid; mp 170À171 °C; IR (KBr) (
m
max, cmÀ1) 3343, 2921, 2825,
log, MIC[SA] = 0.5 lg/mL; MIC[BC] = 0.4 lg/ML; MIC[CA] = 0.5 lg/
mL, close to nofloxacin and fluconazole), which paves the way to
finding promising leads for antimicrobials in the future.
2217, 1628, 1527, 1468, 868; 1H NMR (500 MHz, DMSO-d6): d 7.94 (br, 1H,
NH), d 6.90À6.88 (br, 2H, NH2), 3.70–3.31 (m, 2H, CH2NH), 2.51À2.38 (m, 2H,
CH2N), 2.18 (s, 6H, 2CH3N), 1.75 (m, 2H, CH2); 13C NMR (125 MHz, DMSO-d6): d
167.3 (d, J = 253.8 Hz), 149.1 (d, J = 6.3 Hz), 148.9 (d, J = 6.3 Hz), 114.0, 112.5,
96.7, 75.5 (d, J = 18.8 Hz), 73.5 (d, J = 18.8 Hz), 57.8, 45.4, 45.3, 44.7, 26.3; 19F
NMR (470 MHz, DMSO-d6) d À102.6 (s, 1F); HRMS (TOF ESÀ) m/z calcd for
Acknowledgments
C
13H15ClFNÀ [(MÀH)À], 294.0927; found, 294.0977. 4-Amino-6-(3-
5
(dimethylamino)propylamino)-2,5-difluoroisophthalonitrile (3m): white solid;
This work was supported by the NSFCs (Nos. 21202142,
21262042, 81160384, 21162037), the NSFYNs (Nos. 2009CC017,
2011Z042, 2009B08Q, KKSA201126061, 2010120303) and the Key
Project of Chinese Ministry of Education (No. 212161), Start-up
funds and Youth funds (No. 11QN01) of Yunnan University of
Nationalities.
mp 162À164 °C; IR (KBr) (
m
max, cmÀ1) 3355, 2954, 2827, 2220, 1631, 1524,
1291, 569; 1H NMR (500 MHz, DMSO-d6): d 7.41 (br, 1H, NH), d 6.88 (br, 2H,
NH2), 3.65À3.55 (m, 2H, CH2NH), 2.39À2.28 (m, 2H, CH2N), 2.15 (s, 6H,
2CH3N), 1.72À1.70 (m, 2H, CH2); 13C NMR (125 MHz, DMSO-d6): d 165.4 (d,
J = 252.5 Hz), 142.2 (q, J = 7.5 Hz), 141.5, 133.2 (d, J = 226.3 Hz), 113.4, 112.4,
75.0 (d, J = 20.0 Hz), 74.3 (d, J = 18.8 Hz), 57.4, 45.4, 45.3, 43.8, 27.2; 19F NMR
(470 MHz, DMSO-d6) d À106.7 (d, J = 9.4 Hz, 1F), À159.9 (s, 1F); HRMS (TOF
ESÀ) m/z calcd for C13H15F2NÀ5 [(MÀH)À], 278.1223; found, 278.1230. 4-Amino-
5-chloro-2,6-di(piperidin-1-yl)isophthalonitrile
(3n): yellow solid;
mp
Supplementary data
120À121 °C; IR (KBr) (
m
max, cmÀ1) 3352, 2934, 2851, 2207, 1621, 1551, 1444,
865; 1H NMR (500 MHz, DMSO-d6): d 6.65 (br, 2H, NH2), 3.38À3.23 (m, 8H,
4CH2N), 1.62À1.60 (m, 12H, 6CH2); 13C NMR (125 MHz, DMSO-d6): d 160.3,
156.8, 152.9, 117.9, 116.8, 104.7, 89.8, 84.5, 53.1, 53.1, 52.3, 52.3, 31.0, 26.6,
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2013.02.
033.
26.6, 26.4, 24.0, 23.9; HRMS (TOF ESÀ) m/z calcd for C18H21ClNÀ [(MÀH)À],
5
342.1491; found, 342.1499. 2,4,5-Trichloro-6-(phenylthio)isophthalonitrile (4a):

C. Huang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 2399–2403
2403
yellow solid; mp: 154À156 °C; IR (KBr) (
m
max, cmÀ1) 3437, 2228, 1527, 1345,
1.57À1.48 (m, 2H, CH2), 0.98À0.82 (m, 3H, CH3); 13C NMR (125 MHz, DMSO-
d6): d 151.4, 143.1, 139.6, 123.0, 115.3, 113.8, 105.2, 96.4, 37.7, 23.0, 13.2;
HRMS (TOF ESÀ) m/z calcd for C11H8Cl2N3SÀ [(MÀH)À], 283.9821; found,
283.9828. 4-Amino-5-chloro-2-fluoro-6-(propylthio)isophthalonitrile (4g): white
1219, 750, 496; 1H NMR (500 MHz, DMSO-d6): d 7.37À7.17 (m, 5H, PhH); 13C
NMR (125 MHz, DMSO-d6): d 144.2, 143.5, 140.6, 133.3, 130.6, 130.0, 130.0,
129.6, 129.6, 128.7, 121.6, 114.1; HRMS (TOF ESÀ): m/z calcd for C14H4Cl3N2SÀ
[(MÀH)À],
336.9166;
found,
336.9175.
5-Chloro-2-fluoro-4,6-
solid; mp 155À156 °C; IR (KBr) (m
max, cmÀ1) 3324, 2965, 2232, 1635, 1593,
bis(phenylthio)isophthalonitrile (4b): yellow solid; mp: 170À171 °C; IR (KBr)
1239, 787; 1H NMR (500 MHz, DMSO-d6): d 7.79À7.68 (br, 2H, NH2), 3.09À2.88
(m, 2H, CH2S), 1.56À1.48 (m, 2H, CH2), 0.97À0.81 (m, 3H, CH3); 13C NMR
(125 MHz, DMSO-d6): d 165.5 (d, J = 261.3 Hz), 152.4 (d, J = 5.0 Hz), 143.6,
120.6, 113.7, 112.3, 93.4 (d, J = 13.8 Hz), 85.9 (d, J = 18.8 Hz), 38.4, 23.9, 14.0;
19F NMR (470 MHz, DMSO-d6) d À102.2 (s, 1F); HRMS (TOF ESÀ) m/z calcd for
(m
max, cmÀ1) 3445, 2230, 1581, 1477, 1338, 1226, 744, 473; 1H NMR (500 MHz,
DMSO-d6): d 7.38À7.27 (m, 10H, PhH); 13C NMR (125 MHz, DMSO-d6): d 145.4,
143.6, 141.8, 133.6, 133.3, 130.1, 130.1, 130.1, 129.5, 129.1, 129.1, 128.1, 128.1,
126.7, 114.4, 114.4; 19F NMR (470 MHz, DMSO-d6): d = À100.7 (s, 1F); HRMS
(TOF ESÀ): m/z calcd for C20H9ClFN2SÀ2 [(MÀH)À], 394.9885; found, 394.9891.
5-Fluoro-2,4,6-tris(phenylthio)isophthalonitrile (4c): yellow solid; mp:
C
11H8ClFN3SÀ [(MÀH)À], 268.0117; found, 268.0127. 4-Amino-5-chloro-2,6-
bis(propylthio)isophthalonitrile (4h): white solid; mp 106À107 °C; IR (KBr)
122À124 °C; IR (KBr) (
m
max, cmÀ1) 3436, 2230, 1576, 1477, 1376, 1296, 746,
(m
max, cmÀ1) 3338, 2963, 2222, 1622, 1545, 1203, 724; 1H NMR (500 MHz,
474; 1H NMR (500 MHz, DMSO-d6): d 7.53À7.20 (m, 15H, PhH); 13C NMR
(125 MHz, DMSO-d6): d 162.1 (d, J = 251.3 Hz), 138.6, 133.7, 133.2, 133.1,
132.9, 132.2, 131.6, 130.3, 130.1, 130.0, 129.7, 129.5, 128.9, 128.5, 128.2, 125.4,
114.2, 110.9, 107.2 (d, J = 16.3 Hz); 19F NMR (470 MHz, DMSO-d6): d = À88.7 (s,
1F); HRMS (TOF ESÀ): m/z calcd for C26H14FN2SÀ3 [(MÀH)À], 469.0309; found,
469.0319. 5-Chloro-2-fluoro-4,6-bis(propylthio)isophthalonitrile (4d): yellow
DMSO-d6): d 7.53 (br, 2H, NH2), 3.08À3.02 (m, 4H, 2CH2S), 1.54À1.47 (m, 4H,
2CH2), 0.97À0.92 (m, 6H, 2CH3); 13C NMR (125 MHz, DMSO-d6): d 151.0, 142.9,
142.7, 124.1, 116.4, 115.0, 111.0, 101.7, 38.3, 37.6, 23.0, 22.9, 13.2, 13.2; HRMS
(TOF ESÀ) m/z calcd for C14H15ClN3SÀ2 [(MÀH)À], 324.0401; found, 324.0409. 4-
Amino-5-fluoro-2,6-bis(propylthio)isophthalonitrile (4i): yellow solid; mp
81À82 °C; IR (KBr) (
m
max, cmÀ1) 3344, 2966, 2219, 1631, 1472, 1273, 606; 1H
solid; mp: 60À62 °C; IR (KBr) (
m
max, cmÀ1) 3451, 2967, 2235, 1566, 1394,
NMR (500 MHz, DMSO-d6): d 7.38 (br, 2H, NH2), 3.05À3.01 (m, 4H, 2CH2S),
1.56À1.48 (m, 4H, 2CH2), 0.98À0.93 (m, 6H, 2CH3); 13C NMR (125 MHz, DMSO-
d6): d 150.0 (d, J = 242.5 Hz), 144.6 (d, J = 17.5 Hz), 139.9, 129.7 (d, J = 17.5 Hz),
116.0, 114.8, 108.3, 101.8, 38.4, 36.7, 23.0, 22.9, 13.1, 13.1; HRMS (TOF ESÀ) m/
z calcd for C14H15FN3SÀ2 [(MÀH)À], 308.0697; found, 308.0706.
25. Alam, S. J. Chem. Sci. 2004, 166, 325.
1236, 1093, 794; 1H NMR (500 MHz, DMSO-d6): d 3.26À3.13 (m, 4H, 2CH2S),
1.58À1.57 (m, 4H, 2CH2), 0.96 (m, 6H, 2CH3); 13C NMR (125 MHz, DMSO-d6): d
162.9 (d, J = 268.8 Hz), 145.5, 145.5, 139.3, 111.6, 111.6, 108.0, 107.9, 38.1,
38.1, 23.1, 23.1, 13.1, 13.1; 19F NMR (470 MHz, DMSO-d6): d = À100.3 (s, 1F);
HRMS (TOF ESÀ): m/z calcd for C14H13ClFN2SÀ2 [(MÀH)À], 327.0198; found,
327.0209. 4-Amino-2,5,6-tris(phenylthio)isophthalonitrile (4e): white solid; mp
26. Reddy, P. M.; Ho, Y. P.; Shanker, K.; Rohini, R.; Ravinder, V. Eur. J. Med. Chem.
2009, 44, 2621.
27. Smith, J. A.; Henry, D.; Ngui-Yen, J.; Castell, A.; Coderre, S. J. Clin. Microbiol.
1986, 23, 1104.
28. Kiehlbauch, J. A.; Hannett, G. E.; Salfinger, M.; Archinal, W.; Monserrat, C.;
Carlyn, C. J. Clin. Microbiol. 2000, 38, 3341.
29. Omrum, U.; Arikan, S.; KocagÖz, S.; Sancak, B.; Unal, S. Diagn. Microbiol. Infect.
Dis. 2000, 38, 101.
249À250 °C; IR (KBr) (
m
max, cmÀ1) 3309, 2225, 1624, 1529, 746, 470; 1H NMR
(500 MHz, DMSO-d6): d 7.52À7.14 (m, 17H, PhH, NH2); 13C NMR (125 MHz,
DMSO-d6): d 156.1, 150.8, 144.7, 135.2, 134.3, 133.8, 130.0, 129.8, 129.8, 129.5,
129.1, 127.9, 127.4, 127.1, 126.8, 122.2, 115.6, 115.0, 110.6, 102.1; HRMS (TOF
ESÀ) m/z calcd for C26H16N3SÀ3 [(MÀH)À], 466.0512; found, 466.0520. 4-Amino-
2,5-dichloro-6-(propylthio)isophthalonitrile (4f): white solid; mp 121À123 °C; IR
(KBr) (m
max, cmÀ1) 3327, 2964, 2227, 1637, 1556, 1211, 726, 528; 1H NMR
(500 MHz, DMSO-d6): d 7.67À7.62 (br, 2H, NH2), 3.10À3.04 (m, 2H, CH2S),
30. Malue, M.; Bastide, J. M.; Biancard, A. Int. J. Antimicrob. Agents 2005, 25, 321.