Sulfonamides and trimethoprim (TMP) drugs are normally used to inhibit the action of dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) enzymes, respectively. In this work, a new series of N-sulfonamide 2-pyridone derivatives that combine the inhibitory activities of DHPS and DHFR into one molecule were synthesized and evaluated for its in vitro antimicrobial activity and the ability to inhibit the action of both enzymes simultaneously. The synthesis was carried out via the reaction of novel benzothiazol sulfonylhydrazide with ketene dithioacetal derivatives, and the structures of the resultant compounds were confirmed using spectral and elemental techniques. Among the synthesized compounds, five compounds 3b, 5a, 5b, 11a, and 11b were found to possess significant antimicrobial activities against tested bacterial and fungi strains. The compounds were also examined for their cytotoxicity on HFB4 human dermal fibroblast cell line using MTT assay. The in vitro enzyme assay study of these compounds against DHPS and DHFR enzymes showed that compound 11a was the most potent inhibitor against both enzymes with IC 50 values of 2.76 and 0.20 μg/mL, respectively. Docking studies showed that this compound has occupied both the p-aminobenzoic acid and pterin binding pockets of DHPS as well as the pterin binding pocket of DHFR. The results of these investigations confirmed that compound 11a is the most potent dual DHPS/DHFR inhibitor.
A new strategy for designing and
assembling a novel class of functionalized
pyridine-based benzothiazole and benzimidazole incorporating sulfonamide
moieties was developed. The synthesis was carried out by reacting
N
-cyanoacetoarylsulfonylhydrazide with various electrophiles
such as 2-(benzo[
d
]thiazol-2-yl)-3,3-bis(alkylthio)acrylonitriles
and 2-(benzo[
d
]imidazol-2-yl)-3,3-bis(methylthio)-acrylonitriles,
as well as 2-ethoxyl acrylonitrile derivatives. The synthesized compounds
were tested for their antiviral and antimicrobial potency. Two of
the synthesized compounds,
15c
and
15d
,
showed more than 50% viral reduction against HSV-1 and CBV4, with
significant IC
50
and CC
50
values. The two potent
compounds
15c
and
15d
have also shown inhibitory
activity against Hsp90α protein with IC
50
values
of 10.24 and 4.48 μg/mL, respectively. A combination of
15c
and
15d
with acyclovir has led to IC
50
values that are lower than that of acyclovir alone. Molecular
modeling studies were used to identify the interactions between the
15c
and
15d
compounds and the active site of
Hsp90α enzyme. The antimicrobial investigation of the new compounds
has also shown that
8b
and
15d
exhibited
a higher inhibition zone (IZ) than sulfadiazine and gentamicin against
Klebsiella pneumonia,
whereas
9a
showed
higher IZ than ampicillin against
Staphylococcus aureus
. According to the enzyme assay study on dihydrofolate reductase,
9a
was shown to be the most potent compound among all examined
compounds.
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