Purpose: To synthesise a new series of 5-substituted-1,3,4-Oxadiazol-2yl-4-(morpholin-4yl
sulfonyl)benzyl sulfide and evaluate their antibacterial activity.
Methods: Different organic acids were converted consecutively into corresponding esters, hydrazides
and 5-substituted-1,3,4-Oxadiazol-2-thiols (
4a-e). The targets,
6a-e were synthesized by stirring
4a-e
with 4-(4-(bromomethyl)phenylsulfonyl) morpholine (
5) in the presence of N,N-dimethylformamide
(DMF) and sodium hydride (NaH). All the structures were elucidated by modern spectroscopic
techniques and screened against bacteria using standard procedure and ciprofloxacin drug as positive
control.
Results: The yield of the synthesized compounds (
4a-e and
6a-e) were moderate (65 - 90 %).
Compounds
6a-e had antibacterial activity against
Pseudomonas aeruginosa
,
Bacillis subtilis
and
Staphylococcus aureus
while some had activity against the other bacteria used. One of the compounds,
6b, exhibited significant activity against all the bacterial strains, i.e.,
S. typhi
(-),
E. coli
(-),
K. pneumoniae
(-),
P. aeruginosa (-),
B. subtilis (+) and
S. aureus (+) with MIC (μM) values of 11.01 ±
0.31, 15.37 ± 3.33, 16.11 ± 1.14, 9.70 ± 1.96, 10.01 ± 2.70 and 9.15 ± 0.29, respectively. However,
none of the compounds had any inhibitory activity against any bacteria as high as that of ciprofloxacin.
Conclusion: Five new compounds with antibacterial activities have been synthesized. Their potential
as therapeutic agents is, however, yet to be evaluated.
