A. B. Sarıgüney, E. Kocabaş, F. Erci, E. Torlak, and A. Coşkun
Vol 000
General procedure for the preparation of thiadiazine
derivatives. synthesized
Standards Institute (CLSI) [17]. The stock solutions of the
compounds were prepared in DMSO (10%, Merck,
Germany) at a concentration of 1 mg/mL. Twofold dilutions
of filter-sterilized stock solutions were used as working solu-
tions. Gentamycin (Sigma-Aldrich, USA) at the same con-
centration range served as the positive control. Volumes of
130-μL fresh Mueller Hinton Broth and 20-μL inoculum
were added to each well of sterile 96-well microplates
(Anicrin, Venezia, Italy). Then, 50 μl of the working solu-
tions of compounds were dispensed into the 10 consecutive
wells of each microplate row with a final DMSO concentra-
tion of 2.5%. Wells 11 and 12 of each row served as the
growth control (compound and DMSO-free) and negative
control (compound-free), respectively. Contents of each well
were mixed thoroughly to give final concentrations of com-
pounds ranging from 0.49 to 250 μg/mL. Then, microplates
were sealed and incubated at 35°C. After 24-h incubation,
cell growth in each well was determined by measuring
optical density with a microplate reader (Biotek, Winooski,
VT, USA) at 600 nm. MICs were defined the lowest com-
pound concentrations at which growth was not apparent, as
measured by optical density.
Thiadiazine
derivatives
according to method described in literature [16].
Chloroacetophenone derivative (8 mmol) and an
appropriate thiosemicarbazide (8 mmol for 6–8, 16 mmol
for 9) are taken in 5 mL of anhydrous ethanol, refluxed for
about 2 h. The solid obtained on cooling was washed with
cold ethanol and recrystallized.
5-(4-Phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine (6):
yield (82%); this compound was obtained as white
crystal; mp 126–128°C; FT-IR: 3409, 3280, 3243, 3151,
1
3042, 1582, 1504, 1487, 1278,1081, 962, 737 cmꢀ1; H
NMR (CDCl3, 400 MHz): δ = 3.51 (s, 2H, CH2S), 7.62–
7.24 (m, 9H, Ar─H), 8.75 (s, 2H, NH2); 13C NMR
(CDCl3, 100 MHz): δ = 13.71, 127.17, 128.27, 129.48,
129.70, 132.80, 133.96, 135.31, 139.93, 147.60, 179.38.
Anal. Calcd for C15H13N3OS: C, 63.53; H, 4.59; N,
14.82%. Found: C, 63.37; H, 4.46; N, 14.65%.
N-methyl-5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-
amine (7): yield (75%); this compound was obtained as
yellowish solid; mp 137–139°C; FT-IR: 3366, 3243,
3066, 1602, 1546, 1498, 1288, 1233, 1108, 831,
1
738 cmꢀ1; H NMR (CDCl3, 400 MHz): δ = 2.93 (s, 3H,
Me), 3.58 (s, 2H, CH2S), 5.20 (s, br, NH), 7.68–7.14 (m,
Ar─H); 13C NMR (CDCl3, 100 MHz): δ = 13.87, 20.67,
127.17, 128.27, 129.32, 129.54, 132.75, 133.82, 135.47,
139.81, 147.7, 179.5. Anal. Calcd for C16H15N3OS: C,
64.62; H, 5.08; N, 14.13; S, 10.78%. Found: C, 64.71; H,
4.94; N, 14.22; S, 10.49%.
Acknowledgment. The authors are grateful for the grant
sponsored by the Necmettin Erbakan University Scientific
Research Projects (171210014).
REFERENCES AND NOTES
N-phenyl-5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-
amine (8): yield (70%); this compound was obtained
as white solid; mp 146–148°C; FT-IR: 3298, 3182,
3050, 1615, 1598, 1516, 1482,1444, 1289, 1189, 971,
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1
746 cmꢀ1; H NMR (CDCl3, 400 MHz): δ = 3.62 (s, 2H,
[4] Ashtekar, D. R.; Fernandes, F.; Khadse, B. G.; Shirodkar, M.
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CH2S), 7.75–7.08 (m, Ar─H), 8.91 (s, H, NH); 13C
NMR (CDCl3, 100 MHz): δ = 13.9, 125.46, 127.17,
128.27, 128.90, 129.54, 129.72, 132.88, 133.97, 135.34,
139.70, 147.58, 179.46. Anal. Calcd for C21H17N3OS: C,
70.19; H, 4.77; N, 11.67; S, 8.93%. Found: C, 70.26; H,
4.60; N, 11.65; S, 8.89%.
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5,50-(Oxybis(4,1-phenylene))bis(6H-1,3,4-thiadiazin-2-
amine) (9): yield (67%); this compound was obtained as
white solid; mp 225–227°C; FT-IR: 3420, 3276, 3240,
3018, 2905, 1628, 1588, 1565, 1453, 1323,1084, 906,
1
707 cmꢀ1; H NMR (CDCl3, 400 MHz): δ = 3.64 (s, 4H,
CH2S), 7.60–7.24 (m, 8H, Ar─H), 8.82 (s, 4H, NH2); 13C
NMR (CDCl3, 100 MHz): δ = 13.9, 128.27, 129.48,
129.70, 132.80, 133.98, 135.34, 139.89, 147.55, 179.40.
Anal. Calcd for C18H18N6OS2: C, 54.53; H, 4.07; N, 21.20;
S, 16.17%. Found: C, 54.48; H, 4.01; N, 21.33; S, 16.09%.
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[17] Villanova, P., National Committee for Clinical Laboratory Stan-
dards. Methods for dilution antimicrobial susceptibility tests for bacteria that
grow aerobically. Approved Standard. NCCLS Document M7-A4 1997.
Antimicrobial activity assay.
Antimicrobial activities
of synthesized compounds were evaluated by broth
microdilution method and expressed as MIC, in accordance
with the procedure outlined by Clinical & Laboratory
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet