RSC Advances
Paper
General procedure for the synthesis of target compounds 7a–
7p
I ¼ (C ꢀ T)/(C ꢀ 0.4) ꢃ 100%
In this formula, the C represented the average mycelial diam-
eter of negative control, and T represented the average mycelial
diameter of the tested compound-treated PDA.
A mixture of triazole 5 (50 mg, 0.13 mmol), potassium carbonate
(18 mg, 0.13 mmol) and the corresponding amide intermediates
6a–6p (0.13 mmol) was added to acetone (4 mL) and then stirred
at 40 ꢁC until the reaction was complete as indicated by TLC (2–
4 h). Subsequently, the reaction mixture was poured into cold
water and the resulted precipitate was ltered off, washed with
water and dried to give compounds 7a–7p in 58–92% yield.
Conclusion
In conclusion, a class of novel 1,2,4-triazole derivatives con-
taining both quinazolinylpiperidinyl moiety and N-(substituted
phenyl)acetamide group were designed and synthesized as
agricultural bactericides. The bioassay results showed that
some of the target compounds possessed good to excellent
antibacterial activities against phytopathogenic bacterium Xoo.
For example, compounds 7e, 7g, 7i, 7l and 7n had EC50 values of
Antibacterial bioassay
Antibacterial activities of target compounds 7a–7p were deter-
mined against two phytopathogenic bacteria (Xoo and Rs),
based on the turbidimetric method.23 Firstly, the tested
compounds were prepared with two concentrations of 200 and
100 mg mLꢀ1. Pure DMSO in sterile distilled water was used as
blank control, and commercially available bactericide Bismer-
thiazol (BMT) and Thiodiazole copper (TDC) were used as
positive control. About 40 mL of solvent NB (3 g of beef extract,
5 g of peptone, 1 g of yeast powder, 10 g of glucose, 1 L of
distilled water, pH ¼ 7.0–7.2) containing the bacterium Xoo or
Rs was added to the mixed solvent system including 4 mL of
solvent NB and 1 mL of 0.1% Tween-20 containing tested
compound or BMT/TDC. The above test tube was incubated at
34.5–47.5 mg mLꢀ1
, which was signicantly better than
commercial bactericide Bismerthiazol (85.6 mg mLꢀ1). The
above studies proved that 1,2,4-triazole derivatives containing
quinazolinylpiperidinyl heterocycle and acetamide unit were
promising candidates for the development of new and more
efficient agricultural bactericides against the pathogen Xoo,
deserving further investigation in the future.
Acknowledgements
ꢁ
This work was nancially supported by the National Natural
Science Foundation of China (No. 21362003) and the Agricul-
tural Research Projects of Guizhou Province (No. 20093010).
30 ꢂ 1 C and continuously shaken at 180 rpm for three days.
The bacterial growth was monitored by measuring the optical
density at 600 nm (OD600), given by turbiditycorrected
¼
values
ODbacterium ꢀ ODno bacterium, I ¼ (Ctur ꢀ Ttur)/Ctur ꢃ 100%. The
Ctur represented the corrected turbidity value of bacterial
growth of untreated NB (blank control), and Ttur represented the
corrected turbidity value of bacterial growth of tested
compound-treated NB. The I represented the inhibition rate of
tested compound against the bacterium.
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34010 | RSC Adv., 2017, 7, 34005–34011
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