SYNTHESIS OF FERROCENYL CHALCONES AND THEIR EVALUATION AGAINST PLANT PATHOGENIC FUNGI AND ROOT KNOT NEMATODE
Loading...
Date
2020
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
DIVISION OF AGRICULTURAL CHEMICALS ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
Chalcones and their derivatives are conventionally known to possess biological activity
due to their highly reactive unsaturated carbonyl group. Chalcone nucleus containing
compounds have been a subject of interest for the scientists all over the world and
research is directed towards the development of potent crop protection chemicals based
on this nucleus. However, poor solubility is a major concern and prevents their use in
crop protection. In order to overcome this, thirty four substituted ferrocenyl chalcones
have been synthesized by microwave method (MM) and compared the reaction time
and yield of products with that of conventional method (CM).
Microwave Assisted Organic Synthesis (MAOS) has provided a great impetus
to organic synthesis during the last few decades and has become most useful for
functional group inter conversions. The use of microwave has several advantages such
as shorter reaction times, higher yields, ease of manipulation and lower costs.
Furthermore, reactions under microwave have great advantage of not using organic
solvents (solvent-free) and thus such reactions are environment friendly and generate
less waste. Environmentally benign character of the microwave method is desirable for
large scale industrial applications.
A series of ferrocenyl chalcones was synthesized by base-catalyzed
condensation of acetylferrocene with different benzaldehydes and
ferrocenecarboxyaldehyde with different acetophenones. All the products were
obtained in appreciable amounts and the yields for different compounds were higher in
microwave method (77-92%) as compared to conventional method (71-87%). The
synthesized compounds were characterized by various spectroscopic techniques viz. IR,
1H-NMR, 13C-NMR and LC-HRMS.
All synthesised compounds were tested against root knot nematode,
Meloidogyne incognita. Although all the compounds possessed activity against M.
incognita, but compounds 3b, 3f, 3h, 3m, 3o, 6g, 6h, 6j, 6k and 6p were found to be
more potent. However, all the synthesized compounds were found to be less active than
commercially available carbofuran and velum prime. Pot study revealed that, all plant
growth parameters (shoot length, shoot weight, root length, root weight, average no. of
galls/plant and yield (g)) were positively influenced by these compounds. As the
nematicial activity of test compounds increased, plant growth parameters were also
increased. The activity was highest in compounds 3f, 3h, 6g, and 6h @ 80 ppm at 30
DAI and 60 DAI. The activity was higher in soil drenching method compared to root
dipping method.
All the synthesized compounds showed antifungal activity. Among (3a-3p)
series compounds, 3o i.e. (2E)-1-Ferrocenyl-3-(2,6-dichlorophenyl)-prop-2-en-1-one
showed highest fungicidal activity against Sclerotium rolfsii with ED50 of 23.24 ppm.
But in case of Alternaria solani, among (3a-3p) series compounds, 3c i.e. (2E)-1-
Ferrocenyl-3-(4-fluorophenyl)-prop-2-en-1-one, having value ED50 = 29.9 ppm
showed highest activity.
Among (6a-6r) series compounds, 6o i.e. (2E)-1-(5-Chloro-2-hydroxyphenyl)-
3-ferrocenyl-prop-2-en-1-one showed highest fungicidal activity against S. rolfsii with
ED50 of 21.50 ppm. In case of A. solani, among (6a-6r) series compounds, 6b i.e. (2E)-
1-(4-Bromophenyl)-3-ferrocenyl-prop-2-en-1-one showed highest fungicidal activity
with ED50 of 31.14 ppm.
Based on in vitro results, three most effective compounds 3b, 3o and 6o were
chosen for pot experiment against S. rolfsii. The study revealed that shoot length was
significantly increased as compared to control. The shoot length wasfound to be highest
(24.50 cm) in plants treated with 3b followed by 3o and 6o @ 1000 ppm at 60 DAI.
The percent disease incidence was significantly decreased as compared to control. The
percent disease incidence was found to be minimum in plants treated with 3b @ 1000
ppm. The disease incidence was minimum in soil drenching method compared to root
dipping method. In conclusion, this is the first attempt to synthesise a series of
ferrocenyl chalcones by Microwave Synthesis Reactor. Study revealed that microwave
method was quick and green method as compared to conventional method. All the
synthesized compounds were found to have good to moderate nematicidal and
fungicidal activity.
Keywords:
Description
T-10332