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S.V. Rajmane et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 115 (2013) 393–398
Experimental
Instrumentation
UV–visible spectra was recorded in ethanol on Shimadzu A 600
UV–visible spectrometer. IR spectra was recorded in KBr pellets on
Shimadzu FT-IR 8400 spectrometer. 1H NMR spectra was recorded
in CDCl3 using TMS as the standard on Varian 300 MHz spectrom-
eter. GC–MS was recorded on Shimadzu GC–MS QP 5050 mass
spectrometer. Thermogram was recorded on V2 4F TA thermal
analyzer at the heating rate 1 °C per minute in nitrogen atmo-
sphere. Microwave mediated reaction was carried out in conven-
tional 25 DLX microwave oven. X-ray diffractogram was run in
the range 10–90° using a Philips PW-1710 diffractometer attached
to a digitized computer along with graphical assembly where Cu
Ka radiation source connected with a tube of Cu–NF 2 kV/20 mA
was used. The carbon, hydrogen and nitrogen contents were deter-
mined on Perkin–Elmer (2400) CHNS analyzer.
All reagents used such as 20-chloroacetophenones, thiourea and
iodine were pure AR grade. Solvents such as ethanol and diethyl
ether were purified prior to use as per standard procedure.
Fig. 1. Root knot nematodes.
Microwave mediated synthesis of 4-(o-chlorophenyl)-2-aminothiazole
(CPAT)
(Fig. 1) is the most important species associated with tomato (Lyc-
opersicon esculentum) [17]. This phytonematode species causes
chlorosis, premature leaf drop and stunting. The disease is becom-
ing one of the most serious calamities for the successful cultivation
of tomato crop. These nematodes cause up to 70–90% yield losses
in tomatoes and brinjal. In India, yield loss of tomato due to
root-knot nematodes (Meloidogyne spp.) ranges from 39.7% to
46.0%. The present investigation was made to study the nematicid-
al activity of newly synthesized CPAT on M. javanica.
The fresh water snails Lymnea auricularia family Lymnaeidae
are familiar members of the fauna of ponds, lakes, ditches and
other kind of standing waters throughout the World. It is an inter-
mediate host of liver fluke. The Fasciola spp. causes great damage
to live stock throughout the world. It is responsible not only for li-
ver rot, the uncomplicated Fascioliasis, but also the notorious
‘black disease’. The considerations of the family Lymnaeidae and
of species of snails which act as intermediate host [18] for F. hepat-
ica and F. Gigantia. The present investigation was made to study the
molluscicidal activity of newly synthesized CPAT on L. auricularia.
Among thiazoles, 2-aminothiazoles have attracted the attention
of researchers because they form Schiff bases with aldehydes.
Schiff bases possess strong ability to form metal complexes [19,20].
Microwave synthesis of aminothiazoles is of interest in view of
green chemistry approach. Kabalka et al. [21] reported MW pro-
CPAT was synthesized (Reaction 1) [22] by reacting 20-chloroac-
etophenone (0.05 mol), iodine (0.1 mol) and thiourea (0.1 mol).
They were mixed well with mortar-pestle and placed in small con-
ical flask at room temperature. The mixture was then exposed to
microwave irradiations for 5 min with 30 s pause at 180 W. Then
100 ml distilled water was added to the mixture and heated in
microwave for 5–6 min at 270 W with 1 min pause till the precip-
itate dissolve. Filter the yellow solution and alkaline it with ammo-
nia solution. Separate out the product and recrystallize with ethyl
alcohol followed by diethyl ether and dried under reduced
pressure.
Biological evaluation
Antibacterial and antifungal activity
Antibacterial and antifungal activity of CPAT was tested by seri-
al dilution technique [23]. Eight test tubes containing 5 ml of ster-
ile nutrient/sabouraud broth were inoculated with 0.02 ml of 24 h
old culture of bacteria S. aureus and K. pneumoniae and fungi A. ni-
ger and C. albicans respectively. Different amounts of CPAT in eth-
anol were aseptically added with the help of sterile pipettes from
moted synthesis of 2-(N-substituted) aminothiazoles from
a-bro-
the stock solution 200
lg/ml to 5 ml quantities of respective media
moketones. Khrustalev et al. [22] reported synthesis of 2-amino-
4-phenylthiazole under microwave irradiation. In the present com-
munication, we are reporting the microwave mediated synthesis of
CPAT by reacting 20-chloroacetophenone, iodine and thiourea un-
der microwave irradiation. The compound CPAT (Fig. 2) was iden-
tified by spectral (UV–visible, IR, NMR and GC–MS), X-ray
diffraction and thermal analysis.
so as to reach the concentration from 1
l
g/ml to 50 g/ml. All test
l
tubes were inoculated at 37 °C and at room temperature for bacte-
ria and fungi respectively. Test tubes inoculated with organism
were observed for presence of turbidity after 24 h and 48 h, respec-
tively. The lowest concentration of CPAT inhibiting the growth of
organism was determined as MIC value.
Nematicidal activity
For the toxicity and efficacy ratio of CPAT on root-knot nema-
tode M. javanica, they were isolated from roots of tomato plants
(L. esculentum) for in vitro study by using sieve plate method
[24]. More eggs were recovered by repeated sieving and rinsing.
The number of nematodes in an aqueous suspension was deter-
mined by using a counting dish.
Cl
H2N
N
The newly synthesized CPAT was tested in vitro nematicidal
activity against root-knot nematodes M. javanica isolated from
roots of tomato plants. The infected roots were macerated in 2%
sodium hypochloride solution for 5 min to extract eggs and
S
Fig. 2. 4-(o-Chlorophenyl)-2-aminothiazole (CPAT).
Rajmane
