- IARI, New Delhi
- Chemistry, Organic Chemistry, Analytical Chemistry, Natural Products Chemistry, Phytochemistry, Digital Library, and 22 moreNano Synthesis, Plant Protection, IPM, Pesticide Residues, Pesticide Chemistry, Nutraceuticals and phytochemicals, Nanopesticides, Nanoscience, Nanotechnology, Agriculture, Nanomaterials, Pathology, Post Harvest Technology, Nanoparticles, Synthesis of nanoparticles, Pest Management, Crop Processing and Storage, Neem Tree and Its Derivatives, Click chemistry, Nanosulphur, Heterocycles, Nitrification, and Azadirachtinedit
Nitrate is prevalent in environment and present in foods of plant origin as part of nitrogen cycle. It is now one of the most pervasive and persistent contaminants in animal food chain. Present work is focussed on development of a novel... more
Nitrate is prevalent in environment and present in foods of plant origin as part of nitrogen cycle. It is now one of the most pervasive and persistent contaminants in animal food chain. Present work is focussed on development of a novel green nanosensor using corn silk extract for nitrate detection in leafy vegetables (Spinacia oleracea, Amaranthus viridis and Amaranthus cruentus). The green reduced graphene oxide (rGO) and a nanocomposite (G-Fe 3 O 4 @rGO) was synthesized for the first-time using corn silk extract and used for fabrication of the nanosensor. Various characterization techniques were used to expose the optical, crystallographic and surface morphology details of the nanosubstrates. Electrochemical studies of the fabricated nanosensor were conducted using the electrochemical impedance spectroscopy (EIS) technique. The performance of NiR/G-Fe 3 O 4 @rGO/ITO green nanosensor was the best, in terms of the electrochemical performance parameters among different fabricated nanosensors in the study. The developed green nanosensor demonstrated high sensitivity of 122.1 Ohm/log(mg/ L)/cm 2 and lower limit of detection 0.076 mg/L for detection of nitrate in leafy vegetables. The green nanosensor exhibited higher recovery rates (>86%) and high precision in nitrate detection in leafy vegetables (RSD <5.2%). Validation studies were conducted with HPLC technique also. The results of green nanosensor were found in good agreement with HPLC studies (p < 0.05) highlighting the market acceptability with usefulness and effectiveness of the nanosensor for food quality and safety evaluation.
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The use of inhibitors retain nitrogen as ammonium in soil, giving plants ample time for its uptake. This can reduce nitrous oxide (N 2 O) emissions, but extended retention may increase ammonia (NH 3) volatilization. This study assessed... more
The use of inhibitors retain nitrogen as ammonium in soil, giving plants ample time for its uptake. This can reduce nitrous oxide (N 2 O) emissions, but extended retention may increase ammonia (NH 3) volatilization. This study assessed the efficacy of coated urea fertilizers in reducing greenhouse gas (GHG) emissions and NH 3 volatilization in rice fields. A field experiment with Pusa 44 rice in the kharif seasons of 2019 and 2020 compared unfertilized control (No N), prilled urea (PU), nitrification inhibitors (NIs): neem oil-coated urea (NCU), karanj oil-coated urea, and dual inhibitor (DI: Limus + NCU). The coated urea fertilizers were analysed with scanning electron microscopy, fourier transform infrared spectrometry, and energy-dispersive spectroscopy. Compared to PU, DI reduced N 2 O emissions by 23.7%, methane by 11.9%, and NH 3 by 29.8%. DI also reduced NH 3 emissions by 36-39% compared to other NIs. Overall, DI can lower the global warming potential of rice cultivation in trans Indo-Gangetic plains region by 17.1% for both direct and indirect emissions, suggesting its significant potential to reduce India's contribution to total agricultural GHG emissions.
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ABSTRACT We have recently reported the development of nanosulphur with remarkable fungicidal properties, much better than the conventional sulphur. The nanosulphur could substitute the toxic conventional synthetic fungicides. The lack of... more
ABSTRACT We have recently reported the development of nanosulphur with remarkable fungicidal properties, much better than the conventional sulphur. The nanosulphur could substitute the toxic conventional synthetic fungicides. The lack of estimation protocols for active ingredient in nanoformulations and exploitation of nanosulphur as a new technology for fungal management necessitates the need for estimation protocols to ensure the quality and quantity of sulphur in nanoformulations. Therefore, a method was developed for the estimation of sulphur in its nanoformulations using UV–visible spectrophotometry. Thirty-four samples of nanosulphur were analysed to validate the method. The percentage estimation of the active ingredient in all the samples was above 80.
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ABSTRACT
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In this paper, we report the development, characterization and bioefficacy evaluation of fipronil nanoformulations against brown plant hopper (BPH); Nilaparvata lugens in rice. Nanoformulations were characterized for nanosizing and... more
In this paper, we report the development, characterization and bioefficacy evaluation of fipronil nanoformulations against brown plant hopper (BPH); Nilaparvata lugens in rice. Nanoformulations were characterized for nanosizing and stability under variable conditions. Bioefficacy of nanoformulations were evaluated under field condition at farms of Indian Agricultural Research Institute, New Delhi during Kharif 2015. At milking stage BPH populations were above economic threshold level; followed by foliar application of fipronil nanoformulations at four doses (viz., 30, 45, 60 and 90 g a.i./ha) along with commercial formulation of fipronil. The mean mortality clearly indicated that all the insecticidal treatments were significantly superior over untreated control where, highest mortalities were observed in nanodispersions followed by monolithic dispersion and commercial formulation of fipronil. Treated plots 7 days after application @ 60 g a.i./ha has shown 93.47%, 86.89% and 80.47% reduction BPH population in nanodispersion, encapsulated monolithic dispersion and commercial formulation treated plots respectively. In comparison to commercial formulation @ 60 g a.i./ha yield has increased by 0.56 t ha−1 (28.76%) and 0.26 t ha−1 (14.04%) in nanodispersion and monolithic dispersion.
Neeraj Kumar, Rajesh Kumar, Najam Akhtar Shakil, Dhruba Jyoti Sarkar & Subhash Chander (2019) Evaluation of fipronil nanoformulations for effective management of brown plant hopper (Nilaparvata lugens) in rice, International Journal of Pest Management, 65:1, 86-93, DOI: 10.1080/09670874.2018.1468046
Neeraj Kumar, Rajesh Kumar, Najam Akhtar Shakil, Dhruba Jyoti Sarkar & Subhash Chander (2019) Evaluation of fipronil nanoformulations for effective management of brown plant hopper (Nilaparvata lugens) in rice, International Journal of Pest Management, 65:1, 86-93, DOI: 10.1080/09670874.2018.1468046
Research Interests: Botany, Entomology, Chemistry, Organic Chemistry, Synthesis of nanoparticles, and 15 moreSustainable agriculture, Pest Management, Biology, Agriculture, Nanomaterials, Nanoparticles, Agricultural Entomology, Nanotechnology, Biological Sciences, Pesticides, Nanoscience, Insects, CHEMICAL SCIENCES, Rice wheat Cropping System, and Rice Cropping System
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Current interest in our laboratory1 in the use of microwave2 energy led us to investigate it use for the synthesis of azlactones which are important synthons for biologically active m0lecules.7~~ A literature survey showed that arylidene... more
Current interest in our laboratory1 in the use of microwave2 energy led us to investigate it use for the synthesis of azlactones which are important synthons for biologically active m0lecules.7~~ A literature survey showed that arylidene oxazolones have been prepared by the condensation of hippuric acid with aromatic aldehydes in the presence of catalyst such as acetic anhydride and sodium a~etate,~ potassium carbonate? zinc chloride7 and N-chloroacetyl-benzamide-sodium acetate.R The reactions involve cyclodehydration of hippuric acid to its azlactone followed by condensation of methylene group of the azlactone with the aromatic aldeh~de.~ We now report a new convenient method for the synthesis of azlactones. Arylaldehydes along with hippuric acid when subjected to microwave irradiation (MWI) at 2450 MHz for 1.5-2.0 min using N,N-dimethylacetamide (DMAC) as a suitable energy transfer solvent and N,N-dicyclohexylcarbodiimide (DCC) as a condensing agent. A shortcoming of classical preparation of aromatic azlactones from phenolic aldehydes with acetic anhydride and sodium acetate5 is that the hydroxy group are always acetylated and also 1-1.5 h heating is required: In comparison, the reaction using microwave energy is completed in just 1.5-2.0 r 1 A r c H M O Ph 1 PhCONHCH2COOH M.W.I. min without affecting the phenolic hydroxyl groups and provide good to excellent yields of products compared to 48-60% yields using conventional heating. The analytical and spectral data of products (la-j) are in agreement with those reported in literat~re.'.~,~~ Thus the present method is superior to 45 1
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A series of triazines have been synthesized starting from 5-alkyl-1,3,4-thiadiazole-2-thioles (1a-d). On reaction with ethyl bromoacetate in the presence of anhydrous K 2 CO 3 under microwave irradiation (MWI), these yielded corresponding... more
A series of triazines have been synthesized starting from 5-alkyl-1,3,4-thiadiazole-2-thioles (1a-d). On reaction with ethyl bromoacetate in the presence of anhydrous K 2 CO 3 under microwave irradiation (MWI), these yielded corresponding esters (2a-d) which on hydrazinolysis under MWI produced (5-alkyl-1,3,4-thiadiazol-2-yl sulfanyl) acetohydrazides (3a-d). The reaction of 3a-d with-bromoacetophenone under MWI yielded 6-aryl-3-[(5-alkyl-1,3,4-thiadiazol-2-yl sulfanyl)methyl]-1,2,4-triazines (4a-h). All the synthesized triazines showed in vitro antitubercular activity.
Research Interests:
Current interest in our laboratory1 in the use of microwave2 energy led us to investigate it use for the synthesis of azlactones which are important synthons for biologically active m0lecules.7~~ A literature survey showed that arylidene... more
Current interest in our laboratory1 in the use of microwave2 energy led us to investigate it use for the synthesis of azlactones which are important synthons for biologically active m0lecules.7~~ A literature survey showed that arylidene oxazolones have been prepared by the condensation of hippuric acid with aromatic aldehydes in the presence of catalyst such as acetic anhydride and sodium a~etate,~ potassium carbonate? zinc chloride7 and N-chloroacetyl-benzamide-sodium acetate.R The reactions involve cyclodehydration of hippuric acid to its azlactone followed by condensation of methylene group of the azlactone with the aromatic aldeh~de.~ We now report a new convenient method for the synthesis of azlactones. Arylaldehydes along with hippuric acid when subjected to microwave irradiation (MWI) at 2450 MHz for 1.5-2.0 min using N,N-dimethylacetamide (DMAC) as a suitable energy transfer solvent and N,N-dicyclohexylcarbodiimide (DCC) as a condensing agent. A shortcoming of classical preparation of aromatic azlactones from phenolic aldehydes with acetic anhydride and sodium acetate5 is that the hydroxy group are always acetylated and also 1-1.5 h heating is required: In comparison, the reaction using microwave energy is completed in just 1.5-2.0 r 1
A series of novel 6-¯uoro-7-(5-alkyl-1,3,4-thiadiazol/oxadiazol-2-ylsulfanyl)-4-quino-lone-3-carboxylic acids were synthesized using microwave irradiation. The compounds were tested for their in vitro antibacterial activity. All compounds... more
A series of novel 6-¯uoro-7-(5-alkyl-1,3,4-thiadiazol/oxadiazol-2-ylsulfanyl)-4-quino-lone-3-carboxylic acids were synthesized using microwave irradiation. The compounds were tested for their in vitro antibacterial activity. All compounds containing the 1,3,4-thiadiazole/oxadiazole moiety at position 7 showed promising antibacterial activity.
Mercury derivatives of substituted 1,3,4-thiadiazoles and 1,2,4-triazine have been synthesized under microwave irradiation in open vessels using a domestic microwave oven as well as in a conventional way. The reaction time could be cut... more
Mercury derivatives of substituted 1,3,4-thiadiazoles and 1,2,4-triazine have been synthesized under microwave irradiation in open vessels using a domestic microwave oven as well as in a conventional way. The reaction time could be cut down from hours to minutes employing microwaves, accompanied by marginally improved yields. The compounds show promising fungi-cidal activity.
— The tetrazines (V) are prepared by conventional methods and under microwave irradiation. In comparison with the conventional method the reaction rate is enhanced about 250 times by using microwaves and the yields are improved up to 23%.... more
— The tetrazines (V) are prepared by conventional methods and under microwave irradiation. In comparison with the conventional method the reaction rate is enhanced about 250 times by using microwaves and the yields are improved up to 23%. The reaction of (I) with the cyanates (VI) yields the thiosemicarbazide (VIIa) and semicarbazide (VIIb) which are elaborated further to the thiazole (IXa), the oxazole (IXb), a thiazolidinone and a triazole. — (KIDWAI, M.; KUMAR, R.; Gazz. Chim.
Chemical pesticides of micronized form have been widely used for controlling pests and diseases of crop plants. Recently nano formulation of these chemicals has received much attention. Synthesis of nano particles (NPs) of metallic... more
Chemical pesticides of micronized form have been widely used for controlling pests and diseases of crop plants. Recently nano formulation of these chemicals has received much attention. Synthesis of nano particles (NPs) of metallic compounds are being done by biological means using different species of bacteria (Pseudomonas,) and algae (Sargassum, Chlorella). They are also prepared synthetically. Silver nano particles are reported for controlling phytopathogens like Fusarium culmorum, Rafflaea sp., Rhizoctonia solani, Sclerotinia sclerotiorum, Bipolaris sorokiniana and Magnaporthe grisea. Nano copper was also effective in controlling rice bacterial blight disease caused by Xanthomonas oryzae pv. oryzae and leaf spot of mung caused by X. campestris pv. phseoli. Nano-silica could provide successful control of insects like white fly (Trialeuroded vaporarium), coconut mite (Dermanyssus gallinae) and mustard weevil (Phaedon cochleariae). Our consortium has developed novel nano-silica for the management of rice weevil (Sitophilus oryzae), a major storage insect pest. Nano forms of hexaconazole and sulfur were found highly effective against two phytopathogens Rhizoctonia solani and Erysiphe cichoracearum. Nano sulfur was also found superior in controlling the red spider mite (Tetranychus urticae). It was more than ten times effective as compared to commercial sulfur. This implies lesser cost for pest management.
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A series of heteroarenes based [1,2,3]-triazole derivatives 8a-h and 9a-f has been synthesized via click chemistry through Huisgen [2+3] cycloaddition reaction of heteroarylazides 7a-e with alkynes (3a-c, propargyl alcohol or phenyl... more
A series of heteroarenes based [1,2,3]-triazole derivatives 8a-h and 9a-f has been synthesized via click chemistry through Huisgen [2+3] cycloaddition reaction of heteroarylazides 7a-e with alkynes (3a-c, propargyl alcohol or phenyl acetylene) in the presence of CuSO 4 .5H 2 O and sodium ascorbate in t-butanol and water (1:1) mixture at 25°C in good to excellent yields (74-94%). All the newly synthesized compounds have been characterized on the basis of analytical and spectral data. The compounds 8a, 8e, 9a, 9b, 9c and 9e have been evaluated for their preliminary in-vitro antibacterial efficacy against a panel of two Gram-positive bacteria viz. Staphylococcus aureus and Streptococcus mutans and two Gram-negative bacteria viz. Escherichia coli and Pseudomonas aeruginosa using the Agar disc diffusion method.
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To cite this article: Bijoy P. Mathew , Nisha Aggarwal , Rajesh Kumar & Mahendra Nath (2013): Synthesis and anti-bacterial activity of novel dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones, Journal of Sulfur Chemistry, A novel series of... more
To cite this article: Bijoy P. Mathew , Nisha Aggarwal , Rajesh Kumar & Mahendra Nath (2013): Synthesis and anti-bacterial activity of novel dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones, Journal of Sulfur Chemistry, A novel series of sulfur-containing dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones has been synthesized through an eco-friendly Mannich-type condensation cyclization reaction of 7-hydroxy-4-methyl-2-thiocoumarin or 6-chloro-7-hydroxy-4-methyl-2-thiocoumarin with formaldehyde and primary amines in water at 80–90 • C for 2 h. All the synthesized compounds were screened for their in vitro anti-bacterial efficacy against two Gram-positive and three Gram-negative bacterial strains by using the disc diffusion method. The compound (8c) was found to be most potent with the zone of inhibition of 16 and 15 mm against Staphylococcus aureus ATCC 2937 and Klebsiella pneumoniae ATCC 31488, respectively.
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Phytotoxic and agro beneficial properties of antimicrobially efficient Sulfur nanoparticles (SNPs) and ZnO nanoparticles (ZNPs) were evaluated on Mung (Vigna radiata). Mung seeds were germinated with an increasing concentration gradient... more
Phytotoxic and agro beneficial properties of antimicrobially efficient Sulfur nanoparticles (SNPs) and ZnO nanoparticles (ZNPs) were evaluated on Mung (Vigna radiata). Mung seeds were germinated with an increasing concentration gradient of nanoparticles. The extent of phtotoxicity were assessed depending upon the effect of used nanoparticles on physical factors (relative root and shoot length, dry weight and area of leaves), photosynthetic pigments (chlorophyll , carotene and xanthophyll content) and mitochondrial stress indicator level (thiol), A simultaneous study was undertaken to understand the effect of SNPs and ZNPs on overall plant growth and nutrition. The nutritive values of nanoparticles 301 were determined in terms of total lipid and protein content. All the aforementioned biochemical assays were performed in triplicate for statistical viability.
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The present study evaluated rice husk ash (RHA) as an adsorbent for simultaneous removal of a mixture of seven different pesticides (alachlor, metolachlor, chlorpyriphos, fipronil, a-endosulfan, b-endosulfan, and p,p 0-DDT) and two... more
The present study evaluated rice husk ash (RHA) as an adsorbent for simultaneous removal of a mixture of seven different pesticides (alachlor, metolachlor, chlorpyriphos, fipronil, a-endosulfan, b-endosulfan, and p,p 0-DDT) and two metabolites (p,p 0-DDE and endosulfan sulfate) from water. The adsorbent RHA was prepared in the laboratory and characterized by techniques such as X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectrometry. Adsorption kinetics were well described by the pseudo-second-order kinetic model. The Freundlich isotherm model fitted the equilibrium data better than the Langmuir model, and the maximum sorption capacity varied from 0.078 to 0.166 mg/g. The column elution studies showed that 10 L of mixed pesticide-contaminated water (0.05 mg/L) can be treated with only 10 g of RHA at a removal efficiency of 90%. The results implied that RHA can be used as a low-cost, easily available, and efficient adsorbent for the simultaneous removal of pesticides from contaminated water.
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In an attempt to identify plants having anti-tick properties, the 95% ethanolic and 50% hydro-ethanolic extracts of the fruits of Semecarpus anacardium and leaves of Datura stramonium were evaluated against reference tick lines of... more
In an attempt to identify plants having anti-tick properties, the 95% ethanolic and 50% hydro-ethanolic extracts of the fruits of Semecarpus anacardium and leaves of Datura stramonium were evaluated against reference tick lines of Rhipicephalus (Boophilus) microplus. The 95% ethanolic extracts of S. anacardium and D. stramonium caused 50% and 20% mortality, respectively, within 72 h of treatment by adult immersion test. The LC 90 value of the ethanolic fruit extract of S. anacardium was determined as 13.5% (CI 12.05–15.12). The extract was also found efficacious (73.3% ± 3.3%) against the multi-acaricide-resistant IVRI-V line of R.(B.) microplus. The S. anacardium extract significantly affected the reproductive physiology of treated ticks by inhibiting the oviposition and was found safe. The HPTLC fingerprinting profile revealed the presence of pyrocatechol as a marker compound. The acaricidal property of S. anacardium against chemical acaricide-resistant R. (B.) microplus was discussed.
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To develop an eco-friendly tick control method, seven plant extracts were prepared using 50 and 95 % ethanol and evaluated for acaricidal activity against cattle tick, Rhipicephalus (Boophilus) microplus. The adult immersion test was... more
To develop an eco-friendly tick control method, seven plant extracts were prepared using 50 and 95 % ethanol and evaluated for acaricidal activity against cattle tick, Rhipicephalus (Boophilus) microplus. The adult immersion test was adopted for testing different extracts. Based on 72 h screening criterion, 95 % ethanolic extracts of Datura metel fruits and Argemone mexicana whole plant were found effective showing more than 50 % mortality of treated ticks. The 95 % ethanolic extracts of D. metel fruits and A. mexicana whole plant exhibited acaricidal and reproductive inhibitory effects on treated ticks. The LC 90 values of D. metel and A. mexicana extracts were determined as 7.13 and 11.3 %, respectively. However, although both the extracts were found efficacious against deltamethrin-resistant IVRI-4 and multi-acaricide resistant IVRI-5 lines of R. (B.) mi-croplus, they caused less mortality than treated ticks of the reference IVRI-I line. Phyto-chemical studies indicated the presence of alkaloids and glucosides in D. metel fruits and alkaloids, terpenoids, flavonoids and phenolics in A. mexicana whole plant extracts. The results indicated that these botanicals may play an important role in reducing the use of
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In India, Rhipicephalus (Boophilus) microplus populations have developed a certain level of resistance to most of the acaricides marketed against tick species. To manage the problem, the present study was undertaken to evaluate the... more
In India, Rhipicephalus (Boophilus) microplus populations have developed a certain level of resistance to most of the acaricides marketed against tick species. To manage the problem, the present study was undertaken to evaluate the acaricidal potential of Ageratum conyzoides plants against acaricides-resistant ticks infesting cattle and buffaloes. The regression analysis of dose-response data of ethanolic extract of A. conyzoides revealed LC 90 value of 8.91% against reference susceptible IVRI-1 line of R.(B.) microplus. The ethanolic extract was found efficacious against 76.7–90% acaricides-resistant field ticks and adversely affected oviposition showing 7.04–31.3% reduction in egg laying capacity. The extract was also showed an in vitro efficacy of 52.5 and 76.7% against reference resistant IVRI-4 and 5 lines. The GC/MS/MS profiling of hexane extract, two bioactive sub-fractions and essential oils revealed the presence of 6,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (precocene II) as a major phyto-compound. The bioactive sub-fractions showed 96.2–97.5% efficacy against larvae of IVRI-1 and 77.1–94.9% against multi-acaricide resistant larvae of IVRI-5 line of R.(B.) microplus. The results of this study provided significant support for the development of a phyto-formulation based on A. conyzoides species.
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Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the... more
Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hex-aconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.
Crop losses due to bacterial pathogens are a major global concern. Most of the available pesticides for these pathogens suffer from various drawbacks such as complicated synthesis, high cost, high toxicity, pesticide resistance and... more
Crop losses due to bacterial pathogens are a major global concern. Most of the available pesticides for these pathogens suffer
from various drawbacks such as complicated synthesis, high cost, high toxicity, pesticide resistance and environmental hazards. To
overcome these drawbacks, the present study was undertaken to find a potent bactericide. Therefore, a series of compounds comprising
bioactive furyl and oxazolone rings was synthesized under microwave irradiation and screened for in vitro antibacterial activity. The
reactions were completed in fewer than 2 minutes with minimal use of solvents and resulted in high yields. These compounds were
screened for antibacterial activity against plant pathogens, Xanthomonas oryzae, Ralstonia solanacearum and nitrifying bacteria,
Nitrosomonas species under laboratory conditions. Five compounds were active as antibacterial agents against Xanthomonas oryzae
and Ralstonia solanacearum. However, all compounds were effective against the Nitrosomonas species and the best one was 2-furyl-4-
(3-methoxy-4-hydroxybenzylidene)-5(4H)-oxazolone. The study revealed the fast and environmentally friendly synthesis of bioactive
title compounds, which also hold promise to be used as prototypes for the discovery of potent analogues.
from various drawbacks such as complicated synthesis, high cost, high toxicity, pesticide resistance and environmental hazards. To
overcome these drawbacks, the present study was undertaken to find a potent bactericide. Therefore, a series of compounds comprising
bioactive furyl and oxazolone rings was synthesized under microwave irradiation and screened for in vitro antibacterial activity. The
reactions were completed in fewer than 2 minutes with minimal use of solvents and resulted in high yields. These compounds were
screened for antibacterial activity against plant pathogens, Xanthomonas oryzae, Ralstonia solanacearum and nitrifying bacteria,
Nitrosomonas species under laboratory conditions. Five compounds were active as antibacterial agents against Xanthomonas oryzae
and Ralstonia solanacearum. However, all compounds were effective against the Nitrosomonas species and the best one was 2-furyl-4-
(3-methoxy-4-hydroxybenzylidene)-5(4H)-oxazolone. The study revealed the fast and environmentally friendly synthesis of bioactive
title compounds, which also hold promise to be used as prototypes for the discovery of potent analogues.
Research Interests:
A series of novel 6-¯uoro-7-(5-alkyl-1,3,4-thiadiazol/oxadiazol-2-ylsulfanyl)-4-quinolone- 3-carboxylic acids were synthesized using microwave irradiation. The compounds were tested for their in vitro antibacterial activity. All compounds... more
A series of novel 6-¯uoro-7-(5-alkyl-1,3,4-thiadiazol/oxadiazol-2-ylsulfanyl)-4-quinolone-
3-carboxylic acids were synthesized using microwave irradiation. The compounds were tested
for their in vitro antibacterial activity. All compounds containing the 1,3,4-thiadiazole/oxadiazole
moiety at position 7 showed promising antibacterial activity.
3-carboxylic acids were synthesized using microwave irradiation. The compounds were tested
for their in vitro antibacterial activity. All compounds containing the 1,3,4-thiadiazole/oxadiazole
moiety at position 7 showed promising antibacterial activity.
Research Interests:
A series of triazines have been synthesized starting from 5-alkyl-1,3,4-thiadiazole-2-thioles (1a–d). On reaction with ethyl bromoacetate in the presence of anhydrous K2CO3 under microwave irradiation (MWI), these yielded corresponding... more
A series of triazines have been synthesized starting from 5-alkyl-1,3,4-thiadiazole-2-thioles
(1a–d). On reaction with ethyl bromoacetate in the presence of anhydrous K2CO3 under
microwave irradiation (MWI), these yielded corresponding esters (2a–d) which on
hydrazinolysis under MWI produced (5-alkyl-1,3,4-thiadiazol-2-yl sulfanyl) acetohydrazides
(3a–d). The reaction of 3a–d with g-bromoacetophenone under MWI yielded 6-aryl-3-[(5-
alkyl-1,3,4-thiadiazol-2-yl sulfanyl)methyl]-1,2,4-triazines (4a–h). All the synthesized triazines
showed in vitro antitubercular activity
(1a–d). On reaction with ethyl bromoacetate in the presence of anhydrous K2CO3 under
microwave irradiation (MWI), these yielded corresponding esters (2a–d) which on
hydrazinolysis under MWI produced (5-alkyl-1,3,4-thiadiazol-2-yl sulfanyl) acetohydrazides
(3a–d). The reaction of 3a–d with g-bromoacetophenone under MWI yielded 6-aryl-3-[(5-
alkyl-1,3,4-thiadiazol-2-yl sulfanyl)methyl]-1,2,4-triazines (4a–h). All the synthesized triazines
showed in vitro antitubercular activity
Research Interests:
The tetrazines (V) are prepared by conventional methods and under microwave irradiation. In comparison with the conventional method the reaction rate is enhanced about 250 times by using microwaves and the yields are improved up to 23%.... more
The tetrazines (V) are prepared by
conventional methods and under microwave irradiation. In comparison with
the conventional method the reaction rate is enhanced about 250 times by
using microwaves and the yields are improved up to 23%. The reaction of (I)
with the cyanates (VI) yields the thiosemicarbazide (VIIa) and semicarbazide
(VIIb) which are elaborated further to the thiazole (IXa), the oxazole (IXb), a
thiazolidinone and a triazole.
conventional methods and under microwave irradiation. In comparison with
the conventional method the reaction rate is enhanced about 250 times by
using microwaves and the yields are improved up to 23%. The reaction of (I)
with the cyanates (VI) yields the thiosemicarbazide (VIIa) and semicarbazide
(VIIb) which are elaborated further to the thiazole (IXa), the oxazole (IXb), a
thiazolidinone and a triazole.
Research Interests:
Mercury derivatives of substituted 1,3,4-thiadiazoles and 1,2,4-triazine have been synthesized under microwave irradiation in open vessels using a domestic microwave oven as well as in a conventional way. The reaction time could be cut... more
Mercury derivatives of substituted 1,3,4-thiadiazoles and 1,2,4-triazine have been
synthesized under microwave irradiation in open vessels using a domestic microwave oven as well as
in a conventional way. The reaction time could be cut down from hours to minutes employing
microwaves, accompanied by marginally improved yields. The compounds show promising fungicidal
activity.
synthesized under microwave irradiation in open vessels using a domestic microwave oven as well as
in a conventional way. The reaction time could be cut down from hours to minutes employing
microwaves, accompanied by marginally improved yields. The compounds show promising fungicidal
activity.
Research Interests:
Research Interests:
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The objective of this study was to evaluate in vitro the insecticidal activity of pyridalyl nanosuspension in comparison to technical material and commercial formulation against larvae of Helicoverpa armigera. Suspension of pyridalyl... more
The objective of this study was to evaluate in vitro the insecticidal activity of pyridalyl nanosuspension in comparison to technical material and commercial formulation against larvae of Helicoverpa armigera. Suspension of pyridalyl nanocapsules was prepared, for reducing its dose of application. Compatibility of pyridalyl with sodium alginate was ascertained and a formulation was obtained by optimizing various parameters. Average micelle size of different formulations was around 138 nm and size of pyridalyl was less than 100 nm. Spherical shape and nanosize of capsules was confirmed by Transmission electron microscopy. Zeta potential of optimized formulation was found to be about (−)20 ± 1 Mv indicating acceptable range for expressing physical stability of the nano-capsules. The pyridalyl nanosuspension insecticidal activity increased remarkably, with LC50 values of 40 μg mL−1 in comparison to LC50 values of technical material (90 μg mL−1) and commercial product (250 μg mL−1). Bioassay results by leaf dip method showed that nanoformulation is 2.26 and 6.25 times more effective against H. armigera as stomach poison than the technical product and commercial formulation respectively. By topical method, the LC50 values obtained were 80, 150, and 250 μg mL−1 for nanoformulation, technical material, and commercial formulation, respectively, proving our hypothesis. Pyridalyl nanocapsule suspension performed effectively than technical material and commercial product against tomato fruit and shoot borer (Helicoverpa armigera), showing that insecticide load to the environment can be reduced by using nanoformulations.
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Removal of mixed pesticides, namely alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, p,p′-DDT and two metabolites p,p′-DDE and endosulfan sulphate from aqueous solution by batch adsorption onto three commercial... more
Removal of mixed pesticides, namely alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, p,p′-DDT and two metabolites p,p′-DDE and endosulfan sulphate from aqueous solution by batch adsorption onto three commercial organo-modified montmorillonite clays [modified with octadecylamine (ODA-M), modified with dimethyl- dialkylamine (DMDA-M) and modified with octadecylamine and aminopropyltriethoxysilane (ODAAPS-M)] were investigated. Effect of process variables, mainly contact time and initial concentration of mixed pesticides, on adsorption phenomenon were evaluated. To understand the adsorption kinetic pseudo-first-order and pseudo-second-order models were tested. The pseudo-second-order model provided the best fit for explaining adsorption kinetics, on the basis of high correlation coefficient (r) and normalized percent deviation values. The adsorption equilibrium was explained by the Freundlich isotherm (r = 0.951–0.992). High values (0.17–0.52 mg g−1) of Freundlich constant (Kf) indicated higher affinity of pesticides towards all three organoclays, as a result of hydrophobic interaction between the adsorbent/adsorbate systems. Pesticides with high octanol–water partition coefficient (Kow) and low water solubility showed faster adsorption with higher Kf values as compared to the pesticides with low Kow and high water solubility. The order of organoclays for removal efficiency of mixed pesticide was ODAAPS-M > DMDA-M > ODA-M. These findings may find application to decontaminate or treat mixed pesticide contaminated industrial/agricultural waste waters.
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BACKGROUNDDiacyl hydrazines have attracted significant interest in medicine, pesticide chemistry and material science. It is an important class of insect growth regulators. In this study, acyl hydrazine, the essential active group was... more
BACKGROUNDDiacyl hydrazines have attracted significant interest in medicine, pesticide chemistry and material science. It is an important class of insect growth regulators. In this study, acyl hydrazine, the essential active group was incorporated in to nalidixic acid with the aim of combining the active groups to generate more potent agrochemical.Diacyl hydrazines have attracted significant interest in medicine, pesticide chemistry and material science. It is an important class of insect growth regulators. In this study, acyl hydrazine, the essential active group was incorporated in to nalidixic acid with the aim of combining the active groups to generate more potent agrochemical.RESULTSVarious nalidixic acid based diacyl and sulphonyl acyl hydrazines derivatives were synthesized and characterized by spectral techniques. These compounds were screened for the antifungal activity against five pathogenic fungi, nitrification inhibitory activity and insect growth regulator (IGR) activity against Spodoptera litura. The fungicidal activity was screened against R. bataticola, S. rolfsii, R. solani, F. oxysporum and A. porri. Most of the compounds showed moderate to good antifungal activity against A. porri (ED50 = 29.6-495.9 µg/mL). All the compounds showed significant nitrification inhibitory activity at 5% level. IGR activity was examined by feeding method against S. litura.Various nalidixic acid based diacyl and sulphonyl acyl hydrazines derivatives were synthesized and characterized by spectral techniques. These compounds were screened for the antifungal activity against five pathogenic fungi, nitrification inhibitory activity and insect growth regulator (IGR) activity against Spodoptera litura. The fungicidal activity was screened against R. bataticola, S. rolfsii, R. solani, F. oxysporum and A. porri. Most of the compounds showed moderate to good antifungal activity against A. porri (ED50 = 29.6-495.9 µg/mL). All the compounds showed significant nitrification inhibitory activity at 5% level. IGR activity was examined by feeding method against S. litura.CONCLUSIONThe study revealed that a few compounds possessed good activity against three different pests namely certain fungus, soil bacteria and insect, among which, compound 37 (R' = 4-chlorophenyl) behaved the best. © 2013 Society of Chemical IndustryThe study revealed that a few compounds possessed good activity against three different pests namely certain fungus, soil bacteria and insect, among which, compound 37 (R' = 4-chlorophenyl) behaved the best. © 2013 Society of Chemical Industry
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Research Interests: Pharmacology, Environmental Science, Chemistry, Analytical Chemistry, Computational Chemistry, and 40 moreInorganic Chemistry, Organic Chemistry, Pharmacy, Environmental Education, Research Methodology, Synthesis of nanoparticles, Medicinal Chemistry, Chemistry Education, Polymer Chemistry, Natural Products Chemistry, Green Chemistry, Sustainable agriculture, Nanomaterials Characterization, Microwave, Nanobiotechnology, Pharmaceutical Technology, Agriculture, Nanomaterials, Nanoparticles, Chemical, Environmental Chemistry, Food Chemistry, Nanotechnology, Environmental Sustainability, Pharmaceutical Chemistry, Environmental Pollution, Medicine, Synthetic Organic Chemistry, Organic Synthesis, Chemicals, Nitrification, Pesticides, Nanoscience, Organic synthesis of bioactive molecules, Biopesticides, Agrochemicals, Nitrification Inhibitor, Botanical pesticides, Neem Tree and Its Derivatives, and Agrochemical and Pesticide Markets
The fertilizer nitrogen use efficiency (NUE) in lowland rice is quite low (20–50%) in India. Coating of nitrification inhibitors, such as neem cake or neem oil, onto prilled urea may improve NUE. Hence, a field experiment was conducted at... more
The fertilizer nitrogen use efficiency (NUE) in lowland rice is quite low (20–50%) in India. Coating of nitrification inhibitors, such as neem cake or neem oil, onto prilled urea may improve NUE. Hence, a field experiment was conducted at the Indian Agricultural Research Institute, New Delhi, during the wet seasons of 2005 and 2006 to study the effect of prilled urea coated with varying doses of major neem oil components on grain yield and NUE of scented rice.
Research Interests: Chemistry, Organic Chemistry, Climate Change, Sustainable agriculture, Agriculture, and 9 moreEnvironmental Pollution, Salinity, Nitrification potentials of organic soil amendments and incubation procedures in fields and laboratory, Biological Nitrogen Fixation, Biofertilizers, Neem, Soil Microbiology, Mycorrhizae, and Neem Coated Urea
Pesticides are indispensable tools, contributing to sustainable production of food, fodder and fibres and securing public health. Without crop protection, we would require thrice the area of arable land, which means, we would lose a large... more
Pesticides are indispensable tools, contributing to sustainable production of food, fodder and fibres and securing public health. Without crop protection, we would require thrice the area of arable land, which means, we would lose a large part of area meant for forest. This article reflects on issues governing their safe and sound management in India, various international agreements to which India is a Party and the avenues of improvement in the regulatory framework.
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An expeditious, solvent free one pot method for the preparation of hydrazides from corresponding acids directly under microwave irradiation is developed. The method has been assessed using green chemistry measures and found superior to... more
An expeditious, solvent free one pot method for the preparation of hydrazides from corresponding acids directly under microwave irradiation is developed. The method has been assessed using green chemistry measures and found superior to conventional method with higher E (environmental) factor, atom economy, atom efficiency, carbon efficiency, reaction mass efficiency.
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full... more
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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ABSTRACT Freshly harvested banana fruits were dipped in 500 ppm benomyl solution for 2 minutes to sterilise the field carry-over fungal infection. These fruits were air dried before being subjected to modified atmosphere (MA) storage... more
ABSTRACT Freshly harvested banana fruits were dipped in 500 ppm benomyl solution for 2 minutes to sterilise the field carry-over fungal infection. These fruits were air dried before being subjected to modified atmosphere (MA) storage studies. A controlled ventilation system, called the silicone membrane system, was developed to obtain the desired MA condition at a low control and energy cost. The benomyl treated fruits were stored at ambient and cold storage (at 13 C) conditions. The bananas could store for more than 30 days and ...
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A series of 1-(alkyl/alkenyl/alkynyl/aryl)-4-aza-1-azoniabicyclo [2, 2, 2] octane halides were synthesized by the reaction of 1, 4-diazabicyclo [2, 2, 2] octane with corresponding alkyl/alkenyl/alkynyl/aryl halides. The monoquaternary... more
A series of 1-(alkyl/alkenyl/alkynyl/aryl)-4-aza-1-azoniabicyclo [2, 2, 2] octane halides were synthesized by the reaction of 1, 4-diazabicyclo [2, 2, 2] octane with corresponding alkyl/alkenyl/alkynyl/aryl halides. The monoquaternary structures were confirmed by estimation of their halide contents. These were screened on rice inoculated with Rhizoctonia solani Kuhn in a pot culture experiment by spraying aqueous solutions (1000 mg ml− 1) at maximum tillering stage. All the test salts exhibited fungicidal activity. 1-Propyl-4-aza-1- ...
Research Interests: Heterocyclic chemistry, Sustainable agriculture, Agriculture, Chemical, Synthetic Organic Chemistry, and 8 moreOrganic Synthesis, Chemicals, Fungicides, Heterocyclic Synthesis, Organic synthesis of bioactive molecules, Crop Science, Synthesis of heterocyclic compounds, and Organic Heterocyclic Chemistry
A series of 1, 4-diazabicyclo-[2, 2, 2]-octane (DABCO) salts has been synthesized and evaluated for nitrification inhibitory activity in a laboratory incubation experiment at 10% of applied urea-N. Most derivatives showed 11.9–38.6 and... more
A series of 1, 4-diazabicyclo-[2, 2, 2]-octane (DABCO) salts has been synthesized and evaluated for nitrification inhibitory activity in a laboratory incubation experiment at 10% of applied urea-N. Most derivatives showed 11.9–38.6 and 3.4–18.7% nitrification inhibition after 10 and 20 days, respectively. 1-Benzyl-4-aza-1-azoniabicyclo-[2, 2, 2]-octane chloride showed 33.8% nitrification inhibition followed by 1-propyl-4-aza-1-azonnabicyclo-[2, 2, 2]-octane chloride. On the basis of four parameters viz., concentration of ammonium-N and ...
Research Interests: Environmental Science, Chemistry, Organic Chemistry, Environmental Education, Heterocyclic chemistry, and 15 moreOrganic agriculture, Sustainable agriculture, Agriculture, Chemical, Environmental Sustainability, Environmental Pollution, Synthetic Organic Chemistry, Organic Synthesis, Chemicals, Nitrification, Heterocyclic Synthesis, Crop Science, Synthesis of heterocyclic compounds, Nitrification Inhibitor, and Crop Nutrition
Series of S-benzylisothiouronium derivatives have been synthesized and evaluated for nitrification inhibitory activity under laboratory conditions. S-Benzyiisothiouronium chloride and its formic, acetic, chloroacetic, propanoic, butanoic,... more
Series of S-benzylisothiouronium derivatives have been synthesized and evaluated for nitrification inhibitory activity under laboratory conditions. S-Benzyiisothiouronium chloride and its formic, acetic, chloroacetic, propanoic, butanoic, pentanoic, benzoic and furoic acid derivatives showed significant nitrification inhibitory activity. At 20% dose, the furoate showed 33.5% nitrification inhibition (NI) on 56th day of incubation in comparison with 47.6% in 5% nitrapyrin. At 5 and 20% doses, the furoate exhibited 50.3 and 74.2% NI on ...
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Abstract The efficacy and persistence of 0.1% carbendazim were studied in mango fruits in storage at room temperature in August in India (35-40 C) following post-harvest dip treatment. The treatment gave effective control against stem end... more
Abstract The efficacy and persistence of 0.1% carbendazim were studied in mango fruits in storage at room temperature in August in India (35-40 C) following post-harvest dip treatment. The treatment gave effective control against stem end rot [? Botryodiplodia theobromae] and anthracnose [Glomerella cingulata] diseases for up to 10 days. The carbendazim residues were found to persist beyond 8 days on the fruits, but the residue level was below the MRL value.
Research Interests: Environmental Science, Horticulture, Sustainable agriculture, Agriculture, Pesticide Chemistry, and 12 moreChemical, Environmental Sustainability, Pesticide Residues, Chemicals, Horticulture, fruit culture, Pesticide, Postharvest Horticulture, Pesticides, Horticultural Sciences, Plant Pathology, HORTICULTURA, and Sustainable Horticulture
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6, 6-Disubstituted-l, 4, 5, 6-tetrahydro-l, 2, 4, 5-tetrazine-3 (2H) thiones, synthesized by condensing aldehydes/ketones with thiocarbohydrazide, and combining N containing hyterocyclics with the C= S moiety, have been found as only mild... more
6, 6-Disubstituted-l, 4, 5, 6-tetrahydro-l, 2, 4, 5-tetrazine-3 (2H) thiones, synthesized by condensing aldehydes/ketones with thiocarbohydrazide, and combining N containing hyterocyclics with the C= S moiety, have been found as only mild nitrification inhibitors. 6-Methyl-l, 4, 5, 6-tetrahydro-l, 2, 4, 5-tetrazine-3 (3H) thione was the mosl effective, showing 56% nitrification inhibition up to 16 d at 10% of the applied nitrogen.
Research Interests: Environmental Science, Soil Science, Chemistry, Organic Chemistry, Soil, and 17 moreHeterocyclic chemistry, Sustainable agriculture, Environmental Management, Agriculture, Chemical, Environmental Chemistry, Environmental Sustainability, Environmental Soil Science, Chemicals, Heterocyclic Synthesis, Plant, Crop Science, Synthesis of Heterocycles, Soil Fertility, Synthesis of heterocyclic compounds, Organic Heterocyclic Chemistry, and Heterocycles
Thiocarbohydrazide, a compound containing the nitrification inhibitory C= S moiety, has been found to significantly inhibit nitrification upto 28 d at 10% of N-applied as compared to urea alone. N-serve, a well-known nitrification... more
Thiocarbohydrazide, a compound containing the nitrification inhibitory C= S moiety, has been found to significantly inhibit nitrification upto 28 d at 10% of N-applied as compared to urea alone. N-serve, a well-known nitrification inhibitor was however significantly superior than it at concentrations of 2% and above of the applied N. No nitrite accumulation was observed in any of the treatments. Thiocarbohydrazide is under investigation as a starting material for the preparation of more potent nitrification inhibitors.
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With increasing global population, demands have been increased to meet the requirements and consequently the industrial pollution. To control this detrimental phenomenon, the term... more
With increasing global population, demands have been increased to meet the requirements and consequently the industrial pollution. To control this detrimental phenomenon, the term &amp;amp;amp;amp;amp;#x27;&amp;amp;amp;amp;amp;#x27;green chemistry&amp;amp;amp;amp;amp;#x27;&amp;amp;amp;amp;amp;#x27;has come into existence [2]. Green chemistry is a package of technologies, design principles, and tools to reduce toxicity, resource energy use, and pollution of chemicals [2, 3]. Due to environmental awareness [4], chemists have focused their attention to examine bioactive products such as heterocycles and processes in terms of ...