title: Microwave assisted solvent-free synthesis and biological activities of novel imines (Schiff bases).
abstract: Twelve new ortho-Hydroxyketimines were synthesized by conventional as well as microwave method and evaluated for their antinemic activity against Meloidogyne incognita [(Kofoid and White) Chitwood]. Conventional methods for synthesis of Schiff bases require refluxing at 140 degrees C of the reactants in different solvents for at least 24 h or more, where as the microwave-assisted synthesis has brought down the reaction time from 24 h to 1 minute. The procedure reported is simple as it does not require any organic solvents and the time has been reduced to only 1 minute. Comparative yields of all compounds by different methods revealed that the yield was low in conventional method (79-87%) as compared to microwave assisted synthesis (94-97%). The bioassay revealed that all the test compounds exhibited promising nematicidal activity; N-propyl-2-hydroxypropiophenonimine being the most effective with LC(50) value of 74.46 mgL(-1) followed by N-hexyl-2-hydroxyacetophenonimine with LC(50) value of 99.60 mgL(-1) after 72 h of exposure. The results obtained from bioassay indicated that this class of compounds has not only given a lead with regard to potential of Schiff bases in pest control, but has suggested that a carbon chain length of 6 atoms in the side chain is optimum on the basis of structure activity relationship (SAR).
authors.affiliation: Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Aditi
authors.initials: A
authors.lastname: Kundu
authors.forename: Najam Akhtar
authors.initials: NA
authors.lastname: Shakil
authors.forename: Dinesh B
authors.initials: DB
authors.lastname: Saxena
authors.forename: Jitendra
authors.initials: J
authors.lastname: Kumar
authors.forename: Suresh
authors.initials: S
authors.lastname: Walia
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000737:chemistry / Q000494:pharmacology*; D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D007097:Imines / Q000138:chemical synthesis* / Q000494:pharmacology*; D007700:Kinetics; D007928:Lethal Dose 50; D008872:Microwaves; D010571:Pest Control; D010575:Pesticides / Q000737:chemistry / Q000494:pharmacology*; D012997:Solvents; D018411:Spodoptera / Q000187:drug effects* / Q000254:growth & development; D013329:Structure-Activity Relationship; D014431:Tylenchoidea / Q000187:drug effects* / Q000254:growth & development; D014675:Vegetables / Q000469:parasitology
chemical_list: D000871:Anthelmintics; D007097:Imines; D010575:Pesticides; D012997:Solvents