Synthesis and antimosquito properties of 2,6-substituted benzo[d]thiazole and 2,4-substituted benzo[d]thiazole analogues against Anopheles arabiensis

• Novel 2,6-substituted benzo[d]thiazole and 2,4-substituted benzo[d]thiazole analogues have been synthesized.
• Characterization was done by IR, NMR, LCMS and elemental analysis.
• Compounds 4b, 4d and 4p exhibit the highest repellent activity.
• Active compound 4b has been subjected for single crystal X-ray studies.

A novel and efficient one pot synthesis was developed for 2,6-substituted-benzo[d]thiazole analogues 4a–k and 2,4-substituted-benzo[d]thiazole analogues 4l–pvia three component condensation reaction of substituted arylaldehyde, 2-amino-6-halo/4-methyl-benzo[d]thiazole and 2-naphthol or 6-hydroxyquinoline in presence of 10% w/v NaCl in water by microwave method. This method enabled for short reaction times, easy work-up and significant high yields. The title compound 4b was used for single crystal X-ray studies in order to understand its conformation and packing features. The title compounds 4a–p were screened for antimosquito properties such as repellency, insecticidal and larvicidal activity against Anopheles arabiensis by mosquito feeding-probing assay, cone bio-assay and standard WHO larvicidal assay, respectively. Among these analogous 4b, 4d and 4p exhibit the highest repellent activity comparable to the positive control DEET, and 4a and 4k knockdown most mosquitoes on repellent assays.

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