Intermolecular interaction of thiosemicarbazone derivatives to solvents and a potential Aedes aegypti target

• Thiosemicarbazones (TSCZ) derivatives exhibit large A. aegypti larvicide activity.
• Semicarbazone (SCZ) derivatives exhibit low A. aegypti larvicide activity.
• The high 1H NMR δ of NNH in TSCZ was in the literature credited to H-bond to DMSO.
• Our NMR experiments and theoretical calculations shown NNH interactions with water.
• TSCZ and SCZ make distinct H-bond interaction to AeSCP-2’s residues.

DFT calculations were used to access information about structure, energy and electronic properties of series of phenyl- and phenoxymethyl-(thio)semicarbazone derivatives with demonstrated activity against the larvae of Aedes aegypti in stage L4. The way as the thiosemicarbazone derivatives can interact with solvents like DMSO and water were analyzed from the comparison between calculated and experimental 1H NMR chemical shifts. The evidences of thiosemicarbazone derivatives making H-bond interaction to solvent have provide us insights on how they can interact with a potential A. aegypti’s biological target, the Sterol Carrier Protein-2.

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