The hemi-synthesis of chiral imine, benzimidazole and benzodiazepine structures is reported by the condensation of (S)-(−)-perillaldehyde, the major phytochemical of Ammodaucus leucotrichus subsp. leucotrichus essential oil, with different amine derivatives of 2,3-diaminomaleonitrile, o-phenylenediamine and 3-[(2-aminoaryl)amino]dimedone. The reaction proceeds in situ at ambient temperature without prior isolation of the natural (S)-(−)-perillaldehyde. Final products precipitate in the ethanolic reaction medium. 2D NMR and single-crystal X-ray diffraction studies were used to unequivocally characterize the structures in solution and in the solid state, respectively. Chiral HPLC analysis confirms the formation of unique enantiomers and diastereomeric mixtures.

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An efficient in situ condensation of citronellal, the main constituent of Eucalyptus citriodora essential oil (51%), with different amine derivatives of 2,3diaminomaleonitrile and 3-[(2-aminoaryl)amino]dimedone has led to novel chiral benzodiazepine structures. All reactions were precipitated in ethanol and pure products were obtained in good yields (58%-75%) without any purification. The synthesized benezodiazepines were characterized by spectroscopic techniques, namely 1 H and 13 C-NMR, 2D NMR and FTIR. Differential Scanning Calorimetry (DSC) and HPLC were used to confirm the formation diastereomeric mixtures of benzodiazepine derivatives.