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Seven helicid derivatives containing decahydroacridine-1,8-dione were prepared via the reactions between 1,3-cyclohexanedione or 5,5-dimethyl-1,3-cyclohexanedione and the corresponding Schiff base. The structures of the helicid derivatives were characterized by IR, 1H NMR, and HR-MS spectrum. The target compounds were evaluated by their hypnotic-sedative activity in vivo. The preliminary bioassay tests showed that some of the compounds had more potent activity than that of helicid.

Reactions of natural helicid with a number of 1,3-dicarbonyl compounds or β-ketoester in the presence of ammonium acetate or 1-naphthylamine gave a series of helicid derivatives containing a 1,4-dihydropyridine fragment (2a–2h). Eight novel helicid derivatives were structurally confirmed by IR, 1H NMR, 13C NMR, and HR-MS spectroscopy and evaluated for their sedative-hypnotic activities on mice. The results demonstrated that two compounds had higher sedative-hypnotic activity compared with helicid.

The title compound, C(15)H(16)N(2), contains two aromatic rings linked through an imino group. The mol-ecule exhibits an E configuration with respect to the C=N bond. The dihedral angle between the aromatic rings is 61.96 (1)°.

The title compound, C(21)H(21)ClO(7)·C(2)H(5)OH was synthesized by the condensation reaction between helicid [systematic name: 4-(β-d-allopyranos-yloxy)benzaldehyde] and 4-chloro-aceto-phen-one in ethanol. In the mol-ecular structure, the pyran-oside ring adopts a chair conformation. In the crystal structure, the molecules are linked by inter-molecular O-H⋯O hydrogen bonds involving the OH groups from the pyran-oside unit and from the ethanol solvent mol-ecule.

The title compound, C(34)H(54)O(5), was synthesized by the reaction of ursolic acid with ethyl chloro-acetate in the presence of DMA. All six-membered rings of the penta-cyclic triterpene skeleton adopt chair conformations. In the crystal structure, mol-ecules are linked by inter-molecular O-H⋯O hydrogen-bond inter-actions, forming zigzag chains along the c axis.