In the mol-ecule of the title compound, C(17)H(8)Cl(2)F(8)N(2)O(3), the two aromatic rings are oriented at a dihedral angle of 50.12 (3)°. Intra-molecular N-H⋯O, C-H⋯O and N-H⋯Cl hydrogen bonds result in the formation of two six- and one five-membered rings. The six-membered rings have flattened-boat conformations, while the five-membered ring adopts an envelope conformation. In the crystal str...

The title mol-ecule, C(28)H(28)Cl(4)N(6)O(6), is built up from four fused rings, viz. two nearly planar imidazole five-membered rings which adopt envelope conformations with the C=O groups at the flap position, and two triazine six-membered rings which adopt chair conformations. Each six-membered ring has a 2,4-dichloro-benzyl substituent attached to an N atom. In the mol-ecule, the two ethyl g...

The title compound, C(17)H(22)O(6), was semi-synthesized from 9-hy-droxy-arthenolide, which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule contains fused five- and ten-membered rings: the five-membered lactone ring has a twisted conformation, whereas the ten-membered ring displays an approximate chair-chair conformation. The dihedral angle betwe...

The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from two fused seven-membered rings and an additional three-membered ring. I...

The title compound, C(16)H(22)Cl(2), a derivative of β-himachalene, was semi-synthesized from natural essential oils of Cedrus atlantica. The mol-ecule is built up from two fused six- and seven-membered rings. The six-membered ring has a perfect chair conformation, whereas the seven-membered ring displays a screw boat conformation; the dihedral angle between the rings is 46.48 (9)°.

The title compound, C(34)H(47)NO(12), is the norditerpenoid alkaloid aconifine isolated from the leaves and tubers of Aconitum karakolicum Rapaics. It has a lycoctonine carbon skeleton and contains four six-membered rings and two five-membered rings; its geometry is similar to that observed in other lycoctonine-type diterpenoid alkaloids. There are two intra-molecular O-H⋯O hydrogen bonds which...

The mol-ecular structure of the title compound, C(17)H(20)N(4)O(5), contains a central fused-ring system, comprised of six- and five-membered rings. This unit is linked by C(2) chains to two 2-oxo-1,3-oxazolidine five-membered rings. The central fused-ring system is essentially planar, with a maximum deviation of 0.008 (1) Å from the mean plane. Both oxazolidine five-membered rings are also nea...

The title compound, C22H29NO4, a stemona alkaloid, is composed of two lactone rings (A and E), a six-membered ring (B), a pyrrole ring (C) and a seven-membered ring (D). The five-membered rings A and E exhibit envelope conformations (C atoms as flaps) while ring C is planar. Ring B exhibits a twist-chair conformation due to fusion with pyrrole ring C while ring D adopts a chair conformation. Th...

The title compound, C(19)H(32)O(4), was synthesized from γ-himachalene, wich was isolated from essential oils of Cedrus atlantica. The mol-ecule is built up from two fused six- and seven-membered rings. The six-membered ring has a screw-boat conformation, whereas the seven-membered ring displays a half-chair conformation; the dihedral angle between the mean planes of the rings is 61.99 (6)°.

The title compound, C17H17NO4, lacks crystallographic symmetry with one mol-ecule per asymmetric unit. The mol-ecule exists in a folded butterfly-like conformation; the benzene rings form a dihedral angle of 84.72 (7)°. The central eight-membered imino-bridged dioxocin ring adopts a twisted-boat conformation. In the crystal, inversion-related mol-ecules are linked by pairs of weak C-H⋯O hydroge...