9α-Hy­droxy-12-{[4-(4-hy­droxy­phen­yl)piperazin-1-yl]meth­yl}-4,8-dimethyl-3,14-dioxatri­cyclo­[9.3.0.0^2,4]tetra­dec-7-en-13-one

The title compound, C₂₅H₃₄N₂O₅, was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methylen-3, 14-dioxa-tri­cyclo­[9.3.0.0^2,4]tetra­dec-7-en-13-one), which in turn was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The mol­ecule comprises a ten-membered ring fused to a five-membered ring with an additional ep­oxy ring system fused to the ten-membered ring. The five-membered ring also carries a 4-hy­droxy­phenyl-piperazin-1-ylmethyl substituent. The ten-membered ring adopts an approximate chair–chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy­droxy group forming the flap. Two C atoms in the phenyl ring and the O atom of the hydroxyl group are disordered over two sites, with an occupancy ratio of 0.53 (5):0.47 (5). An intra­molecular O—H...N hydrogen-bond stabilizes the mol­ecular conformation. In the crystal, C—H...O hydrogen bonds link the mol­ecules into zigzag chains running along the a-axis direction.

Ethyl 2-amino-4-(3-nitro­phen­yl)-4H-1-benzothieno[3,2-b]pyran-3-carboxyl­ate

The mol­ecule of the title compound, C₂₀H₁₆N₂O₅S, is built up by one fused five-membered and two fused six-membered rings linked to eth­oxy­carbonyl and 3-nitro­phenyl groups. The benzothieno­pyran ring system is nearly planar (r.m.s deviation = 0.0392 Å) and forms a dihedral angle of 86.90 (6)° with the aromatic ring of the nitro­benzene group. In the crystal, mol­ecules are linked by N—H...O hydrogen bonds and by π–π inter­actions between the phenyl ring and the six-membered heterocyle [inter­centroid distance = 3.5819 (8) Å], forming a three-dimensional network.

(1S,2R,3S,6S,7R)-3,7,11,11-Tetra­methyl-6,7-epoxybi­cyclo­[5.4.0]undecane-2-ol

The title compound, C₁₅H₂₆O₂, was synthesized from β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from the Atlas cedar (cedrus atlantica). The mol­ecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The seven- and six-membered rings each have a twist-boat conformation. In the crystal, O—H...O hydrogen bonds link the mol­ecules into zigzag chains running along the b-axis direction.

(2Z)-2-Benzyl­idene-4-(prop-2-yn-1-yl)-2H-1,4-benzo­thia­zin-3(4H)-one

The mol­ecule of the title compound, C₁₈H₁₃NOS, is build up from two fused six-membered rings, with the heterocyclic component linked to a benzyl­idene group and to a prop-2-yn-1-yl chain. The six-membered heterocycle adopts a distorted screw-boat conformation. The prop-2-yn-1-yl chain is almost perpendicular to the mean plane through benzo­thia­zine as indicated by the C-N-C-C torsion angle of 86.5 (2)°. The dihedral angle between the benzene rings is 47.53 (12)°. There are no specific inter­molecular inter­actions in the crystal packing.

N-(2-Allyl-4-eth­oxy-2H-indazol-5-yl)-4-methyl­benzene­sulfonamide

The indazole ring system of the title compound, C₁₉H₂₁N₃O₃S, is almost planar (r.m.s. deviation = 0.0192 Å) and forms dihedral angles of 77.99 (15) and 83.9 (3)° with the benzene ring and allyl group, respectively. In the crystal, centrosymmetrically related mol­ecules are connected by pairs of N—H...O hydrogen bonds into dimers, which are further linked by C—H...O hydrogen bonds, forming columns parallel to the b axis.