(Nitrato-κ²O,O′)bis­(tryptanthrin-κN)silver(I)

In the crystal structure of the title compound, [Ag(NO₃)(C₁₅H₈N₂O₂)₂], tryptanthrin (indolo[2,1-b]quinazoline-6,12-dione) and silver nitrate form a 2:1 complex. The silver ion is surrounded by two tryptanthrin ligands, each coordinating through the N atoms, with Ag—N bond lengths of 2.247 (3) and 2.264 (3) Å, and an anionic nitrate ligand coordinating through two O atoms, with Ag—O bond lengths of 2.499 (3) and 2.591 (3) Å. The N—Ag—N plane and the O—Ag—O plane are roughly perpendicular, making a dihedral angle of 81.6 (2)°. In the crystal, C—H...O inter­actions between aromatic H atoms and keto and nitrate O atoms as well as π–π inter­actions [centroid-centroid distance = 3.706 (4) Å] give rise to a three-dimensional network.

Evodiamide

The title compound, C₁₉H₂₁N₃O, was isolated from the fruits of Evodia rutaecarpa. The indole and benzene rings are both essentially planar with mean derivations of 0.0094 (4) Å and 0.0077 (3) Å, respectively. The dihedral angle between these two planes is 78.24 (9)°. The amide carbonyl plane is roughly parallel to the indole ring with a dihedral angle of 7.0 (2)°, but makes a dihedral angle of 82.9 (3)° with the benzene ring. Inter­molecular N—H...O hydrogen-bonding inter­actions involving the amino and carbonyl groups give rise to a three-dimensional network.

Secohellebrigeninamide

The title compound, C₂₆H₃₇NO₅, was the reaction product of hellebrigenin with N,N-dimethyl­formamide. It consists of three cyclo­hexane rings (A, B and C), one five-membered ring (D) and one dihydro­pyran ring (E). The stereochemistry of the ring junctions is is A/B cis, B/C trans, C/D cis and C/E trans. The cyclo­hexane rings A, B and C have chair conformations. Both the five-membered ring D and the dihydro­pyran ring adopt an envelope conformation. Two orientations are found for the aldehyde group with occupancies of 0.608 (10) and 0.392 (10). In the crystal, short O—H...O hydrogen bonds and short C—H...O contacts involving the hy­droxy group, terminal methyl group and carbonyl group link the mol­ecules into a three-dimensional network.

2,3,4-Trihy­droxy­benzoic acid 0.25-hydrate

The asymmetric unit of the title compound, C₇H₆O₅·0.25H₂O, contains two mol­ecules of 2,3,4-trihy­droxy­benzoic acid, with similar conformations, and one water mol­ecule which lies on a twofold rotation axis. Both acid mol­ecules are essentially planar [maximum r.m.s deviations = 0.0324 (2) and 0.0542 (3) Å for the two acid molecules]. The mol­ecular conformations are stabilized by intra­molecular O(phenol)—H...O(carbox­yl/phenol) inter­actions. A cyclic inter­molecular association is formed between the two acid and one water mol­ecule [graph set R₃³(12)] involving O—H...O hydrogen bonds. The two acid mol­ecules are further linked through a cyclic R₂²(8) carb­oxy­lic acid hydrogen-bonding association, which together with inter­molecular O—H...O hydrogen-bonding inter­actions involving the phenol groups and the water mol­ecule, and weak π–π inter­actions [minimum ring centroid separation = 3.731 (3) Å], give a three-dimensional network.

3-Benzyl-2H-chromen-2-one

The title compound, C₁₆H₁₂O₂, is a coumarin which was isolated from stones of the Chinese traditional medicine Clausena lansium. The pyrone ring is almost planar, with a mean deviation of 0.0135 (4) Å. The benzene ring (A) of the benzopyrone unit forms dihedral angles of 1.82 (5) and 72.86 (2)° with the pyrone ring and the substituent benzene ring, respectively. The crystal structure is stabilized by weak π–π stacking inter­actions, with a minimum centroid–centroid distance between benzene rings of 3.6761 (7) Å.

Brusatol

The title compound, C₂₆H₃₂O₁₁, is composed of an α,β-unsaturated cyclo­hexa­none ring (A), two cyclo­hexane rings (B and C), a six-membered lactone ring (D) and tetra­hydro­furan ring (E). Ring A exists in a half-chair conformation with a C atom displaced by 0.679 (2) Å from the mean plane through the remaining five atoms. Ring B exists in a normal chair conformation. Both rings C and D exist in a twisted-chair conformation due to the O-atom bridge and the carbonyl group in rings C and D, respectively. Ring E shows an envelope conformation with a C atom displaced by 0.761 (1) Å from the mean plane through the remaining five atoms. The ring junctions are A/B trans, B/C trans, C/D cis and D/E cis. An intra­molecular O—H...O hydrogen bond occurs. In the crystal, O—H...O hydrogen bonds involving the hy­droxy, lactone and ester groups and C—H...O inter­actions are observed.

14,15-Didehydro­hellebrigenin

The title compound, C₂₄H₃₀O₅, is the didehydro product of the steroid hellebrigenin (systematic name: 3β,5,14-trihy­droxy-19-oxo-5β-bufa-20,22-dienolide). It consists of three cyclo­hexane rings (A, B and C), a five-membered ring (D) and a six-membered lactone ring (E). The stereochemistry of the ring junctions are A/B cis, B/C trans and C/D cis. Cyclo­hexane rings A, B and C have normal chair conformations. The five-membered ring D with the C=C bond adopts an envelope conformation. Lactone ring E is essentially planar with a mean derivation of 0.006 (4) Å and is β-oriented at the C atom of ring D to which it is attached. There is an O—H...O hydrogen bond in the mol­ecule involving the hy­droxy groups. In the crystal, O—H...O hydrogen bonds link the mol­ecules into chains propagating along [010]. The chains are linked by C—H...O contacts into a three-dimensional network.