7-Acetoxy­cochinchinone I1

The title compound {systematic name: 12-[(2E)-3,7-dimethyl-2,6-octa­dien­yl]-5,8-dihydr­oxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen-6-one}, C30H32O6, has four fused rings (A/B/C/D) and the xanthone ring system (A/B/C) is essentially planar, with dihedral angles of 1.85 (13) and 2.47 (13)°, respectively, between rings A and B, and between rings B and C. The chromene ring D is in a sofa form. The geranyl side chain is axially attached to ring C with an (−)-synclinal conformation. The 3-methyl-2-butenyl terminal of the geranyl side chain is disordered with the site-occupancy ratio of 0.513 (5):0.487 (5). The acet­oxy group is attached axially to ring A with an (+)-synclinal conformation. An intra­molecular O—H⋯O hydrogen bond involving the carbonyl and hydroxyl groups generates an S(6) ring motif. In the crystal, weak C—H⋯O and C—H⋯π inter­actions, and π–π inter­actions with centroid–centroid distances of 3.6562 (16) and 3.6565 (16) Å are observed

Vieillardiixanthone B1

The title compound [systematic name: 1,5-dihydr­oxy-3,6-dimeth­oxy-4-(2-methyl­but-3-en-2-yl)-9H-xanthen-9-one], C20H20O6, is a xanthone, which was isolated from the roots of Cratoxylum formosum ssp. pruniflorum. The three rings in the mol­ecule are approximately coplanar, with an r.m.s. deviation of 0.0372 (2) Å for the plane through the 14 non-H atoms. The O atoms of the two hydr­oxy substituents also lie close to this plane with deviations of 0.0669 (2) and 0.1122 (2) Å, respectively. The 1,1-dimethyl-2-propenyl substituent is in a (−)-anti­clinal conformation. Intra­molecular O—H⋯O hydrogen bonds generate S(5) and S(6) ring motifs. In the crystal, mol­ecules are linked into infinite chains along [010] by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions. π–π inter­actions with centroid–centroid distances of 3.6172 (10) and 3.6815 (10) Å are also observed

3-O-Methyl-1-isomangostin

In the title xanthone derivative [systematic name: 9-hy­droxy-5,10-dimeth­oxy-2,2-dimethyl-11-(3-methyl­but-2-en-1-yl)-2,3,4,12-tetra­hydro-1,7-dioxatetra­phen-12-one], C25H28O6, the xanthone ring system is roughly planar, with an r.m.s. deviation of 0.1038 (1) Å. The chromane ring is in a half-chair conformation and the 3-methyl­but-2-enyl substituent is axially attached with an (+)-anti­clinal conformation. Two weak intra­molecular C—H⋯O inter­actions generate two S(6) ring motifs. In the crystal, mol­ecules are linked into ribbons along the c axis by O—H⋯O and weak C—H⋯O hydrogen bonds. A π–π inter­action, with a centroid–centroid distance of 3.5413 (8) Å, is also observed

(Z)-3-(9-Anthr­yl)-1-(2-thien­yl)prop-2-en-1-one1

There are two crystallographically independent mol­ecules in the asymmetric unit of the title heteroaryl chalcone, C21H14OS: the dihedral angle between the thio­phene and anthracene rings is 75.07 (17)° in one mol­ecule and 76.32 (17)° in the other. The crystal structure is consolidated by short C⋯O [3.348 (5)–3.394 (5) Å], C⋯S [3.607 (5)–3.666 (5) Å] and S⋯O [2.926 (3) Å] contacts, as well as by C—H⋯π and π–π inter­actions [Cg⋯Cg = 3.745 (3) Å]

Brasilixanthone1

The title xanthone [systematic name: 5,13-dihy­droxy-3,3,10,10-tetra­methyl-3H-dipyrano[3,2-a:2′,3′-i]xanthen-14(10H)-one], C23H20O6, was isolated from the roots of Cratoxylum formosum ssp. pruniflorum. There are two mol­ecules (A and B) in the asymmetric unit, which show chemical but not crystallographic inversion symmetry. The xanthone skeleton in both mol­ecules is approximately planar, with an r.m.s. deviation of 0.0326 (9) Å for mol­ecule A and 0.0355 (9) Å for mol­ecule B from the plane through the 14 non-H atoms. The pyran rings in both mol­ecules adopt sofa conformations. Intra­molecular O—H⋯O hydrogen bonds generate S(5) and S(6) ring motifs. Viewed onto the bc plane, the crystal structure resembles a herringbone pattern. Stacks of mol­ecules are stabilized by π–π inter­actions with centroid–centroid distances of 3.600 (5) Å. The crystal structure is further stabilized by weak C—H⋯O and C—H⋯π inter­actions

Redetermination and absolute configuration of pruniflorone M monohydrate

The title xanthone known as pruniflorone M (systematic name: (2R)-5,10-dihy­droxy-2-hy­droxy­methyl-1,1-dimethyl-1H-furo[2,3-c]xanthen-6-one), crystallized in a monohydrate form, C18H16O6·H2O. It was isolated from the green fruits of Cratoxylum formosum ssp. pruniflorum. The structure of the title compound has been reported previously [Boonnak et al. (2010 ▶). Aust. J. Chem. 63, 1550–1556], but we report here the absolute configuration determined using Cu Kα radiation. There are two crystallograpically independent mol­ecules in the asymmetric unit, which differ slightly in the bond angles. The hy­droxy­methyl substituents at position 2 of the furan rings of both pruniflorone M mol­ecules adopt R configurations. In both mol­ecules, the three rings of the xanthone skeleton are approximately coplanar, with an r.m.s. deviation of 0.0124 (2) Å for one mol­ecule and 0.0289 (2) Å for the other, and the furan ring adopts an envelope conformation. In the crystal, mol­ecules of pruniflorone M and water are linked into a two-dimensional network by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions. The crystal structure is further consolidated by π–π inter­actions with centroid–centroid distances in the range 3.5987 (13)–3.7498 (14) Å. Short C⋯C [3.378 (3) Å] and O⋯O [2.918 (3) Å] contacts are also observed

(E)-4-Methoxy-N00-(2,4,5-trimethoxybenzylidene) benzohydrazide hemihydrate

The title compound crystallizes as a hemihydrate, C18H20N2O5�0.5H2O. The molecule exists in an E conformation with respect to the C N imine bond. The 4-methoxyphenyl unit is disordered over two sets of sites with a refined occupancy ratio of 0.54 (2):0.46 (2). The dihedral angles between the benzene rings are 29.20 (9) and 26.59 (9)�, respectively, for the major and minor components of the 4- methoxy-substituted ring. All methoxy substituents lie close to the plane of the attached benzene rings [the Cmethyl—O—C— C torsion angles range from �4.0 (12) to 3.9 (2)�]. In the crystal, the components are linked into chains propagating along [001] via N—H� � �O and O—H� � �O hydrogen bonds and weak C—H� � �O interactions

2,2'-[2,4-Bis(naphthalen-1-yl)cyclobutane- 1,3-diyl]bis(1-methylpyridinium) bis(4-chlorobenzenesulfonate): thermalinduced [2 + 2] cycloaddition reaction of a heterostilbene

The asymmetric unit of the title salt, C36H32N2 2+�- 2C6H4ClO3S�, consists of one anion and one half-cation, the other half being generated by inversion symmetry. The dihedral angle between the pyridinium ring and the napthalene ring system in the asymmetric unit is 42.86 (6)�. In the crystal, cations and anions are linked by weak C—H...O interactions into chains along [010]. Adjacent chains are further arranged in an antiparallel manner into sheets parallel to the bc plane. �–� interactions are observed involving the cations, with centroid–centroid distances of 3.7664 (8) and 3.8553 (8) A °

(E)-2-[4-(Diethylamino)styryl]-1-methylquinolin- 1-ium 4-chlorobenzenesulfonate monohydrate

The asymmetric unit of the title hydrated salt, C22H25N2 +·C6H4ClO3S−·H2O, comprises two 2-[4-(di­ethyl­amino)­styr­yl]-1-methyl­quinolin-1-ium cations, two 4-chloro­benzene­sul­fon­ate anions and two solvent water mol­ecules. One ethyl group of both cations displays disorder over two positions in a 0.659 (2):0.341 (2) ratio in one mol­ecule and in a 0.501 (2):0.499 (2) ratio in the other. The sulfonate group of one anion is also disordered over two positions in a 0.893 (7):0.107 (7) ratio. The dihedral angle between the mean plane of the quinolinium ring system and that of benzene ring is 10.57 (18)° in one cation and 14.4 (2)° in the other. In the crystal, cations, anions and water mol­ecules are linked into chains along the [010] direction by O—H⋯Osulfonate hydrogen bonds, together with weak C—H⋯Osulfonate and C—H⋯Cl inter­actions. The cations are stacked by π–π inter­actions, with centroid–centroid distances in the range 3.675 (2)–4.162 (3) Å

(E)-2-[(2,4,6-Trimethoxybenzylidene)- amino]phenol

There are two independent molecules in the asymmetric unit of the title compound, C16H17NO4, with similar conformations but some differences in their bond angles. Each molecule adopts a trans configuration with respect to the methylidene C N bond and is twisted with a dihedral angle between the two substituted benzene rings of 80.52 (7)� in one molecule and 83.53 (7)� in the other. All methoxy groups are approximately coplanar with the attached benzene rings, with Cmethyl—O—C—C torsion angles ranging from �6.7 (2) to 5.07 (19)�. In the crystal, independent molecules are linked together by O—H� � �N and O—H� � �O hydrogen bonds and a �–� interaction [centroid–centroid distance of 3.6030 (9) A ° ], forming a dimer. The dimers are further linked by weak C— H� � �O interactions and another �–� interaction [centroid– centroid distance of 3.9452 (9) A ° ] into layers lying parallel to the ab plane