Huey Chong Kwong

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The title dammarane triterpenoid, C(30)H(50)O(4), assigned the name chrysura, was isolated from an ethyl acetate extract of Walsura chrysogyne leaves (Meliaceae). It has 20S*,24S* relative stereochemistry and an oxepanone ring with two methyl groups at position 4. The two cyclo-hexane rings adopt chair conformations. The cyclo-pentane and tetra-hydro-furan(More)
The title compound, C23H22FN5S, exists in a trans conformation with respect to the methene C=C and the acyclic N=C bonds. The 1,2,4-triazole-5(4H)-thione ring makes dihedral angles of 88.66 (9) and 84.51 (10)°, respectively, with the indole and benzene rings. In the crystal, mol-ecules are linked by pairs of N-H⋯S hydrogen bonds, forming inversion dimers(More)
The asymmetric unit of the titled compound, C22H20FN5S, comprises two independent mol-ecules (A and B), both of which have a trans conformation with respect to the methene C=C [1.342 (2) and 1.335 (2) Å] and the acyclic N=C [1.283 (2) and 1.281 (2) Å] bonds. In mol-ecule A, the triazole ring makes dihedral angles of 55.01 (12) and 18.17 (9)° with the(More)
The title compound, C16H14N2O3, has an E conformation about the azo-benzene [-N=N- = 1.2481 (16) Å] linkage. The benzene rings are almost coplanar [dihedral angle = 1.36 (7)°]. The O atoms of the carb-oxy-lic acid group are disordered over two sets of sites and were refined with an occupancy ratio of 0.5:0.5. The two disordered components of the(More)
The asymmetric unit of the title compound, C17H18O3, comprises three independent mol-ecules with similar geometries. In each mol-ecule, the carbonyl group is twisted away from the napthalene ring system, making dihedral angles of 1.0 (2), 1.05 (19)° and 1.5 (2)°. The butene group in all three mol-ecules are disordered over two sets of sites, with a refined(More)
In the title compound, C24H23NO2, a whole mol-ecule is disordered over two sets of sites with occupancies in a ratio of 0.692 (6):0.308 (6). In the major disorder component, the naphthalene ring system forms a dihedral angle of 68.6 (5)° with the benzene ring. The corresponding angle in the minor component is 81.6 (10)°. In the crystal, mol-ecules are(More)
The title compound, C(17)H(16)N(2)O(3), has an E conformation about the azobenzene (-N=N-) linkage. The benzene rings are twisted slightly with respect to each other [6.79 (9)°], while the dihedral angle between the plane through the carb-oxy group and the attached benzene ring is 3.2 (2)°. In the crystal, mol-ecules are oriented with the carb-oxy groups(More)
The title compound congestiflorone, C(28)H(32)O(4), which was isolated from the stem bark of Mesua congestiflora, consists of a benzophenone skeleton with two attached pyran rings to which a cyclo-hexane ring and a C6 side chain are bonded. The benzene ring is significantly distorted from planarity (r.m.s. deviation = 0.0007 Å) due to the constraints(More)
THE TITLE COMPOUND [SYSTEMATIC NAME: 5,10-di-hy-droxy-2,2-di-methyl-12-(2-methyl-but-3-en-2-yl)-pyrano[3,2-b]xanthen-6(2H)-one], C(23)H(22)O(5), isolated from the stem bark of Calophyllum soulattri, consists of four six-membered rings and a 2-methyl-but-3-en-2-yl side chain. The tricyclic xanthone ring system is almost planar [maximum deviation = 0.093 (2)(More)
The triazole ring in the title compound, C(14)H(12)N(4)O(2)·H(2)O, makes dihedral angles of 36.9 (1) and 37.3 (1)° with the two benzene rings. Each hy-droxy group is a hydrogen-bond donor to a two-coordinate N atom of an adjacent mol-ecule; these O-H⋯N hydrogen bonds generate a layer parallel to the ab plane. Adjacent layers are linked by N--H⋯O and(More)
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