A novel 6-hydroxy-8,11,11-trimethyl-bicyclo[7.2.0]undec-4-ene-4-carboxylic acid: a potent antioxidant agent from Iphiona scabra.

A novel 6-hydroxy-8,11,11-trimethyl-bicyclo[7.2.0]undec-4-ene-4-carboxylic acid 1 has been isolated from leaves of Iphiona scabra DC. Its structure has been established on the basis of chemical and physical evidence (IR, ¹H NMR, ¹³C NMR, and MS) and further confirmed by single-crystal X-ray diffraction study. The in vitro antioxidant activities of isolated compound 1 and extracts were evaluated by 1,1-diphenyl-2-picrylhydrazyl method.

Synthesis, bioassay, crystal structure and ab initio studies of Erlenmeyer azlactones.

Several 4-arylidene-2-phenyl-5(4H)-azlactones have been synthesized via Erlenmeyer method. The synthesized compounds have been characterized on the basis of systematic spectral studies (IR, (1)H NMR, (13)C NMR, and MS). The compound (4Z)-4-(3,5-dimethoxybenzylidene)-2-phenyl-1,3-oxazol-5(4H)-one, C(18)H(15)NO(4), (5), crystallizes in the orthorhombic system, space group P2(1)2(1)2(1), with a=5.6793(3) Å, b=15.2038(7) Å, c=17.6919(10) Å, Mr=309.31, V=1527.64(14) Å(3), Z=4 and R=0.0547. The compound (4Z)-2-phenyl-4-(3,4,5-trimethoxybenzylidene)-1,3-oxazol-5(4H)-one, C(19)H(17)NO(5), (6) crystallizes in triclinic geometry with space group P-1, having unit cell parameters a=7.3814(3) Å, b=8.1446(3) Å, c=13.9845(5) Å, α=86.918(3), ß=83.314(2), γ=82.462(3), Mr=339.34, V=827.16(5) Å(3), Z=2 and R=0.0433. The DFT calculations of compounds (5) and (6) have been carried out to ascertain the stability of Z-conformer. The in vitro antimicrobial activity of all the compounds (1-6) was evaluated by the disk diffusion method against gram +ve and gram -ve microorganism and fungal strains. The MIC of the synthesized compounds was determined by agar well diffusion method in 96-well microtiter plate. All the synthesized compounds were also screened for their free radical scavenging activity by DPPH method.

8-Iodo-5,7-dimeth-oxy-4-methyl-2H-chromen-2-one.

In the title compound, C(12)H(11)IO(4), the C and O atoms of both meth-oxy groups lie very close to the mean plane of the six C atoms of the benzene ring. The O and C atoms of the group lying closest to the I atom are 0.012 (3) and 0.022 (4) Å, respectively, out of the mean plane. For the other meth-oxy group, the corresponding distances are 0.020 (3) and 0.078 (4) Å. In the crystal, there are only very weak inter-molecular C-H⋯O hydrogen bonds and O⋯I contacts [3.080 (2) Å]. The mol-ecules are approximately parallel to (100), forming a layered structure.

Bis(2-amino-6-methyl-pyrimidin-1-ium-4-olate-κN,O)bis-(nitrato-κO,O')cadmium(II).

In the title compound, [Cd(NO(3))(2)(C(5)H(7)N(3)O)(2)], the Cd(II) atom is eight-coordinated by two amine N atoms and two O atoms from two zwitterionic, biodentate 2-amino-6-methyl-pyrimidin-1-ium-4-olate ligands and by four O atoms from two nitrate groups. Intra-molecular N-H⋯O hydrogen bonds occur. The crystal packing is stabilized by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds, two of which are bifurcated, between the nitrate anions and the organic groups.

Guanidinium 4-amino-benzoate.

In the title compound, CH(6)N(3) (+)·C(7)H(6)NO(2) (-), the cation and anion lie on crystallographic mirror planes. The 4-amino-benzoate anion is almost in a planar conformation with a maximum deviation of 0.024 (2) Šfor the N atom. The bond length in the deprotonated carboxyl group is inter-mediate between those of normal single and double Csp(2)=O bonds, indicating delocalization of the charge over both O atoms of the COO(-) group. In the crystal, N-H⋯O hydrogen bonds assemble the ions in layers propagating in the bc plane. This structure is very similar to that of guanidinium benzoate.

6,8-Diiodo-5,7-dimeth-oxy-4-methyl-coumarin.

In the title compound, C(12)H(10)I(2)O(4), the meth-oxy groups are twisted considerably with respect to the plane of the aromatic ring [CH(3)-O-C-C torsion angles = -85.9 (3) and -92.8 (3)°]. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds and O⋯I contacts [3.194 (2) Å].

Bis[2-amino-6-methyl-pyrimidin-4(1H)-one-κN,O]dichloridocadmium(II).

In the title compound, [CdCl(2)(C(5)H(7)N(3)O)(2)], the Cd(II) atom is six-coordinated by two heterocyclic N atoms [Cd-N = 2.261 (2) and 2.286 (2) Å] and two O atoms [Cd-O = 2.624 (2) and 2.692 (2) Å] from two bidentate chelate 2-amino-6-methyl-pyrimidin-4(1H)-one ligands and two chloride ions [Cd-Cl = 2.4674 (6) and 2.4893 (7) Å]. The crystal packing is characterized by an open-framework architecture with the crystal packing stabilized by inter-molecular N-H⋯Cl and N-H⋯O hydrogen bonds.

7,7'-Dihy-droxy-4,4'-dimethyl-3,4-dihydro-2H,2'H-4,6'-bichromene-2,2'-dione.

The title compound, C(20)H(16)O(6), which contains one chiral centre, crystallizes as a racemate. The mean planes of the two coumarin units make a dihedral angle of 88.07 (2)°. The pyrone ring containing the chiral centre adopts a sofa conformation. In the crystal, four mol-ecules are linked by O-H⋯O hydrogen bonds, forming a tetrameric ring with graph-set motif R(4) (4)(32). These tetramers are further linked by O-H⋯O hydrogen bonds into a three-dimensional network.

Redetermination of ethyl (3a-cis)-3a,8b-dihydr-oxy-2-methyl-4-oxo-3a,8b-dihydro-4H-indeno[1,2-b]furan-3-carboxyl-ate monohydrate.

The crystal structure of the title compound, C(15)H(14)O(6)·H(2)O, has been redetermined from single-crystal X-ray data. The structure was originally determined by Peet et al. [J. Heterocycl. Chem. (1995), 32, 33-41] but the atomic coordinates were not reported or deposited in the Cambridge Structural Database. The ethyl substituent is disordered over two sites with refined occupancies of 0.815 (6) and 0.185 (6). The indeno group is almost planar [maximum deviation 0.0922 (14) Å] and makes an angle of 68.81 (4)° with the furan ring. The fused ring molecules are assembled in pairs by intermolecular O-H⋯O hydrogen bonds. The resulting dimers are also hydrogen bonded to the water molecules, forming double-stranded chains running along the a axis.

N,N',N''-Triphenyl-guanidinium 5-nitro-2,4-dioxo-1,2,3,4-tetra-hydro-pyrimidin-1-ide.

In the title compound, C(19)H(18)N(3) (+.)C(4)H(2)N(3)O(4) (-), the dihedral angles between the phenyl rings and the plane defined by the central guanidinium fragment are in the range 41.3 (1)-66.6 (1)°. The pyrimidine ring of the anion is distorted towards a boat conformation and the nitro group is rotated 11.4 (2)° out of the uracil plane. Hydrogen bonds assemble the ions in infinite helical chains along the b axis.

A new polymorph of 5-nitro-uracil monohydrate.

In the title compound, C(4)H(3)N(3)O(4)·H(2)O, mol-ecules of 5-nitro--uracil are hydrogen bonded in pairs across crystallographic centers of symmetry. The resulting dimers are also hydrogen bonded to the water mol-ecules, forming a three-dimensional network. The pyrimidine ring is almost planar (with a maximum deviation of 0.0156 (9) Šfor the one of the N atoms) and the nitro group is rotated by 12.4 (1)° out of the uracil plane, while in the other polymorph the value for the same angle is 5°.

Bis(triphenyl-guanidinium) tetra-chlorido-cuprate(II).

The structure of the title compound, (C(19)H(18)N(3))(2)[CuCl(4)], consists of square-planar [CuCl(4)](2-) anions and triphenyl-guanidinium cations. The Cu(II) ion occupies a crystallographic inversion centre. In the cation, the dihedral angles between the phenyl rings and the plane defined by the central guanidinium fragment are in the range 51.9 (4)-64.4 (3)°. N-H⋯Cl hydrogen bonds assemble the ions into infinite chains running along the b axis.