Crystal structure of 5-[(benzo-yloxy)meth-yl]-5,6-dihy-droxy-4-oxo-cyclo-hex-2-en-1-yl benzoate.

The crystal structure of the natural product zeylenone, C21H18O7, was confirmed by single-crystal X-ray diffraction. The crystal structure has three chiral centers at positions C1, C5 and C6 of the cyclo-hexa-none ring, but the absolute configuration could not be determined reliably. The methyl benzoate and benzo-yloxy substituents at positions C1 and C5 of the cyclo-hexenone ring are on the same side of the ring with the dihedral angle between their mean planes being 16.25 (10)°. These rings are almost perpendicular to the cyclo-hexenone ring. The benzoate groups and two hydroxyl groups on the cyclo-hexenone ring form strong hydrogen bonds to consolidate the crystal structure. In addition, weak C-H⋯O hydrogen bonds also contribute to the packing of the structure.

Crystal structure, Hirshfeld surface analysis and computational study of 2-chloro-N-[4-(methyl-sulfan-yl)phen-yl]acetamide.

In the title compound, C9H10ClNOS, the amide functional group -C(=O)NH- adopts a trans conformation with the four atoms nearly coplanar. This conformation promotes the formation of a C(4) hydrogen-bonded chain propagating along the [010] direction. The central part of the mol-ecule, including the six-membered ring, the S and N atoms, is fairly planar (r.m.s. deviation of 0.014). The terminal methyl group and the C(=O)CH2 group are slightly deviating out-of-plane while the terminal Cl atom is almost in-plane. Hirshfeld surface analysis of the title compound suggests that the most significant contacts in the crystal are H⋯H, H⋯Cl/Cl⋯H, H⋯C/C⋯H, H⋯O/O⋯H and H⋯S/S⋯H. π-π inter-actions between inversion-related mol-ecules also contribute to the crystal packing. DFT calculations have been performed to optimize the structure of the title compound using the CAM-B3LYP functional and the 6-311 G(d,p) basis set. The theoretical absorption spectrum of the title compound was calculated using the TD-DFT method. The analysis of frontier orbitals revealed that the π-π* electronic transition was the major contributor to the absorption peak in the electronic spectrum.

5-Methyl-1,3-phenyl-ene bis-[5-(di-methyl-amino)-naphthalene-1-sulfonate]: crystal structure and DFT calculations.

The title compound, C31H30N2S2O6, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methyl-phenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the N-methyl groups. Stacking of the dansyl group is not observed. From the DFT calculations, the HOMO-LUMO energy gap was found to be 2.99 eV and indicates n→π* and π→π* transitions within the mol-ecule.

Crystal structure of 3-meth-oxy-4-[2-(thia-zol-2-yl)diazen-1-yl]aniline monohydrate.

In the title hydrated azo dye, C10H10N4OS·H2O, the benzene and thia-zole, are nearly coplanar, with a dihedral angle between their mean planes of 4.69 (17)°. The aromatic rings on the -N=N- moiety exhibit a trans configuration. The crystal structure features many types of inter-molecular inter-actions involving all the functional groups - strong hydrogen bonds (N⋯H and O⋯H), weak hydrogen bonds (C-H⋯O and C-H⋯N), C-H⋯π and π-π inter-actions - resulting in the formation of a three-dimensional framework.

Base-Mediated Cascade Cyclization: Stereoselective Synthesis of Benzooxazocinone.

A new strategy for the synthesis of the oxa-azabicyclo[3.3.1]nonane subunit, a component of the naucleamide E core structure, has been developed. This annulation reaction between 1-substituted 3,4-dihydroisoquinolines and coumarin derivatives conveniently affords the oxa-azabicyclo[3.3.1]nonane framework via a base-mediated cascade cyclization under aqueous conditions. The value of this work lies in the efficient formation of the oxa-azabicyclo[3.3.1]nonane skeleton via a process whereby all the C-C, C-O, and C-N bond formations occur in a single chemical operation. In addition, the subsequent ring opening of these compounds furnished pyridoisoquinoline derivatives.

Aluminum complexes containing salicylbenzoxazole ligands and their application in the ring-opening polymerization of rac-lactide and ε-caprolactone.

Two series of four-coordinate aluminum () and five-coordinate aluminum () complexes were successfully synthesized via the reactions between the corresponding salicylbenzoxazole ligands and 1 or 0.5 equivalents of AlMe3, respectively. The synthesized aluminum complexes were characterized by (1)H and (13)C NMR spectroscopy and elemental analysis. The solid-state structures of complexes and were determined using single crystal X-ray diffraction. Upon addition of 1 equivalent of benzyl alcohol, all complexes were efficient initiators for the ring-opening polymerization (ROP) of rac-lactide (rac-LA) and ε-caprolactone (ε-CL). The polymerizations were living with a good control over molecular weights and molecular weight distributions. Under immortal polymerization conditions, all four-coordinate aluminum complexes () exhibited a living polymerization with the obtained molecular weights proportional to the ratio of monomer/benzyl alcohol and the PDIs were narrow. Kinetic studies revealed that both rac-LA and ε-CL polymerizations mediated by all complexes were first-order in monomers. The effects of ligand structure and coordination geometry on the catalytic activity and stereoselectivity were discussed. A good isoselectivity control was achieved for the polymerizations mediated by complexes (Pm = 0.75), (Pm = 0.74), and (Pm = 0.74).

The crystal structure of 2-[5-(di-methyl-amino)-naphthalene-1-sulfonamido]-phenyl 5-(di-methyl-amino)-naphthalene-1-sulfonate.

The complete mol-ecule of the title compound, C30H29N3O5S2, is generated by a crystallographic twofold axis: the O atom and NH group attached to the central benzene ring are statistically disordered. The dihedral angle between the naphthalene ring system and the central benzene ring is 52.99 (6)°, while the pendant naphthalene ring systems subtend a dihedral angle of 68.17 (4)°. An intra-molecular C-H⋯O hydrogen bond closes an S(6) ring. In the crystal, the mol-ecules are linked by weak C-H⋯O hydrogen bonds.

2-Meth-oxy-1-(2-meth-oxy-4-nitro-naphthalen-1-yl)-6-nitro-naphthalene.

In the title compound, C22H16N2O6, the naphthalene ring systems form a dihedral angle of 65.2 (1)°. Two O atoms of one of the nitro groups are disordered over two sets of sites with occupancy factors of 0.586 (15) and 0.414 (15). Weak C-H⋯O inter-molecular inter-actions are present, forming a ladder like structure along the a axis.

2,2'-({4-[(4-Nitro-phen-yl)diazen-yl]phen-yl}imino)-diethanol.

In the title compound, C16H18N4O4, the mol-ecule assumes an E conformation with respect to the N=N double bond. The aromatic rings are not coplanar, with a dihedral angle of 7.51 (8)°. The nitro group is tilted by 4.71 (11)° relative to the attached benzene ring. In the crystal, mol-ecules are connected through O-H⋯O hydrogen bonds forming a double-stranded chain parallel to the b axis.

3-Amino-benzoic acid-4,4'-bipyridine (2/3).

The asymmetric unit of the title compound, 3C(10)H(8)N(2)·2C(7)H(7)NO(2), consists of three mol-ecules of 4,4'-bipyridine (bpy) and two mol-ecules of 3-amino-benzoic acid (bza). Two mol-ecules of bza and two mol-ecules of bpy are connected via O-H⋯N, N-H⋯N and N-H⋯O hydrogen bonds, forming forming infinite double-stranded zigzag chains along the c axis. The third mol-ecule of bpy is linked to the chain by weak C-H⋯O inter-actions. Adjacent chains are linked via π-π inter-actions [centroid-centroid distances = 3.759 (3)-3.928 (3) Å] involving the pyridine rings of bpy mol-ecules, resulting in a sheet-like structure parallel to (100). These sheets are stacked via C-H⋯π inter-actions, resulting finally in the formation of a three-dimensional supra-molecular structure.

4,4'-Dimeth-oxy-2,2'-[methyl-aza-ne-diyl-bis(methyl-ene)]diphenol.

The title compound, C(17)H(21)NO(4), shows an intra-molecular hydrogen bond between a phenol OH group and the N atom. In the crystal, mol-ecules are connected by pairs of O-H⋯O hydrogen bonds into inversion dimers.

2-{[(2-Hy-droxy-3,5-dimethyl-benz-yl)(meth-yl)amino]-meth-yl}-4,6-dimethyl-phenol.

In the title compound, C(19)H(25)NO(2), the dihedral angle between the benzene rings is 53.15 (8)°. One of the -OH groups forms an intra-molecular O-H⋯N link, generating an S(6) ring. The other -OH group forms an inter-molecular O-H⋯N hydrogen bond in the crystal, generating centrosymmetric R(2) (2)(20) loops.

(-)-crebanine.

THE ASYMMETRIC UNIT OF THE TITLE COMPOUND [SYSTEMATIC NAME: 9,10-dimeth-oxy-7-methyl-6,7,7a,8-tetra-hydro-5H-benzo[g][1,3]benzodioxolo[6,5,4-de]quinoline], C(20)H(21)NO(4), contains two independent mol-ecules with very similar bond lengths and angles. The crystal packing exhibits voids of 131 Å(3).

catena-Poly[[diaqua-dipyridine-zinc(II)]-µ-succinato].

In the title compound, [Zn(C(4)H(4)O(4))(C(5)H(5)N)(2)(H(2)O)(2)](n), the Zn(II) ion (site symmetry ) is coordinated in an octahedral geometry by two pyridine mol-ecules, two water mol-ecules and two bridging centrosymmetric O-monodentate succinate dianions to create one-dimensional polymeric chains. The chains are cross-linked by O-H⋯O hydrogen bonds, forming sheets.